bluuebunny/crossref_metadata_2025_split huggingface dataset:
A CRITICAL REVIEW OF CRACK TIP STRESS INTENSITY FACTORS FOR SEMI‐ELLIPTIC CRACKS*
Authors: SCOTT P. M. , THORPE T. W. 
Published: April 2007

AbstractSeveral crack tip stress intensity factor solutions have been published for semi‐elliptic, surface breaking cracks in plates subjected to tension or bending forces. These solutions do not agree with each other particularly well and the basis for choosing which one is the best has not been established. In this paper, the development of fatigue crack shape is used as a diagnostic tool to test the accuracy of these theoretical stress intensity solutions in predictive fatigue crack growth calculations. Those solutions giving the best engineering estimate of crack tip stress intensity factors are identified. Single equations are also given for each loading case at the deepest point or surface intersection point of semi‐elliptic cracks in order to facilitate calculations on programmable calculators. A rational basis for calculating the progress of a crack which snaps through the thickness and continues to propagate in a stable way by fatigue is suggested.
STRESS‐RATIO EFFECT OF FATIGUE CRACK PROPAGATION IN A BIAXIAL STRESS FIELD
Authors: HOSHIDE T. , TANAK.A K. , YAMADA A. 
Published: April 2007

AbstractFatigue crack propagation tests were conducted under conditions of equibiaxial, uniaxial and shear loading by using a cruciform specimen in a servo hydraulic testing machine. The effect of non‐singular stress cycling on the fatigue crack propagation rate was examined based on the observation of crack opening behavior. The crack propagation rate was significantly influenced by the non‐singular stress parallel to the crack when it was correlated to the stress intensity range. The crack closure behavior was greatly affected by the non‐singular stress. The crack propagation rate was uniquely correlated to the effective range of the stress intensity factor except for the case of completely reversed shear loading where significant plasticity was detected. The crack opening displacement range was concluded to be a parameter controlling the crack propagation rate for all the stress conditions examined in the present experiments. Some discussion is made on the effect of material anisotropy on fatigue crack propagation in a biaxial stress field.
FATIGUE DAMAGE IN 1045 STEEL UNDER CONSTANT AMPLITUDE BIAXIAL LOADING
Authors: Hua C. T. , Socie D. F. 
Published: April 2007

The progressive nature of fatigue damage under multiaxial stress states has been investigated. Experiments were performed on thin‐wall tubular specimens of 1045 steel in tension, torsion and combined tension‐torsion loading. Two equivalent strain amplitudes, one in the high cycle fatigue (HCF) region and one in low cycle fatigue (LCF) region were employed in this study. Four recently proposed damage theories were evaluated. Crack depth was used as a damage parameter in comparing damage curves under different loading modes.Different types of crack systems were observed in the HCF and LCF regions. The damage curve obtained in tension loading can be used to evaluate the damage behavior under combined tension—torsion loading. The results of torsion loading show that torsional damage behavior is different from the above two loading modes.
EFFECTS OF PRE‐MOULDED WOVEN CFRP PATCHES ON FATIGUE CRACK GROWTH AND RESIDUAL STRENGTH IN 7475‐T761 ALUMINIUM ALLOY SHEET
Authors: Kemp R. M. J. , Murphy D. J. , Butt R. I. , Wilson R. N. , Phillips L. N. 
Published: April 2007

Fatigue crack propagation tests have been made on 150 mm wide panels of 1.6 mm thick 7475‐T761 clad aluminium alloy sheet with and without adhesively bonded patches of pre‐formed carbon fibre reinforced plastic (CFRP). The test frequency was 10 Hz, the minimum stress: maximum stress ratio, R, was 0.1 and the peak applied fatigue stress was 60 MPa.The tests were undertaken to assess the possibility of preventing the growth of fatigue cracks, or reducing their rate of growth, by the application of CFRP patches to one face only of pre‐cracked aluminium alloy sheet. The variables examined included the type of patch and adhesive; the size, shape and thickness of the patch; and the effect of chamfering the edges of the patch and the removal of the cladding prior to patching.Results indicated that correctly designed and bonded CFRP patches substantially decreased the subsequent crack growth rate. The size and thickness of the patch had significant effects upon the reduction of fatigue crack growth rate whereas the shape of the patch, chamfering and the removal of the cladding prior to patching had little influence.
FATIGUE CRACK GROWTH RATE BEHAVIOUR OF STAINLESS STEEL CLADDINGS IN AIR AND UNDER VACUUM AT 300°C
Authors: Pedron J. P. , Diboine A. , Pineau A. 
Published: April 2007

AbstractCT type specimens containing two layers of 309L and 308L cladding stainless steels welded to A508 carbon steel and 316 stainless steel were specially devised to test the influence of R ratio and environment on the crack propagation rate behaviour of cladding materials at 300°C. Large effects are shown. The crack growth rate under vacuum can be smaller by more than one order of magnitude as compared to air. Large differences are also shown on the fracture surfaces, where it is observed than vacuum promotes the formation of large crystallographic {111} facets. The effect of environment is briefly discussed on the basis of existing gas adsorption models.
THE EFFECTS OF MEAN STRESS AND STRESS CONCENTRATION ON FATIGUE UNDER COMBINED BENDING AND TWISTING
Authors: McDiarmid D. L. 
Published: April 2007

AbstractThe Gough test data on fatigue under combined bending and twisting with superimposed mean bending and torsion stresses with and without stress raisers has been re‐investigated in terms of the stresses acting on the plane of maximum range of shear stress. It has been shown that the allowable amplitude of shear stress on this plane can be predicted from an equation of the formτa= [t ‐ c1 (Kt×σa)1.5−c2σ2m]/Ktwhere σa and σm are the normal stress amplitude and mean normal stress respectively on the plane of maximum range of shear stress, c1 and c2 are defined material constants and Kt is the theoretical stress concentration factor.
MODELLING FOR FATIGUE CRACK GROWTH PREDICTION IN AIRCRAFT
Authors: Finney J. M. 
Published: April 2007

AbstractFatigue crack growth models, having application to Mirage III0 aircraft, have been calibrated with test data. Of the four crack growth retardation models examined—Wheeler, Willenborg, modified Willenborg and Crack Closure—the Wheeler and modified Willenborg models are the most satisfactory but both require calibration by test. Even so, crack growth is not accurately predicted when the specimen geometry and the test sequence are varied from those used in calibrating the models.Apart from the crack growth models, the main sources of inaccuracy in predicting crack growth are the inadequacy of the growth rate basic data, incorrect assumptions of crack shape and uncertainty in stress history. Thus, crack growth life may not be confidently predicted to better than a factor of two on actual life and, in some cases, the factor may be as high as ten.
FATIGUE LIFE BEHAVIOR OF MONOCRYSTALLINE COPPER IN 0.1 M PERCHLORIC ACID
Authors: Yan Benda , Farrington GregoryC. , Laird Campbell 
Published: April 2007

AbstractWe have studied the fatigue lives of single crystals of copper in 0.1 M HClO4under different polarization potentials. Perchloric acid was chosen for the aqueous environment because it allows us to control the corrosion reactions rigorously. Persistent slip band (PSB) behaviour and crack nucleation were studied during life, and fracture surfaces after failure.Different behavior was observed depending on strain amplitude. At 2 × 10‐3 plastic shear strain amplitude, anodic potential was observed to decrease life, whereas cathodic potenlial was found to be less damaging than laboratory air. Crack nucleation and propagation occurred along the primary slip plane for both conditions. The reduction of fatigue life under anodic potential is explained by enhanced localized strain at the PSB's and preferential dissolution within them.However, for a strain amplitude of 4 × 10‐3, cracks nucleated and propagated along the secondary slip system. We observed crack nucleation to be associated with deformation‐induced stress concentrations, and the aqueous solution showed no aggressive effect under either anodic or cathodic potential.
FATIGUE OF POLYCRYSTALLINE COPPER AT CONSTANT AND VARIABLE PLASTIC STRAIN AMPLITUDES
Authors: Kuokkala V.‐T. , Kettunen P. 
Published: April 2007

AbstractFatigue behavior of polycrystalline copper of two different grain sizes was studied using constant and randomly varying plastic strain amplitude tests. The different regimes in the ess‐curves of large‐grained samples (d˜ 2.0 mm) were found to be reflected also in the measured fatigue lives in both test modes. The variable amplitude fatigue lives of the small‐grained samples (d˜ 0.03 mm) seemed to follow the Coffin–Manson linear law. The damage accumulation rate in variable amplitude tests was found to be lower than in the corresponding constant amplitude tests, e.g. when expressed as cumulative plastic strains to failure. The fatigue life predictions based on the Palmgren–Miner rule, rain‐flow analysis and the constant amplitude life data measured in this work were also conservative.
FATIGUE DAMAGE IN 1045 STEEL UNDER VARIABLE AMPLITUDE BIAXIAL LOADING
Authors: Hua C. T. , Socie D. F. 
Published: April 2007

Abstract—During constant amplitude loading, two different types of crack systems have been reported In the high cycle fatigue (HCF) region, cracks nucleate on a small number of maxium shear strain amplitude planes One of these cracks becomes a dominant crack and leads to failure of the specimen In the low cycle fatigue (LCF) region, equally developed microcracks are observed over the entire gage section and grow during the majority of the life. The failure is due to a linking in which the microcracks join up during the last few cycles of the fatigue life.To investigate the interaction of these two types of crack systems in biaxial fatigue, experiments were performed on thin‐wall tubular specimens in tension, torsion and combined tension‐torsion loading The test program included step loading and block loading in which two equivalent strain amplitudes were employed. One of the equivalent strain amplitudes is in the HCF region and the other was in the LCF regionFatigue lives were predicted from constant amplitude damage curves when a single crack system dominated the fatigue process Two competitive crack systems were sometimes developed on the maximum shear strain amplitude planes in a single specimen under block loading This resulted in a conservative prediction of the fatigue life.
ON FATIGUE CRACK SIZE DISTRIBUTIONS IN COPPER SINGLE CRYSTALS
Authors: Bao‐Tong Ma , Laird Campbell 
Published: April 2007

AbstractMeasurements of crack depths by newly developed sectioning techniques raise questions about the validity of the optical microscopy technique used by Cheng and Laird for measuring crack size distributions. Accordingly, these measurements have been repeated using an improved technique. The cracks have thus been found deeper than reported earlier. This result suggests that random‐walk mechanisms for crack nucleation apply to the earliest stages of fatigue life. Moreover, it is found that the crack size distribution matches the distribution of local strains in persistent slip bands, suggesting that Stage I crack propagation kinetics are controlled by the local plastic strain.
FATIGUE AT LOW GROWTH RATES IN A MARAGING STEEL
Authors: Clark Graham 
Published: April 2007

AbstractThis paper describes an experimental investigation of fatigue‐crack growth in an ultra‐high strength maraging steel, with particular attention to the relationship between crack growth rate and microstructural element size. The occurrence of intergranular fracture is shown to be unrelated to any grain size‐plastic zone size equivalence, while inflections in the growth rate vs ΔK relationship are discussed in terms of the interaction between the plastic zone and other microstructural dimensions. The incidence of intergranular fracture and crack surface oxide is shown to decrease with decreasing test frequency.
CYCLIC STRESS‐STRAIN RESPONSE OF 2 1/4Cr‐1 Mo STEEL AT ELEVATED TEMPERATURES
Authors: Polák J. , Klesnil M. , Helešic J. 
Published: April 2007

AbstractThe temperature dependence of the cyclic stress‐strain response of 2 1/4 Cr‐1 Mo steel has been studied in the temperature range 20–550°C. Fatigue hardening‐softening curves and cyclic stress‐strain curves were obtained. A more detailed analysis was based on the statistical theory of the hysteresis loop and the concept of internal and effective stresses. A stress‐dip procedure allowed the separation of the contribution of internal and effective stresses both in dependence on temperature and during fatigue life in high temperature cyclic straining. The high effective stress contributes to the fatigue resistance of the steel. In high temperature fatigue both the internal and the effective stress decrease with cyclic straining.
AN EGF EXERCISE IN PREDICTING DUCTILE INSTABILITY: PHASE 2, CRACKED PRESSURE VESSEL
Authors: Milne I. , Knee N. 
Published: April 2007

AbstractThis report discusses the results of a collaborative European Group on Fracture exercise to predict the pressure‐crack size relationships of an experimental cracked pressure vessel which was undergoing tests for the CEGB. The details of the test and background mechanical properties data had been circulated to interested parties with a request for predictions to be returned prior to the vessel test results being published. The results of this exercise are described here, analysed in detail and compared with the test results.Collectively, eighteen individuals provided thirty eight different estimates of the vessel behaviour. The procedures used included R6 and variants of it, crack tip opening displacement approaches, engineering J design curve approaches, simple plastic collapse criteria and the GE J estimation scheme.Analysis of the predictions showed that:(1) in the prediction of maximum pressures, the plastic limit pressure was important;(2) in the prediction of initiation pressures the initiation toughness dominated;(3) the detailed form of the resistance curve had little influence on either the crack growth predictions or the maximum pressure predictions.(4) all forms of failure assessment diagram based upon the R6 axes were capable of producing accurate predictions.(5) where a poor model was used to represent the cracked section the results were unsatisfactory.
THE EFFECTS OF SUB‐CRITICAL CRACK GROWTH ON THE FRACTURE BEHAVIOUR OF CRACKED FERRITIC STEELS AFTER WARM PRESTRESSING
Authors: Chell G. G. 
Published: April 2007

AbstractThe effects of sub‐critical crack extension on the fracture properties of ferritic steels after they have been subjected to warm prestressing are investigated. The crack growth is assumed to occur at the temperature of the final loading, after the warm prestressing and the subsequent unloading. Predictions of the fracture behaviour are made using continuum mechanics and a fracture criterion based on a modified J‐integral. The results of these calculations are consistent with those of a micromechanistic model of cleavage fracture from a sharp crack. Both the theories predict that the beneficial elevation in fracture load produced by warm prestressing is maintained after sub‐critical crack growth provided the latter is not greater than the compressive yielded zone formed on unloading.
A STUDY OF SHORT CRACK GROWTH IN TORSIONAL LOW CYCLE FATIGUE FOR A MEDIUM CARBON STEEL
Authors: Carbonell E. Perez , Brown M. W. 
Published: April 2007

AbstractA study of short crack growth for a medium carbon steel in low cycle torsional fatigue has been carried out in order to measure crack length and derive growth laws. Comparison with a previous analysis of uniaxial tests in low cycle fatigue for the same material provides a tentative basis for formulating an equivalent stress approach to describe uniquely the propagation of short cracks under multiaxial stress.
A SINGLE EXPRESSION FORMULA FOR INVERTING STRAIN‐LIFE AND STRESS‐STRAIN RELATIONSHIPS
Authors: Manson S. S. , Muralidharan U. 
Published: April 2007

AbstractStarting with the basic fatigue life formulaΔε/ΔεT= (Nf/NT)b+ (Nf/NT)can inversion formula is derived in the form N
f/NT= [(Δε/ΔεT)z/b+ (Δε/ΔεT)z/c]1/zwhere z is a function of strain range and the ratio c/b. The inversion formula is valid over the entire life range of engineering interest for all materials examined. Conformity between the two equations is extremely close, suitable for all engineering problems. The approach used to invert the life relation is also suitable for the inversion of other formulas involving the sum of two power‐law terms.
A STUDY OF FATIGUE FRACTURE SURFACES OF A CAST NICKEL‐BASE SUPERALLOY
Authors: Weicheng Yu , Jincai Yuan , Zhongguang Wang 
Published: April 2007

AbstractMorphological features of fatigue fracture surfaces of a cast nickel‐base super‐alloy were investigated over the range of crack growth rates, 10‐10 ‐10‐6m/cycle. The cleavage facet growth in stage I and the transition of crack propagation from state I to stage II were studied by a combined study of surface crack growth rate and fracture surface examinations. A correlation between fatigue crack growth and the fracture surface appearance plus microstructural aspects has been established. It is suggested that fatigue‐induced vacancies might play a significant part in cleavage facet growth at lower crack growth rates.
FATIGUE ANALYSIS OF A RAIL SUBJECTED TO CONTROLLED SERVICE CONDITIONS
Authors: Rice R. C. , Rungta R. 
Published: April 2007

Abstract— A fatigue analysis was conducted on a rail that was placed in the Facility for Accelerated Service Testing (FAST) after a detail fracture was detected in service. The initial detail crack produced in service was grown to failure under controlled FAST conditions simulating service. Knowledge of the FAST wheel/rail load history for this rail made it an ideal candidate for quantitative fatigue crack growth analysis.The investigation revealed that undulations in the detail fracture surface were caused by changes in the direction of traffic. The angle of the facture surface, with respect to the running surface of the rail, was measured for each direction change. These results showed that the angles did not change significantly as the depth of the crack increased, relative to the running surface.The change in the direction of traffic and the associated change in the angle of the detail fracture provided benchmarks on the surface that were used to estimate the crack growth rate between each train reversal. The results showed that the rate of detail crack growth remained relatively constant from its initial size, until it broke out on the gage side of the rail. After gage‐side break out, the crack growth rate increased until failure of the rail occurred.This paper provides documentation on the process of detail fracture development in this specific rail. A discussion is also included which addresses the question of why detail fractures develop, and what the probable driving forces are for their growth.
FRACTURE TOUGHNESS OF NODULAR GRAPHITE CAST IRONS UNDER STATIC, IMPACT AND CYCLIC LOADING
Authors: Krasowsky A. J. , Kramarenko I. V. , Kalaida V. V. 
Published: April 2007

Abstract— The paper deals with the fracture toughness of nodular cast irons of differing microstructure and manganese content. Fracture toughness was determined for static and impact loading in the temperature range from 77 to 523 K. The dependences of fracture toughness on manganese content and microstructure were obtained.Fatigue crack growth rate curves were obtained at room temperature and a correlation between the parameters characterizing fatigue crack growth rate was found.Fractographic studies revealed an important role of graphite inclusions in the process of fracture. On the one hand, as stress raisers they favour the nucleation of microcracks while on the other hand, they cause local retardation of fatigue crack growth probably due to the residual compressive stress surrounding them. In the mid‐range of the fatigue crack growth rate curve a correlation was found between fatigue striation (or blocks of striations) spacings and the crack growth rate.
CEGB ASSESSMENT PROCEDURE FOR DEFECTS IN PLANT OPERATING IN THE CREEP RANGE
Authors: Ainsworth R. A. , Chell G. G. , Coleman M. C. , Goodall I. w. , Gooch D. J. , Haigh J. R. , Kimmins S. T. , Neate G. J. 
Published: April 2007

AbstractIn recent years considerable progress has been made in research work addressing the behaviour of defects at elevated temperature. Developments have been made both in structural assessment techniques and in methods for analysing representative materials data. On the basis of these developments a procedure has been produced within the CEGB for the assessment of defects in plant operating in the creep range under loadings for which creep rather than creep‐fatigue is the dominant failure mechanism. This paper describes the CEGB procedure. Calculations are required for three events: the time for overall structural failure by continuum damage mechanisms; the time for incubation prior to crack extension; and the time for subsequent growth to a maximum tolerable defect size. Methods are presented for calculating these times and for obtaining the materials data required to perform the calculations.
EXAMPLE OF AN APPLICATION OF AN ASSESSMENT PROCEDURE FOR DEFECTS IN PLANT OPERATING IN THE CREEP RANGE
Authors: Ainsworth R. A. , Coleman M. C. 
Published: April 2007

AbstractA worked example is presented to illustrate the application of a CEGB procedure for the assessment of defects in plant that operates within the creep range. The example chosen is a large cylindrical pressure vessel with a fully circumferential crack for which experimental results are available. The example demonstrates that it is straightforward to perform the calculations required in the procedure for the time for structural failure by continuum damage mechanisms, the time for crack incubation and the time for crack growth. It is predicted that crack incubation in the pressure vessel occurs at about one‐third of life with the remaining life being taken up by crack growth. The predictions are in close agreement with the experimentally observed incubation, growth and final failure times.
A MODEL FOR SHORT FATIGUE CRACK PROPAGATION WITH AN INTERPRETATION OF THE SHORT‐LONG CRACK TRANSITION
Authors: Navarro A. , Rios E. R. deLOS 
Published: April 2007

AbstractThe behaviour of short cracks approaching growth barriers (e.g. grain boundaries) is considered. The crack model of Bilby, Cottrell and Swinden is applied to simulate the blocking of the plastic zone at the grain boundary and to obtain the stress concentration ahead of the crack as it approaches the barrier. The idea of the Hall‐Petch type relationship that the transmission of slip across grain boundaries needs the previous achievement of a critical stress has been used. By making the crack growth rate proportional to the plastic displacement at the root of the crack the deceleration behaviour of short cracks and the existence of non‐propagating cracks may be explained. The fatigue limit is related to the stress below which a crack growing in a single grain is unable to promote slip in the neighbouring grain. The different behaviour in the so‐called long crack period has been rationalized in terms of the plastic zone exceeding the grain size. For this case, and in the grain completely included within the plastic zone, the Hall‐Petch analysis must be applied. Hence the maximum back‐stress sustained by this grain cannot exceed the yield stress. After this point the Bilby et al. model is used with uy as a friction stress (i.e. the Dugdale model). Finally use is made of Fracture Mechanics to correlate the results in the long crack phase.