bluuebunny/crossref_metadata_2025 huggingface dataset:
Analyzing Interlaboratory Data According to ASTM Standard E691
Authors: Mandel J
Published: March 2009

ASTM Standard Practice E691-92 deals with the design and the analysis of the data of an interlaboratory study of a test method. This paper explains the procedure of E691 and goes beyond it in a discussion of the linear model analysis of interlaboratory test data. The explanations are illustrated in terms of a real set of interlaboratory data.
All You Ever Wanted to Know About Control Charts: But Never Asked
Authors: Levine BH , McCune DC
Published: March 2009

Statistical Control Charts developed over 60 years ago have seen many applications in process analysis and control in the past decade. To some users, the control charts are a recent invention of the Japanese, to many there is a confusion about the underlying assumptions and where and how this analytical tool may be applied. The effect of some of these assumed assumptions for control charts is discussed followed by suggested areas of application.
The Transition from Sampling to SPC
Authors: Schilling EG
Published: March 2009

Modern quality control practice emphasizes the importance of process control in the creation of a quality product. When the process is in control it is possible to characterize the product forthcoming from the process, for the particular characteristic controlled, at the point in the process at which the control is instituted. When the process is out of control, the relationship between product and process is lost. It is then necessary to rely on acceptance sampling procedures to characterize the process. By combining the power of process control with the assurance of acceptance sampling, the process experimentation necessary for continual improvement can be undertaken with minimal risk to the consumer. An approach has been developed to transition from a process lacking control and/or capability to a controlled process with a Cpk value 1.33 indicating that the process is operating at an average level four sigma from the specification (s).
Overview of Technical and Social Systems in Organizational Change
Authors: Kowalewski MJ , Farrar CR
Published: March 2009

What light does Behavioral Science and Organization Development shed on Total Quality Management (TQM) in Earth's global environment ? The social and technical systems of Europe have been joined together in the European Community 1992 (EC '92) coalition. As part of EC '92 the International Organization of Standardization (ISO) has provided the technical standardization system for inter-country approval and use. Other non-European countries have joined the ISO movement including the United States of America. Change has been a result of this movement. Most of it has been on technical, quality, and management systems. The next century will require and reveal changes in behavioral thinking and organizational structure. TQM is at the frontier of this change. A case-study of change resulting from TQM in government is presented in this paper.
Implementation of a Quality Assurance System in Clothing Establishments
Authors: Yeung KW , Taylor G
Published: March 2009

The clothing industry is the most important manufacturing industry in Hong Kong. In an effort to cope with recent changes and developments, there are signs that the clothing establishments are becoming more quality conscious. A recent survey however reveals that these establishments are still not paying enough attention to this important aspect of their business and a proactive, innovative approach to quality improvement is less common than responsiveness to market forces on a needs basis. Based on a case study of implementing the ISO 9000 quality assurance standard in a clothing establishment, areas of interest and potential problems have been identified which are unique to the clothing industry, and solutions have been suggested to how these could be overcome.
Frequency Effects on Damping/Modulus of Cohesive Soil
Authors: Zavoral DZ , Campanella RG
Published: March 2009

In order to assess the effect of frequency on the dynamic response of clay, a modified resonant column/torsional shear apparatus was employed to test undisturbed samples of marine clay at various frequencies. Details of the modified apparatus are described and test results over a wide range of frequencies at different strain levels are presented.

Results show that the dynamic shear modulus of samples tested by the resonant column was always greater than the dynamic shear modulus of the same samples tested at lower frequencies in torsional shear. To confirm that the increase in shear modulus was due to frequency (strain rate), samples were tested in torsional shear at various frequencies. Results indicated that the shear modulus always increased with frequency, though the effect was fairly minor.

No observable effect of frequency on damping ratio was measured for samples tested in either resonant column or torsional shear modes. As well, there was no significant variation in damping ratio for samples tested in torsional shear under various frequencies.

Significantly lower residual pore pressure response was measured for samples tested by resonant column than for those tested at a lower frequency in torsional shear.
OCR of Chemical Structure Diagrams
Authors: McDaniel JR , Balmuth JR
Published: March 2009

Standards for the communication of chemical structure data in a computer-readable format have not emerged. While several standards have been proposed, the structure diagram continues to be the primary “standard.” Structure databases and computational chemistry programs cannot directly process the diagrammatic format. Kekulé has been created to provide a way for easily converting the defacto graphical standard into computer-readable formats.
Object Data Models for Shared Molecular Structures
Authors: Maier D , Cushing JB , Hansen DM , Purvis GD , Bair RA , DeVaney DM , Feller DF , Thompson MA
Published: March 2009

In a perfect world, output from one program could be transparently used as input to another. The world of scientific computation is far from perfect, and its rich legacy of data and programs carries a major disadvantage: lack of interoperability. Business data processing largely solved this problem through common data models and shared databases, but current record-oriented database technology does not support scientific applications well. We believe object-oriented systems might alleviate such shortcomings, and are exploring object-oriented environments integrating diverse programs and data. Our approach constructs for each domain a unifying data model that creates a “plug-and-play” environment.

This paper outlines the utility of object data models and object databases, and describes three projects using them to model shared molecular structures. The first presents a conceptual model for chemical experiments, the second an object-oriented database to improve interoperability of ab initio chemistry programs, and the third a uniform object interface to diverse materials science datasets.
Evolution of an Interchange Specification for Mass Spectrometric Data
Authors: Stranz D , Campbell S , Christopher R , Watt J , Zakett D
Published: March 2009

The first version of the Analytical Instrument Association Data Interchange Specification for Mass Spectrometry was released in the second quarter of 1993. This specification has two components: a model which describes the information content of mass spectrometric experimental data sets and spectral libraries, and an implementation of the model as a programming tool kit in portable computer source code. This model and tool kit evolved during four years of discussions, proposals, reviews, and prototypes involving a large group of participants from the vendor and end-user communities. External resources and support, including the AIA, the ADISS Project, the Unidata Program Center, and the American Society for Mass Spectrometry were essential in identifying key technologies used in the specification and in providing a platform for promotion and discussion.
Considerations in the Maintenance and Dissemination of the Powder Diffraction File Database
Authors: Jenkins R , Fornoff MM , Holomany MA , King MM
Published: March 2009

The Powder Diffraction File (PDF®) is a collection of singlephase X-ray powder diffraction patterns in the form of inter-planar spacings (d) and relative intensities (I/I1), characteristic of the compound. Other information is included, when available, along with the references of the source information. The PDF® has been used for more than five decades and, as of 1992, contains about 67,000 patterns. The distribution and maintenance of the PDF® is carried out by the International Centre for Diffraction Data, located in Newtown Square, Pennsylvania. In the early days of the powder method, X-ray patterns were recorded on film, but the development of the powder diffractometer in the mid 1940s allowed the pattern to be recorded in a (generally) more useful analog trace form. However, because of storage considerations, in the case of both film and trace, it was necessary to “reduce” the experimental data to a d/I list. While the basic principle of the X-ray powder method has not changed too much during the last half century, there have been dramatic changes in the instrumentation used to record diffraction data, as well as in the data reduction methods used to produce the d/I lists which make up the core of the PDF®. This paper discusses the approaches taken by the ICDD to meet changing technology in maintaining the PDF® database in a way that is manageable, cost effective and, above all, satisfactory to a majority of the X-ray powder diffraction community.
Measured and Calculated Pavement Response in the Danish Road Testing Machine
Authors: Krarup J
Published: March 2009

This paper reports results from a research program assessing pavement response from heavy vehicles. The Technical University of Denmark and The Danish Road Institute cooperated in the research program. To estimate the validity of theoretical values of stress and strain in pavements, stress and strain distributions were measured under two types of loads. One was the rolling truck tires of the Road Testing Machine, and the other was falling weight deflectometer (FWD) loadings. Distributions of stress and strain are explored and mapped in three-dimensional graphs. Some steps are taken in an attempt to test measured response distributions against calculated distributions. The measured responses are: (1) vertical contact stress in the tire/pavement interface, (2) longitudinal and transversal strain at the bottom of the asphalt concrete layer, (3) vertical soil stress, and (4) vertical soil strain.

As temperatures and layer thicknesses in the Road Testing Machine are well known, only Poisson's ratio is estimated for the calculations. The layer's E-values were backcalculated from the FWD load and measured surface deflections. Using the elastic layer theory with backcalculated E-values and the chosen values of Poisson's ratio, values of stress and strain are calculated at the positions of the instruments. FWD load response values are considered the means for in situ calibration of stress cells.
Reflections on Progress in Fracture Mechanics Research
Authors: Paris PC
Published: March 2009

Professor Jerold L. Swedlow was an outstanding student, educator, and researcher in the field of fracture mechanics, and he was a genuine friend to all. Indeed, his special assistance to his colleagues in transmitting their work in the field, which included his enormous and effective efforts in editorial work for the International Journal of Fracture Mechanics and his guidance as Chairman of the National Symposium Organizing Committee for many years, leaves us with a great debt of gratitude to him. It is a distinct pleasure and honor to present the “Third Annual Jerry L. Swedlow Memorial Lecture” as a tribute not only to “Jerry” but to his special friends, such as the late Dr. John Srawley, and many others.
Two-Parameter Fracture Mechanics: Theory and Applications
Authors: O'Dowd NP , Shih CF
Published: March 2009

A family of self-similar fields provides the two parameters required to characterize the full range of high- and low-triaxiality crack tip states. The two parameters, J and Q, have distinct roles: / sets the size scale of the process zone over which large stresses and strains develop, whereas Q scales the near-tip stress distribution relative to a high-triaxiality reference stress state. An immediate consequence of the theory is this: it is the toughness values over a range of crack-tip constraint that fully characterize the material's fracture resistance. It is shown that Q provides a common scale for interpreting cleavage fracture and ductile tearing data, thus allowing both failure modes to be incorporated in a single toughness locus.

The evolution of Q, as plasticity progresses from small-scale yielding to fully yielded conditions, has been quantified for several crack geometries and for a wide range of material strain hardening properties. An indicator of the robustness of the J-Q fields is introduced; Q as a field parameter and as a pointwise measure of stress level is discussed.
Crack Tip Opening Displacement (CTOD) Testing Method for Heat-Affected Zone (HAZ) Toughness of Steel Welds with Particular Reference to Local Inhomogeneity
Authors: Toyoda M
Published: March 2009

In the multi-passed weld heat-affected zone (HAZ), the occurrence of mechanical and metallurgical heterogeneity is inevitable. For the fracture toughness evaluation of the steel weld HAZ, the effect of the inhomogeneity shall be considered, particularly in relation to determination of the appropriate testing procedures such as the extraction of test specimens from welded joints. In the weld HAZ of the recently developed high strength steels, the occurrence of the local brittle zones (LBZs) and the local hard/soft zones is often observed. The effect of local heterogeneity is an important problem to be solved to clarify the testing methods and understand the significance of toughness obtained by a specific toughness testing method. In this paper, two kinds of heterogeneity, that is, heterogeneity in toughness and strength mismatch, will be considered. The toughness value is significantly dependent on the specimen types and the extraction method of specimen from the multi-passed welded joints, that is, the size of LBZs existing in the vicinity of the crack tip is one of the dominant controlling factors. The size effect of LBZs on the scattering of toughness is discussed based on the weakest link model (WLM). Moreover, the mechanical heterogeneity, such as the distribution of strength in HAZ, is a considerably important factor controlling the fracture toughness. Mechanical inhomogeneity influences not only the deformation behaviors in the vicinity of crack tip, that is, the evaluation of toughness parameter, but also the critical toughness value. In this paper, both effects are proved by the experimental results, and discussions have been conducted on the appropriate evaluation methods for CTOD testing of steel weld HAZs with considering the effect of the local mechanical heterogeneity.
Analysis of Results from the MPC/JSPS Round Robin Testing Program in the Ductile to-Brittle Transition Region
Authors: Miglin MT , Oberjohn LA , Van Der Sluys WA
Published: March 2009

Excessive scatter in fracture toughness data for ferrous materials tested in the ductile-to-brittle transition region makes it difficult to develop conservative estimates of fracture toughness for use in structural analysis and design. Several procedures are developed to predict fracture toughness from scattered data sets. These procedures either rely solely on statistical analysis or else combine a correction for excess plasticity with statistical analysis.

A round robin testing program including 150 fracture toughness tests of SA508C13 in the ductile-to-brittle transition region has been conducted by the Materials Property Council (MPC) in conjunction with the Japan Society for the Promotion of Science (JSPS). This test program, which uses IT compact fracture specimens tested at three transition region temperatures, provides a large database for comparing procedures designed for dealing with data scatter. In this work, the Anderson-Dodds constraint correction procedure is compared to the available energy analysis procedure based upon their suitability for correcting for excess plasticity in scattered transition region fracture toughness data sets such as the MPC/JSPS round robin results. Various forms of two- and three-parameter Weibull statistics are reviewed for the ability to fit uncorrected and plasticity corrected data sets.
Ductile-Brittle Fracture Transition as a Result of Increasing In-Plane Constraint in a Medium Carbon Steel
Authors: Wu S-X , Mai Y-W , Cotterell B
Published: March 2009

Crack-tip opening displacement (CTOD) tests and large deformation finite element analyses have been carried out for double-edge notched tension [DE(T)] specimens with a/W = 0.9 [DE(T)9] and 0.5 [DE(T)5], single-edge notched tension [SE(T)] specimens with a/W = 0.5 [SE(T)5], three-point bend [SE(B)] specimens with a/W = 0.5 [SE(B)5] and 0.1 [SE(B)1], and center-cracked tension [M(T)] specimens with a/W = 0.5 [M(T)5]. The results of the CTOD tests show that the fracture toughness of the material decreases, and a ductile-brittle fracture transition takes place as the in-plane plastic constraint of the specimens increases. In M(T)5 and SE(B)1 specimens with low constraints, fracture is ductile and no transition occurs. In DE(T)5, SE(T)5, and SE(B)5 with higher constraints, fracture initiates by ductile tearing and then changes to cleavage. In the DE(T)9 specimens with the highest constraint, fracture initiates by brittle cleavage. The results of the finite element analyses show that the maximum achievable tensile stress outside the finite strain zone ahead of the crack tip increases with increasing plastic constraint in the order of M(T)5, SE(B)1, DE(T)5, SE(T)5, SE(B)5, and DE(T)9. The ductile-brittle transition is due to the maximum tensile stress ahead of the crack tip reaching the critical stress for cleavage fracture as the plastic constraint increases.
A New Application of Normalization: Developing J-R Curves from Displacement Versus Crack Length and from Displacement Alone
Authors: Lee K , Landes JD
Published: March 2009

Two new experimental approaches are presented in this study to develop J-R curves: (1) from displacement versus crack length without load measurement and (2) from displacement alone without load and crack length measurement. The approaches are new applications of the method of normalization, which is based on the principle of load separation suggested by Ernst et al. The latest version of the method of normalization introduced by Landes et al. uses the three-parameter LMN functional form to relate the three variables, load, displacement, and crack length. Given any two, the third can be determined. Previously, the method of normalization has been successfully used to develop J-R curves from load versus displacement without measuring crack length and from load versus crack length without measuring displacement. The new approaches can be applied to develop J-R curves for the crack-line wedge-loaded specimen, C(W), for which the load cannot be measured.

This study was conducted in two steps. In the first step, the method of normalization was used for developing J-R curves from displacement versus crack length without load measurement. A power law fit was used to determine some calibration points at the initial part of the deformation curve. They are needed for evaluating the LMN function. In the second step, normalization was used to develop J-R curves from displacement only, without load and crack length measurements. Two new equations that relate load, displacement, and crack length were proposed in this study to use with the method of normalization for predicting the load and crack length from displacement measurements alone.

The approaches developed in both steps have been applied to analyze a number of test results from compact specimens for which all of three variables, load, displacement, and crack length, have already been determined. Five different steels were included. For the first approach the test records were assumed to have only the displacement and crack length measurements, while for applying the second approach, the test records were assumed to have only a displacement measurement. The results show that both new approaches worked very well. Compared with the test data, the predicted error for the load measurement was found within 5% for the first approach and 10% for the second approach. Compared with both the standard compliance method and the regular normalization method, the difference between J-R curves developed was found within 5% for both new approaches.
Crack Growth Under Small Scale and Transition Creep Conditions in Creep-Ductile Materials
Authors: Saxena A , Yagi K , Tabuchi M
Published: March 2009

The Ct parameter has been proposed for characterizing creep crack growth rate in the small scale to extensive creep regimes. In this paper, creep crack growth data from compact specimens ranging in widths from 50.8 to 254 mm and in thickness from 63.5 to 6.3 mm are analyzed to evaluate the Ct parameter. A second objective is to use the load-line deflection rate data obtained during these tests to evaluate the expressions used for estimating Ct in components. These expressions use creep deformation data obtained from uniaxial specimens for estimating Ct.

The analysis of the above data clearly shows that Ct may be used to characterize creep crack growth rate data over a wide range of deformation conditions. For 12.7-mm thick specimens, Ct failed to characterize the creep crack growth rate during the first 1 mm of crack extension. It is further shown that the expressions used for estimating Ct in components are reasonably accurate in the small scale creep region but are not accurate in the extensive creep region. The measured values of load-line deflection rates in the extensive creep region lay between the predicted values based on the assumptions of plane stress and plane strain.
Effects of Mean Load on Creep and Fatigue Crack Growth at Elevated Temperature
Authors: Hour K-Y , Stubbins JF
Published: March 2009

The effects of mean stress on crack growth behavior have been studied by performing various load ratio experiments at elevated temperature. It was found that at low load ratios a transgranular crack growth mode dominates whereas at high load ratios an intergranular crack growth mode was observed. The crack closure phenomenon was observed for experiments in which the transgranular crack growth mode was significant. In such cases, the crack opening stress was found to be constant for Stage II crack growth for each individual experiment at fixed load ratio, but varied with load ratio. Based on this, it was found that the crack growth rate correlated well with the effective stress intensity factor range, ΔKeff. At R = 0.6 and above, crack closure effects were not observed and the linear rate line integral parameter, C*, based on elastic-plastic fracture mechanics, was found to correlate better crack growth rate because time-dependent processes were significant in those experiments. In the regime where both fatigue and creep mechanisms might interact, the linear cumulative rule, which combines the two parameters ΔKeff and C*, accounting for fatigue and creep effects, respectively, was found to overestimate crack growth rates.
Evaluation of the Relationship Between C*, δ5, and δt during Creep Crack Growth
Authors: Saxena A , Dogan B , Schwalbe K-H
Published: March 2009

The relationships between C*, δ5 and δt, during creep crack growth are explored analytically and experimentally in this paper. The experimental part of the program used a Cr-Mo-V steel that exhibits a creep-ductile behavior, a Ti-6242Si alloy containing an equiaxed microstructure that is on the borderline of creep-ductile and creep-brittle behavior, and a Ti-6242Si-alloy containing a lamellar microstructure that exhibits an essentially creep-brittle behavior. It is shown that for creep-ductile materials, the rate of creep component of δ5, δ5C, and δt, are essentially similar for crack extensions smaller than 15% of the initial crack size. Either parameter is able to correlate creep crack growth rates in the extensive creep regime in these materials. It is recommended that, for limited amounts of crack extension, δ5C be used as an operational definition of δt, in creep-ductile materials.

For high crack growth rates in the creep-brittle materials, a correlation between da/dt and δ5 is found. However, it is analytically shown that δ5 values are dominated by crack growth under these conditions, therefore, this correlation is not of any significant value and should not be used for structural life predictions.
The Application of a Ductile Fracture Method to Polymer Materials
Authors: Zhou Z , Landes JD
Published: March 2009

The objective of this paper is to investigate the applicability of an advanced ductile fracture mechanics method to polymeric materials. This method was originally proposed by Ernst and Landes. It has been further developed by the authors and successfully used to predict the behavior of various metallic structural components containing crack-like defects. The inputs needed for this method are calibration functions and fracture toughness. The calibration functions used here are based upon the load separation principle; the fracture toughness is given in terms of the J-R curve. A critical step in the method is the determination of the calibration functions. Two procedures for doing this are introduced in this paper. One is a transformation procedure that can be used to transfer the calibration function for a fracture toughness specimen to one for a structural component. The other is a numerically based one in which the deformation pattern is numerically simulated and the load separation method is applied to define the calibration parameters.

The materials used in this study include two polymers, a toughened nylon and a polycarbonate. The method is used to predict the load versus displacement for a nylon single-edge notched bend specimen and the compact specimens of the polycarbonate. The predictions are compared with the experimental results. It is shown that the ductile fracture method applies to these polymers. However, in the case where the material fracture toughness is strongly dependent on geometry and constraint, accurate prediction can only be ensured when the correct J-R curve is used.
A Sampling of Mechanical Test Automation Methodologies Used in a Basic Research Laboratory
Authors: Hartman GA , Ashbaugh NE , Buchanan DJ
Published: March 2009

Basic research laboratories typically perform a variety of material tests and obtain the associated data to model material behavior phenomena and develop life prediction methodologies. In this research environment, a mechanical test automation system must meet challenges that are not always present in an industrial testing setting. For example, real-time crack closure load analyses, at the present time, are not widely performed in industrial crack propagation testing. In the research environment, however, on-line crack closure studies are used to make decisions in real-time about changes in test conditions.

A previous paper described the overall system strategy and hardware and one of the crack propagation software modules from the fourth generation of the material analysis and testing environment (MATE) automation system. The present paper discusses selected methodologies that the current (fifth) generation of the MATE system uses to meet the challenges posed while automating research style mechanical tests. The methodologies addressed in this paper include waveform generation and synchronization for cyclic, monotonic, and thermomechanical (TMF) testing as well as specimen damage computation for self-similar cracked geometries.
Automation of Fatigue Crack Growth Data Acquisition for Contained and Through-Thickness Cracks Using Eddy-Current and Potential Difference Methods
Authors: Halliday MD , Beevers CJ
Published: March 2009

A brief review of crack length measurement is made with respect to fatigue crack growth. Two contrasting, closed-loop, computer-automated systems are presented for obtaining fatigue crack growth data. A d-c potential difference method is described that can obtain long crack growth data down to threshold using a high frequency, resonance-type test machine. Measurements of load/back face strain data are made automatically while the test is running and are used to obtain values of crack closure load using two regression analyses. An automated method for measuring the crack depth, length, and profile of small cracks growing in holes using eddy currents is described. A resonance-type or a servohydraulic test machine for variable amplitude loading can be controlled by the system. The method can detect and measure cracks with depths in the range of about 0.1 to 2 mm and more than one crack can be present in a hole. Results are presented in terms of crack depth as functions of distance into the hole and angular position around the hole. The printout includes the presentation of crack profiles with increasing load cycles. Both systems can be used under constant, decreasing, or increasing ΔK and at constant R-ratio or controlled values of Kmax or Kmin. The achievement of a range of target events can be used to initiate subsequent action, and on-line control is maintained through a wide range of keyboard options. Examples of the fatigue crack growth output from long and short cracks using both systems are given for a 2024 aluminum alloy. Crack profiles are shown for reamed and cold-worked holes.
Spectrum Fatigue Life Assessment of Notched Specimens Using a Fracture Mechanics Based Approach
Authors: Vormwald M , Heuler P , Krae C
Published: March 2009

Local strain based approaches have been used frequently for the prediction of crack initiation life of notched components. Limitations of the transferability of smooth specimen fatigue data to the notch root as well as cumulative damage problems have been handled by use of fatigue notch factors and consideration of some damage contribution below the fatigue limit. This type of a conventional approach has been applied as a reference case for the present study.

Based on the mechanics of local strain approaches, a model for crack initiation life prediction is outlined. It takes explicitly into account the phenomena related to transferability (size, multiaxiality) as well as a load-sequence dependent damage accumulation. It is based on the closure behavior of short cracks that gives rise to load sequence dependent effective load ranges and continuously decreasing fatigue limits under spectrum loading.

Prediction results are compared to experimental data from notched aluminum 7075-T7351 specimens of various shapes and sizes under both Gaussian and MINITWIST loading. The conventional approach provides unconservative estimates with a broad scatter of life ratios. The fracture mechanics based model gives a relatively low scatter of life ratios around a mean value of unity.
Spectrum Fatigue Testing Using Dedicated Software
Authors: Marquis G , Solin J
Published: March 2009

A series of modular spectrum fatigue test control and data collection programs have been developed. Specially tailored modifications of the software are used for different types of tests. Simulated service spectra with predetermined amplitudes and frequencies for one or more control channels can be produced. Simultaneous monitoring of the test machine and specimen response permits run-time analysis of the actual spectrum, measuring of fatigue crack initiation or growth, and speed optimization. The full-scale testing of a locomotive bogie employing eight hydraulic actuators is described. The three-million kilometre service simulation verified the fatigue resistance of the structure. The importance of meaningful run-time analysis is emphasized.
High-Cycle Fatigue of Austenitic (316L) and Ferritic (A508) Steels Under Gaussian Random Loading
Authors: Gauthier J-P , Amzallag C , Le Duff J-A , Diaz E-S
Published: March 2009

A random loading fatigue test program has been conducted on materials used in pressurized water reactors. The four materials considered were low alloy steels and austenitic stainless steels, including both base metals and associated welds.

The present study concerns crack initiation in the high cycle fatigue domain. Standardized Gaussian stationary sequences were chosen. Both analytical and numerical calculations have been performed in order to determine the parameters necessary for the accurate prediction of fatigue life under random loading.

The general objective of the study is to provide a better knowledge of safety margins taken in the design of nuclear components.

Analysis of results has shown: 1. for the irregularity factor, I = 99% (narrow band spectrum—overall mean stress equal to zero), the calculation of damage is possible using both analytical and numerical methods; and 2. for the other irregularity factors, I ≠ 99% (wide band spectrum—variable mean stress), the damage calculation seems possible using an analytical method or a semianalytical method, but it is difficult to perform.

Numerical calculations have been performed using a rainflow counting method of cycles, the Haigh diagram, constant amplitude S-N curve without fatigue limit, and the linear Miner rule of damage cumulation.

Numerical calculations led to predicted fatigue lives slightly higher than those obtained experimentally, for I = 99% and 70%. This excess of nonconservatism is accentuated in the case of I = 30%, except in the case of the austenitic stainless steel.

Good agreement was observed between damage values obtained using analytical and numerical calculations for the case of I = 99%.
Neuber-Based Life Prediction Procedure for Multiaxially Loaded Components
Authors: Hanschmann D , Maldfeld E , Nowack H
Published: March 2009

The development of crack initiation life prediction methods for multiaxially loaded components is still at an early stage. In the present paper, a life prediction procedure that combines the finite element method (FEM) and the convenient notch analysis is presented. Transfer factors as derived by elastic FEM are used to calculate the multiaxial stress components at fatigue critical locations. From the individual stress components equivalent stresses are derived by a hypothesis that is based on the normal stress hypothesis and specially extended to treat multiaxial fatigue problems. A special algorithm is presented for the evaluation of equivalent stresses for multiaxial stress components with different frequencies and amplitudes. The continuous sequence of equivalent stress values is then used as an input to the Neuber-based notch analysis where the stress concentration factor is set equal to 1.
An Automatic Ultrasonic Fatigue Testing System for Studying Low Crack Growth at Room and High Temperatures
Authors: Wu T , Ni J , Bathias C
Published: March 2009

In this paper, an automatic ultrasonic fatigue testing system is presented, including a computer control and acquisition system, a video-camera-television system, an induction heating device, a magneto-strictive vibrator, and other electronic apparatus. The test machine controlled by an IBM PS/2 computer with analog to digital (A/D) and digital to analog (D/A) convertors runs at a very high frequency, about 20 kHz, and it carries out endurance tests and crack growth tests at room or high temperature. In this paper, a S-Ncurve for UDIMET 500 at room temperature and two fatigue crack growth rate (FCGR) curves in near-threshold regime for ASTROLOY at 20 and 400°C under ultrasonic fatigue testing are published.
Database for Aluminum Fatigue Design
Authors: Kosteas D , Ondra R , Sanders WW
Published: March 2009

The initial development of the Aluminum Data Bank (AlDaBa) covering primarily fatigue behavior of aluminum components has led to the concept of a comprehensive system of information sources linked to design procedures and reliability estimates for aluminum structures. The system is defined as the Aluminum Fatigue Behaviour and Evaluation Task (ALFABET) and is summarized in this paper.
Hypertext and Expert Systems Application in Fatigue Assessment and Advice
Authors: McMahon CA , Banerjee S , Williams JHS , Devlukia J
Published: March 2009

Hypertext, expert systems, and database techniques have been used to develop three systems to assist in design for fatigue. The first is used to provide life assessment. It integrates life prediction algorithms, including stress-life and local strain methods, using a network of computing elements comprising rule-based systems, text, and images for explanation and procedural code. Linking between nodes of the network is accomplished by active links using the hypertext computing paradigm. The second system uses a combination of expert systems, hypertext, and database search to assist in the provision of advice on the modification of designs to improve fatigue performance. It incorporates advice on geometry, materials, component duty and environment, surface condition, and treatment. The third is a hypertext book for the provision of advice on good design practice. In each case, an advantage of using hypertext and expert systems is that the systems may readily be customized or extended by the user.
A Software System for the Enhancement of Laboratory Calculations
Authors: Galtier A
Published: March 2009

The efficiency of a research team is closely related to its ability to take advantage of the results achieved by the scientific community as a whole. The team's ability to manage this documentation, coordinate the knowledge, and harmonize their activities are the factors that lead to success.

The software that is described in this paper has not been completed. However, it can provide a research team with an investigative tool that creates a collective memory, selection procedures, operation modules, and individual or collective work spaces.
Methods of Predicting the Adhesion of Silicone Sealants to Anodized Aluminum
Authors: Descamps P , Iker J , Wolf AT
Published: March 2009

The quality of silicone sealant adhesion to anodized aluminum varies widely. Key parameters that affect adhesion are the degree of surface sealing, the nature of the cleaner, and the time period allowed between cleaning the substrate and sealant application. While the cleaners display different effectiveness in removing organic contamination from the anodized aluminum surface, this effectiveness does not correlate with adhesion quality. It is hypothesized that by adsorbing on the anodized aluminum substrate the cleaning solvents ‘condition’ the surface for improved silicone sealant adhesion. This conditioning effect diminishes, as the cleaning solvents desorb over time. For a given cleaning solvent, optimum adhesion is observed for a certain degree of surface sealing. Adhesion to unpigmented anodized aluminum substrates can be predicted by measuring the degree of surface sealing according to the ISO 2143 acid etch method. For pigmented anodized aluminum substrates, electrical phase shift measurements can be used to predict adhesion quality.
A Concept for Preventing Repeated Weld Repairs of Bridge Structures
Authors: Welsch WH
Published: March 2009

Recent studies and publications have discussed methods of improving fatigue life in welded structures. The writer investigates the mechanism for fatigue failures in weldments as well as the data supporting various post-weld treatments. The paper will deal in depth with the control of these processes and how to achieve consistent improvements in post-weld treatments.
Automated Rapid Multielement Analysis of Oils for Wear Metals by Flame Atomic Absorption Using a Single Aspiration Per Sample
Authors: Carter JM , Batie W , Bernhard AE
Published: March 2009

In recent years, atomic absorption (AA) has been abandoned by some laboratories as the technique of choice for wear metal analysis in favor of other techniques. Although AA has been generally regarded as a good method for this type of analysis, economic considerations seem to have dictated this trend. Conventional AA analysis is too slow and tedious for multielement analyses. Laboratories need faster turnaround times and less labor intensive methods such as inductively coupled plasma (ICP) and spark emission, both of which are better suited to multielement analysis. A new sequential atomic absorption spectrophotometer, capable of rapid multielement analysis for up to 24 elements per sample in a single run, has been evaluated for oil analysis. The instrument is able to change hollow cathode lamps and other instrumental parameters automatically within 2 s, thus allowing 10 elements to be determined per minute. Unlike conventional AA, a sample is completely analyzed for all elements before the following sample is aspirated.
Elemental Analysis of Crude and Lubricating Oils by Energy Dispersive X-Ray Fluorescence
Authors: Wheeler BD
Published: March 2009

Most aspects of petroleum research, exploration, and refining require elemental analysis from trace to minor elemental concentrations. Numerous elements ranging from atomic numbers 15 to 92 can be found in many crudes. Elements such as vanadium, iron, nickel, copper, and arsenic can have deleterious effects on the catalysts utilized in the catalytic cracking process. Other elements purposely introduced as additives into finished lubricating oils must also be measured and controlled. Typically elements such as phosphorus, sulphur, calcium, zinc, and molybdenum are in the range of 0.00 to 5.00 wt%.

In addition to crude oils and finished lubricating oils, engine and turbine bearing wear analysis are often performed by X-ray fluorescence. In these cases, typical bearing and piston ring elements such as copper, chromium, zinc, lead, tin, and silver are usually quantified.

The techniques for preparing samples of crude oil, finished lubricating oils, and used engine oils are basically identical. The sample is transferred into a polypropylene sample cup with a 6.3 μm polypropylene support film. Errors in volume or sample depth can produce significant intensity deviations for higher energy X-rays. The error for lead, for example, is approximately 1.5% relative per 0.1 mL error at volumes of 3 mL. Minimum detectable limits or several tenths of parts per million for atomic numbers 30 to 92 from a range of 5 to 800 parts per million can be expected.
Ultrasonic Imaging of Delamination Damage around Fastener Holes in a Graphite/Epoxy Composite
Authors: McRae KI , McCray AG , Russell AJ , Bowers CP
Published: March 2009

Matrix cracking and multiple level delaminations around fastener holes in aircraft composite components can be associated with the overtorquing of fasteners. The damage can be repaired using a resin injection procedure. To determine the effectiveness of the procedure, an improved ultrasonic imaging technique was developed. The basis of this improved ultrasonic imaging technique is the acquisition of ultrasonic data that represent a three-dimensional volume of the specimen in the region surrounding the fastener. Because delaminations near the outer surface will obscure those located deeper within the specimen, two data sets, one from each surface, were collected from the specimen, deconvolved with respect to the transducer impulse response, and combined to form a more complete unified ultrasonic image. Using this image, a precise determination of delamination depth and area was accomplished by creating a series of C-scan images. The ultrasonic images obtained were compared to metallographic data and their correlation with the restoration of strengths and stiffnesses discussed.
Flavor and Aroma Permeability in Plastics
Authors: DeLassus PT , Strandburg G
Published: March 2009

Plastics have evolved into sophisticated food packages. This evolution requires flavor management from the package. Flavor loss can occur from a variety of mechanisms. Of particular interest are flavor losses that result from interactions of flavor molecules with the package. This paper presents the permeability, P, and the component parts, the diffusion coefficient, D, and the solubility coefficient, S, for selected flavor molecules. Use of these parameters to estimate flavor loss is included. The effects of temperature, humidity, concentration of the flavor, combination of flavors, size of the flavor molecule, and type of flavor molecule on the diffusion and solubility coefficients are discussed.
Particulate-Associated Endosteal Osteolysis in Titanium-Base Alloy Cementless Total Hip Replacement
Authors: Jacobs JJ , Urban RM , Schajowicz F , Gavrilovic J , Galante JO
Published: March 2009

Fourteen cases of diaphyseal endosteal erosions adjacent to the femoral stem have been identified in our patient population of 308 primary cementless titanium alloy total hip replacements at minimum two-year follow-up. Three of these cases were associated with unstable prostheses that resulted in revision surgery. Eleven cases were associated with radiographically stable prostheses. one of which was revised. Capsular tissue and interfacial membrane tissue were harvested from the four cases that were revised. All the tissues were analyzed histologically. and selected tissues were analyzed with electron microprobe analysis (EMA). analytic electron microscopy (AEM). and Fourier transform infrared spectroscopy (FTIR). Standard hematoxylin and eosin sections demonstrated histiocytic infiltration of the capsular and interfacial membrane tissue. These cells were laden with fine intracellular birefringent material. EMA revealed the presence of titanium alloy particles and AEM documented titanium alloy particles as well as silicate particles. FTIR positively identified polyethylene-like particles, but this technique was not able to identify particles less than 10 μm in diameter. Femoral endosteal osteolysis appears to be mediated by histiocytes containing both metallic and polymeric wear debris.
Photon Correlation Spectroscopy Analysis of the Submicrometre Particulate Fraction in Human Synovial Tissues Recovered at Arthroplasty or Revision
Authors: Kossovsky N , Liao K , Gelman A , Campbell PA , Amstutz HC , Finerman GAM , Nasser S , Thomas BJ
Published: March 2009

Wear debris is produced by both the gross and microscopic motion between all implant, bone, and cement interfaces in prosthetic arthroplasty. It has been hypothesized that this debris elicits an inflammatory biological reaction, resulting in bone loss, implant loosening, and subsequent arthroplasty failure. It is generally accepted that factors influencing the bioreactivity of tissue to debris include the amount (mass burden) of debris and the size, shape, and surface properties of the particles. There have been several qualitative studies of particulates visible by light microscopy in human tissues, but there are few studies with clinically derived data on the submicrometre fraction. Therefore, in this study, data on the size and mass of submicrometre human synovial-derived arthroplasty wear debris have been obtained. The particulates extracted from both tissues and isolated macrophages recovered at revision surgery were relatively monodispersed, with a mean diameter of 425 nm, and constituted approximately 1.8% of the tissue mass. In a hypothetical example involving debris from a sample of ASTM F 75 alloy in a 6-g sample of synovium, these numbers translate to 2.9 × 1011 particles, with a combined surface area of 1600 cm2. These findings suggest that particulates smaller than 500 nm may have an effect on material biocompatibility in arthroplasty.