DOT/FAA/AR-05/15 

Office of Aviation Research 

Washington, D.C. 20591 

Fatigue Crack Growth Database 

for Damage Tolerance Analysis 

 

August 2005 

Final Report 

This document is available to the U.S. public 

through the National Technical Information 

Service (NTIS), Springfield, Virginia 22161. 

U.S. Department of Transportation 

Federal Aviation Administration
NOTICE 

This document is disseminated under the sponsorship of the U.S. 

Department of Transportation in the interest of information exchange. The 

United States Government assumes no liability for the contents or use 

thereof. The United States Government does not endorse products or 

manufacturers. Trade or manufacturer's names appear herein solely 

because they are considered essential to the objective of this report. This 

document does not constitute FAA certification policy. Consult your local 

FAA aircraft certification office as to its use. 

This report is available at the Federal Aviation Administration William J. 

Hughes Technical Center’s Full-Text Technical Reports page: 

actlibrary.tc.faa.gov in Adobe Acrobat portable document format (PDF). 
 Technical Report Documentation Page

1. Report No.

DOT/FAA/AR-05/15

2. Government Accession No. 3. Recipient's Catalog No.

5. Report Date

August 2005

 4. Title and Subtitle 

FATIGUE CRACK GROWTH DATABASE FOR DAMAGE TOLERANCE 

ANALYSIS 6. Performing Organization Code

7. Author(s)

R.G. Forman1

, V. Shivakumar2, J.W. Cardinal3, L.C. Williams2, and 

P.C. McKeighan3

8. Performing Organization Report No. 

9. Performing Organization Name and Address 10. Work Unit No. (TRAIS) 

1

NASA Johnson Space Center 

Houston, TX 77058 

2

Lockheed Martin Space Operations 

Houston, TX 77058 

3

Southwest Research Institute 

San Antonio, TX 78228 11. Contract or Grant No.

DTFA03-00-X-90015

13. Type of Report and Period Covered

Final Report 

12. Sponsoring Agency Name and Address

U.S. Department of Transportation 

Federal Aviation Administration

Office of Aviation Research 

Washington, DC 20591

14. Sponsoring Agency Code

 

ANM-100 

15. Supplementary Notes

The FAA William J. Hughes Technical Center COTR was Felix L. Abali. 

16. Abstract

The objective of this project was to begin the process of developing a fatigue crack growth database (FCGD) of metallic materials 

for use in damage tolerance analysis of aircraft structure. For this initial effort, crack growth rate data in the NASGRO® database, 

the United States Air Force Damage Tolerant Design Handbook, and other publicly available sources were examined and used to 

develop a database that characterizes crack growth behavior for specific applications (materials). The focus of this effort was on 

materials for general commercial aircraft applications, including large transport airplanes, small transport commuter airplanes, 

general aviation airplanes, and rotorcraft. The end products of this project are the FCGD software and this report. The specific 

goal of this effort was to present fatigue crack growth data in three usable formats: (1) NASGRO equation parameters, (2) 

Walker equation parameters, and (3) tabular data points. The development of this FCGD will begin the process of developing a 

consistent set of standard fatigue crack growth material properties. It is envisioned that the end product of the process will be a 

general repository for credible and well-documented fracture properties that may be used as a default standard in damage 

tolerance analyses. 

17. Key Words 

Fatigue, Fracture, Crack growth rate, Damage tolerance, 

Curve fits, Database 

18. Distribution Statement 

This document is available to the public through the National 

Technical Information Service (NTIS) Springfield, Virginia 

22161.

19. Security Classif. (of this report)

 Unclassified 

20. Security Classif. (of this page)

 Unclassified

21. No. of Pages

 126

22. Price

Form DOT F1700.7 (8-72) Reproduction of completed page authorized 
TABLE OF CONTENTS 

Page 

EXECUTIVE SUMMARY vii 

1. INTRODUCTION 1 

1.1 Objectives 1 

1.2 Background 1 

2. DATA SOURCES 2 

2.1 Industry Surveys 2 

2.2 Existing Data 2 

3. CRITERIA FOR INCLUSION IN DATABASE 2 

4. CURVE FITTING METHODOLOGY 3 

4.1 NASGRO Equation 4 

4.2 Walker Equation 4 

4.3 Cubic Spline 5 

5. SUMMARY OF FCGD DATA 6 

5.1 Included Materials 6 

5.2 Presentation 7 

6. FATIGUE CRACK GROWTH DATA SOFTWARE OPTIONS 10 

6.1 Viewing of the FCGD Curve Fits 10 

6.2 Compare FCGD Curves With User Data 11 

6.3 Tutorial 12 

7. THE USE OF FCGD IN DTA 12 

8. REFERENCES 13 

APPENDICES 

A—Industry Survey Results and Priority List

B—Fatigue Crack Growth Data and Curve Fits 

 C—Fatigue Crack Growth Database Software Operation 

 D—Examples

iii
LIST OF FIGURES 

Figure Page 

1 Fatigue Crack Growth Rate Data Illustrating the Three Regions of Crack 

Growth Behavior 3 

2 NASGRO Equation Fit for 2024-T3 Clad and Bare Sheet, L-T (M2EA11AB1) 7 

3 Walker Equation Fit for 2024-T3 Clad and Bare Sheet, L-T (M2EA11AB1) 8 

4 Spline Curve Fits for 2024-T3 Clad and Bare Sheet, L-T (M2EA11AB1) 8 

5 Opening Window of the FCGD Software 10 

6 Material Selection Window for Plotting Standard Data and Curve Fits 11 

7 Input Window for User-Defined Fatigue Crack Growth Data 12 

LIST OF TABLES 

Table Page 

1 List of Materials in the Database 6 

2 Spline Fit Data Points for 2024-T3 Clad and Bare Sheet, L-T (M2EA11AB1) 9 

iv
LIST OF ACRONYMS 

ACO Aircraft Certification Offices 

DER Designated engineering representatives 

DTA Damage tolerance analysis 

FAA Federal Aviation Administration 

FCGD Fatigue crack growth database 

GUI Graphic User Interface 

SwRI Southwest Research Institute 

USAF United States Air Force 

v/vi
EXECUTIVE SUMMARY

The objective of this project was to begin the process of developing a fatigue crack growth 

database (FCGD) of metallic materials for use in damage tolerance analysis (DTA) of aircraft 

structure. For this initial effort, crack growth rate data in the NASGRO® database, the United 

States Air Force Damage Tolerant Design Handbook, and other publicly available sources were 

examined and used to develop a database that characterizes crack growth behavior for specific 

applications (materials). The focus of this effort was on materials for general commercial 

aircraft applications, including large transport airplanes, small transport commuter airplanes, 

general aviation airplanes, and rotorcraft. The end products of this project are the FCGD 

software and this report. The specific goal of this effort was to present fatigue crack growth data 

in three usable formats: (1) NASGRO Equation parameters, (2) Walker Equation parameters, 

and (3) tabular data points. The development of this fatigue crack growth database will begin the 

process of developing a consistent set of standard fatigue crack growth material properties. It is 

envisioned that the final end product will be a general repository for credible and welldocumented fracture properties that may be used as a default standard in damage tolerance 

analyses. 

This report and software were developed under funding provided by the Airworthiness 

Assurance Branch of the Federal Aviation Administration William J. Hughes Technical Center. 

The NASA Johnson Space Center was the prime contractor and Lockheed Martin Space 

Operations and Southwest Research Institute were subcontractors. 

vii/viii
1. INTRODUCTION.

1.1 OBJECTIVES. 

The objective of this project was to begin the process of developing a Fatigue Crack Growth 

Database (FCGD) of metallic materials used in damage tolerance analysis (DTA) of aircraft 

structure. For this initial effort, crack growth rate data in the NASGRO® database [1], the United 

States Air Force (USAF) Damage Tolerant Design Handbook [2], and other publicly available 

sources were examined and used to develop the database that characterizes crack growth 

behavior for specific applications (materials). The focus of this effort was on materials for 

general commercial aircraft applications, including large transport airplanes, small transport 

commuter airplanes, general aviation airplanes, and rotorcraft. As such, an early objective of the 

project was to determine from the end users a prioritized list of materials for inclusion into the 

database. In addition, any voids or deficiencies in existing data were to be identified that would 

preclude characterization for any of the applications. In addition to this report, the end product 

of this project is the FCGD software. The specific goal of the effort was to present fatigue crack 

growth data in three usable formats: (1) NASGRO equation parameters, (2) Walker equation 

parameters, and (3) tabular data points. 

1.2 BACKGROUND. 

Fracture mechanics properties are required to perform damage tolerance evaluations of primary 

aircraft structure. These fracture mechanics properties principally include fatigue crack growth 

data and fracture toughness. More basic material properties such as yield strength, Poisson’s 

ratio, and elastic modulus are also used in DTA but are not considered fracture mechanics 

properties. 

Damage tolerance analyses are required to support the establishment of in-service inspection 

programs per Title 14 Code of Federal Regulations 25.571 and 23.573 and Advisory 

Circular 91-56. Currently, data used to perform damage tolerance analyses can vary 

significantly from applicant to applicant. Large original equipment manufacturers typically 

employ their own proprietary data developed from a significant amount of coupon testing. On 

the other hand, data used by consulting engineering firms, small manufacturers, supplemental 

type certificate holders, etc., may be of unknown or questionable origin. This can create a 

significant problem for the Federal Aviation Administration (FAA) Aircraft Certification Offices 

(ACO), Aviation Safety Engineers, and FAA designated engineering representatives (DER) with 

respect to evaluating the adequacy of applicant’s demonstrations of compliance to FAA 

regulatory certification requirements. 

There has been a vast amount of fracture mechanics data generated and collected over the past 30 

years. The problem facing structural engineers is selecting the appropriate properties from the 

vast database. Uncertainties and inconsistencies in DTA input data create a problem for the FAA 

ACO engineers and FAA DERs when evaluating DTAs for compliance with the regulations. 

This FCGD task will initialize the process of developing a consistent set of standard fracture 

mechanics properties. It is envisioned that the end product will be a general repository for 

credible and well-documented fracture properties that may be used as a default standard in 

damage tolerance analyses. The intended end users of the FCGD are the applicants and their 

1
engineering staffs. The beneficiaries are the FAA DERs and FAA ACO engineers whose task is 

simplified by having available a credible material data set that can be used and referenced with 

confidence in performing, reviewing, and approving DTA. The use of this data set relieves the 

certification engineers of the task of having to validate the basic material data for compliance 

with the regulations. The initial phase of the FCGD development was focused on the 

characterization of fatigue crack growth rate behavior for specific applications as identified by 

the end users. Fracture toughness material properties are not addressed in the current effort. 

2. DATA SOURCES.

2.1 INDUSTRY SURVEYS.

To identify and prioritize the material applications to be included in the FCGD, the FAA and 

Southwest Research Institute (SwRI) each developed a crack growth rate data questionnaire. 

The FAA questionnaire was distributed to approximately 150 FAA damage tolerance DERs 

(including candidates and applicants), while the SwRI questionnaire was distributed to the 14 

members of the NASGRO Industry Consortium. Respondents were asked to supply a list of the 

most common materials that they work with by providing the alloy, temper, form, orientation, 

environment, and thickness of each application. These responses were used to assist in 

prioritizing and selecting data for inclusion in the database. Appendix A provides a compilation 

of the industry surveys and the resulting priority lists along with copies of the questionnaires. 

Thirteen and six responses were received from the FAA and SwRI questionnaires respectively. 

2.2 EXISTING DATA. 

The principal source for fatigue crack growth data examined for inclusion in the FCGD was the 

NASGRO material database [1]. The NASGRO database has been continuously improved over 

the years, and the NASGRO 4.0 database now contains material properties for fatigue crack 

growth and fracture for 476 different metallic materials, including 3000 sets of fatigue crack 

growth data, 6000 fracture toughness data points, and statistically derived crack growth 

equations for all 476 materials. These data were obtained over the years from a variety of 

sources in the literature and in-house, and other data collected by NASA Johnson Space Center, 

including Hudson’s Compendiums [3 and 4], the USAF Damage Tolerant Design Handbook [2], 

and a University of Dayton Research Institute survey report [5]. In addition to the NASGRO 

database, data from FAA-funded projects were also considered [6-8]. 

3. CRITERIA FOR INCLUSION IN DATABASE.

To include data in the FCGD for use in developing curve fits for the crack growth models, a set 

of characterization criteria were developed. These criteria evolved during the course of the 

project as a result of discussions between the FAA project technical monitor and NASA, 

Lockheed Martin Space Operations, and SwRI project team. They were developed to ensure that 

the data chosen, sufficiently described a wide range of the parameters needed to perform the 

requisite curve fits. The criteria for including data in the database are as follows: 

• Minimum of three positive, wide-ranging load ratios (e.g., R = 0.1, 0.4, and 0.7). 

2
• Sufficient data covering a minimum of two log cycles on the crack growth rate (da/dN) 

scale. 

• Data consistency (matching) requirements: 

− Three consistent sets (i.e., from three or more different sources) when other 

available data sets are not consistent 

− Two consistent data sets if there are no other conflicting data sets 

• Laboratory air or high-humidity test environments 

It was recognized that identifying and assessing the suitability of a given set of data for inclusion 

in the database necessitated considerable engineering judgment and experience, and a subjective 

evaluation was sometimes required. 

4. CURVE FITTING METHODOLOGY. 

In the fitting process, crack growth data are fitted with each of the following three equations: 

NASGRO, Walker, and cubic spline. The algorithms use least-squares minimization of error in 

the log-log domain to determine the constants for each fitting method. Figure 1 provides a 

schematic of a fatigue crack growth curve illustrating the three regions of behavior that are 

referenced by the different methods. 

Region 2

linear Paris

ΔK, ksi√in

1 10 100

da/dN, in/cycle

10-11

10-10

10-9

10-8

10-7

10-6

10-5

10-4

10-3

Region 1

near-threshold

Region 3

toughness 

asymptote

Region 2

linear Paris

ΔK, ksi√in

1 10 100

da/dN, in/cycle

10-11

10-10

10-9

10-8

10-7

10-6

10-5

10-4

10-3

Region 1

near-threshold

Region 3

toughness 

asymptote

FIGURE 1. FATIGUE CRACK GROWTH RATE DATA ILLUSTRATING THE THREE 

REGIONS OF CRACK GROWTH BEHAVIOR 

3
4.1 NASGRO EQUATION.

The NASGRO crack growth equation, described in detail in the NASGRO manual [1], is 

expressed as 

( )

( ) q

c

p

th n

K

K

K

K

K

R

f C

dN

da

⎟

⎟

⎠

⎞

⎜

⎜

⎝

⎛ −

⎟

⎠

⎞ ⎜

⎝

⎛

Δ

Δ −

⎟

⎟

⎠

⎞

⎜

⎜

⎝

⎛ Δ −

− =

max 1

1

1

1 (1) 

where da/dN is the crack growth rate, ΔK is the applied stress-intensity factor range, and R is the 

stress ratio; ΔKth is the fatigue threshold, Kmax is the stress-intensity factor corresponding to peak 

applied load, and Kc is the critical stress intensity; p and q control the shape of the asymptotes in 

the threshold and critical crack growth regions, respectively; f is Newman’s crack opening 

function [9]. 

The constants C and n, the main fit parameters, are determined through minimization of the sum 

of square of the errors, where the error term corresponding to the ith data pair, ( ) , is i Δ /, dNdaK

( ) ( )

( )

i

q

c

p

th

i i

i

K

K

K

K

LogK R

f LognCLog dNda Loge

⎟

⎟

⎟

⎟

⎟

⎠

⎞

⎜

⎜

⎜

⎜

⎜

⎝

⎛

⎟

⎟

⎠

⎞

⎜

⎜

⎝

⎛ −

⎟

⎠

⎞ ⎜

⎝

⎛

Δ

Δ −

− ⎟

⎟

⎠

⎞

⎜

⎜

⎝

⎛ Δ −

− ⎟ −− ⎠

⎞ ⎜

⎝

⎛ =

max 1

1

1

1 (2) 

Curve fitting crack growth data is an iterative process, which consists of using established values 

of the various constants (other than C and n), specifying the data sets that typify the material, 

applying the least-squares algorithm to compute C and n, and plotting the data at various 

R values with the curve fit of each stress ratio. The process was continued by making slight 

modifications, if warranted, to the entered values until the best fit to the experimental data was 

obtained. 

4.2 WALKER EQUATION. 

The Walker crack growth equation [10] used a single linear segment to fit the data. The equation 

is given by 

( )

n

m R

K C

dN

da

⎟

⎟

⎠

⎞

⎜

⎜

⎝

⎛

−

Δ = 1− 1 (3) 

where the three constants, C, n, and m define the fit. The ith error term is given by 

4
() ( ) ( ) ( ) i i

i

i RLogmnKLognCLog dN

da Loge ⎟ −−+Δ−− ⎠

⎞ ⎜

⎝

⎛ = 11 (4) 

Application of the least-squares method [11] yields a nonlinear set of algebraic equations, which 

is solved using a three-stage numerical procedure. In the first stage, the Paris constants for the 

multiple-R data were obtained, ignoring the dependence on R. The second stage used a coarse 

trial-and-error process along trial intervals centered around the initially obtained values to obtain 

improved values of C and n, and a first estimate of m. In the third stage, the Newton-Raphson 

technique was used to solve the nonlinear set of error minimization equations and obtain final, 

accurate values of C, n, and m. Using the first two priming stages ensures that the NewtonRaphson technique is robust and converges to the correct results. 

The Walker fit algorithms work best for crack growth data drawn from many different values of 

R and will not work at all unless at least two different R values are used. Since separate values 

of the exponent m: m+ and m- are obtained for positive and negative values of R, respectively, it 

is necessary that crack growth data be available for both positive and negative values of R. In 

the procedure used herein, the constants C and n (and m+

) are obtained exclusively from positive 

R data, and m- is obtained from negative R data. 

Fitting of the Walker equation was confined to the linear part of the data, region 2, as shown in 

figure 1. The lower and upper bounds for region 2 are set during the fitting process by 

examining the data for linearity. Eliminating data that depart from linearity (and belong in 

region 1 near-threshold, or region 3 near-criticality) ensures that the Walker fits are accurate 

representations of the linear portion of the crack growth. Generally, for any material, the same 

lower bound is applicable to all the R values for which data are available, while at the upper end, 

variable bounds are used since the point of departure from linearity tends to vary with R. 

4.3 CUBIC SPLINE. 

The cubic spline fit algorithm employed here divides the (ΔKLog ) domain of the crack growth 

data into a uniformly spaced sequence of intervals and fits piecewise cubic polynomials that 

minimize the sum of the square of the errors 

( ( ) n

i

n

nI

i

i KLogA dN

da Loge ⎟ − Δ ⎠

⎞ ⎜

⎝

⎛ = ∑=

3

0

, ) (5) 

for all the data. The AI,n in equation 5 are coefficients (to be determined) of the cubic polynomial 

for the ith interval, with the index i referring to the ith data pair. The piecewise polynomials 

were constructed according to the rules for splines: function and its first derivative continuities 

were imposed at the knots between intervals. However, in contrast to standard splines [12], no 

conditions were imposed on the second derivative, at either the knots or the end points. This 

hybrid procedure yields a curve that accommodates local movements of the data that can be 

matched well in their vicinity without extending their effects (as with standard splines) to distant 

parts of the curve. 

5
Since the procedure achieves acceptably low values of the root mean square error by choice of an 

adequate number of uniformly spaced knots, any need to develop or use special curve-specific 

algorithms for knot placement is obviated. In the penultimate step of the procedure used, an 

over-determined system of equations with more equations than unknowns is obtained. This 

system is made square in the final step by minimization of the squares of components of the 

residual vector. 

The spline fits use the same lower bounds that were used for the Walker equation fits. However, 

at the upper end, spline fitting is continued beyond the Walker bounds into the nonlinear region 

3, producing a curve that fits the crack growth data near criticality. 

5. SUMMARY OF FCGD DATA. 

5.1 INCLUDED MATERIALS.

A list of the 13 materials included in this version of the database is given in table 1. The data for 

these materials met the criteria for inclusion, as discussed in section 3. Table 1 provides the 

name of the materials, conditions, and the orientations. In all cases, the environment was 

laboratory air or high-humidity air. 

The last column of table 1 contains material identification codes that were chosen to be 

consistent with the ones used in the NASGRO and NASMAT databases [1]. The first letter of 

the material ID code identifies the material category or group (M = aluminum) and the second 

character (numeral) identifies the alloy group (2 = 2000 series, 7 = 7000 series, etc.). 

Subsequent letters and numbers identify the heat treatment, product form, crack orientation, 

environment, and temperature. A complete description of this nomenclature can be found in the 

NASGRO documentation [1]. 

TABLE 1. LIST OF MATERIALS IN THE DATABASE 

Material Condition Orientation Material ID Code 

2014-T6 Sheet T-L M2AD12AB1 

2024-T3 Clad and Bare Sheet L-T M2EA11AB1 

2024-T3 Clad and Bare Sheet T-L M2EA02AB1 

2024-T351 Plate L-T M2EB11AB1 

2024-T3511 Extrusion L-T M2EC31AB1 

2024-T62 Sheet and Plate L-T M2EG11AB1 

2024-T81 Sheet L-T M2EI11AB01 

7050-T7451 Plate L-T M7GJ11AB1 

7075-T651 Plate L-T M7HB11AB1 

7075-T7351 Plate L-T M7HH11AB1 

7475-T7351 Plate L-T M7TF11AB1 

7475-T761 Clad Sheet L-T M7TI01AB1 

7475-T7651 Sheet and Plate L-T M7TJ11AB1 

6
5.2 PRESENTATION.

For each material included in the database, appendix B provides material data summary tables 

and plots of each of the fitted crack growth equations (NASGRO, Walker, and cubic spline). 

The NASGRO and the Walker equation parameters are listed on their respective plots. The data 

for the spline curve fits are listed by stress ratio in separate tables for each material. Note that 

not every material included in the database contains curve fits for negative R value because the 

data either did not exist or were not sufficient to provide a reasonable fit. 

Figures 2, 3, and 4 provide an illustration of the fits to 2000-series aluminum data for each of the 

three equations and positive R values. In each case, the plots show only the data points that were 

used to generate the curve fits. Figure 2 shows a plot of the full range of crack growth data since 

the NASGRO equation can accommodate all three regions: near-threshold (region 1), the linear 

or Paris regime (region 2), and the near-critical asymptotic behavior at higher ΔK (region 3). In 

comparison, since the fitting of the Walker equation was intended to span only the central linear 

region of the data, regions 1 and 3 data are excluded from the Walker plots, as shown in figure 3. 

Similarly, since the cubic spline fits did not consider the near-threshold region 1 data, figure 4 

displays the spline fits for regions 2 and 3 data only. Table 2 lists the spline fit data points for 

three positive R values. Figures 2 through 4 and table 2 provide an illustration of the type of 

information for each material contained in appendix B. All the plots and tables provided in 

appendix B are accessible directly from the FCGD software. 

1e-09

1e-08

1e-07

1e-06

1e-05

0.0001

0.001

0.01

1 10 100

da/dN [in/cycle]

Delta K [ksi*SQRT(in)] 

q ;

R THK REF NASGRO Data ID _____________________________

NASGRO 4.0

EQUATION FIT:

_____________

Smax/SIGo = 0.30 

Alpha = 2.000 

K1c = 30.0

YS = 53.0

Ak = 1.00, Bk = 1.50

Kc = 74.3 (t= 0.100)

DK1 = 1.22

Cth+ = 1.21

Cth- = 0.10

p = 0.250, q = 1.000

C = 0.800E-08

n = 3.200

M2EA11AB01I3

M2EA11AB01K3

M2EA01AB01C2

M2EA01AB01G2

M2EA11AB01A4

M2EA11AB01A2

M2EA01AB01B2

M2EA11AB01G1

M2EA11AB01H2

M2EA11AB01I4

M2EA01AB01A1

M2EA11AB01K4

M2EA11AB01K5

M2EA11AB01A1

 0.00 0.090 189 

 0.00 0.090 459 

 0.00 0.150 189 

 0.00 0.063 468 

 0.00 0.090 A73 

 0.50 0.090 A73 

 0.50 0.126 189 

 0.50 0.195 93 

 0.50 0.157 189 

 0.50 0.090 189 

 0.50 0.039 181 

 0.50 0.090 459 

 0.70 0.090 459 

 0.70 0.090 A73 

R = 0.000

R = 0.500

R = 0.700

FIGURE 2. NASGRO EQUATION FIT FOR 2024-T3 CLAD AND 

BARE SHEET, L-T (M2EA11AB1) 

7
1e-08

1e-07

1e-06

1e-05

0.0001

0.001

1 10

da/dN [in/cycle]

Delta K [ksi*SQRT(in)] 

q ;

R THK REF NASGRO Data ID _____________________________

NASGRO 4.0

WALKER FIT:

___________

C = 0.167E-08

n = 3.273

m+ = 0.618

M2EA11AB01A4

M2EA11AB01I3

M2EA01AB01C2

M2EA01AB01G2

M2EA11AB01K3

M2EA01AB01A1

M2EA11AB01A2

M2EA01AB01G3

M2EA11AB01G1

M2EA11AB01H2

M2EA11AB01I4

M2EA01AB01B2

M2EA11AB01K4

M2EA11AB01K5

M2EA11AB01A1

 0.00 0.090 A73 

 0.00 0.090 189 

 0.00 0.150 189 

 0.00 0.063 468 

 0.00 0.090 459 

 0.50 0.039 181 

 0.50 0.090 A73 

 0.50 0.063 468 

 0.50 0.195 93 

 0.50 0.157 189 

 0.50 0.090 189 

 0.50 0.126 189 

 0.50 0.090 459 

 0.70 0.090 459 

 0.70 0.090 A73 

R = 0.000

R = 0.500

R = 0.700

FIGURE 3. WALKER EQUATION FIT FOR 2024-T3 CLAD AND 

BARE SHEET, L-T (M2EA11AB1) 

1e-08

1e-07

1e-06

1e-05

0.0001

0.001

0.01

1 10 100

da d/ N [in/cycle]

Delta K [ksi*SQRT(in)] 

p ;

R THK REF NASGRO Data ID _____________________________

M2EA11AB01A4

M2EA11AB01I3

M2EA01AB01C2

M2EA01AB01G2

M2EA11AB01K3

M2EA01AB01A1

M2EA11AB01A2

M2EA01AB01G3

M2EA11AB01G1

M2EA11AB01H2

M2EA11AB01I4

M2EA01AB01B2

M2EA11AB01K4

M2EA11AB01K5

M2EA11AB01A1

 0.00 0.090 A73 

 0.00 0.090 189 

 0.00 0.150 189 

 0.00 0.063 468 

 0.00 0.090 459 

 0.50 0.039 181 

 0.50 0.090 A73 

 0.50 0.063 468 

 0.50 0.195 93 

 0.50 0.157 189 

 0.50 0.090 189 

 0.50 0.126 189 

 0.50 0.090 459 

 0.70 0.090 459 

 0.70 0.090 A73 

R = 0.000

R = 0.500

R = 0.700

FIGURE 4. SPLINE CURVE FITS FOR 2024-T3 CLAD AND BARE 

SHEET, L-T (M2EA11AB1) 

8
TABLE 2. SPLINE FIT DATA POINTS FOR 2024-T3 CLAD AND 

BARE SHEET, L-T (M2EA11AB1) 

ID Code = M2EA11AB1 

R = 0.0000

da/dN ΔK

8.5277e-08 3.3806 

1.0000e-07 3.4799 

1.8000e-07 4.8636 

3.2000e-07 5.6622 

6.0000e-07 6.2613 

1.0000e-06 6.8082 

1.8000e-06 7.5591 

3.2000e-06 8.5678 

6.0000e-06 10.9383 

1.0000e-05 14.4607 

1.8000e-05 18.4912 

3.2000e-05 22.1001 

6.0000e-05 25.6959 

1.0000e-04 28.4466 

1.8000e-04 31.4230 

3.2000e-04 34.1080 

6.0000e-04 36.8131 

1.0000e-03 38.8665 

1.8000e-03 41.0983 

3.1829e-03 43.1519 

(a) 

ID Code = M2EA11AB1 

R = 0.5000

da/dN ΔK

1.0285e-07 2.2182 

1.8000e-07 3.3220 

3.2000e-07 4.1352 

6.0000e-07 4.8493 

1.0000e-06 5.4034 

1.8000e-06 6.0484 

3.2000e-06 6.9138 

6.0000e-06 8.6642 

1.0000e-05 10.5084 

1.8000e-05 12.9641 

3.2000e-05 15.3066 

6.0000e-05 17.8753 

1.0000e-04 20.3083 

1.8000e-04 22.6137 

3.2000e-04 24.3847 

6.0000e-04 25.9843 

7.2687e-04 26.4241 

(b) 

ID Code = M2EA11AB1 

R = 0.7000

da/dN ΔK 

1.0217e-07 2.1677 

1.8000e-07 2.8901 

3.2000e-07 3.7327 

6.0000e-07 4.3227 

1.0000e-06 4.9276 

1.8000e-06 5.8777 

3.2000e-06 7.2772 

6.0000e-06 8.5971 

1.0000e-05 9.6496 

1.8000e-05 11.0169 

2.4964e-05 11.9399 

(c) 

9
6. FATIGUE CRACK GROWTH DATA SOFTWARE OPTIONS. 

Figure 5 shows the opening window, of the FCGD software. This window provides either an 

access to the database of materials and the corresponding curve fits or the option to enter a set of 

data to compare with that in the FCGD. In addition, from this opening window, as well as any of 

the other windows, detailed source information regarding the materials contained in the database 

can be obtained by clicking on References in the menu bar. Specific details of the primary 

FCGD options are discussed in the sections that follow. 

FIGURE 5. OPENING WINDOW OF THE FCGD SOFTWARE 

6.1 VIEWING OF THE FCGD CURVE FITS.

To view the curve fits for a specific material in the material database, the user can select the 

Choose Material menu tab to display the window shown in figure 6. In figure 6, the 2024-T3 

Clad and Bare Sheet (L-T) material has been selected, and note that the ID code for the material 

is automatically displayed in the material identification box for reference. Clicking on any of the 

buttons labeled NASGRO Equation, Walker Equation, or Spline displays each curve fit 

respectively. These curve fits are shown in appendix B for all the materials in the database. The 

data points of the spline fit can be saved to a text file by clicking on the Save Spline Tables 

button. 

10
FIGURE 6. MATERIAL SELECTION WINDOW FOR PLOTTING 

STANDARD DATA AND CURVE FITS 

6.2 COMPARE FCGD CURVES WITH USER DATA.

A key feature of the FCGD software is that user-entered fatigue crack growth data can be 

compared to data in the material database. The FCGD window shown in figure 7 facilitates this 

task and is selected by choosing the Enter/Edit User Data menu tab. This window allows the 

user to specify the characteristics of their material, create a material ID code for that data, and 

save it to a file. Data source types that can be accommodated include direct keyboard input and 

a text file. The capability to directly digitize fatigue crack growth (plots/curves) is also provided. 

Data that has been entered into the user-defined database can be compared to the curve fits in the 

database by returning to the material selection window (figure 6) and selecting the standard crack 

growth equation against which to compare the data. 

In both this report and the FCGD software, all data are displayed using U.S. customary units 

(ksi√in and in/cycle). Note, however, that the window of figure 7 shows options to select 

different systems of units via the choose units pull-down menu to input data in SI units (MPa√m 

and m/cycle) as well as a number of other nonstandard unit combinations that are sometimes 

employed. These units of the data are then converted by the software to U.S. customary units for 

comparison with the FCGD standard curves. 

11
FIGURE 7. INPUT WINDOW FOR USER-DEFINED 

FATIGUE CRACK GROWTH DATA 

6.3 TUTORIAL. 

The yellow User Instructions button displayed in figure 7 provides guidance to the user for input 

and plotting of data. Specific details of the operation of the FCGD software are described in 

appendix C, and a number of illustrative examples are provided in appendix D. Appendix C also 

summarizes system requirements for installation and operation of the software on a personal 

computer. 

7. THE USE OF FCGD IN DTA.

The objective of this project was to develop a database of fatigue crack growth rate data of 

metallic materials used in DTAs of aircraft structure. The focus of this effort was on materials 

for general commercial aircraft applications, including large transport airplanes, small transport 

commuter airplanes, general aviation airplanes, and rotorcraft. Fatigue crack growth rate data (or 

model) is only one of the many key sets of input data that must be assembled to perform DTA. 

The use of FCGD in a DTA will depend on the choice of fatigue crack growth analysis software 

and the level of expertise/experience of the analyst in performing fracture and fatigue crack 

growth analyses. In general, most commercially available fatigue crack growth analysis software 

contains a menu of different models (or laws) to choose from. In addition, most codes also 

accept as input fatigue crack growth rate data in tabular form (pairs of ΔK and da/dN data, at 

different stress ratios, R). 

12
The FCGD curve fits to the NASGRO equation are intended for use with the latest version of the 

NASGRO software [1]. The NASGRO equation is unique among crack growth rate models in 

that it fits the asymptotes in both the threshold and critical crack growth regions, accounting for 

the influence of R on the fatigue threshold and considering the effects of crack closure. The 

parameters of the FCGD NASGRO equation fits can be entered into NASGRO via the NASGRO 

material property window. 

The FCGD curve fits to the Walker equation result in the Walker constant values of C, n, and m; 

however, the separate values of the exponent m (m+ and m-

) were obtained for positive and 

negative values, of R respectively. Care must be taken to ensure that the crack growth software 

being used accommodates this specific representation of the Walker model. This is particularly 

true for the negative R portion of the model since there are other Walker-type models that model 

negative R behavior differently, e.g., Walker-Chang. 

The FCGD spline curve fits were developed with the intention of providing spline points (pairs 

of ΔK and da/dN data at different stress ratios, R) that could be input into crack growth software 

in tabular form to model crack growth rate data. These data are listed in appendix B, following 

the spline plots for each material. 

As discussed in sections 4.2 and 4.3, neither the Walker nor the spline fits model the nearthreshold region of the fatigue crack growth rate data. When using these models in DTA, the 

analyst must be cognizant of how the crack growth software extrapolates data to the crack 

growth rates beyond (above or below) the end of the data. 

Ultimately, the analyst must make the choice of which fatigue crack growth rate model to use in 

DTA. In some cases, a given model may more accurately represent the behavior than another; 

however, it is not possible to state that a single model is always the best to use. Moreover, the 

analyst may be restricted in choice of models by the features available in the crack growth 

analysis software. 

8. REFERENCES. 

1. “NASGRO® Fracture Mechanics and Fatigue Crack Growth Analysis Software,” Version 

4.02, NASA-JSC and SwRI, September 2002. 

2. “Damage Tolerant Design Handbook,” WL-TR-94-4054, D.A. Skinn, J.P. Gallagher, 

A.P. Berens, P.D. Huber and J. Smith, eds., May 1994. 

3. Hudson, M.C. and Seward, S.K., “Compendium of Sources of Fracture Toughness and 

Fatigue Crack Growth Data for Metallic Alloys,” International Journal of Fracture, Vol. 

14, 1978. 

4. Hudson, M.C. and Seward, S.K., “Compendium of Sources of Fracture Toughness and 

Fatigue Crack Growth Data for Metallic Alloys,” International Journal of Fracture, Vol. 

20, 1982. 

13
5. References in “Collection, Processing, and Reporting of Damage Tolerant Design Data 

for Non-Aerospace Structural Materials,” University of Dayton Research Institute Report 

UDR-TR-94-88, June 1994 – development performed under NASA JSC grant NAG9-

600. 

6. Cardinal, J.W., McMaster, F.J., and McKeighan, P.C., “Testing and Analysis for DTA of 

Fairchild SA226 Main Wing Spar Lower Cap at WS99,” Final Report, SwRI Project No. 

06-8520, for Fairchild Aircraft, Inc., San Antonio, TX, January 1999. 

7. Dwyer, W., “Development of a Supplemental Inspection Document for the Fairchild 

SA226 and SA227 Aircraft, Part 2,” Vols. 1 and 2, FAA Report DOT/FAA/AR-99/20, 

October 1999. 

8. McKeighan, P.C., “Fatigue Testing in Support of Learjet Model 60 Service Life 

Analysis,” Final Report, SwRI Project No. 06-7571, for E-Systems, Inc., Greenville 

Division, Greenville, TX, April 1996. 

9. Newman, Jr., J.C., “A Crack Opening Stress Equation for Fatigue Crack Growth,” 

International Journal of Fracture, Vol. 24, No. 3, March 1984, pp. R131-R135. 

10. Walker, K., “The Effect of Stress Ratio During Crack Propagation and Fatigue for 2024-

T3 and 7075-T6 Aluminum,” ASTM STP 462, American Society for Testing and 

Materials, 1970. 

11. Carnahan, B., Luther, H.A., and Wilkes, J.O., Applied Numerical Methods, Wiley, 1969. 

12. De Boor, C., A Practical Guide to Splines, Springer, 2001. 

14
APPENDIX A—INDUSTRY SURVEY RESULTS AND PRIORITY LIST

TABLE A-1. STATUS OF MATERIALS EVALUATION AND FITTING 

Material Form Orientation 

2014-T6 Sheet and Plate L-T 

2014-T6 Sheet T-L 

2024-T3 Clad Sheet L-T 

2024-T3 Clad and Bare Sheet T-L 

2024-T351 Plate L-T 

2024-T3511 Extrusion L-T 

2024-T62 Sheet and Plate L-T 

2024-T81 Sheet L-T 

7050-T7451 Plate L-T 

7075-T651 Plate L-T 

7075-T7351 Plate L-T 

7475-T7351 Plate L-T 

7475-T761 Clad Sheet L-T 

7475-T7651 Sheet and Plate L-T 

(a) Materials curve fitted that met the criteria 

Material Form Orientation 

2024-T351 Sheet and Plate T-L 

2024-T4 and -T42 Sheet and Plate 

2024-T7351 Extrusion 

7050-T7451 Plate T-L 

7050-T76511 Extrusion 

7075-T6 Plate and Forged 

7075-T73 Plate and Forged 

7075-T76 

(b) Important materials identified (by 3 or more survey sheets) which 

lack sufficient data to meet criteria or to generally fit 

Material 

4340 (180-200UTS) steel 

15-5Ph (H1025) steel 

Ti-6-4 Annealed (?) titanium 

(c) Other

Note: All materials listed in survey sheets having NASGRO fits were evaluated for meeting criteria. 

A-1 
TABLE A-2. SURVEY IDENTIFIED MATERIALS HAVING NASGRO 4.0 FITS 

Material Form Orientation Environment 

Survey 

Votes 

4340; 120-140 UTS Plate and Bar 1 

4340; 180-200 UTS Plate and Forged LA and HHA 3 

300M; 270-300 UTS Plate and Forged 2 

AF1410; 220-240 

 UTS 

Plate and Forged LA HHA/DW >1 

Hz 

1 

D6AC: 220-240 UTS Plate and Forged Nom KIc (70) 2 

AISI 301/302 1⁄2 Hard Sheet 1 

PH13-8Mo H1000 Plate Forged Extrusion 1 

15-5PH H1025 Forged 1 

17-4PH H1025 Round Bar C-L 2 

2014-T6 Sheet T-L LA 1 

2024-T3 Clad and Bare Sheet L-T LA 12 

2024-T3 Clad and Bare Sheet T-L LA 1 

2024-T351 Plate L-T LA 6 

2024-T351 Plate and Sheet T-L LA and HHA 3 

2024-T3511 Extrusion L-T LA and HHA 4 

2024-T62 Sheet and Plate L-T LA HHA 1 

2024-T81 Sheet L-T LA 1 

2219-T62 Plate and Sheet T-L 1 

6061-T6 Plate T-L 1 

7049-T73 Forged L-T HHA 1 

7050-T73511 Extrusion L-T DA/LA/HHA 2 

7050-T7451 Plate L-T LA 2 

7050-T7451 Plate and Sheet T-L LA 2 

7050-T7452 Plate L-T and T-L LA 2 

7050-T7452 Forged L-T and T-L LA 2 

7050-T76 Clad Sheet T-L HHA 1 

7050-T76 Sheet T-L HHA 1 

7050-T7651 Plate and Sheet L-T LA 1 

7050-T76511 Extrusion L-T LA 3 or 4 

7075-T651 Plate L-T LA 2 

Notes: 

1. Bold listed materials meet criteria for FCGD report and software. 

2. The italic signifies a material that did not meet criteria for FCGD report and software.

A-2 
TABLE A-2. SURVEY IDENTIFIED MATERIALS HAVING NASGRO 4.0 FITS (Continued) 

Material Form Orientation Environment 

Survey 

Votes 

7075-T6511 Extrusion L-T LA and HHA 1 

7075-T73 Plate and Sheet T-L LA 2 

7075-T73 Forged L-T LA 3 

7075-T7351 Plate L-T LA/HHA 2 

7075-T7351 Plate and Sheet T-L LA 2 

7075-T73510 Extrusion L-T LA 1 

7075-T73511 Extrusion L-T LA/DA 2 

7075-T7352 Plate T-L LA 1 

7075-T76 Sheet T-L HHA 1 

7075-T76511 Extrusion L-T DA 1 

7079-T6 Plate and Forged L-T and T-L LA 2 

7150-T651 Plate L-T LA 2 

7175-T74 Forged L-T and T-L LA 1 

7178-T6 and T651 Plate and Sheet L-T LA/HHA 2 

7475-T7351 Plate L-T LA 3 

7475-T7351 Plate T-L LA/HHA 1 

7475-T761 Clad Sheet L-T LA and HHA 1 

7475-T7651 Plate and Sheet L-T LA 1 

A357-T6 Cast Al; Cast LA 2 

Ti-3Al-2.5V CW SR(750F) Extrusion 1 

Ti-6Al-4V MA(1350F/2h Forged) 1 

Ti-6Al-4V BA(1900F/.5h+ 

1325F/2h) Plate and 

Sheet 

LA DA3.5% Nacl 1 

Ti-6Al-4V RA(1700F/4h) Plate and 

Sheet 

L-T and T-L 1 

Ti-6Al-4V RA (1700F/4h) Forged 1 

Ti-6Al-4V STA Plate and Sheet 1 

Ti-6Al-6V-2Sn MA Plate Forged 

Extrusion 

LA DA HHA DW 1 

Notes: 

1. Bold listed materials meet criteria for FCGD report and software. 

2. The italic signifies a material that did not meet criteria for FCGD report and software.

A-3 
TABLE A-3. FAA SURVEY IDENTIFIED MATERIALS NOT HAVING NASGRO 4.0 FITS 

Aluminum Alloys Form Survey Votes 

2010-T6 and T651 Sheet and Plate 2 

2024-T3 Bare Sheet 2 

2024-T3510 Extrusion 2 

2024-T4 Clad Sheet 1 

2024-T4 and T42 Sheet and Plate 6 

2224-T3511 Extrusion 1 

2329-T39 Plate 1 

2525-T3 and T42 Clad and Bare Sheet 1 

6013-T6 Sheet 2 

6061-T3 and T4 Sheet 2 

7010-T6 Sheet 2 

7010-T6511 Extrusion 1 

7050-T6 Sheet (L-T) 2 

7075-T4 Sheet 1 

7075-T6 Plate (T-L and L-T) 7 

7075-T6 Forged 3 

7075-T62 Clad Sheet 1 

7075-T76 Sheet (T-L) 1 

7149-T73 Plate and Bar (S-T) 1 

7150-T7751 Plate 1 

7150-T77511 Extrusion 1 

7175-T74 Plate 1 

7178-T651 Extrusion 1 

AZ91C-T6 1 

Steel Types 

4130 Normalized 1 

4340 (150 ksi) 1 

9310 (? HT) Bar 1 

HY100 1 

15-5PH (? HT) Bar (L-T and T-L) 1 

PH13-8 (?HT) Bar (L-T and T-L) 1 

A301 1 

301 – 1⁄4 Hard Sheet 1 

Note: Some materials may have data in NASMAT, but not sufficient for fitting. 

A-4 
TABLE A-4. MATERIALS IDENTIFIED IN SURVEY LACKING 

ADEQUATE DATA FOR INCLUSION IN THE DATABASE 

Material 

15-5 PH 

INCO 718 

Ti-6-4 

4330V (Mod) 

Ti-10V-2Fe-3Al 

TABLE A-5. ADDITIONAL MATERIALS FROM RECENT FAA AND SwRI 

PROJECTS REVIEWED FOR INCLUSION IN THE DATABASE 

Material Form Orientation 

2024-T3 Sheet L-T and T-L * 

2014-T6511 Extrusion L-T 

7075-T7351 Plate L-T 

7475-T761 Sheet L-T 

*Used in data fits 

A-5 
Crack Growth Rate Standardization Questionnaire 

An effort is being launched to develop a database for crack growth rate data for commonly used 

aerospace metals. This effort will include a review of all publicly available existing data for a 

particular application* and development (if certain criteria are met) of a recommended data set in 

several commonly used formats. Your input is requested to help focus this effort. Please list, in 

your order of priority, those applications that you recommend be addressed. You may direct any 

questions regarding this effort to John Bakuckas, FAA William J. Hughes Technical Center, 609-

485-4784, john.bakuckas@faa.gov. 

* Application = Alloy, Temper, Form, Orientation, Environment, Thickness, (e.g., 2024, T3, Sheet, L-T, Laboratory 

Air, 0.071 inch) 

User Information:

Name:____________________________________________________Date:__________ 

Company:_______________________________________________________________ 

Address:________________________________________________________________ 

Phone:________________FAX:_________________e-mail:_______________________ 

Priority Alloy Temper Form Orientation Environment 

Thickness

(inch) 

e.g. 2024 T3 Sheet L-T Laboratory Air 0.071 

1. 

2. 

3. 

4. 

5. 

6. 

7. 

8. 

9. 

10. 

11. 

12. 

13. 

14. 

15. 

16. 

17. 

18. 

19. 

20. 

FIGURE A-2. FAA QUESTIONNAIRE 

A-6 
Crack Growth Rate Standardization Questionnaire 

An effort is being launched to develop a database for crack growth rate data for commonly used 

aerospace metals. This effort will review publicly available existing data for a particular application 

(alloy, temper, form, orientation, environment, and thickness) and development of a recommended data 

set in several commonly used formats. Your input is requested to help focus this effort. Thanks for 

taking the time to complete this questionnaire. 

User Information:

Name: Date: 

Company: 

Address: 

Phone: e-mail: 

(1) What type/models of aircraft/rotorcraft does your organization service? 

(2) Briefly describe the features/scope of your damage tolerance analyses (DTAs) by checking as 

many of the boxes below that apply to your activities: 

linear elastic (LEFM) Load Interaction Models: Crack Growth Models: 

elastic plastic (EPFM) Wheeler NASGRO 

threshold behavior Willenborg (s) Walker 

residual strength Constant closure Forman 

coldworked holes Strip yield Tabular data 

_______________ _______________ _______________ 

(3) Use the table below to list the most common materials (applications) that you work with. Does 

your organization have data suitable for the database that is unavailable to others that you would be 

willing to include in the database? If so, please indicate in the last column of the table. 

FIGURE A-2. NASGRO INDUSTRY CONSORTIUM QUESTIONNAIRE

Priority Alloy Temper Form Orien. Environ. 

Thickness 

(inch) 

Data You Can 

Provide* 

e.g. 2024 T3 Sheet L-T Laboratory Air 0.071 yes 

1. 

2. 

3. 

4. 

5. 

A-7 
(4) What are the sources for the DTA material property data that you have used in the past or are 

currently using? 

(5) For what materials do you not have adequate fatigue and fracture data available? If this material 

is listed in (3), simply indicate priority number. 

(6) Where have you traditionally found the largest gaps in DTA material property data? 

(7) In what instances do you find it necessary to make assumptions and/or use minimum 

values/curves for either fatigue or fracture properties? How do you establish what these 

minimums are? 

(8) Would your organization like to be a beta test reviewer of the database once it has been 

developed? YES __________ NO__________ 

(9) Please provide any additional comments or feedback you feel would assist this effort. 

Return questionnaire by e-mail or fax to: 

 Joseph W. Cardinal 

 Southwest Research InstituteTM 

 P. O. Drawer 28510 

 San Antonio, Texas 78228-0510 

 Fax: 210/522-3042 

 E-mail: jcardinal@swri.org

FIGURE A-2. NASGRO INDUSTRY CONSORTIUM QUESTIONNAIRE (Continued) 

A-8 
APPENDIX B—FATIGUE CRACK GROWTH DATA AND CURVE FITS

Included in the FCGD software menu is a Reference tab that opens up a complete list of 

references for the different materials selected. The following provides an explanation of the 

NASMAT Coding System used for Data Source References: 

"A" Prefaced References 

----------------------- 

References in "Compendium of Sources of Fracture 

Toughness and Fatigue Crack Growth Data for Metallic Alloys", by Hudson, 

M.C. and Seward, S.K., IJF, Vol. 14, 1978. 

"B" Prefaced References 

----------------------- 

References in "Compendium of Sources of Fracture 

Toughness and Fatigue Crack Growth Data for Metallic Alloys - Part II" by 

Hudson, M.C. and Seward, S.K., IJF, Vol. 20, 1982. 

"C" Prefaced References 

----------------------- 

References in "Damage Tolerant Design Handbook", 

MCIC-HB-01, University of Dayton Research Institute, Prepared for Air Force 

Wright Aeronautical Laboratories, Dec. 1983. 

"D" Prefaced References 

----------------------- 

References in "Damage Tolerant Design Handbook", 

WL-TR-94-4052, Materials Directorate, WPAFB, Ohio, May 1994. 

"E" Prefaced References 

----------------------- 

References in FRAMES_2, European Space Agency data 

base software for metallic materials. 

"F" Prefaced References 

----------------------- 

References in "Collection, Processing, and Reporting of Damage Tolerant Design Data for NonAerospace Structural Materials", University of Dayton Research Institute Report UDR-TR-94-

88, June 1994 - development performed under NASA JSC Grant NAG 9-600. 

Non-Prefaced References 

----------------------- 

References for other data obtained from NASA JSC in-house 

testing or from miscellaneous other sources. 

B-1
TABLE B-1. MATERIAL DESCRIPTION AND SPECIMEN TESTING INFORMATION OF 

2024-T6 SHEET, T-L 

Material ID Code M2AD12AB1 

Alloy Type 2014 Al 

Alloy Condition/HT T6 

Product Form 0.04′′-0.063′′ Sheet 

Test Environments Laboratory Air 

Specimen Types M(T) 

Crack Orientation T-L 

Specimen Thickness (in.) 0.04-0.063 

Specimen Width (in.) 6.0-6.3 

Yield Strength (ksi) 60-67 

Ultimate Strength (ksi) 70-74 

Cyclic Frequency, Hz 2-30 

Data References for Table B-1. 

112 Data of 2014-T6, 7475-T61, 2024-T62, 7475-T761, 2124-T851, 7475-T7351 - Materials 

received from L. Schwarmann, MBB Transport, Germany. 

C83 Smith, S.H., “Fracture Mechanics Application to Materials Evaluation and Selection for 

Aircraft Structure and Fracture Analysis,” Report No. D6-17756, The Boeing Company, 

Commercial Airplane Division, Renton, Washington, July 19, 1966. 

B-2
1e-07

1e-06

1e-05

0.0001

0.001

1 10

d

a/d

N [in/c

y

cle]

Delta K [ksi*SQRT(in)] 

R THK REF NASGRO Data ID _____________________________

NASGRO 4.0

EQUATION FIT:

_____________

Smax/SIGo = 0.30 

Alpha = 2.000 

K1c = 20.0

YS = 63.0

Ak = 1.00, Bk = 1.50

Kc = 48.2 (t= 0.063)

DK1 = 0.77

Cth+ = 2.20

Cth- = 0.10

p = 0.500, q = 0.500

C = 0.230E-07

n = 3.000

M2AD12AB01A4

M2AD12AB01C5

M2AD12AB01C4

M2AD12AB01A3

M2AD12AB01B1

M2AD12AB01C3

M2AD12AB01A2

M2AD12AB01A1

M2AD12AB01C2

 0.05 0.063 C83 

 0.05 0.040 C83 

 0.25 0.040 C83 

 0.25 0.063 C83 

 0.38 0.063 112 

 0.40 0.040 C83 

 0.40 0.063 C83 

 0.50 0.063 C83 

 0.50 0.040 C83 

R = 0.050

R = 0.250

R = 0.385

R = 0.400

R = 0.500

FIGURE B-1. NASGRO EQUATION FOR FIT 2014-T6 SHEET, T-L (M2AD12AB1) 

B-3
1e-07

1e-06

1e-05

0.0001

0.001

1 10

d

a/d

N [in/c

y

cle]

Delta K [ksi*SQRT(in)] 

R THK REF NASGRO Data ID _____________________________

NASGRO 4.0

WALKER FIT:

___________

C = 0.206E-08

n = 3.575

m+ = 0.597

M2AD12AB01A4

M2AD12AB01C5

M2AD12AB01C4

M2AD12AB01A3

M2AD12AB01B1

M2AD12AB01C3

M2AD12AB01A2

M2AD12AB01A1

M2AD12AB01C2

 0.05 0.063 C83 

 0.05 0.040 C83 

 0.25 0.040 C83 

 0.25 0.063 C83 

 0.38 0.063 112 

 0.40 0.040 C83 

 0.40 0.063 C83 

 0.50 0.063 C83 

 0.50 0.040 C83 

R = 0.050

R = 0.250

R = 0.385

R = 0.400

R = 0.500

FIGURE B-2. WALKER EQUATION FIT FOR 2014-T6 SHEET, T-L (M2AD12AB1) 

B-4
1e-07

1e-06

1e-05

0.0001

0.001

1 10

d

a

d/ N [in/c

y

cle]

Delta K [ksi*SQRT(in)] 

R THK REF NASGRO Data ID _____________________________

M2AD12AB01A4

M2AD12AB01C5

M2AD12AB01C4

M2AD12AB01A3

M2AD12AB01B1

M2AD12AB01C3

M2AD12AB01A2

M2AD12AB01A1

M2AD12AB01C2

 0.05 0.063 C83 

 0.05 0.040 C83 

 0.25 0.040 C83 

 0.25 0.063 C83 

 0.38 0.063 112 

 0.40 0.040 C83 

 0.40 0.063 C83 

 0.50 0.063 C83 

 0.50 0.040 C83 

R = 0.050

R = 0.250

R = 0.385

R = 0.400

R = 0.500

FIGURE B-3. SPLINE FIT FOR 2014-T6 SHEET, T-L (M2AD12AB1) 

B-5
TABLE B-2. da/dN-ΔK SPLINE FIT DATA FOR 2014-T6 SHEET T-L (M2AD12AB1) 

ID Code = M2AD12AB1 

R = 0.0500

da/dN ΔK

1.0909e-06 5.6494 

1.8000e-06 6.3876 

3.2000e-06 7.5718 

6.0000e-06 9.1953 

1.0000e-05 10.8559 

1.8000e-05 12.6778 

2.4745e-05 13.5207 

(a) 

ID Code = M2AD12AB1 

R = 0.2500

da/dN ΔK

1.4164e-06 5.5463 

1.8000e-06 5.7737 

3.2000e-06 6.7665 

6.0000e-06 8.4463 

1.0000e-05 9.7512 

1.8000e-05 11.6662 

2.9142e-05 12.9122 

(b) 

ID Code = M2AD12AB1 

R = 0.3850

da/dN ΔK

2.4613e-06 5.6624 

3.2000e-06 6.1848 

6.0000e-06 7.5733 

1.0000e-05 8.8701 

1.8000e-05 10.5918 

3.2000e-05 12.5655 

6.0000e-05 15.0162 

1.0000e-04 17.1638 

1.8000e-04 19.7483 

3.2000e-04 22.3548 

6.0000e-04 25.2594 

6.1196e-04 25.3513 

(c) 

ID Code = M2AD12AB1 

R = 0.400

da/dN ΔK

1.2033e-06 4.9204 

1.8000e-06 5.3015 

3.2000e-06 6.2179 

6.0000e-06 7.6336 

1.0000e-05 8.7926 

1.8000e-05 10.0942 

3.2000e-05 11.1996 

3.7598e-05 11.4815 

(d) 

ID Code = M2AD12AB1 

R = 0.500

da/dN ΔK

1.1057e-06 4.2658 

1.8000e-06 5.2013 

3.2000e-06 6.0382 

6.0000e-06 7.1813 

1.0000e-05 8.2055 

1.1770e-05 8.6696 

(e) 

B-6
TABLE B-3. MATERIAL DESCRIPTION AND SPECIMEN TESTING INFORMATION 

FOR 2024-T3 CLAD SHEET, L-T 

Material ID Code M2EA11AB1 

Alloy Type 2024 Al 

Alloy Condition/HT T3 

Product Form 0.04′′-0.15′′ Clad Sheet 

Test Environments Laboratory Air 

Specimen Types M(T) 

Crack Orientation L-T 

Specimen Thickness (in.) 0.04-0.15 

Specimen Width (in.) 4.0-15.7 

Yield Strength (ksi) 41-51 

Ultimate Strength (ksi) 62-64 

Cyclic Frequency, Hz 5-15 

Data References for Table B-3. 

181 Frediani, University of PISA experimantal results forwarded to JSC by ESA. 

189 Wanhill, R.J.H., “Low Stress Intensity Fatigue Crack Growth in 2024-T3 and T351,” 

Engineering Fracture Mechanics, Vol. 30, 1988. 

469 McKeighan, P., Data for FAA Project provided to JSC, May 2003. 

B-7
1e-09

1e-08

1e-07

1e-06

1e-05

0.0001

0.001

0.01

1 10 100

d

a

d/ N [in/c

y

cle]

Delta K [ksi*SQRT(in)] 

R THK REF NASGRO Data ID _____________________________

NASGRO 4.0

EQUATION FIT:

_____________

Smax/SIGo = 0.30 

Alpha = 2.000 

K1c = 30.0

YS = 53.0

Ak = 1.00, Bk = 1.50

Kc = 74.3 (t= 0.100)

DK1 = 1.22

Cth+ = 1.21

Cth- = 0.10

p = 0.250, q = 1.000

C = 0.800E-08

n = 3.200

M2EA11AB01I3

M2EA11AB01K3

M2EA01AB01C2

M2EA01AB01G2

M2EA11AB01A4

M2EA11AB01A2

M2EA01AB01B2

M2EA11AB01G1

M2EA11AB01H2

M2EA11AB01I4

M2EA01AB01A1

M2EA11AB01K4

M2EA11AB01K5

M2EA11AB01A1

 0.00 0.090 189 

 0.00 0.090 459 

 0.00 0.150 189 

 0.00 0.063 468 

 0.00 0.090 A73 

 0.50 0.090 A73 

 0.50 0.126 189 

 0.50 0.195 93 

 0.50 0.157 189 

 0.50 0.090 189 

 0.50 0.039 181 

 0.50 0.090 459 

 0.70 0.090 459 

 0.70 0.090 A73 

R = 0.000

R = 0.500

R = 0.700

FIGURE B-4a. NASGRO EQUATION FIT FOR 2024-T3 CLAD AND BARE SHEET, L-T 

(M2EA11AB1) WITH POSITIVE R VALUES 

B-8
1e-09

1e-08

1e-07

1e-06

1e-05

0.0001

0.001

0.01

1 10 100

d

a

d/ N [in/c

y

cle]

Delta K [ksi*SQRT(in)] 

R THK REF NASGRO Data ID _____________________________

NASGRO 4.0

EQUATION FIT:

_____________

Smax/SIGo = 0.30 

Alpha = 2.000 

K1c = 30.0

YS = 53.0

Ak = 1.00, Bk = 1.50

Kc = 74.3 (t= 0.100)

DK1 = 1.22

Cth+ = 1.21

Cth- = 0.10

p = 0.250, q = 1.000

C = 0.800E-08

n = 3.200

M2EA11AB01K1

M2EA01AB01C1

M2EA11AB01K2

M2EA11AB01I2

M2EA11AB01A5

M2EA11AB01G4

-2.00 0.090 459 

-1.00 0.150 189 

-1.00 0.090 459 

-1.00 0.090 189 

-1.00 0.090 A73 

-0.50 0.195 93 

R = -2.000

R = -1.000

R = -0.500

FIGURE B-4b. NASGRO EQUATION FIT FOR 2024-T3 CLAD AND BARE SHEET, L-T 

(M2EA11AB1) WITH NEGATIVE R VALUES 

B-9
1e-08

1e-07

1e-06

1e-05

0.0001

0.001

1 10

d

a/d

N [in/c

y

cle]

Delta K [ksi*SQRT(in)] 

R THK REF NASGRO Data ID _____________________________

NASGRO 4.0

WALKER FIT:

___________

C = 0.167E-08

n = 3.273

m+ = 0.618

M2EA11AB01A4

M2EA11AB01I3

M2EA01AB01C2

M2EA01AB01G2

M2EA11AB01K3

M2EA01AB01A1

M2EA11AB01A2

M2EA01AB01G3

M2EA11AB01G1

M2EA11AB01H2

M2EA11AB01I4

M2EA01AB01B2

M2EA11AB01K4

M2EA11AB01K5

M2EA11AB01A1

 0.00 0.090 A73 

 0.00 0.090 189 

 0.00 0.150 189 

 0.00 0.063 468 

 0.00 0.090 459 

 0.50 0.039 181 

 0.50 0.090 A73 

 0.50 0.063 468 

 0.50 0.195 93 

 0.50 0.157 189 

 0.50 0.090 189 

 0.50 0.126 189 

 0.50 0.090 459 

 0.70 0.090 459 

 0.70 0.090 A73 

R = 0.000

R = 0.500

R = 0.700

FIGURE B-5a. WALKER EQUATION FIT FOR 2024-T3 CLAD AND BARE SHEET, L-T 

(M2EA11AB1) WITH POSITIVE R VALUES 

B-10
1e-08

1e-07

1e-06

1e-05

0.0001

0.001

1 10 100

d

a/d

N [in/c

y

cle]

Delta K [ksi*SQRT(in)] 

R THK REF NASGRO Data ID _____________________________

NASGRO 4.0

WALKER FIT:

___________

C = 0.158E-08

n = 3.301

m- = 0.164

M2EA11AB01K1

M2EA11AB01I1

M2EA01AB01C1

M2EA11AB01I2

M2EA11AB01K2

M2EA11AB01A5

M2EA11AB01G4

-2.00 0.090 459 

-2.00 0.090 189 

-1.00 0.150 189 

-1.00 0.090 189 

-1.00 0.090 459 

-1.00 0.090 A73 

-0.50 0.195 93 

R = -2.000

R = -1.000

R = -0.500

FIGURE B-5b. WALKER EQUATION FIT FOR 2024-T3 CLAD AND BARE SHEET, L-T 

(M2EA11AB1) WITH NEGATIVE R VALUES 

B-11
1e-08

1e-07

1e-06

1e-05

0.0001

0.001

0.01

1 10 100

d

a

d/ N [in/c

y

cle]

Delta K [ksi*SQRT(in)] 

R THK REF NASGRO Data ID _____________________________

M2EA11AB01A4

M2EA11AB01I3

M2EA01AB01C2

M2EA01AB01G2

M2EA11AB01K3

M2EA01AB01A1

M2EA11AB01A2

M2EA01AB01G3

M2EA11AB01G1

M2EA11AB01H2

M2EA11AB01I4

M2EA01AB01B2

M2EA11AB01K4

M2EA11AB01K5

M2EA11AB01A1

 0.00 0.090 A73 

 0.00 0.090 189 

 0.00 0.150 189 

 0.00 0.063 468 

 0.00 0.090 459 

 0.50 0.039 181 

 0.50 0.090 A73 

 0.50 0.063 468 

 0.50 0.195 93 

 0.50 0.157 189 

 0.50 0.090 189 

 0.50 0.126 189 

 0.50 0.090 459 

 0.70 0.090 459 

 0.70 0.090 A73 

R = 0.000

R = 0.500

R = 0.700

FIGURE B-6a. SPLINE FIT FOR 2024-T3 CLAD AND BARE SHEET, L-T (M2EA11AB1) 

WITH POSITIVE R VALUES 

B-12
1e-08

1e-07

1e-06

1e-05

0.0001

0.001

1 10 100

d

a

d/ N [in/c

y

cle]

Delta K [ksi*SQRT(in)] 

R THK REF NASGRO Data ID _____________________________

M2EA11AB01K1

M2EA11AB01I1

M2EA01AB01C1

M2EA11AB01I2

M2EA11AB01K2

M2EA11AB01A5

M2EA11AB01G4

-2.00 0.090 459 

-2.00 0.090 189 

-1.00 0.150 189 

-1.00 0.090 189 

-1.00 0.090 459 

-1.00 0.090 A73 

-0.50 0.195 93 

R = -2.000

R = -1.000

R = -0.500

FIGURE B-6b. SPLINE FIT FOR 2024-T3 CLAD AND BARE SHEET, L-T (M2EA11AB1) 

WITH NEGATIVE R VALUES 

B-13
TABLE B-4a. da/dN-ΔK SPLINE FIT DATA FOR 2024-T3 CLAD AND BARE SHEET, L-T 

WITH POSITIVE R VALUES 

ID Code = M2EA11AB1 

R = 0.0000

da/dN ΔK

8.5277e-08 3.3806 

1.0000e-07 3.4799 

1.8000e-07 4.8636 

3.2000e-07 5.6622 

6.0000e-07 6.2613 

1.0000e-06 6.8082 

1.8000e-06 7.5591 

3.2000e-06 8.5678 

6.0000e-06 10.9383 

1.0000e-05 14.4607 

1.8000e-05 18.4912 

3.2000e-05 22.1001 

6.0000e-05 25.6959 

1.0000e-04 28.4466 

1.8000e-04 31.4230 

3.2000e-04 34.1080 

6.0000e-04 36.8131 

1.0000e-03 38.8665 

1.8000e-03 41.0983 

3.1829e-03 43.1519 

(a) 

ID Code = M2EA11AB1 

R = 0.5000

da/dN ΔK

1.0285e-07 2.2182 

1.8000e-07 3.3220 

3.2000e-07 4.1352 

6.0000e-07 4.8493 

1.0000e-06 5.4034 

1.8000e-06 6.0484 

3.2000e-06 6.9138 

6.0000e-06 8.6642 

1.0000e-05 10.5084 

1.8000e-05 12.9641 

3.2000e-05 15.3066 

6.0000e-05 17.8753 

1.0000e-04 20.3083 

1.8000e-04 22.6137 

3.2000e-04 24.3847 

6.0000e-04 25.9843 

7.2687e-04 26.4241 

(b) 

ID Code = M2EA11AB1 

R = 0.7000

da/dN ΔK

1.0217e-07 2.1677 

1.8000e-07 2.8901 

3.2000e-07 3.7327 

6.0000e-07 4.3227 

1.0000e-06 4.9276 

1.8000e-06 5.8777 

3.2000e-06 7.2772 

6.0000e-06 8.5971 

1.0000e-05 9.6496 

1.8000e-05 11.0169 

2.4964e-05 11.9399 

(c) 

B-14
TABLE B-4b. da/dN-ΔK SPLINE FIT DATA FOR 2024-T3 CLAD AND BARE SHEET, L-T 

WITH NEGATIVE R VALUES 

ID Code = M2EA11AB1 

R = -2.0000

da/dN ΔK

1.2075e-07 8.9125 

1.8000e-07 11.6085 

3.2000e-07 13.6923 

6.0000e-07 16.1057 

1.0000e-06 17.9171 

1.8000e-06 20.0262 

3.2000e-06 22.6636 

4.5772e-06 27.4157 

(a) 

ID Code = M2EA11AB1 

R = -1.0000

da/dN ΔK

1.0888e-07 6.3533 

1.8000e-07 8.2301 

3.2000e-07 9.6250 

6.0000e-07 11.1004 

1.0000e-06 12.3732 

1.8000e-06 14.0171 

3.2000e-06 15.9597 

6.0000e-06 18.9031 

1.0000e-05 24.3345 

1.8000e-05 30.9254 

3.2000e-05 35.8164 

6.0000e-05 41.0296 

1.0000e-04 45.4478 

1.8000e-04 50.9521 

3.2000e-04 57.0239 

6.0000e-04 64.8903 

1.0000e-03 72.8839 

1.8000e-03 85.8906 

1.9123e-03 87.7001 

(b) 

ID Code = M2EA11AB1 

R = -0.500

da/dN ΔK

2.0231e-06 11.1944 

3.2000e-06 12.6387 

6.0000e-06 14.8885 

1.0000e-05 17.1952 

1.8000e-05 21.3866 

3.2000e-05 29.1606 

6.0000e-05 33.8456 

1.0000e-04 37.4357 

1.8000e-04 41.8421 

3.2000e-04 46.9176 

5.6040e-04 53.7032 

(c) 

B-15
TABLE B-5. MATERIAL DESCRIPTION AND SPECIMEN TESTING INFORMATION 

FOR 2024-T3 CLAD AND BARE SHEET, T-L 

Material ID Code M2EA02AB1 

Alloy Type 2024 Al 

Alloy Condition/HT T3 

Product Form 0.04′′-0.09′′ Clad and Bare Sheet 

Test Environments Laboratory Air 

Specimen Types M(T) 

Crack Orientation T-L 

Specimen Thickness (in.) 0.04-0.09 

Specimen Width (in.) 4.0-15.7 

Yield Strength (ksi) Clad: 41-46 Bare: 47-53 

Ultimate Strength (ksi) Clad: 62-66 Bare: 66-68 

Cyclic Frequency, Hz 5-15 

Data References for Table B-5. 

361 Larson, B.F., “C-17 Material Specimen Tests for Fracture Mechanics Data,” Phase I, Lot 

1 Aluminum Alloys. 

362 Kahandal, R.S., “C-17 Material Specimen Tests for Fracture Mechanics Data,” Phase I, 

Lot 2 Aluminum Alloys. 

468 Widespread Fatigue Damage Evaluation Final Report, Submitted to FAA Technical 

Center, The Boeing Co. Phantom Works, February 2003. 

C104 MacKay, T.L., “Fatigue Crack Propagation Rate at Low Delta K of Two Aluminum 

Sheet Alloys - 2024-T3 and 7075-T6,” Engineering Fracture Mechanics, Volume II, 

1979, pp.753-761. 

B-16
1e-08

1e-07

1e-06

1e-05

0.0001

0.001

0.01

1 10 100

d

a

d/ N [in/c

y

cle]

Delta K [ksi*SQRT(in)] 

R THK REF NASGRO Data ID _____________________________

NASGRO 4.0

EQUATION FIT:

_____________

Smax/SIGo = 0.30 

Alpha = 2.000 

K1c = 27.0

YS = 48.0

Ak = 1.00, Bk = 1.50

Kc = 67.0 (t= 0.090)

DK1 = 1.00

Cth+ = 1.50

Cth- = 0.10

p = 0.250, q = 1.000

C = 0.130E-07

n = 3.000

M2EA02AB01A2

M2EA02AB01E3

M2EA02AB01D3

M2EA02AB01C3

M2EA12AB01B3

M2EA02AB01A1

M2EA02AB01D2

M2EA02AB01C2

M2EA12AB01B2

M2EA12AA09A2

M2EA12AA09A1

M2EA02AB01D1

M2EA02AB01C1

 0.00 0.090 C81 

 0.00 0.063 468 

 0.05 0.090 362 

 0.05 0.090 361 

 0.05 0.090 C104

 0.33 0.090 C81 

 0.40 0.090 362 

 0.40 0.090 361 

 0.40 0.090 C104

 0.40 0.090 C104

 0.70 0.090 C104

 0.80 0.090 362 

 0.80 0.090 361 

R = 0.000

R = 0.050

R = 0.330

R = 0.400

R = 0.700

R = 0.800

FIGURE B-7. NASGRO EQUATION FIT FOR 2024-T3 CLAD AND BARE SHEET, 

T-L (M2EA02AB1) 

B-17
1e-07

1e-06

1e-05

0.0001

0.001

1 10

d

a

d/ N [in/c

y

cle]

Delta K [ksi*SQRT(in)] 

R THK REF NASGRO Data ID _____________________________

NASGRO 4.0

WALKER FIT:

___________

C = 0.116E-08

n = 3.477

m+ = 0.623

M2EA02AB01A2

M2EA02AB01E3

M2EA02AB01D3

M2EA02AB01C3

M2EA12AB01B3

M2EA02AB01A1

M2EA02AB01D2

M2EA02AB01C2

M2EA12AB01B2

M2EA12AA09A2

M2EA12AA09A1

M2EA02AB01D1

M2EA02AB01C1

 0.00 0.090 C81 

 0.00 0.063 468 

 0.05 0.090 362 

 0.05 0.090 361 

 0.05 0.090 C104

 0.33 0.090 C81 

 0.40 0.090 362 

 0.40 0.090 361 

 0.40 0.090 C104

 0.40 0.090 C104

 0.70 0.090 C104

 0.80 0.090 362 

 0.80 0.090 361 

R = 0.000

R = 0.050

R = 0.330

R = 0.400

R = 0.700

R = 0.800

FIGURE B-8. WALKER EQUATION FIT FOR 2024-T3 CLAD AND BARE SHEET, 

T-L (M2EA02AB1) 

B-18
1e-08

1e-07

1e-06

1e-05

0.0001

0.001

0.01

1 10 100

d

a

d/ N [in/c

y

cle]

Delta K [ksi*SQRT(in)] 

R THK REF NASGRO Data ID _____________________________

M2EA02AB01A2

M2EA02AB01E3

M2EA02AB01D3

M2EA02AB01C3

M2EA12AB01B3

M2EA02AB01A1

M2EA02AB01D2

M2EA02AB01C2

M2EA12AB01B2

M2EA12AA09A2

M2EA12AA09A1

M2EA02AB01D1

M2EA02AB01C1

 0.00 0.090 C81 

 0.00 0.063 468 

 0.05 0.090 362 

 0.05 0.090 361 

 0.05 0.090 C104

 0.33 0.090 C81 

 0.40 0.090 362 

 0.40 0.090 361 

 0.40 0.090 C104

 0.40 0.090 C104

 0.70 0.090 C104

 0.80 0.090 362 

 0.80 0.090 361 

R = 0.000

R = 0.050

R = 0.330

R = 0.400

R = 0.700

R = 0.800

FIGURE B-9. SPLINE FIT FOR 2024-T3 CLAD AND BARE SHEET, 

T-L (M2EA02AB1) 

B-19
TABLE B-6. da/dN-ΔK SPLINE FIT DATA FOR 2024-T3 CLAD AND BARE SHEET, 

T-L (M2EA02AB1) 

ID Code = M2EA02AB1 

R = 0.0000 

da/dN ΔK

1.3265e-06 8.4918 

1.8000e-06 8.8929 

3.2000e-06 9.8437 

6.0000e-06 11.7948 

1.0000e-05 14.8983 

1.8000e-05 18.4770 

3.2000e-05 21.4044 

6.0000e-05 24.5501 

1.0000e-04 27.4624 

1.6591e-04 30.9030 

(a) 

ID Code = M2EA02AB1 

R = 0.050 

da/dN ΔK

7.2719e-08 2.6303 

1.0000e-07 2.8505 

1.8000e-07 4.5371 

3.2000e-07 5.4593 

6.0000e-07 6.1800 

1.0000e-06 6.8122 

1.8000e-06 7.6375 

3.2000e-06 8.6277 

6.0000e-06 10.1978 

1.0000e-05 12.6918 

1.8000e-05 15.5656 

3.2000e-05 18.5999 

6.0000e-05 22.8197 

1.0000e-04 26.3730 

1.8000e-04 29.5891 

3.2000e-04 32.6070 

6.0000e-04 36.0431 

1.0000e-03 39.1073 

1.8000e-03 43.1970 

3.2000e-03 48.3751 

3.2125e-03 48.4172 

(b) 

ID Code = M2EA02AB1 

R = 0.4000 

da/dN ΔK

8.7184e-08 2.3496 

1.0000e-07 2.4807 

1.8000e-07 3.5217 

3.2000e-07 4.2284 

6.0000e-07 4.7368 

1.0000e-06 5.1743 

1.8000e-06 5.9073 

3.2000e-06 7.0457 

6.0000e-06 8.7120 

1.0000e-05 10.0453 

1.8000e-05 11.9807 

3.2000e-05 14.3355 

6.0000e-05 17.1197 

1.0000e-04 19.3656 

1.8000e-04 22.3736 

3.2000e-04 25.6294 

6.0000e-04 29.0384 

1.0000e-03 31.5700 

1.8000e-03 34.2346 

3.2000e-03 36.6329 

4.1606e-03 37.6704 

(c) 

ID Code = M2EA02AB1 

R = 0.700 

da/dN ΔK

1.9071e-07 3.0479 

3.2000e-07 3.5258 

6.0000e-07 3.8992 

1.0000e-06 4.2919 

1.8000e-06 5.0071 

3.2000e-06 5.9231 

6.0000e-06 7.0672 

1.0000e-05 8.1534 

1.8000e-05 9.5707 

3.2000e-05 11.0110 

4.1155e-05 11.7490 

(d) 

B-20
TABLE B-6. da/dN-ΔK SPLINE FIT DATA FOR 2024-T3 CLAD AND BARE SHEET, 

T-L (M2EA02AB1) (Continued) 

ID Code = M2EA02AB1 

R = 0.8000 

da/dN ΔK

7.0726e-08 1.5812 

1.0000e-07 1.8180 

1.8000e-07 2.5351 

3.2000e-07 3.0626 

6.0000e-07 3.7047 

1.0000e-06 4.2768 

1.8000e-06 4.9757 

3.2000e-06 5.7129 

6.0000e-06 6.6530 

1.0000e-05 7.6199 

1.8000e-05 8.7015 

3.2000e-05 9.6146 

6.0000e-05 10.6938 

1.0000e-04 11.8212 

1.4088e-04 13.0918 

(e) 

B-21
TABLE B-7. MATERIAL DESCRIPTION AND SPECIMEN TESTING INFORMATION 

FOR 2024-T351 PLATE, L-T 

Material ID Code M2EB11AB1 

Alloy Type 2024 Al 

Alloy Condition/HT T351 

Product Form 0.25′′-1.2′′ Plate 

Test Environments Laboratory Air 

Specimen Types C(T), M(T) 

Crack Orientation L-T 

Specimen Thickness (in.) C(T): 0.25-0.5 M(T): 0.16-0.0 

Specimen Width (in.) C(T): 2.0 M(T): 4-12 

Yield Strength (ksi) 48-57 

Ultimate Strength (ksi) 66-71 

Cyclic Frequency, Hz 3-30 

Data References for Table B-7. 

91 Schra, L., et al., “Engineering Property Comparisons for 2324-T39 and 2024-T351 

Aluminum Alloy Plate,” National Aerospace Laboratory, Amsterdam, The Netherlands, 

NLR TR 84021 U, 1984. 

93 Levy, M., “Assessment of Damage Tolerance Requirements and Analyses - Tasks II and 

IV Report,” AFWAL-TR-86-3003, Vol. 4,1986. 

361 Larson, B.F., “C-17 Material Specimen Tests for Fracture Mechanics Data,” Phase I, Lot 

1 Aluminum Alloys.” 

B218 Liu, A.F., et al., “Effect of Multi-axial Loading on Crack Growth,” Vol. I & II, AFFDLTR-78-175, 1978. 

C8 Fatigue Crack Growth Rate Data Sheets on Al Alloys 2024, 7010, 7050, 7075, 7475 and 

Steel Alloys 17-4 PH, 17-7PH, 4340, A286, H-11, HY-180 and 12-9-2, Sent by Paul 

Abelkis, Douglas Aircraft Co., Long Beach, CA, 1982. 

C122 Cervay, R.R., “An Empirical Model for Load Ratio and Test Temperature Effects on the 

Fatigue Crack Growth Rate of Aluminum Alloy 2024-T351,” UDRI, Dayton, OH, Report 

AFWAL-TR-82-4025, March 1982. 

B-22
1e-09

1e-08

1e-07

1e-06

1e-05

0.0001

0.001

0.01

1 10 100

d

a

d/ N [in/c

y

cle]

Delta K [ksi*SQRT(in)] 

R THK REF NASGRO Data ID _____________________________

NASGRO 4.0

EQUATION FIT:

_____________

Smax/SIGo = 0.30 

Alpha = 2.000 

K1c = 36.0

YS = 54.0

Ak = 1.00, Bk = 2.00

Kc = 105.7 (t= 0.200)

DK1 = 0.80

Cth+ = 2.20

Cth- = 0.10

p = 0.500, q = 1.000

C = 0.400E-08

n = 3.600

M2EB11AB01C1

M2EB11AB01D1

M2EB11AB01E1

M2EB11AB01H4

M2EB11AB01F2

M2EB11AB01G3

M2EB11AB01L2

M2EB11AB01N2

M2EB11AB01G1

M2EB11AB01L1

M2EB11AB01F1

M2EB11AB01N1

 0.10 0.180 B218

 0.10 0.157 91 

 0.10 0.390 91 

 0.10 0.500 C122

 0.40 0.185 C8 

 0.40 0.240 C8 

 0.40 0.200 361 

 0.40 0.250 362 

 0.80 0.240 C8 

 0.80 0.200 361 

 0.80 0.185 C8 

 0.80 0.250 362 

R = 0.100

R = 0.400

R = 0.800

FIGURE B-10a. NASGRO EQUATION FIT FOR 2024-T351 PLATE, L-T (M2EB11AB1) 

WITH POSITIVE R VALUES 

B-23
1e-09

1e-08

1e-07

1e-06

1e-05

0.0001

0.001

0.01

1 10 100

d

a

d/ N [in/c

y

cle]

Delta K [ksi*SQRT(in)] 

R THK REF NASGRO Data ID _____________________________

NASGRO 4.0

EQUATION FIT:

_____________

Smax/SIGo = 0.30 

Alpha = 2.000 

K1c = 36.0

YS = 54.0

Ak = 1.00, Bk = 2.00

Kc = 105.2 (t= 0.220)

DK1 = 0.80

Cth+ = 2.20

Cth- = 0.10

p = 0.500, q = 1.000

C = 0.400E-08

n = 3.600

M2EB11AB01F4

M2EB11AB01G6

M2EB11AB01G5

M2EB11AB01J4

-1.00 0.185 C8 

-1.00 0.240 C8 

-0.50 0.240 C8 

-0.50 0.250 93 

R = -1.000

R = -0.500

FIGURE B-10b. NASGRO EQUATION FIT FOR 2024-T351 CLAD AND BARE SHEET, L-T 

(M2EB11AB1) WITH NEGATIVE R VALUES 

B-24
1e-08

1e-07

1e-06

1e-05

0.0001

0.001

0.01

1 10 100

d

a

d/ N [in/c

y

cle]

Delta K [ksi*SQRT(in)] 

R THK REF NASGRO Data ID _____________________________

NASGRO 4.0

WALKER FIT:

___________

C = 0.667E-09

n = 3.815

m+ = 0.691

M2EB11AB01C1

M2EB11AB01D1

M2EB11AB01E1

M2EB11AB01H4

M2EB11AB01F2

M2EB11AB01G3

M2EB11AB01L2

M2EB11AB01N2

M2EB11AB01G1

M2EB11AB01L1

M2EB11AB01F1

M2EB11AB01N1

 0.10 0.180 B218

 0.10 0.157 91 

 0.10 0.390 91 

 0.10 0.500 C122

 0.40 0.185 C8 

 0.40 0.240 C8 

 0.40 0.200 361 

 0.40 0.250 362 

 0.80 0.240 C8 

 0.80 0.200 361 

 0.80 0.185 C8 

 0.80 0.250 362 

R = 0.100

R = 0.400

R = 0.800

FIGURE B-11a. WALKER EQUATION FIT FOR 2024-T351 PLATE, L-T (M2EB11AB1) 

WITH POSITIVE R VALUES 

B-25
1e-06

1e-05

0.0001

0.001

0.01

10 100

d

a

d/ N [in/c

y

cle]

Delta K [ksi*SQRT(in)] 

R THK REF NASGRO Data ID _____________________________

NASGRO 4.0

WALKER FIT:

___________

C = 0.667E-09

n = 3.815

m- = 0.023

M2EB11AB01F4

M2EB11AB01G6

M2EB11AB01G5

M2EB11AB01J4

-1.00 0.185 C8 

-1.00 0.240 C8 

-0.50 0.240 C8 

-0.50 0.250 93 

R = -1.000

R = -0.500

FIGURE B-11b. WALKER EQUATION FIT FOR 2024-T351 PLATE, L-T (M2EB11AB1) 

WITH NEGATIVE R VALUES 

B-26
1e-08

1e-07

1e-06

1e-05

0.0001

0.001

0.01

1 10 100

d

a

d/ N [in/c

y

cle]

Delta K [ksi*SQRT(in)] 

R THK REF NASGRO Data ID _____________________________

M2EB11AB01C1

M2EB11AB01D1

M2EB11AB01E1

M2EB11AB01H4

M2EB11AB01F2

M2EB11AB01G3

M2EB11AB01L2

M2EB11AB01N2

M2EB11AB01G1

M2EB11AB01L1

M2EB11AB01F1

M2EB11AB01N1

 0.10 0.180 B218

 0.10 0.157 91 

 0.10 0.390 91 

 0.10 0.500 C122

 0.40 0.185 C8 

 0.40 0.240 C8 

 0.40 0.200 361 

 0.40 0.250 362 

 0.80 0.240 C8 

 0.80 0.200 361 

 0.80 0.185 C8 

 0.80 0.250 362 

R = 0.100

R = 0.400

R = 0.800

FIGURE B-12a. SPLINE FIT FOR 2024-T351 PLATE, L-T (M2EB11AB1) 

WITH POSITIVE R VALUES 

B-27
1e-06

1e-05

0.0001

0.001

0.01

10 100

d

a/d

N [in/c

y

cle]

Delta K [ksi*SQRT(in)] 

R THK REF NASGRO Data ID _____________________________

M2EB11AB01F4

M2EB11AB01G6

-1.00 0.185 C8 

-1.00 0.240 C8 

R = -1.000

FIGURE B-12b. SPLINE FIT FOR 2024-T351 PLATE, L-T (M2EB11AB1) WITH 

NEGATIVE R VALUE 

B-28
TABLE B-8a. da/dN-ΔK SPLINE FIT FOR 2024-T351 PLATE, L-T WITH 

POSITIVE R VALUES (M2EB11AB1)

ID Code = M2EB11AB1 

R = 0.1000 

da/dN ΔK

6.3673e-08 3.0339 

1.0000e-07 3.3757 

1.8000e-07 5.1702 

3.2000e-07 5.9223 

6.0000e-07 6.5530 

1.0000e-06 7.0657 

1.8000e-06 7.6931 

3.2000e-06 8.3879 

6.0000e-06 9.3368 

1.0000e-05 10.5182 

1.8000e-05 13.8864 

3.2000e-05 18.0508 

6.0000e-05 21.9594 

1.0000e-04 24.9567 

1.8000e-04 28.9025 

3.2000e-04 34.6169 

3.9892e-04 39.9945 

(a) 

ID Code = M2EB11AB1 

R = 0.4000 

da/dN ΔK

9.2159e-08 2.8510 

1.0000e-07 2.9115 

1.8000e-07 3.5314 

3.2000e-07 4.4315 

6.0000e-07 5.2924 

1.0000e-06 5.8499 

1.8000e-06 6.4669 

3.2000e-06 7.2092 

6.0000e-06 8.2548 

1.0000e-05 9.3848 

1.8000e-05 11.2285 

3.2000e-05 13.7530 

6.0000e-05 16.2123 

1.0000e-04 18.2590 

1.8000e-04 20.9230 

3.2000e-04 24.2488 

6.0000e-04 29.6101 

1.0000e-03 34.5724 

1.8000e-03 40.0619 

3.2000e-03 44.9797 

6.0000e-03 49.8926 

1.0000e-02 53.6063 

1.0138e-02 53.7032 

(b) 

B-29
TABLE B-8b. da/dN-ΔK SPLINE FIT FOR 2024-T351 PLATE, L-T WITH 

NEGATIVE R VALUES (M2EB11AB1) 

ID Code = M2EB11AB1 

R = 0.800 

da/dN ΔK

7.6776e-08 2.1086 

1.0000e-07 2.3709 

1.8000e-07 2.9481 

3.2000e-07 3.5670 

6.0000e-07 4.2057 

1.0000e-06 4.6605 

1.8000e-06 5.2121 

3.2000e-06 5.8584 

6.0000e-06 6.8357 

1.0000e-05 7.6194 

1.8000e-05 8.5390 

3.2000e-05 9.5439 

6.0000e-05 10.9219 

1.0000e-04 12.2700 

1.8000e-04 13.7774 

3.2000e-04 15.2465 

6.0000e-04 16.8709 

1.0000e-03 18.2183 

1.4100e-03 19.1426 

(a) 

ID Code = M2EB11AB1 

R = -1.0000 

da/dN ΔK

3.2007e-06 15.0314 

6.0000e-06 18.4501 

1.0000e-05 21.7282 

1.8000e-05 26.4713 

3.2000e-05 33.1420 

6.0000e-05 40.6908 

1.0000e-04 45.7057 

1.8000e-04 51.5887 

3.2000e-04 58.0457 

6.0000e-04 66.9812 

9.3364e-04 76.5597 

(b) 

ID Code = M2EB11AB1 

R = -0.500 

da/dN ΔK

A spline fit for R = -0.500 data was 

not done since there is considerable 

scatter in them; consequently, a table 

was not developed for R = -0.500. 

(c) 

B-30
TABLE B-9. MATERIAL DESCRIPTION AND SPECIMEN TESTING INFORMATION 

FOR 2024-T3511 EXTRUSION, L-T 

Material ID Code M2EC31AB1 

Alloy Type 2024 Al 

Alloy Condition/HT T3511 

Product Form Extrusion 

Test Environments Laboratory Air, High-Humidity Air 

Specimen Types C(T), M(T) 

Crack Orientation L-T 

Specimen Thickness (in.) C(T): 0.25-0.37 M(T): 0.19-0.37 

Specimen Width (in.) C(T): 2.0-4.0 M(T): 2.25-5.0 

Yield Strength (ksi) 48-58 

Ultimate Strength (ksi) 62-79 

Cyclic Frequency, Hz 9-20 

Data References for Table B-9. 

93 Levy, M., “Assessment of Damage Tolerance Requirements and Analyses -Tasks II and 

IV Report,” AFWAL-TR-86-3003, Vol.4, Raw Test Data, 1986. 

C65 Horsely, J.J., et al., “Durability and Damage Tolerance Assessment (DADTA) of B-52 

G/H Structure, Task II, Damage Tolerance Assessment Final Report,” Boeing Company, 

Wichita, KS, Contract No. F34601-79-C-1515, Document No. D3-11560-3, June 1980. 

D4 Fitzgerald, J., Southwest Research Institute, San Antonio, Texas, submitted data. 

B-31
1e-08

1e-07

1e-06

1e-05

0.0001

0.001

1 10 100

d

a

d/ N [in/c

y

cle]

Delta K [ksi*SQRT(in)] 

R THK REF NASGRO Data ID _____________________________

NASGRO 4.0

EQUATION FIT:

_____________

Smax/SIGo = 0.30 

Alpha = 2.000 

K1c = 35.0

YS = 55.0

Ak = 1.00, Bk = 1.00

Kc = 67.9 (t= 0.250)

DK1 = 1.00

Cth+ = 2.50

Cth- = 0.10

p = 0.500, q = 1.000

C = 0.400E-08

n = 3.500

M2EC31AB01A2

M2EC31AD01A2

M2EC31AB01B2

M2EC31AB01C2

M2EC31AB01D1

M2EC31AB01C1

M2EC31AB01A1

M2EC31AB01D2

M2EC31AB01B1

M2EC31AD01A1

M2EC31AB01D3

 0.05 0.250 93 

 0.05 0.370 C65 

 0.05 0.191 93 

 0.05 0.370 C65 

 0.10 0.250 D4 

 0.50 0.370 C65 

 0.50 0.250 93 

 0.50 0.250 D4 

 0.50 0.191 93 

 0.50 0.370 C65 

 0.80 0.250 D4 

R = 0.050

R = 0.100

R = 0.500

R = 0.800

FIGURE B-13. NASGRO EQUATION FIT FOR 2024-T3511 EXTRUSION, 

L-T (M2EC31AB1) 

B-32
1e-08

1e-07

1e-06

1e-05

0.0001

0.001

1 10

d

a

d/ N [in/c

y

cle]

Delta K [ksi*SQRT(in)] 

R THK REF NASGRO Data ID _____________________________

NASGRO 4.0

WALKER FIT:

___________

C = 0.199E-09

n = 4.216

m+ = 0.660

M2EC31AB01A2

M2EC31AD01A2

M2EC31AB01B2

M2EC31AB01C2

M2EC31AB01D1

M2EC31AB01C1

M2EC31AB01A1

M2EC31AB01D2

M2EC31AB01B1

M2EC31AD01A1

M2EC31AB01D3

 0.05 0.250 93 

 0.05 0.370 C65 

 0.05 0.191 93 

 0.05 0.370 C65 

 0.10 0.250 D4 

 0.50 0.370 C65 

 0.50 0.250 93 

 0.50 0.250 D4 

 0.50 0.191 93 

 0.50 0.370 C65 

 0.80 0.250 D4 

R = 0.050

R = 0.100

R = 0.500

R = 0.800

FIGURE B-14. WALKER EQUATION FIT FOR 2024-T3511 EXTRUSION, 

L-T (M2EC31AB1) 

B-33
1e-08

1e-07

1e-06

1e-05

0.0001

0.001

1 10 100

d

a

d/ N [in/c

y

cle]

Delta K [ksi*SQRT(in)] 

R THK REF NASGRO Data ID _____________________________

M2EC31AB01A2

M2EC31AD01A2

M2EC31AB01B2

M2EC31AB01C2

M2EC31AB01D1

M2EC31AB01C1

M2EC31AB01A1

M2EC31AB01D2

M2EC31AB01B1

M2EC31AD01A1

M2EC31AB01D3

 0.05 0.250 93 

 0.05 0.370 C65 

 0.05 0.191 93 

 0.05 0.370 C65 

 0.10 0.250 D4 

 0.50 0.370 C65 

 0.50 0.250 93 

 0.50 0.250 D4 

 0.50 0.191 93 

 0.50 0.370 C65 

 0.80 0.250 D4 

R = 0.050

R = 0.100

R = 0.500

R = 0.800

FIGURE B-15. SPLINE FIT FOR 2024-T3511 EXTRUSION, 

L-T (M2EC31AB1) 

B-34
TABLE B-10. da/dN-ΔK SPLINE FIT FOR 2024-T3511 EXTRUSION, L-T (M2EC31AB1) 

ID Code = M2EC31AB1 

R = 0.050 

da/dN ΔK

6.3335e-08 4.3853 

1.0000e-07 4.7880 

1.8000e-07 6.1551 

3.2000e-07 6.7743 

6.0000e-07 7.3027 

1.0000e-06 7.8133 

1.8000e-06 8.5306 

3.2000e-06 9.4419 

6.0000e-06 10.8713 

1.0000e-05 12.2808 

1.8000e-05 14.1614 

3.2000e-05 16.6422 

6.0000e-05 21.1610 

9.3906e-05 25.3513 

(a) 

ID Code = M2EC31AB1 

R = 0.100 

da/dN ΔK

5.7363e-08 3.8548 

6.0000e-08 3.8733 

1.0000e-07 4.1521 

1.8000e-07 5.2943 

3.2000e-07 6.3406 

6.0000e-07 6.9574 

1.0000e-06 7.4276 

1.8000e-06 7.9973 

3.2000e-06 8.6517 

6.0000e-06 9.7726 

1.0000e-05 11.5597 

1.8000e-05 13.8763 

3.2000e-05 16.1539 

6.0000e-05 19.0579 

1.0000e-04 21.3785 

1.8000e-04 23.6624 

2.7258e-04 25.0611 

(b) 

ID Code = M2EC31AB1 

R = 0.500 

da/dN ΔK

8.4541e-08 2.3823 

1.0000e-07 2.8834 

1.8000e-07 3.8821 

3.2000e-07 4.7230 

6.0000e-07 5.3165 

1.0000e-06 5.8043 

1.8000e-06 6.4553 

3.2000e-06 7.2914 

6.0000e-06 8.4439 

1.0000e-05 9.4712 

1.8000e-05 10.6305 

3.2000e-05 13.6914 

6.0000e-05 15.2424 

1.0000e-04 15.9647 

1.8000e-04 16.6074 

3.2000e-04 17.1308 

4.1185e-04 17.3380 

(c) 

ID Code = M2EC31AB1 

R = 0.800 

da/dN ΔK

5.8218e-08 2.0137 

6.0000e-08 2.0732 

1.0000e-07 2.4725 

1.8000e-07 3.2892 

3.2000e-07 3.9600 

6.0000e-07 4.4063 

1.0000e-06 4.8039 

1.8000e-06 5.5313 

3.2000e-06 6.1777 

6.0000e-06 6.8245 

9.7299e-06 7.4645 

(d) 

B-35
TABLE B-11. MATERIAL DESCRIPTION AND SPECIMEN TESTING INFORMATION 

FOR 2024-T62 SHEET AND PLATE, L-T 

Material ID Code M2EG11AB1 

Alloy Type 2024 Al 

Alloy Condition/HT T62 

Product Form 0.08′′-0.13′′ Sheet, 1.5′′ Plate 

Test Environments Laboratory Air, High-Humidity Air, A/C Sump 

Water 

Specimen Types C(T), M(T) 

Crack Orientation L-T 

Specimen Thickness (in.) C(T): 0.05-1.50 M(T): 0.08-0.12 

Specimen Width (in.) C(T): 10 M(T): 6.0-6.3 

Yield Strength (ksi) 53-60 

Ultimate Strength (ksi) 64-75 

Cyclic Frequency, Hz 0.1-30 

Data References for Table B-11. 

25 LaSalle, R.M., Rockwell Space Div. Lab. Report LTR 1242-4126, 1976. 

112 Data of 2014-T6, 7475-T61, 2024-T62, 7475-T761, 2124-T851, 7475-T7351-Materials 

received from L. Schwarmann. 

C108 Wolnaski, Z.R., “2024-T81 and -T62 0.125-Inch Sheet Metal Allowables,” General 

Dynamics, Fort Worth Div., Report No.16 PR853, October 1978. 

E 2 MBB Transport, Germany developed data, copied from ESA Software FRAMES-2. 

B-36
1e-08

1e-07

1e-06

1e-05

0.0001

0.001

0.01

1 10 100

da/dN [in/cycle] 

Delta K [ksi*SQRT(in)] 

R THK REF NASGRO Data ID _____________________________

NASGRO 4.0

EQUATION FIT:

_____________

Smax/SIGo = 0.30 

Alpha = 2.000 

K1c = 38.0

YS = 58.0

Ak = 1.00, Bk = 1.00

Kc = 75.5 (t= 0.125)

DK1 = 0.82

Cth+ = 2.20

Cth- = 0.10

p = 1.000, q = 1.000

C = 0.150E-07

n = 3.000

M2EG11AB01A1

M2EG11AB01C1

M2EG11AB01D1

M2EG11AD01A2

M2EG11AB01H1

M2EG11AB01G1

M2EG11AB01F1

M2EG11WE01A1

 0.10 0.056 25 

 0.10 0.250 25 

 0.10 0.500 25 

 0.10 0.125 C108

 0.38 0.080 E2 

 0.38 0.079 112 

 0.38 0.126 112 

 0.70 0.125 C108

R = 0.100

R = 0.385

R = 0.700

FIGURE B-16. NASGRO EQUATION FIT FOR 2024-T62 SHEET AND PLATE, 

L-T (M2EG11AB1) 

B-37
1e-08

1e-07

1e-06

1e-05

0.0001

0.001

1 10 100

d

a

d/ N [in/c

y

cle]

Delta K [ksi*SQRT(in)] 

R THK REF NASGRO Data ID _____________________________

NASGRO 4.0

WALKER FIT:

___________

C = 0.115E-08

n = 3.463

m+ = 0.501

M2EG11AB01A1

M2EG11AB01C1

M2EG11AB01D1

M2EG11AD01A2

M2EG11AB01H1

M2EG11AB01G1

M2EG11AB01F1

M2EG11WE01A1

 0.10 0.056 25 

 0.10 0.250 25 

 0.10 0.500 25 

 0.10 0.125 C108

 0.38 0.080 E2 

 0.38 0.079 112 

 0.38 0.126 112 

 0.70 0.125 C108

R = 0.100

R = 0.385

R = 0.700

FIGURE B-17. WALKER EQUATION FIT FOR 2024-T62 SHEET AND PLATE, 

L-T (M2EG11AB1) 

B-38
1e-08

1e-07

1e-06

1e-05

0.0001

0.001

0.01

1 10 100

d

a/d

N [in/c

y

cle]

Delta K [ksi*SQRT(in)] 

R THK REF NASGRO Data ID _____________________________

M2EG11AB01A1

M2EG11AB01C1

M2EG11AB01D1

M2EG11AD01A2

M2EG11AB01H1

M2EG11AB01G1

M2EG11AB01F1

M2EG11WE01A1

 0.10 0.056 25 

 0.10 0.250 25 

 0.10 0.500 25 

 0.10 0.125 C108

 0.38 0.080 E2 

 0.38 0.079 112 

 0.38 0.126 112 

 0.70 0.125 C108

R = 0.100

R = 0.384

R = 0.385

R = 0.700

FIGURE B-18. SPLINE FIT FOR 2024-T62 SHEET AND PLATE, L-T (M2EG11AB1) 

B-39
TABLE B-12. da/dN-ΔK SPLINE FIT FOR 2024-T62 SHEET AND PLATE, L-T 

(M2EG11AB1) 

ID Code = M2EG11AB1 

R = 0.1000 

da/dN ΔK

2.1948e-07 4.1210 

3.2000e-07 4.9695 

6.0000e-07 6.0992 

1.0000e-06 7.0058 

1.8000e-06 8.1254 

3.2000e-06 9.3701 

6.0000e-06 11.0177 

1.0000e-05 12.7550 

1.8000e-05 15.6337 

3.2000e-05 18.9492 

6.0000e-05 22.9383 

1.0000e-04 26.4748 

1.8000e-04 30.8858 

3.2000e-04 35.5726 

6.0000e-04 41.1287 

1.0000e-03 45.9928 

1.3924e-03 49.3174 

(a) 

ID Code = M2EG11AB1 

R = 0.384 

da/dN ΔK

4.2249e-06 6.9343 

6.0000e-06 7.8788 

1.0000e-05 9.5663 

1.8000e-05 11.6353 

3.2000e-05 13.6142 

6.0000e-05 16.3879 

1.0000e-04 18.8175 

1.8000e-04 21.3611 

3.1543e-04 23.4963 

(b) 

ID Code = M2EG11AB1 

R = 0.385 

da/dN ΔK

2.1979e-06 5.6364 

3.2000e-06 6.4701 

6.0000e-06 8.0071 

1.0000e-05 9.4599 

1.8000e-05 11.4805 

3.2000e-05 13.7988 

6.0000e-05 16.4519 

1.0000e-04 18.6709 

1.8000e-04 21.2781 

3.2000e-04 23.8784 

3.2781e-04 23.9883 

(c) 

ID Code = M2EG11AB1 

R = 0.700 

da/dN ΔK

1.5180e-07 2.6915 

1.8000e-07 2.7754 

3.2000e-07 3.1725 

6.0000e-07 3.8440 

1.0000e-06 4.3601 

1.8000e-06 4.8417 

3.2000e-06 5.6437 

6.0000e-06 7.1096 

1.0000e-05 7.8526 

1.3756e-05 8.2035 

(d) 

B-40
TABLE B-13. MATERIAL DESCRIPTION AND SPECIMEN TESTING INFORMATION 

FOR 2024-T81 SHEET, L-T 

Material ID Code M2EI11AB1 

Alloy Type 2024 Al 

Alloy Condition/HT T81 

Product Form 0.063′′-0.12′′ Sheet 

Test Environments Laboratory Air, Dry Air 

Specimen Types C(T), M(T) 

Crack Orientation L-T 

Specimen Thickness (in.) 0.063-0.125 

Specimen Width (in.) C(T): 5.0 M(T): 6-24 

Yield Strength (ksi) 57-65 

Ultimate Strength (ksi) 70-71 

Cyclic Frequency, Hz 1-25 

Data References Table B-13. 

8 LaSalle, R.M., Rockwell Space Div. Lab. Report LTR 1242-4110, 1975. 

A71 Hudson, C.M., NASA TN D-2743, 1965. 

C82 “Rockwell International, B-1 Program, da/dN Data, Center-Cracked Tension Specimens,” 

Lockheed California Company, Burbank, CA, Report LR25152, Received July 1973, 

Memo from E.W. Cawthorne, July 10, 1973. 

C108 Wolnaski, Z.R., “2024-T81 and -T62 0.125-Inch Sheet Metal Allowables,” General 

Dynamics, Fort Worth Division, Report No. 16 PR853, October 1978. 

B-41
1e-08

1e-07

1e-06

1e-05

0.0001

0.001

0.01

1 10 100

da/dN [in/cycle] 

Delta K [ksi*SQRT(in)] 

R THK REF NASGRO Data ID _____________________________

NASGRO 4.0

EQUATION FIT:

_____________

Smax/SIGo = 0.30 

Alpha = 2.000 

K1c = 22.0

YS = 63.0

Ak = 1.00, Bk = 1.20

Kc = 45.7 (t= 0.100)

DK1 = 0.79

Cth+ = 2.20

Cth- = 0.10

p = 0.250, q = 0.500

C = 0.700E-08

n = 3.300

M2EI11AC01C3

M2EI11AC01B1

M2EI11AC01A3

M2EI11AB01D1

M2EI11AC01A2

M2EI11AC01C2

M2EI11AC01A1

M2EI11AC01C1

M2EI11AB01C1

 0.08 0.100 C82 

 0.08 0.100 C82 

 0.10 0.125 C108

 0.10 0.063 25 

 0.30 0.125 C108

 0.30 0.100 C82 

 0.50 0.125 C108

 0.50 0.100 C82 

 0.76 0.063 A71 

R = 0.080

R = 0.100

R = 0.300

R = 0.500

R = 0.765

FIGURE B-19. NASGRO EQUATION FIT FOR 2024-T81 SHEET, 

L-T (M2EI11AB1) 

B-42
1e-07

1e-06

1e-05

0.0001

0.001

1 10

d

a/d

N [in/c

y

cle]

Delta K [ksi*SQRT(in)] 

R THK REF NASGRO Data ID _____________________________

NASGRO 4.0

WALKER FIT:

___________

C = 0.246E-08

n = 3.376

m+ = 0.750

M2EI11AC01C3

M2EI11AC01B1

M2EI11AC01A3

M2EI11AB01D1

M2EI11AC01A2

M2EI11AC01C2

M2EI11AC01A1

M2EI11AC01C1

M2EI11AB01C1

 0.08 0.100 C82 

 0.08 0.100 C82 

 0.10 0.125 C108

 0.10 0.063 25 

 0.30 0.125 C108

 0.30 0.100 C82 

 0.50 0.125 C108

 0.50 0.100 C82 

 0.76 0.063 A71 

R = 0.080

R = 0.100

R = 0.300

R = 0.500

R = 0.765

FIGURE B-20. WALKER EQUATION FIT FOR 2024-T81 SHEET, 

L-T (M2EI11AB1) 

B-43
1e-07

1e-06

1e-05

0.0001

0.001

0.01

1 10 100

d

a

d/ N [in/c

y

cle]

Delta K [ksi*SQRT(in)] 

R THK REF NASGRO Data ID _____________________________

M2EI11AC01A3

M2EI11AB01D1

M2EI11AC01C2

M2EI11AC01A2

M2EI11AC01A1

M2EI11AC01C1

M2EI11AB01C1

 0.10 0.125 C108

 0.10 0.063 25 

 0.30 0.100 C82 

 0.30 0.125 C108

 0.50 0.125 C108

 0.50 0.100 C82 

 0.76 0.063 A71 

R = 0.100

R = 0.300

R = 0.500

R = 0.765

FIGURE B-21. SPLINE FIT FOR 2024-T81 SHEET, 

L-T (M2EI11AB1) 

B-44
TABLE B-14. da/dN-ΔK SPLINE FIT FOR 2024-T81, L-T (M2EI11AC1) 

ID Code = M2EI11AC1 

R = 0.0800 

da/dN ΔK

A spline fit for R = 0.08 data was 

not done since these data were 

overlapped by R = 0.1 data, and the 

fits ran into each other; 

consequently, a table was not 

developed for R = 0.08. 

(a) 

ID Code = M2EI11AC1 

R = 0.100 

da/dN ΔK

1.5121e-06 5.4828 

1.8000e-06 6.3183 

3.2000e-06 8.1673 

6.0000e-06 10.0740 

1.0000e-05 11.7932 

1.8000e-05 14.1838 

3.2000e-05 16.9242 

6.0000e-05 19.7824 

1.0000e-04 22.1049 

1.8000e-04 24.8411 

3.2000e-04 27.6247 

6.0000e-04 30.8212 

1.0000e-03 33.5613 

1.8000e-03 36.8973 

2.9210e-03 39.8107 

(b) 

ID Code = M2EI11AC1 

R = 0.300 

da/dN ΔK

2.1182e-06 6.1944 

3.2000e-06 6.7855 

6.0000e-06 8.9449 

1.0000e-05 10.8038 

1.8000e-05 12.9153 

3.2000e-05 14.9254 

6.0000e-05 17.2020 

1.0000e-04 19.5218 

1.8000e-04 21.8930 

3.2000e-04 23.7335 

5.2549e-04 25.0611 

(c) 

ID Code = M2EI11AC1 

R = 0.500 

da/dN ΔK

1.3578e-06 5.1642 

1.8000e-06 5.4607 

3.2000e-06 6.3196 

6.0000e-06 7.8112 

1.0000e-05 9.1432 

1.8000e-05 10.4372 

3.2000e-05 11.6590 

6.0000e-05 13.4082 

1.0000e-04 15.0431 

1.8000e-04 16.9024 

3.2000e-04 18.5695 

6.0000e-04 20.2093 

1.0000e-03 21.4259 

1.3373e-03 22.0800 

(d) 

B-45
TABLE B-14. da/dN-ΔK SPLINE FIT FOR 2024-T81, L-T (M2EI11AC1) 

(Continued) 

ID Code = M2EI11AC1 

R = 0.765 

da/dN ΔK

1.4563e-06 4.7973 

1.8000e-06 5.2542 

3.2000e-06 5.9156 

6.0000e-06 7.4386 

1.0000e-05 8.2427 

1.8000e-05 9.0014 

2.7254e-05 9.5280 

(e) 

TABLE B-15. MATERIAL DESCRIPTION AND SPECIMEN TESTING INFORMATION 

FOR 7050-T7451 PLATE, L-T 

Material ID Code M7GJ11AB1 

Alloy Type 7050 Al 

Alloy Condition/HT T7451 

Product Form 1′′-6′′ Plate 

Test Environments Laboratory Air, Dry Air 

Specimen Types C(T), M(T) 

Crack Orientation L-T 

Specimen Thickness (in.) C(T): 0.5-1.0 M(T): 0.18-0.39 

Specimen Width (in.) C(T): 3-6 M(T): 3.9-6.3 

Yield Strength (ksi) 62-68 

Ultimate Strength (ksi) 72-80 

Cyclic Frequency, Hz 6-50 

Data References for Table B-15. 

1 Forman, R.G., Unpublished NASA Johnson Space Center test data. 

108 “Test Data (crack propagation) of 7050 Material,” ref. 4231, LBF, Darmstadt, received 

from L. Schwarmann, MBB Transport, Germany. 

C2 “Fracture Toughness Data Collection, Rockwell International Corporation, from B-1 

Program,” Rockwell International Corporation, Los Angeles, CA, April 1973. 

B-46
1e-09

1e-08

1e-07

1e-06

1e-05

0.0001

0.001

1 10 100

da/dN [in/cycle] 

Delta K [ksi*SQRT(in)] 

R THK REF NASGRO Data ID _____________________________

NASGRO 4.0

EQUATION FIT:

_____________

Smax/SIGo = 0.30 

Alpha = 2.000 

K1c = 32.0

YS = 73.0

Ak = 1.00, Bk = 0.75

Kc = 40.1 (t= 0.500)

DK1 = 0.80

Cth+ = 2.20

Cth- = 0.10

p = 1.000, q = 1.000

C = 0.250E-07

n = 2.500

M7GJ11AC01A3

M7GJ11AB01I1

M7GJ11AB01I2

M7GJ11AB01G1

M7GJ11AB01D1

M7GJ11AB01F1

M7GJ11AC01A1

M7GJ11AB01I3

M7GJ11AB01I4

 0.08 1.000 C2 

 0.10 0.500 1 

 0.40 0.500 1 

 0.50 0.200 108 

 0.50 0.183 108 

 0.50 0.390 108 

 0.50 1.000 C2 

 0.70 0.500 1 

 0.80 0.500 1 

R = 0.080

R = 0.100

R = 0.400

R = 0.500

R = 0.700

R = 0.800

FIGURE B-22. NASGRO EQUATION FIT FOR 7050-T7451, L-T (M7GJ11AC1) 

B-47
1e-08

1e-07

1e-06

1e-05

0.0001

0.001

1 10

d

a

d/ N [in/c

y

cle]

Delta K [ksi*SQRT(in)] 

R THK REF NASGRO Data ID _____________________________

NASGRO 4.0

WALKER FIT:

___________

C = 0.600E-09

n = 3.613

m+ = 0.538

M7GJ11AC01A3

M7GJ11AB01I1

M7GJ11AB01I2

M7GJ11AB01G1

M7GJ11AB01D1

M7GJ11AB01F1

M7GJ11AC01A1

M7GJ11AB01I3

M7GJ11AB01I4

 0.08 1.000 C2 

 0.10 0.500 1 

 0.40 0.500 1 

 0.50 0.200 108 

 0.50 0.183 108 

 0.50 0.390 108 

 0.50 1.000 C2 

 0.70 0.500 1 

 0.80 0.500 1 

R = 0.080

R = 0.100

R = 0.400

R = 0.500

R = 0.700

R = 0.800

FIGURE B-23. WALKER EQUATION FIT FOR 7050-T7451 PLATE, L-T (M7GJ11AB1) 

B-48
1e-08

1e-07

1e-06

1e-05

0.0001

0.001

1 10

d

a/d

N [in/c

y

cle]

Delta K [ksi*SQRT(in)] 

R THK REF NASGRO Data ID _____________________________

M7GJ11AB01I1

M7GJ11AB01I2

M7GJ11AB01G1

M7GJ11AB01D1

M7GJ11AB01F1

M7GJ11AC01A1

M7GJ11AB01I3

M7GJ11AB01I4

 0.10 0.500 1 

 0.40 0.500 1 

 0.50 0.200 108 

 0.50 0.183 108 

 0.50 0.390 108 

 0.50 1.000 C2 

 0.70 0.500 1 

 0.80 0.500 1 

R = 0.100

R = 0.400

R = 0.500

R = 0.700

R = 0.800

FIGURE B-24. SPLINE FIT FOR 7050-T7451 PLATE, L-T (M7GJ11AB1) 

B-49
TABLE B-16. da/dN-ΔK SPLINE FIT FOR 7050-T7451, L-T (M7GJ11AC1) 

ID Code = M7GJ11AC1 

R = 0.0800

da/dN ΔK

8.1560e-07 6.8865 

1.0000e-06 7.1373 

1.8000e-06 8.5740 

3.2000e-06 11.2303 

6.0000e-06 12.6427 

1.0000e-05 13.7598 

1.8000e-05 18.5817 

3.2000e-05 21.4952 

6.0000e-05 23.1962 

(a) 

ID Code = M7GJ11AC1 

R = 0.100 

da/dN ΔK

5.8598e-08 3.9084 

6.0000e-08 3.9241 

1.0000e-07 4.2994 

1.8000e-07 4.8354 

3.2000e-07 5.5089 

6.0000e-07 6.4799 

1.0000e-06 7.5038 

1.8000e-06 8.9768 

3.2000e-06 10.6903 

6.0000e-06 13.0444 

1.0000e-05 15.4584 

1.8000e-05 18.3955 

3.2000e-05 21.1440 

6.0000e-05 23.9296 

1.0000e-04 26.0453 

1.8000e-04 28.3481 

2.6886e-04 29.8538 

(b) 

ID Code = M7GJ11AC1 

R = 0.400 

da/dN ΔK

5.8374e-08 2.5410 

6.0000e-08 2.5675 

1.0000e-07 3.0591 

1.8000e-07 3.6212 

3.2000e-07 4.1691 

6.0000e-07 4.7674 

1.0000e-06 5.3145 

1.8000e-06 6.1336 

3.2000e-06 7.2176 

6.0000e-06 8.8385 

1.0000e-05 10.6337 

1.8000e-05 13.1499 

3.2000e-05 15.5498 

4.3702e-05 16.7494 

(c) 

ID Code = M7GJ11AC1 

R = 0.500 

da/dN ΔK

8.9219e-07 4.7534 

1.0000e-06 4.8525 

1.8000e-06 5.4633 

3.2000e-06 6.2946 

6.0000e-06 7.6432 

1.0000e-05 9.2110 

1.8000e-05 11.4217 

3.2000e-05 13.7010 

6.0000e-05 16.4040 

1.0000e-04 18.8969 

1.8000e-04 22.2837 

3.2000e-04 26.4682 

3.2064e-04 26.4850 

(d) 

B-50
TABLE B-16. da/dN-ΔK SPLINE FIT FOR 7050-T7451, L-T (M7GJ11AC1) 

(Continued) 

ID Code = M7GJ11AC1 

R = 0.700 

da/dN ΔK

5.8414e-08 1.9011 

6.0000e-08 1.9119 

1.0000e-07 2.2139 

1.8000e-07 2.8924 

3.2000e-07 3.3723 

6.0000e-07 3.8130 

1.0000e-06 4.2446 

1.8000e-06 4.8279 

3.2000e-06 5.4787 

5.4116e-06 6.1235 

(e) 

ID Code = M7GJ11AC1 

R = 0.800 

da/dN ΔK

6.3591e-08 1.7701 

1.0000e-07 2.0983 

1.8000e-07 2.5583 

3.2000e-07 2.9669 

6.0000e-07 3.3785 

1.0000e-06 3.8713 

1.8000e-06 4.7429 

3.2000e-06 5.5754 

3.9566e-06 5.8345 

(f) 

B-51
TABLE B-17. MATERIAL DESCRIPTION AND SPECIMEN TESTING INFORMATION 

FOR 7075-T651 PLATE, L-T 

Material ID Code M7HB11AB1 

Alloy Type 7075 Al 

Alloy Condition/HT T651 

Product Form 1′′-5′′ Plate 

Test Environments Laboratory Air 

Specimen Types C(T), M(T), SE(B) 

Crack Orientation L-T 

Specimen Thickness (in.) C(T): 0.2 M(T): 0.15-0.5 SE(B): 0.2 

Specimen Width (in.) C(T): 3.0 M(T): 4.0 SE(B): 1.5 

Yield Strength (ksi) 74-80 

Ultimate Strength (ksi) 75-87 

Cyclic Frequency, Hz 0.1-30 

Data References for Table B-17. 

29 Kathiresan, K., et al., AFWAL-TR-84-3080, 1984. 

367 Henkener, J.A., “The Fatigue Crack Growth Behavior of an Experimental Ternary Al2.6Li-0.09Zr Alloy,” M.S. Thesis, School of Aeronautics and Astronautics, Purdue 

University, December 1989. 

368 Walker, K.F., “The Effect on Fatigue Crack Growth Under Spectrum Loading of an 

Imposed “g” Limit,” M.S. Thesis, School of Aeronautics and Astronautics, Purdue 

University, December 1987. 

C92 FCGR Data Sheets on Aluminum Alloys 7075-T651, -T6510, -T7351, T73510, Plates, 

Bars, and Extrusions, received from R.J. Bucci, Alcoa Laboratories, August 1982. 

C111 Garland, K., et al., “Evaluation of Stress Level Effects Under Plane Stress and Plane 

Strain Conditions,” McDonnell Aircraft Company, St. Louis, MO, Report No. TR 301-

346, TM 256-5597, July 1979. 

B-52
1e-08

1e-07

1e-06

1e-05

0.0001

0.001

0.01

1 10 100

da/dN [in/cycle] 

Delta K [ksi*SQRT(in)] 

R THK REF NASGRO Data ID _____________________________

NASGRO 4.0

EQUATION FIT:

_____________

Smax/SIGo = 0.30 

Alpha = 2.000 

K1c = 28.0

YS = 75.0

Ak = 0.75, Bk = 2.00

Kc = 49.9 (t= 0.450)

DK1 = 0.70

Cth+ = 1.30

Cth- = 0.10

p = 0.500, q = 1.000

C = 0.300E-07

n = 2.800

M7HB11AB01A2

M7HB11AB01D1

M7HB11AB01C1

M7HB11AB01I1

M7HB11AB01E2

M7HB11AB01J2

M7HB11AB01H2

M7HB11AB01G1

M7HB11AB01H1

M7HB11AB01A1

M7HB11AB01E1

M7HB11AB01J1

 0.02 0.250 C112

 0.02 0.500 C111

 0.02 0.150 C111

 0.10 0.200 368 

 0.10 0.500 29 

 0.10 0.200 367 

 0.10 0.500 29 

 0.33 0.250 C92 

 0.50 0.500 29 

 0.50 0.250 C112

 0.50 0.500 29 

 0.75 0.200 367 

R = 0.020

R = 0.100

R = 0.330

R = 0.500

R = 0.750

FIGURE B-25. NASGRO EQUATION FIT FOR 7075-T651 PLATE, L-T (M7HB11AB1) 

B-53
1e-06

1e-05

0.0001

0.001

1 10

d

a

d/ N [in/c

y

cle]

Delta K [ksi*SQRT(in)] 

R THK REF NASGRO Data ID _____________________________

NASGRO 4.0

WALKER FIT:

___________

C = 0.130E-07

n = 2.791

m+ = 0.650

M7HB11AB01A2

M7HB11AB01D1

M7HB11AB01C1

M7HB11AB01I1

M7HB11AB01E2

M7HB11AB01J1

M7HB11AB01H2

M7HB11AB01G1

M7HB11AB01H1

M7HB11AB01A1

M7HB11AB01E1

M7HB11AB01J2

 0.02 0.250 C112

 0.02 0.500 C111

 0.02 0.150 C111

 0.10 0.200 368 

 0.10 0.500 29 

 0.10 0.200 367 

 0.10 0.500 29 

 0.33 0.250 C92 

 0.50 0.500 29 

 0.50 0.250 C112

 0.50 0.500 29 

 0.75 0.200 367 

R = 0.020

R = 0.100

R = 0.330

R = 0.500

R = 0.750

FIGURE B-26. WALKER EQUATION FIT FOR 7075-T651 PLATE, L-T (M7HB11AB1) 

B-54
1e-06

1e-05

0.0001

0.001

0.01

1 10 100

d

a

d/ N [in/c

y

cle]

Delta K [ksi*SQRT(in)] 

R THK REF NASGRO Data ID _____________________________

M7HB11AB01A2

M7HB11AB01D1

M7HB11AB01C1

M7HB11AB01I1

M7HB11AB01E2

M7HB11AB01J1

M7HB11AB01H2

M7HB11AB01G1

M7HB11AB01H1

M7HB11AB01A1

M7HB11AB01E1

M7HB11AB01J2

 0.02 0.250 C112

 0.02 0.500 C111

 0.02 0.150 C111

 0.10 0.200 368 

 0.10 0.500 29 

 0.10 0.200 367 

 0.10 0.500 29 

 0.33 0.250 C92 

 0.50 0.500 29 

 0.50 0.250 C112

 0.50 0.500 29 

 0.75 0.200 367 

R = 0.020

R = 0.100

R = 0.330

R = 0.500

R = 0.750

FIGURE B-27. SPLINE FIT FOR 7075-T651 PLATE, L-T (M7HB11AB1) 

B-55
TABLE B-18. da/dN-ΔK SPLINE FIT FOR 7075-T651 PLATE, L-T (M7HB11AB1) 

ID Code = M7HB11AB1 

R = 0.0200 

da/dN ΔK

1.5807e-06 6.5766 

1.8000e-06 6.6888 

3.2000e-06 7.3231 

6.0000e-06 8.5829 

1.0000e-05 10.8582 

1.8000e-05 13.8534 

3.2000e-05 16.7731 

6.0000e-05 20.1339 

1.0000e-04 23.0400 

1.8000e-04 26.2657 

3.2000e-04 29.1962 

6.0000e-04 32.2217 

1.0000e-03 34.7632 

1.8000e-03 37.9747 

3.2000e-03 41.7090 

6.0000e-03 47.4713 

7.0500e-03 49.7737 

(a) 

ID Code = M7HB11AB1 

R = 0.100 

da/dN ΔK

1.9393e-06 5.9979 

3.2000e-06 6.5679 

6.0000e-06 7.6743 

1.0000e-05 9.2446 

1.8000e-05 11.7065 

3.2000e-05 14.3709 

6.0000e-05 18.4718 

1.0000e-04 22.0157 

1.8000e-04 25.8284 

3.2000e-04 29.3833 

6.0000e-04 33.0371 

1.0000e-03 35.6039 

1.8000e-03 38.1755 

3.2000e-03 40.3990 

6.0000e-03 42.5860 

1.0000e-02 44.2216 

1.2814e-02 44.9780 

(b) 

ID Code = M7HB11AB1 

R = 0.330 

da/dN ΔK

2.7318e-06 5.8344 

3.2000e-06 6.1088 

6.0000e-06 7.2824 

1.0000e-05 8.5283 

1.8000e-05 10.7929 

3.2000e-05 13.3698 

4.3040e-05 14.6218 

(c) 

B-56
TABLE B-18. da/dN-ΔK SPLINE FIT FOR 7075-T651 PLATE, 

L-T (M7HB11AB1) (Continued) 

ID Code = M7HB11AB1 

R = 0.500 

da/dN ΔK

1.2917e-06 4.1783 

1.8000e-06 4.4434 

3.2000e-06 5.1235 

6.0000e-06 6.2293 

1.0000e-05 7.3569 

1.8000e-05 9.5381 

3.2000e-05 11.7040 

6.0000e-05 13.5667 

1.0000e-04 14.7245 

1.8000e-04 15.9835 

3.2000e-04 17.5284 

6.0000e-04 19.3648 

1.0000e-03 20.7486 

1.8000e-03 22.1482 

2.7095e-03 23.0144 

(d) 

ID Code = M7HB11AB1 

R = 0.750 

da/dN ΔK

1.3468e-06 3.8371 

1.8000e-06 4.0614 

3.2000e-06 4.7505 

6.0000e-06 5.7897 

1.0000e-05 6.9182 

1.8000e-05 8.2688 

3.2000e-05 10.0100 

5.1797e-05 11.4815 

(e) 

B-57
TABLE B-19. MATERIAL DESCRIPTION AND SPECIMEN TESTING INFORMATION 

FOR 7075-T7351 PLATE, L-T 

Material ID Code M7HH11AB1 

Alloy Type 7075 Al 

Alloy Condition/HT T7351 

Product Form 0.4′′-5.0′′ Plate 

Test Environments Laboratory Air, High-Humidity Air 

Specimen Types C(T), M(T) 

Crack Orientation L-T 

Specimen Thickness (in.) C(T): 0.25-0.5 M(T): 0.18-0.50 

Specimen Width (in.) C(T): 2-5 M(T): 4-7 

Yield Strength (ksi) 60-64 

Ultimate Strength (ksi) 72-74 

Cyclic Frequency, Hz 0.1-40 

Data References for Table B-19. 

23 LaSalle, R.M., Rockwell Space Div. Lab. Report LTR 1242-4150, 1977. 

B218 Liu, A.F., et al., “Effect of Multiaxial Loading on Crack Growth,” Vol. I & II, AFFDLTR-78-175, 1978. 

C39 Garland, K., et al., “Evaluation of the Effect of Material Cyclic Softening and Hardening 

on Crack Initiation Life and Crack Growth, with and without Overloads, as a Function of 

Stress Ratio,” McDonnell Aircraft Co., St. Louis, MO, April 1978. 

C92 FCGR Data Sheets on Aluminum Alloy 7075-T651, T6510 T7351, T73510, Plates, Bars, 

and Extrusions; Received from R.J. Bucci, Alcoa Laboratories, August 1982. 

C103 Ruff, P.E., et al., “Development of Mil-Hdbk-5 Design Allowable Properties and Fatigue 

Crack-Propagation Data for Several Aerospace Materials,” Battelle Laboratories, 

Columbus, OH, AFML-TR-77-162, 1977. 

C114 Chanani, G.R., et al., “Methodology for Evaluation of Fatigue Crack-Growth Resistance 

of Aluminum Alloys Under Spectrum Loading,” Northrop Corp., Hawthorne, CA, 

Contract No. N00019-80-C-0427, 1982. 

B-58
1e-09

1e-08

1e-07

1e-06

1e-05

0.0001

0.001

0.01

1 10 100

d

a

d/ N [in/c

y

cle]

Delta K [ksi*SQRT(in)] 

R THK REF NASGRO Data ID _____________________________

NASGRO 4.0

EQUATION FIT:

_____________

Smax/SIGo = 0.30 

Alpha = 2.000 

K1c = 32.0

YS = 63.0

Ak = 1.00, Bk = 1.00

Kc = 53.8 (t= 0.400)

DK1 = 0.70

Cth+ = 2.00

Cth- = 0.10

p = 0.500, q = 0.500

C = 0.220E-07

n = 2.900

M7HH11AB01A3

M7HH11AB01Q1

M7HH11AB01H1

M7HH11AB01I1

M7HH11AB01P1

M7HH11AD01C3

M7HH11AD01A2

M7HH11AB01A1

M7HH11AD01C1

M7HH11AD01B1

M7HH11AB01P2

M7HH11AD01A1

-1.00 0.250 C39 

-1.00 0.390 E5 

 0.10 0.500 23 

 0.10 0.180 B218

 0.10 0.390 E5 

 0.10 0.500 C103

 0.33 0.250 C92 

 0.50 0.250 C39 

 0.50 0.500 C103

 0.50 0.500 C103

 0.50 0.390 E5 

 0.80 0.250 C92 

R = -1.000

R = 0.100

R = 0.330

R = 0.500

R = 0.800

FIGURE B-28. NASGRO EQUATION FIT FOR 7075-T7351 PLATE, L-T (M7HH11AB1) 

WITH POSITIVE AND NEGATIVE R VALUES 

B-59
1e-08

1e-07

1e-06

1e-05

0.0001

0.001

0.01

1 10

da/dN [in/cycle] 

Delta K [ksi*SQRT(in)] 

R THK REF NASGRO Data ID _____________________________

NASGRO 4.0

WALKER FIT:

___________

C = 0.451E-08

n = 3.157

m+ = 0.624

M7HH11AD01C3

M7HH11AB01H1

M7HH11AB01I1

M7HH11AD01D1

M7HH11AB01P1

M7HH11AD01G1

M7HH11AD01A2

M7HH11AB01P2

M7HH11AB01A1

M7HH11AD01C1

M7HH11AD01B1

M7HH11AD01A1

 0.10 0.500 C103

 0.10 0.500 23 

 0.10 0.180 B218

 0.10 0.500 C103

 0.10 0.390 E5 

 0.33 0.250 C114

 0.33 0.250 C92 

 0.50 0.390 E5 

 0.50 0.250 C39 

 0.50 0.500 C103

 0.50 0.500 C103

 0.80 0.250 C92 

R = 0.100

R = 0.330

R = 0.500

R = 0.800

FIGURE B-29a. WALKER EQUATION FIT FOR 7075-T7351 PLATE, L-T (M7HH11AB1) 

WITH POSITIVE R VALUES 

B-60
1e-06

1e-05

0.0001

0.001

10 100

d

a

d/ N [in/c

y

cle]

Delta K [ksi*SQRT(in)] 

R THK REF NASGRO Data ID _____________________________

NASGRO 4.0

WALKER FIT:

___________

C = 0.451E-08

n = 3.157

m- = 0.071

M7HH11AB01A3

M7HH11AB01Q1

-1.00 0.250 C39 

-1.00 0.390 E5 

R = -1.000

FIGURE B-29b. WALKER EQUATION FIT FOR 7075-T7351 PLATE, L-T (M7HH11AB1) 

WITH NEGATIVE R VALUE 

B-61
1e-08

1e-07

1e-06

1e-05

0.0001

0.001

0.01

1 10 100

d

a

d/ N [in/c

y

cle]

Delta K [ksi*SQRT(in)] 

R THK REF NASGRO Data ID _____________________________

M7HH11AB01A3

M7HH11AB01Q1

M7HH11AB01H1

M7HH11AB01I1

M7HH11AD01C3

M7HH11AB01P1

M7HH11AD01A2

M7HH11AB01P2

M7HH11AD01B1

M7HH11AB01A1

M7HH11AD01C1

-1.00 0.250 C39 

-1.00 0.390 E5 

 0.10 0.500 23 

 0.10 0.180 B218

 0.10 0.500 C103

 0.10 0.390 E5 

 0.33 0.250 C92 

 0.50 0.390 E5 

 0.50 0.500 C103

 0.50 0.250 C39 

 0.50 0.500 C103

R = -1.000

R = 0.100

R = 0.330

R = 0.500

FIGURE B-30. SPLINE FIT FOR 7075-T7351 PLATE, L-T (M7HH11AB1) WITH POSITIVE 

AND NEGATIVE R VALUES 

B-62
TABLE B-20. da/dN-ΔK SPLINE FIT FOR 7075-T7351 PLATE, L-T (M7HH11AB1) 

ID Code = M7HH11AB1 

R = -1.0000 

da/dN ΔK

1.7090e-06 9.6161 

1.8000e-06 10.6269 

3.2000e-06 13.6988 

6.0000e-06 17.9786 

1.0000e-05 23.1466 

1.8000e-05 28.9537 

3.2000e-05 35.2654 

6.0000e-05 41.6655 

1.0000e-04 47.4594 

1.8000e-04 54.9489 

3.2000e-04 63.0452 

6.0000e-04 72.3735 

1.0000e-03 80.2754 

1.8000e-03 89.7607 

2.6027e-03 95.9401 

(a) 

ID Code = M7HH11AB1 

R = 0.100 

da/dN ΔK

2.3134e-07 4.0738 

3.2000e-07 4.3388 

6.0000e-07 4.9391 

1.0000e-06 5.5348 

1.8000e-06 6.3837 

3.2000e-06 7.4536 

6.0000e-06 9.0343 

1.0000e-05 10.8263 

1.8000e-05 13.8977 

3.2000e-05 17.6080 

6.0000e-05 21.4984 

1.0000e-04 24.6793 

1.8000e-04 28.4276 

3.2000e-04 32.2244 

6.0000e-04 36.5457 

1.0000e-03 40.2063 

1.8000e-03 44.5978 

2.9807e-03 48.5289 

(b) 

ID Code = M7HH11AB1 

R = 0.330

da/dN ΔK

6.4121e-08 2.5119 

1.0000e-07 2.7960 

1.8000e-07 3.1445 

3.2000e-07 3.5413 

6.0000e-07 4.2106 

1.0000e-06 4.7130 

1.8000e-06 5.3223 

3.2000e-06 6.2131 

6.0000e-06 7.6060 

1.0000e-05 9.0726 

1.8000e-05 11.6528 

3.2000e-05 14.6955 

6.0000e-05 18.2230 

1.0000e-04 20.2243 

1.8000e-04 22.0872 

2.8314e-04 23.3346 

(c) 

ID Code = M7HH11AB1 

R = 0.500 

da/dN ΔK

1.0140e-07 1.8408 

1.8000e-07 2.6025 

3.2000e-07 2.9454 

6.0000e-07 3.3527 

1.0000e-06 3.7879 

1.8000e-06 4.5449 

3.2000e-06 5.5883 

6.0000e-06 7.2156 

1.0000e-05 8.8993 

1.8000e-05 10.9133 

3.2000e-05 13.1654 

6.0000e-05 16.3186 

1.0000e-04 19.1591 

1.8000e-04 22.2397 

3.2000e-04 25.5060 

6.0000e-04 29.8414 

9.6208e-04 34.3558 

(d) 

B-63
TABLE B-20. da/dN-ΔK SPLINE FIT FOR 7075-T7351 PLATE, 

L-T (M7HH11AB1) (Continued) 

ID Code = M7HH11AB1 

R = 0.800 

da/dN ΔK

A spline fit for R = 0.800 data was 

not done because of considerable 

scatter in them; consequently, a table 

was not developed for R = 0.800. 

(e) 

TABLE B-21. MATERIAL DESCRIPTION AND SPECIMEN TESTING INFORMATION 

FOR 7475-T7351 PLATE, L-T 

Material ID Code M7TF11AB1 

Alloy Type 7475 Al 

Alloy Condition/HT T7351 

Product Form 1.5′′-3′′ Plate 

Test Environments Laboratory Air 

Specimen Types C(T), M(T) 

Crack Orientation L-T 

Specimen Thickness (in.) C(T): 0.5-0.75 M(T): 0.2-0.3 

Specimen Width (in.) C(T): 0.5-5.0 M(T): 6.3-12.0 

Yield Strength (ksi) 60-67 

Ultimate Strength (ksi) 69-75 

Cyclic Frequency, Hz 1-20 

Data References for Table B-21. 

140 Zhang, S., et al., “Crack Propagation Studies on Al 7475 on the Basis of Constant 

Amplitude and Selective Amplitude Loading Histories,” Fatigue Fract Engr Matr Struct, 

Vol. 10, No. 4, 1987, pp. 315-332. 

361 Larson, B.F., “C-17 Material Specimen Tests for Fracture Mechanics Data,” Phase I, Lot 

1 Aluminum Alloys. 

B177 Cervay, R.R., AFML-TR-75-20, 1975. 

C77 Cervay, R.R., “Engineering Design Data for Aluminum Alloy 7475 in the T761 and T61 

Condition,” Report AFML-TR-72-173, UDRI, Dayton OH, Contract F33615-71-C-1054, 

September 1972. 

B-64
1e-08

1e-07

1e-06

1e-05

0.0001

0.001

0.01

1 10 100

d

a/d

N [in/c

y

cle]

Delta K [ksi*SQRT(in)] 

R THK REF NASGRO Data ID _____________________________

NASGRO 4.0

EQUATION FIT:

_____________

Smax/SIGo = 0.30 

Alpha = 2.000 

K1c = 40.0

YS = 61.0

Ak = 1.00, Bk = 2.00

Kc = 114.0 (t= 0.300)

DK1 = 0.70

Cth+ = 2.40

Cth- = 0.10

p = 0.500, q = 1.000

C = 0.400E-07

n = 2.600

M7TF11AB01H1

M7TF11AB01D1

M7TF11AB01G1

M7TF11AB01A3

M7TF11AB01J3

M7TF11AB01J2

M7TF11AB01J1

M7TF11AB01M1

 0.05 0.200 361 

 0.10 0.750 B177

 0.10 0.650 C77 

 0.10 0.748 C109

 0.10 0.500 361 

 0.40 0.500 361 

 0.80 0.500 361 

 0.80 0.315 140 

R = 0.050

R = 0.100

R = 0.400

R = 0.600

R = 0.800

FIGURE B-31a. NASGRO EQUATION FIT FOR 7475-T7351 PLATE, L-T (M7TF11AB1) 

WITH POSITIVE R VALUES 

B-65
1e-08

1e-07

1e-06

1e-05

0.0001

0.001

0.01

0.1

1 10 100

da/dN [in/cycle] 

Delta K [ksi*SQRT(in)] 

R THK REF NASGRO Data ID _____________________________

NASGRO 4.0

EQUATION FIT:

_____________

Smax/SIGo = 0.30 

Alpha = 2.000 

K1c = 40.0

YS = 61.0

Ak = 1.00, Bk = 2.00

Kc = 114.0 (t= 0.300)

DK1 = 0.70

Cth+ = 2.40

Cth- = 0.10

p = 0.500, q = 1.000

C = 0.400E-07

n = 2.600

M7TF11AB01M8

M7TF11AB01H2

M7TF11AB01M6

-3.33 0.315 140 

-1.00 0.200 361 

-0.33 0.315 140 

R = -3.300

R = -1.000

R = -0.330

FIGURE B-31b. NASGRO EQUATION FIT FOR 7475-T7351 PLATE, L-T (M7TF11AB1) 

WITH NEGATIVE R VALUES 

B-66
1e-08

1e-07

1e-06

1e-05

0.0001

0.001

1 10

da/dN [in/cycle] 

Delta K [ksi*SQRT(in)] 

R THK REF NASGRO Data ID _____________________________

NASGRO 4.0

WALKER FIT:

___________

C = 0.502E-09

n = 3.816

m+ = 0.618

M7TF11AB01A3

M7TF11AB01D1

M7TF11AB01G1

M7TF11AB01J3

M7TF11AB01J2

M7TF11AB01M2

M7TF11AB01J1

M7TF11AB01M1

 0.10 0.748 C109

 0.10 0.750 B177

 0.10 0.650 C77 

 0.10 0.500 361 

 0.40 0.500 361 

 0.60 0.315 140 

 0.80 0.500 361 

 0.80 0.315 140 

R = 0.100

R = 0.400

R = 0.600

R = 0.800

FIGURE B-32a. WALKER EQUATION FIT FOR 7475-T7351 PLATE, L-T (M7TF11AB1) 

WITH POSITIVE R VALUES 

B-67
1e-06

1e-05

0.0001

0.001

10 100

d

a

d/ N [in/c

y

cle]

Delta K [ksi*SQRT(in)] 

R THK REF NASGRO Data ID _____________________________

NASGRO 4.0

WALKER FIT:

___________

C = 0.563E-09

n = 3.781

m- = 0.067

M7TF11AB01M8

M7TF11AB01H2

M7TF11AB01M6

-3.33 0.315 140 

-1.00 0.200 361 

-0.33 0.315 140 

R = -3.330

R = -1.000

R = -0.330

FIGURE B-32b. WALKER EQUATION FIT FOR 7475-T7351 PLATE, L-T (M7TF11AB1) 

WITH NEGATIVE R VALUES 

B-68
1e-08

1e-07

1e-06

1e-05

0.0001

0.001

0.01

1 10 100

da/dN [in/cycle] 

Delta K [ksi*SQRT(in)] 

R THK REF NASGRO Data ID _____________________________

M7TF11AB01H1

M7TF11AB01A3

M7TF11AB01G1

M7TF11AB01D1

M7TF11AB01J3

M7TF11AB01J2

M7TF11AB01M2

M7TF11AB01J1

M7TF11AB01M1

 0.05 0.200 361 

 0.10 0.748 C109

 0.10 0.650 C77 

 0.10 0.750 B177

 0.10 0.500 361 

 0.40 0.500 361 

 0.60 0.315 140 

 0.80 0.500 361 

 0.80 0.315 140 

R = 0.050

R = 0.100

R = 0.400

R = 0.600

R = 0.800

FIGURE B-33a. SPLINE FIT FOR 7475-T7351 PLATE, L-T (M7TF11AB1) 

WITH POSITIVE R VALUES 

B-69
1e-08

1e-07

1e-06

1e-05

0.0001

0.001

0.01

1 10 100

d

a

d/ N [in/c

y

cle]

Delta K [ksi*SQRT(in)] 

R THK REF NASGRO Data ID _____________________________

M7TF11AB01M8

M7TF11AB01H2

M7TF11AB01M6

-3.33 0.315 140 

-1.00 0.200 361 

-0.33 0.315 140 

R = -3.330

R = -1.000

R = -0.330

FIGURE B-33b. SPLINE FIT FOR 7475-T7351 PLATE, L-T (M7TF11AB1) WITH 

NEGATIVE R VALUES 

B-70
TABLE B-22a. da/dN-ΔK SPLINE FIT FOR 7475-T7351 PLATE, L-T WITH POSITIVE 

R VALUES (M7TF11AB1) 

ID Code = M7TF11AB1 

R = 0.0500

da/dN ΔK

6.0976e-05 25.5859 

1.0000e-04 29.1291 

1.8000e-04 34.3384 

3.2000e-04 41.9551 

6.0000e-04 50.5506 

1.0000e-03 57.7136 

1.8000e-03 66.1325 

3.2000e-03 74.9027 

6.0000e-03 82.0848 

7.6571e-03 84.3335 

(a) 

ID Code = M7TF11AB1 

R = 0.100

da/dN ΔK

1.1281e-07 3.7757 

1.8000e-07 4.4395 

3.2000e-07 5.5572 

6.0000e-07 6.6805 

1.0000e-06 7.5536 

1.8000e-06 8.5494 

3.2000e-06 9.5128 

6.0000e-06 10.5654 

1.0000e-05 11.7300 

1.8000e-05 14.0297 

3.2000e-05 16.9336 

6.0000e-05 21.4500 

1.0000e-04 26.1917 

1.3699e-04 28.2488 

(b) 

ID Code = M7TF11AB1 

R = 0.400

da/dN ΔK

2.1311e-06 6.3241 

2.5336e-06 6.6432 

3.1203e-06 6.9783 

3.9647e-06 7.3304 

4.9129e-06 7.7002 

5.8720e-06 8.0886 

6.8358e-06 8.4967 

7.8424e-06 8.9253 

8.8749e-06 9.3756 

(c) 

ID Code = M7TF11AB1 

R = 0.600

da/dN ΔK

7.7646e-07 3.8726 

1.0000e-06 4.0583 

1.8000e-06 4.6362 

3.2000e-06 5.6268 

6.0000e-06 7.5125 

1.0000e-05 8.8901 

1.8000e-05 10.8345 

3.2000e-05 13.3851 

6.0000e-05 15.9949 

8.1597e-05 17.1002 

(d) 

ID Code = M7TF11AB1 

R = 0.800

da/dN ΔK

1.3987e-06 3.6559 

1.8000e-06 3.9536 

3.2000e-06 5.0058 

6.0000e-06 6.3986 

1.0000e-05 7.5841 

1.8000e-05 9.0106 

3.2000e-05 10.9275 

4.6122e-05 11.8850 

(e) 

B-71
TABLE B-22b. da/dN-ΔK SPLINE FIT FOR 7475-T7351 PLATE, L-T WITH 

NEGATIVE R VALUES (M7TF11AB1) 

ID Code = M7TF11AB1 

R = -3.330

da/dN ΔK

1.5109e-06 26.2422 

1.8000e-06 28.3202 

3.2000e-06 34.7824 

6.0000e-06 42.4357 

1.0000e-05 50.0292 

1.8000e-05 61.7240 

3.2000e-05 74.0434 

6.0000e-05 89.4125 

1.0000e-04 105.2751 

1.4422e-04 120.7814 

(a) 

ID Code = M7TF11AB1 

R = -1.000

da/dN ΔK

8.6815e-08 6.9024 

1.0000e-07 7.1356 

1.8000e-07 8.1828 

3.2000e-07 9.3438 

6.0000e-07 10.7922 

1.0000e-06 12.1310 

1.8000e-06 13.8829 

3.2000e-06 15.8568 

6.0000e-06 18.3672 

1.0000e-05 20.8197 

1.8000e-05 25.4103 

3.2000e-05 34.5305 

6.0000e-05 47.3349 

1.0000e-04 55.7073 

1.8000e-04 66.0374 

3.2000e-04 78.5636 

6.0000e-04 93.8108 

1.0000e-03 106.4446 

1.8000e-03 120.6893 

3.2000e-03 134.1643 

6.0000e-03 148.3574 

8.6206e-03 156.3148 

(b) 

ID Code = M7TF11AB1 

R = -0.330

da/dN ΔK

2.6351e-06 8.1470 

3.2000e-06 8.8192 

6.0000e-06 11.6842 

1.0000e-05 14.6625 

1.8000e-05 18.3595 

3.2000e-05 23.1285 

6.0000e-05 29.9840 

1.0000e-04 35.4084 

1.6771e-04 40.3645 

(c) 

B-72
TABLE B-23. MATERIAL DESCRIPTION AND SPECIMEN TESTING INFORMATION 

FOR 7475-T761 CLAD SHEET, L-T 

Material ID Code M7TI01AB1 

Alloy Type 7475 Al 

Alloy Condition/HT T761 

Product Form 0.04′′-0.09′′ Clad Sheet 

Test Environments Laboratory Air, High-Humidity Air 

Specimen Types C(T), M(T) 

Crack Orientation L-T 

Specimen Thickness (in.) C(T): 0.09 M(T): 0.04-0.125 

Specimen Width (in.) C(T): 1.5 M(T): 6-36 

Yield Strength (ksi) 60-65 

Ultimate Strength (ksi) 69-73 

Cyclic Frequency, Hz 2-30 

Data References for Table B-23. 

112 Data of 2014-T6, 7475-T61, 2024-T62, 7475-T761, 2124-T851, 7475-T7351 - Materials 

received from L. Schwarmann, MBB Transport, Germany. 

362 Kahandal, R.S., “C-17 Material Specimen Tests for Fracture Mechanics Data,” Phase I, 

Lot 2 Aluminum Alloys. 

B266 Cervay, R.R., AFML-TR-72-173, 1972. 

C80 McCarty, J.E., et al., “Materials Fracture Data From the Advanced Metallic Structures.” 

B-73
1e-08

1e-07

1e-06

1e-05

0.0001

0.001

1 10 100

d

a

d/ N [in/c

y

cle]

Delta K [ksi*SQRT(in)] 

R THK REF NASGRO Data ID _____________________________

NASGRO 4.0

EQUATION FIT:

_____________

Smax/SIGo = 0.30 

Alpha = 2.000 

K1c = 40.0

YS = 63.0

Ak = 1.00, Bk = 1.20

Kc = 87.5 (t= 0.100)

DK1 = 0.60

Cth+ = 1.50

Cth- = 0.10

p = 1.000, q = 1.000

C = 0.500E-07

n = 2.400

M7TI01AD01B2

M7TI01AD01A2

M7TI01AB01A3

M7TI11AB01F1

M7TI01AB01B3

M7TI11AB01A1

M7TI01AD01A1

M7TI01AD01B1

M7TI11AB01E1

M7TI11AB01C1

M7TI11AB01D1

M7TI11AB01B1

M7TI01AB01B1

 0.05 0.040 C80 

 0.05 0.040 C80 

 0.10 0.074 361 

 0.10 0.090 C77 

 0.10 0.075 362 

 0.10 0.090 B266

 0.25 0.040 C80 

 0.25 0.040 C80 

 0.38 0.039 112 

 0.38 0.126 112 

 0.38 0.079 112 

 0.38 0.197 112 

 0.80 0.075 362 

R = 0.050

R = 0.100

R = 0.250

R = 0.385

R = 0.800

FIGURE B-34. NASGRO EQUATION FIT FOR 7475-T761 CLAD SHEET, 

L-T (M7TI01AB1) 

B-74
1e-06

1e-05

0.0001

1 10

da/dN [in/cycle] 

Delta K [ksi*SQRT(in)] 

R THK REF NASGRO Data ID _____________________________

NASGRO 4.0

WALKER FIT:

___________

C = 0.192E-07

n = 2.570

m+ = 0.747

M7TI01AD01B2

M7TI01AD01A2

M7TI01AB01A3

M7TI11AB01F1

M7TI01AB01B3

M7TI11AB01A1

M7TI01AD01A1

M7TI01AD01B1

M7TI11AB01E1

M7TI11AB01C1

M7TI11AB01D1

M7TI11AB01B1

M7TI01AB01B1

 0.05 0.040 C80 

 0.05 0.040 C80 

 0.10 0.074 361 

 0.10 0.090 C77 

 0.10 0.075 362 

 0.10 0.090 B266

 0.25 0.040 C80 

 0.25 0.040 C80 

 0.38 0.039 112 

 0.38 0.126 112 

 0.38 0.079 112 

 0.38 0.197 112 

 0.80 0.075 362 

R = 0.050

R = 0.100

R = 0.250

R = 0.385

R = 0.800

FIGURE B-35. WALKER EQUATION FIT FOR 7475-T761 CLAD SHEET, 

L-T (M7TI01AB1) 

B-75
1e-06

1e-05

0.0001

0.001

0.01

1 10 100

d

a

d/ N [in/c

y

cle]

Delta K [ksi*SQRT(in)] 

R THK REF NASGRO Data ID _____________________________

M7TI01AD01B2

M7TI01AD01A2

M7TI01AB01A3

M7TI01AB01B3

M7TI11AB01F1

M7TI01AD01A1

M7TI01AD01B1

M7TI11AB01E1

M7TI11AB01B1

M7TI11AB01D1

M7TI11AB01C1

M7TI01AB01B1

 0.05 0.040 C80 

 0.05 0.040 C80 

 0.10 0.074 361 

 0.10 0.075 362 

 0.10 0.090 C77 

 0.25 0.040 C80 

 0.25 0.040 C80 

 0.38 0.039 112 

 0.38 0.197 112 

 0.38 0.079 112 

 0.38 0.126 112 

 0.80 0.075 362 

R = 0.050

R = 0.100

R = 0.250

R = 0.385

R = 0.800

FIGURE B-36. SPLINE FIT FOR 7475-T761 CLAD SHEET, L-T (M7TI01AB1) 

B-76
TABLE B-24. da/dN-ΔK SPLINE FIT FOR 7475-T761 CLAD SHEET, 

L-T (M7TI01AB1) 

ID Code = M7TI01AD1 

R = 0.0500 

da/dN ΔK

6.4211e-06 10.6414 

1.0000e-05 12.3039 

1.8000e-05 15.3166 

3.2000e-05 21.1370 

6.0000e-05 26.8593 

1.0000e-04 30.9441 

1.8000e-04 36.1085 

2.5595e-04 40.7380 

(a) 

ID Code = M7TI01AD1 

R = 0.100 

da/dN ΔK

1.7069e-06 5.5208 

1.8000e-06 5.7600 

3.2000e-06 7.8798 

6.0000e-06 9.9990 

1.0000e-05 11.7692 

1.8000e-05 13.9868 

3.2000e-05 17.3330 

6.0000e-05 23.2501 

1.0000e-04 28.5579 

1.8000e-04 34.0576 

3.2000e-04 39.2800 

6.0000e-04 45.0994 

1.0000e-03 50.0057 

1.8000e-03 55.9171 

3.2000e-03 62.0367 

6.0000e-03 69.1641 

9.7196e-03 74.9894 

(b) 

ID Code = M7TI01AD1 

R = 0.250 

da/dN ΔK

6.7295e-06 8.5704 

1.0000e-05 10.2070 

1.8000e-05 14.2093 

3.2000e-05 17.5303 

6.0000e-05 21.7555 

1.0000e-04 24.6244 

1.8000e-04 29.2023 

2.2532e-04 31.9154 

(c) 

ID Code = M7TI01AD1 

R = 0.385 

da/dN ΔK

2.9083e-06 5.6624 

3.2000e-06 5.9110 

6.0000e-06 7.7464 

1.0000e-05 9.6016 

1.8000e-05 12.2024 

3.2000e-05 15.2651 

6.0000e-05 19.2019 

1.0000e-04 22.7799 

1.1779e-04 23.9883 

(d) 

ID Code = M7TI01AD1 

R = 0.800 

da/dN ΔK

1.3790e-06 3.6475 

1.8000e-06 3.8928 

3.2000e-06 4.7450 

6.0000e-06 6.5211 

1.0000e-05 8.1918 

1.8000e-05 10.2472 

3.2000e-05 12.5215 

6.0000e-05 15.8410 

7.5988e-05 17.5388 

(e) 

B-77
TABLE B-25. MATERIAL AND SPECIMEN TESTING INFORMATION FOR 

7475-T7651 PLATE, L-T 

Material ID Code M7TJ11AB1 

Alloy Type 7475 Al 

Alloy Condition/HT T7651 

Product Form 0.25′′-1.5′′ Plate 

Test Environments Laboratory Air 

Specimen Types C(T), M(T) 

Crack Orientation L-T 

Specimen Thickness (in.) C(T): 0.25 M(T): 0.19-0.25 

Specimen Width (in.) C(T): 2 M(T): 12 

Yield Strength (ksi) 68-69 

Ultimate Strength (ksi) 78-79 

Cyclic Frequency, Hz 5-30 

Data References for Table B-25. 

361 Larson, B.F., “C-17 Material Specimen Tests for Fracture Mechanics Data,” Phase I, Lot 

1 Aluminum Alloys. 

362 Kahandal, R.S., “C-17 Material Specimen Tests for Fracture Mechanics Data,” Phase I, 

Lot 2 Aluminum Alloys. 

B140 Cervay, R.R., AFML-TR-75-220, 1975. 

C222 Ferguson, C.W., et al., “Hypervelocity Impact Effects on Liquid Hydrogen Tanks,” 

NASA CR-54852, Douglas Aircraft Co. Inc., March 1966. 

B-78
1e-08

1e-07

1e-06

1e-05

0.0001

0.001

0.01

0.1

1 10 100

d

a/d

N [in/c

y

cle]

Delta K [ksi*SQRT(in)] 

R THK REF NASGRO Data ID _____________________________

NASGRO 4.0

EQUATION FIT:

_____________

Smax/SIGo = 0.30 

Alpha = 2.000 

K1c = 40.0

YS = 69.0

Ak = 1.00, Bk = 1.50

Kc = 96.7 (t= 0.200)

DK1 = 0.64

Cth+ = 2.15

Cth- = 0.10

p = 0.500, q = 1.000

C = 0.200E-07

n = 2.800

M7TJ11AB01A3

M7TJ11AB01B3

M7TJ11AB01D1

M7TJ11AB01G1

M7TJ11AB01D2

M7TJ11AB01B2

M7TJ11AB01F2

M7TJ11AB01A2

M7TJ11AB01B1

M7TJ11AB01A1

M7TJ11AB01F1

M7TJ11AB01D3

 0.00 0.188 C222

 0.00 0.253 C222

 0.05 0.200 361 

 0.05 0.200 362 

 0.40 0.200 361 

 0.40 0.253 C222

 0.40 0.250 362 

 0.40 0.188 C222

 0.80 0.253 C222

 0.80 0.188 C222

 0.80 0.250 362 

 0.80 0.200 361 

R = 0.000

R = 0.050

R = 0.400

R = 0.800

FIGURE B-37. NASGRO EQUATION FIT FOR 7475-T7651 SHEET AND PLATE, 

L-T (M7TJ11AB1) 

B-79
1e-08

1e-07

1e-06

1e-05

0.0001

0.001

1 10 100

d

a/d

N [in/c

y

cle]

Delta K [ksi*SQRT(in)] 

R THK REF NASGRO Data ID _____________________________

NASGRO 4.0

WALKER FIT:

___________

C = 0.217E-08

n = 3.267

m+ = 0.640

M7TJ11AB01A3

M7TJ11AB01B3

M7TJ11AB01D1

M7TJ11AB01G1

M7TJ11AB01D2

M7TJ11AB01B2

M7TJ11AB01F2

M7TJ11AB01A2

M7TJ11AB01B1

M7TJ11AB01A1

M7TJ11AB01F1

M7TJ11AB01D3

 0.00 0.188 C222

 0.00 0.253 C222

 0.05 0.200 361 

 0.05 0.200 362 

 0.40 0.200 361 

 0.40 0.253 C222

 0.40 0.250 362 

 0.40 0.188 C222

 0.80 0.253 C222

 0.80 0.188 C222

 0.80 0.250 362 

 0.80 0.200 361 

R = 0.000

R = 0.050

R = 0.400

R = 0.800

FIGURE B-38. WALKER EQUATION FIT FOR 7475-T7651 SHEET AND PLATE, 

L-T (M7TJ11AB1) 

B-80
1e-08

1e-07

1e-06

1e-05

0.0001

0.001

0.01

0.1

1 10 100

d

a

d/ N [in/c

y

cle]

Delta K [ksi*SQRT(in)] 

R THK REF NASGRO Data ID _____________________________

M7TJ11AB01A3

M7TJ11AB01B3

M7TJ11AB01D1

M7TJ11AB01G1

M7TJ11AB01D2

M7TJ11AB01B2

M7TJ11AB01F2

M7TJ11AB01A2

M7TJ11AB01B1

M7TJ11AB01A1

M7TJ11AB01F1

M7TJ11AB01D3

 0.00 0.188 C222

 0.00 0.253 C222

 0.05 0.200 361 

 0.05 0.200 362 

 0.40 0.200 361 

 0.40 0.253 C222

 0.40 0.250 362 

 0.40 0.188 C222

 0.80 0.253 C222

 0.80 0.188 C222

 0.80 0.250 362 

 0.80 0.200 361 

R = 0.000

R = 0.050

R = 0.400

R = 0.800

FIGURE B-39. SPLINE FIT FOR 7475-T7651 SHEET AND PLATE, L-T (M7TJ11AB1) 

B-81
TABLE B-26. da/dN-ΔK SPLINE FIT FOR 7475-T7561 CLAD SHEET, L-T (M7TJ11AB1) 

ID Code = M7TJ11AB1 

R = 0.0000

da/dN ΔK

1.8481e-07 3.8905 

3.2000e-07 5.2775 

6.0000e-07 6.6140 

1.0000e-06 7.5311 

1.8000e-06 8.4826 

3.2000e-06 9.4618 

6.0000e-06 10.7314 

1.0000e-05 12.1336 

1.8000e-05 14.3660 

3.2000e-05 17.6823 

6.0000e-05 23.0121 

1.0000e-04 27.4649 

1.8000e-04 34.3773 

3.2000e-04 42.3049 

6.0000e-04 52.6966 

7.3479e-04 57.4116 

(a) 

ID Code = M7TJ11AB1 

R = 0.050

da/dN ΔK

9.7848e-08 3.0832 

1.0000e-07 3.1049 

1.8000e-07 4.3472 

3.2000e-07 5.3300 

6.0000e-07 5.9547 

1.0000e-06 6.4360 

1.8000e-06 7.1359 

3.2000e-06 8.0568 

6.0000e-06 9.5316 

1.0000e-05 11.3905 

1.8000e-05 14.3418 

3.2000e-05 17.7553 

6.0000e-05 21.9446 

1.0000e-04 26.0137 

1.8000e-04 32.1934 

3.2000e-04 39.7875 

6.0000e-04 49.3327 

1.0000e-03 56.9240 

1.8000e-03 64.6548 

3.2000e-03 71.3356 

6.0000e-03 77.9134 

9.1696e-03 82.0352 

(b) 

B-82
TABLE B-26. da/dN-ΔK SPLINE FIT FOR 7475-T7561 CLAD SHEET, L-T (M7TJ11AB1) 

(Continued) 

ID Code = M7TJ11AB1 

R = 0.400 

da/dN ΔK

1.2078e-07 2.6915 

1.8000e-07 3.2988 

3.2000e-07 3.9084 

6.0000e-07 4.4853 

1.0000e-06 4.9264 

1.8000e-06 5.4994 

3.2000e-06 6.3044 

6.0000e-06 7.6562 

1.0000e-05 9.1601 

1.8000e-05 11.5761 

3.2000e-05 15.0749 

6.0000e-05 19.1702 

1.0000e-04 22.6213 

1.8000e-04 26.7859 

3.2000e-04 31.0723 

6.0000e-04 37.2407 

1.0000e-03 43.2472 

1.8000e-03 48.9027 

3.2000e-03 53.2963 

6.0000e-03 57.3154 

6.6786e-03 57.9429 

(c) 

ID Code = M7TJ11AB1 

R = 0.800

da/dN ΔK

1.1626e-07 2.1086 

1.8000e-07 2.3549 

3.2000e-07 2.8021 

6.0000e-07 3.2007 

1.0000e-06 3.5366 

1.8000e-06 4.0855 

3.2000e-06 4.9071 

6.0000e-06 6.7696 

1.0000e-05 8.0711 

1.8000e-05 9.7494 

3.2000e-05 11.5677 

6.0000e-05 14.7456 

7.0066e-05 15.9221 

(d) 

B-83/B-84
APPENDIX C— FATIGUE CRACK GROWTH DATABASE SOFTWARE OPERATION 

C.1 FATIGUE CRACK GROWTH DATABASE SOFTWARE INSTALLATION. 

The Fatigue Crack Growth Database (FCGD) software and its graphical user interface (GUI) 

were developed under Microsoft Windows 98 and would be compatible on most Windows 

platforms. The FCGD software is installed by executing a setup file (setup.exe). The default 

directory for the installation is c:\program files\fcgd, but may be changed to a different one if 

desired. An FCGD icon to run the software is automatically created on the computer’s desktop 

during the FCGD installation process. 

This version of the FCGD software and database require approximately 10 MB of hard disk 

space. As data for additional materials are added to the database, this will increase. Microsoft®

PowerPoint is also required to display the plots for the materials included in the database. 

C.2 OPENING WINDOW. 

The opening window of the FCGD software is shown in figure C-1. Clicking the Agree button 

to accept the displayed disclaimer opens the window shown in figure C-2. Through this window, 

the database of materials could be accessed or an option to input user’s own set of data can be 

selected. 

FIGURE C-1. OPENING WINDOW FOR THE FCGD SOFTWARE 

C-1
C.3 MATERIAL SELECTION. 

Curve fits for specific materials in the database can be displayed by selecting the Choose 

Material menu tab. An example display window is shown in figure C-2. There are currently 13 

materials in the database. Selecting a material automatically displays the ID code in the standard 

material identification box for reference. Choosing any of the buttons labeled NASGRO 

Equation, Walker Equation, or Spline under the blue-highlighted text Plot Std Data with Std 

Curve Fits, displays the respective curve fit and opens a PowerPoint file displaying a table of the 

material description and color plot(s) of the data. These plots are displayed in U.S. customary 

units (ksi√in and in/cycle) and may be printed directly from PowerPoint or copied into another 

document using the copy and paste functions of Windows. 

FIGURE C-2. MATERIAL SELECTION WINDOW FOR PLOTTING 

STANDARD DATA AND CURVE FITS 

Spline data points can be saved into a text file by choosing the Save Spline Tables button. This 

file is stored in the default directory c:\program files\fcgd under the default name material ID.tbl. 

Both the default file name and location can be changed during this operation if desired. 

C.4 ENTERING USER DATA. 

Choosing Enter/Edit User Data from the menu tab in figure C-2 displays an input window, as 

shown in figure C-3, for a set of fatigue crack growth data, which can be compared with the 

standard curve fits in the database. With this window, the material characteristics can be 

specified, a material ID code created, and the information saved to a file. The data source input 

types that are available are direct keyboard input and text file. Data from spreadsheets such as 

C-2
Microsoft Excel, can be entered by using the copy and paste functions of Windows. Data from 

scanned graphical images in bitmap format as well can be digitized and imported into the FCGD 

software. 

FIGURE C-3. INPUT WINDOW FOR USER-DEFINED 

FATIGUE CRACK GROWTH DATA 

Besides the standard U.S. customary units, the FCGD software has the flexibility to 

accommodate data input in SI units (MPa√m and m/cycle) and other nonstandard units by the 

Choose Units pull-down menu. The units of the data are then converted by the software to U.S. 

customary units for comparison to the database curves. 

The first step in specifying a set of user data is to supply the characteristics of the material. By 

clicking on the Build an ID button, the user has the option of creating a material characteristic 

and ID code for the data consistent with the material ID nomenclature used in the database and 

NASGRO. Alternatively, the Header Info box provides a list of items that the user can fill in to 

identify the material characteristics in terms that the user is familiar with. Note that items 

marked with an asterisk are required, others are recommended. 

Next, the data units, the Number of R Values, and the Data Source must be identified in the small 

inset windows of the Enter/Edit User Data window. Each of the various input data sources 

mentioned above are described below in detail. 

C.4.1 KEYBOARD. 

To use the keyboard for data input, the number of R values n for the data set must be entered 

under the label Number of R values. Empty boxes adjacent to the labels R1 through Rn 

automatically open up and are ready for data entry. For example, specifying four R values 

C-3
activates boxes R1 through R4, for which the R values can be entered. Each of the da/dN and 

ΔK data can now be entered in the grid to the right by clicking on the Show Data button of the 

respective R value. 

C.4.2 TEXT FILE. 

Clicking on the Text File button under the data source label brings up a small dialog box (shown 

in figure C-4(a)) for description of the format of the text data file. In this dialog box, the column 

numbers containing the da/dN and ΔK data, the type of delimiter, and the number of header lines 

to skip can be specified. In figure C-4(a), da/dN and ΔK data are in columns 1 and 2, 

respectively, the number of header lines to skip is 2 (space is used as the delimeter) and, it is 

assumed that the data for each R value are in a separate file. A sample text file is shown in figure 

C-4(b). Clicking on OK confirms the specified data format and displays a matrix by which the 

user can specify the file names and their corresponding R values. This matrix is shown in figure 

C-5, along with the help window describing the details of its operation. 

Wing da/dN vs ΔK Data

7075-T351 Aluminum at R = 0.0

 1.0000E-10 1.25 

 4.0000E-09 1.50 

 9.9400E-09 2.00 

 4.8800E-08 3.00 

 1.5100E-07 4.00 

 3.6200E-07 5.00 

 9.7100E-07 6.00 

 2.6300E-06 7.00 

 4.7400E-06 9.00 

 6.4300E-06 10.00 

 6.9600E-06 11.00 

 9.6700E-06 12.00 

 1.3600E-05 13.00 

 1.7800E-05 14.00 

 2.1800E-05 15.00 

 3.5400E-05 18.00 

 6.7800E-05 22.00 

 1.1600E-04 25.00 

 1.4100E-04 26.00 

 2.4100E-04 28.00 

(a) Format Utility 

(b) Sample Text File 

FIGURE C-4. UTILITY TO SUPPLY FORMAT OF TEXT DATA FILE 

C-4
FIGURE C-5. INPUT MATRIX TO SPECIFY FILE NAMES FOR DIFFERENT SETS OF 

CRACK GROWTH RATE DATA AS A FUNCTION OF R VALUE 

C.4.3 SPREADSHEET. 

It is also possible to copy data for each R value directly from a spreadsheet into the data grid 

using the copy and paste functions of Windows. For a given R value, highlight and copy the data 

of interest from an open spreadsheet. With the Show Data button activated for the R value of 

interest, right click on the data grid and a pop-up menu is displayed to paste the copied data, as 

shown in figure C-6. The user may copy and paste a column of data at a time or both columns 

simultaneously. 

FIGURE C-6. THE FCGD KEYBOARD INPUT WINDOW SHOWING THE USE OF 

WINDOW’S COPY AND PASTE FUNCTIONS 

C-5
C.4.4 DIGITIZER. 

A utility is provided to digitize a bitmap (.bmp) file of a scanned graphical image or other 

sources. Detailed instructions for this data input can be accessed by clicking on the button 

labeled Digitizer Help. The contents of the Digitizer Help button are reproduced in figure C-7. 

1. The file to be digitized must be a bitmap(.bmp) obtained 

 from a scanner or other method. 

2. From the File menu of the digitizer screen: Choose "Open" 

 and open the file that is to be digitized. 

3. From the Scale menu: 

 -Choose Log X scale and Log Y scale if appropriate. 

 Do not use the keyboard shortcut Crtl X! 

 -Choose Define 3 Pts. 

 For point 1, click on the top of the Y axis and enter 

 X and Y values. 

 For point 2, click on the axes intersection and enter 

 X and Y values. 

 For point 3, click on the end of the X axis and enter 

 X and Y values. 

4. DIGITIZE THE FIRST POINT ANYWHERE ON THE Y AXIS. 

 (i.e., place the cross hair on the Y axis and double click) 

 This will provide a minimum X value to be used later. 

5. Digitize the values of a data set by DOUBLE CLICKING on 

 each point. 

6. If more than one data set is to be digitized: 

 After each data set is digitized, MOVE THE CROSSHAIR TO 

 THE LEFT OF THE Y AXIS AND DOUBLE CLICK TO DIGITIZE A POINT. 

 This will provide a separator for the data sets by recording 

 a point which is smaller than the minimum X value. 

7. After all points are digitized; From the Data menu choose 

 "Save" and save the file, using a name of your choice. Then 

 close the digitizer program. 

8. When control returns from the digitizer program, you will 

 be prompted for the name of the file which was saved in 

 step 7. Select the file and click the “Open” button. 

 Choose the number of R values and enter the values into 

 the text boxes provided in the same order that the 

 digitizing was done. 

FIGURE C-7. INSTRUCTIONS TO USE THE DIGITIZER UTILITY 

C-6
C.5 COMPARING USER DATA WITH FCGD CURVES. 

The data in the user-defined database can be compared to curve fits in the standard database 

(FCGD) by going to the choose material screen (figure C-2), selecting one material from the Std 

Matl Description column and material from the User Matl Description column and one of the 

standard crack growth equations under plot Std Data with Std Curve Fits. The R values to plot 

are automatically displayed in the data boxes below the green-highlighted text of figure C-2. For 

the spline fit, negative and/or positive R values (at least one R value) must be selected before the 

data may be plotted and compared. A plotting utility automatically appears that provides options 

to send the plot to the screen or to save it to a file for later use. 

Note that the user’s crack growth data can only be compared to the curve fits in the material 

database FCGD. The FCGD software does not have the capability to produce NASGRO, 

Walker, or Spline fits to user-supplied crack growth data. 

C-7/C-8
APPENDIX D—EXAMPLES

D.1 KEYBOARD ENTRY OF USER DATA. 

In this example, a set of fatigue crack growth data of three different R values (0.0, 0.50, and 

0.72) is assumed for a 7000 series aluminum plate material, and will be compared to the 7075-

T7351 plate material data in the fatigue crack growth database (FGCD) software. 

Figure D-1 shows the display of the Enter/Edit User Data window. The Data Source has been 

checked as keyboard, and 3 has been specified as the number of R values. Adjacent and to the 

right of each of labels R1-R3 are the entered R values. By clicking on the Show Data button, 

located to the left of the labels R1-R3, the grid on the right under the da/dN-ΔK labels is 

activated for data entry from the keyboard. Figure D-1 shows the data entered for R = 0.0. 

(Generally, there would be more data points than those shown in this hypothetical example.) 

The required material information under the Header Info box on the left has been filled in for this 

example. Clicking on the Plot Data button located at the lower right of the screen displays the 

da/dN-ΔK plot for this example, as shown in figure D-2. 

Clicking on the Save to file button enters the data into the User Material database under the 

created material ID code’s name (7xxx-T7yy Plate), as shown in the left-hand column of 

figure D-3. At the Choose Material window, the material (7xxx-T7yy Plate) can be selected and 

compared to the FCGD standard curve fits. 

FIGURE D-1. KEYBOARD ENTRY OF USER DATA 

D-1
FIGURE D-2. DISPLAY OF USER-ENTERED DATA 

FIGURE D-3. SELECTION OF USER MATERIAL AND FCGD MATERIAL FOR 

COMPARISON PLOTTING 

D-2
Figure D-4 shows a comparison of the user-entered data (7xxx-T7yy Plate) with the NASGRO 

curve fit for 7075-T7351 Plate from FCGD standard material database at the three R values. 

This plot was obtained by clicking on the user material under User Matl Description and the 

standard material under Std Matl Description (highlighted in figure D-3) followed by clicking 

the NASGRO Eqn button under the Plot Std Data with Std Curve Fits. Note that this is a 

comparison, not a curve fit of the user data. Similar plots are possible for the Walker equation 

and the Spline fits as shown in figures D-5 and D-6, respectively. In the case of the Spline fits 

however, the user must also select at least one R value of the available Spline fits to compare 

against. 

FIGURE D-4. COMPARISON OF USER-ENTERED DATA WITH 

7075-T7351 NASGRO CURVE FIT AT R = 0, 0.5, AND 0.72 

D-3
FIGURE D-5. COMPARISON OF USER-ENTERED DATA WITH 

7075-T7351 WALKER CURVE FIT AT R = 0, 0.5, AND 0.72 

FIGURE D-6. COMPARISON OF USER-ENTERED DATA WITH 

7075-T7351 SPLINE CURVE FIT AT R = 0.1 and 0.5 

D-4
D.2 FILE ENTRY OF USER DATA. 

It is more likely that the sets of da/dN-ΔK data would be in files. Therefore, the FCGD software 

accommodates input of data by text file. By clicking Text File under Data Source of the 

Enter/Edit User Data window (figure D-1), the Text File Information window shown in 

figure D-7(a) is displayed. In this window, the user is able to describe to the FCGD software the 

format of the fatigue crack growth rate data files by specifying the number of header lines to 

skip, the appropriate columns containing specific data (da/dN or ΔK), and a delimiter. It is 

assumed, however, that data for the individual R value are contained in separate files, as shown 

in figure D-7(b). With the format of the data files specified, an input matrix to specify file names 

is displayed by clicking the OK button, as shown in figure D-8. 

Wing da/dN vs ΔK Data

7075-T351 Aluminum at R = 0.0

 1.0000E-10 1.25 

 4.0000E-09 1.50 

 9.9400E-09 2.00 

 4.8800E-08 3.00 

 1.5100E-07 4.00 

 3.6200E-07 5.00 

 9.7100E-07 6.00 

 2.6300E-06 7.00 

 4.7400E-06 9.00 

 6.4300E-06 10.00 

 6.9600E-06 11.00 

 9.6700E-06 12.00 

 1.3600E-05 13.00 

 1.7800E-05 14.00 

 2.1800E-05 15.00 

 3.5400E-05 18.00 

 6.7800E-05 22.00 

 1.1600E-04 25.00 

 1.4100E-04 26.00 

 2.4100E-04 28.00 

 3.9500E-04 30.00 

 7.7800E-04 33.00 

(a) Format Utility 

 (b) Format Utility 

FIGURE D-7. UTILITY TO SUPPLY FORMAT OF TEXT DATA FILE 

D-5
FIGURE D-8. INPUT MATRIX TO SPECIFY FILE NAMES FOR DIFFERENT SETS OF 

CRACK GROWTH RATE DATA AS A FUNCTION OF R VALUE 

For the example discussed in section D.1, the da/dN-ΔK data were in three separate files. Figure 

D-9 illustrates how these files would be specified for each R value. A file name is specified for 

each R value for the case of equal number of file names and R values. In the event that there are 

multiple files for a given R value (e.g., more than one fatigue crack growth rate test), the file 

names could be entered in the rows under the R value column as appropriate. The R values and 

file names in the matrix may now be saved into the user material database by clicking on the 

Save button. Plotting and comparisons to the FCGD curve fits can then be performed, as 

outlined above for the keyboard input example. 

D-6
Example data files: 

Wing Material R = 0.0 

2.99e-08 2.84 

1.97e-07 3.93 

7.28e-07 5.34 

2.85e-06 6.93 

6.79e-06 9.82 

2.43e-05 15.35 

6.14e-05 20.78 

Wing Material R = 0.5 

2.25e-08 1.49 

1.18e-07 2.32 

1.70e-07 2.94 

7.80e-07 4.25 

2.32e-06 5.43 

5.18e-06 7.2 

1.51e-05 10.5 

3.52e-05 13.1 

Wing Material R = 0.72

3.81e-08 1.47 

1.01e-07 2.13 

1.74e-07 2.5 

3.88e-07 2.97 

8.66e-07 3.44 

1.70e-06 4.04 

2.85e-06 4.87 

4.40e-06 5.54 

 7xxxR0.dat 7xxxR5.dat 7xxxR72.dat

FIGURE D-9. FILE ENTRY OF USER DATA 

D.3 ENTERING USER DATA FROM A DIGITIZER. 

Use of the digitizer requires that the da/dN-ΔK data to be digitized must be from a bitmap (.bmp) 

file obtained from a scanner or other method. Figure C-7 provides detailed instructions to use 

the digitizer utility. The digitizer incorporated in the FCGD software is WinDIG 2.0; additional 

instructions are available from the help button within the WinDIG window. 

D-7/D-8