bluuebunny/crossref_metadata_2025_split huggingface dataset:
INTERACTIVE EFFECT OF TWO COPLANAR CRACKS ON PLASTIC YIELDING AND COALESCENCE
Authors: XIN X. J. , RIOS E. R. DE LOS 
Published: April 2007

Abstract—A theoretical study of the conditions for coalescence of two fatigue cracks in a multi‐crack system is presented. As both cracks grow, the near‐side plastic zone sizes of the interacting cracks increase more rapidly than the off‐side zone sizes which results in higher overall crack propagation rates for an interacting crack growth system than the simple addition of individual crack growth rates. The use of a single crack growth model to predict failure in the presence of two or more cracks may therefore underestimate the interaction between cracks and lead to un‐conservative predictions. Some of the theoretical predictions were confirmed by published results of experimental measurements of crack interaction distances in multi‐crack systems.
ELASTIC‐PLASTIC STRESS ANALYSIS OF COLD EXPANDED FASTENER HOLES
Authors: Ball D. L. 
Published: April 2007

AbstractA closed form solution technique first presented by Hsu and Fonnan for the radial expansion of a fastener hole is extended to include elastic‐plastic unloading and therefore the creation of a reverse yielded zone. In addition, the dependence of interface pressure upon interference with an elastic insert is established. Numerous parametric studies are presented to demonstrate the effect of significant model variables and selected example calculations are compared with experimental results.
NOTCH SENSITIVITY OF ALUMINUM‐LITHIUM ALLOYS IN FATIGUE
Authors: Bian J.‐C. , Tokaji K. , Ogawa T. 
Published: April 2007

AbstractIn order to evaluate the notch fatigue strength and notch sensitivity of aluminum‐lithium, 2090 and 8090, alloys, rotary bending fatigue tests have been carried out using circumferentially notched specimens with different stress concentration factors. The results were compared with those of traditional aluminum, 2024T4 and 7075‐T6511, alloys. It was found that 2090 and 8090 alloys showed superior notch fatigue strength in comparison to the conventional aluminum alloys. The notch sensitivities to the crack initiation limit of the aluminum‐lithium alloys were lower than those of 7075‐T6511, while they were nearly equal to those of 2024T4 for blunt notches. The notch sensitivities to the crack propagation limit were also lower in aluminum‐lithium alloys, in particular the 8090 alloy, than in the conventional aluminum alloys. It was suggested that the decreased notch sensitivities of the aluminum‐lithium alloys were attributed to both the crack propagation mode and the excellent propagation resistance related to their microstructures.
A STATISTICAL MULTI‐SITE FATIGUE DAMAGE ANALYSIS MODEL
Authors: Wang G. s. 
Published: April 2007

AbstractA statistical model has been developed to evaluate fatigue damage at multi‐sites in complex joints based on coupon test data and fracture mechanics methods. The model is similar to the USAF model, but modified by introducing a failure criterion and a probability of fatal crack occurrence to account for the multiple site damage phenomenon. The involvement of NDI techniques has been included in the model which can be used to evaluate the structural reliability, the detectability of fatigue damage (cracks), and the risk of failure based on NDI results taken from samples. A practical example is provided for rivet fasteners and bolted fasteners. It is shown that the model can he used even if it is based on conventional S‐N coupon experiments should further fractographic inspections be made for cracks on the broken surfaces of specimens.
DAMAGE MECHANICS APPROACH TO REMOVE THE CONSTRAINT DEPENDENCE OF ELASTIC–PLASTIC FRACTURE TOUGHNESS
Authors: Wang T.‐J. , Kuang Z.‐B. 
Published: April 2007

AbstractIt is now generally agreed that the applicability of a one‐parameter J‐based ductile fracture approach is limited to so‐called high constraint crack geometries, and that the elastic‐plastic fracture toughness J1c, is not a material constant but strongly specimen geometry constraint‐dependent. In this paper, the constraint effect on elastic‐plastic fracture toughness is investigated by use of a continuum damage mechanics approach. Based on a new local damage theory for ductile fracture(proposed by the author) which has a clear physical meaning and can describe both deformation and constraint effects on ductile fracture, a relationship is described between the conventional elastic‐plastic fracture toughness, J1c, and crack tip constraint, characterized by crack tip stress triaxiality T. Then, a new parameter Jdc (and associated criterion, Jd=Jdc) for ductile fracture is proposed. Experiments show that toughness variation with specimen geometry constraint changes can effectively be removed by use of the constraint correction procedure proposed in this paper, and that the new parameter Jdc is a material constant independent of specimen geometry (constraint). This parameter can serve as a new parameter to differentiate the elastic‐plastic fracture toughness of engineering materials, which provides a new approach for fracture assessments of structures. It is not necessary to determine which laboratory specimen matches the structural constraint; rather, any specimen geometry can be tested to measure the size‐independent fracture toughness Jdc. The potential advantage is clear and the results are very encouraging.
FRACTOGRAPHIC ANALYSES OF FATIGUE CRACK GROWTH IN D16T ALLOY SUBJECTED TO BIAXIAL CYCLIC LOADS AT VARIOUS R‐RATIOS
Authors: Shanyavsky A. A. , Orlov E. F. , Koronov M. Z. 
Published: April 2007

Abstract Fractographic peculiarities of fatigue crack development are studied in cruciform specimens of D16T aluminium alloy under biaxial tension and tension‐compression. In the range of the biaxial load ratios λ from ‐ 1 to +1.5, and in the range of R‐ratios 0.05 to 0.8, fatigue striation formation took place over a crack growth rate near to 4×10−8 m/cycle. The striation spacing and the crack growth rate decrease as the ratios λ and R increase. The ratio between the increment of crack growth, da/dN, and the striation spacing, δ, is approximately 1:1 when da/dN is greater than 4×10‐−8 m/cycle. The relationship between the number of cycles from the beginning of a test up to the growth rate of 2.14×10−7 m/cycle (Nd), and the crack growth period, Np, from when the crack initiates up to the instant when that growth rate is reached, was determined for different λ and R‐ratios. The value of Nd increases as the stress ratio, λ, is increased.Cycle loading parameters must be taken into account in order to describe the crack growth period when using a unified method involving an equivalent stress intensity factor Ke, =K1,F(λ, Rs). The values of F(λ, R) for the growth rate (F(λ, R)s) and for the striation spacing (F(λ, Rs) were determined and compared.The fatigue crack growth period, Ntp, applicable to the stage of fatigue striation formation, (predicted by using both of the F(λ, R) values) is correlated with the experimental data and the error is of the order of 15%.
A FATIGUE‐CRACK‐GROWTH‐BASED ANALYSIS OF TWO‐STEP CORROSION FATIGUE TESTS
Authors: Ishihara S. , McEvily A. J. , Shiozawa K. 
Published: April 2007

AbstractA method for the analysis of two‐step fatigue level sequences is proposed and compared with experimental results. Two‐step loading tests of the aluminum alloy 2017‐T4 in 3% sodium chloride solution have been carried out in conjunction with a replica technique used to monitor the growth of fatigue cracks. Fatigue cracks were nucleated at corrosion pits 10–15 μm in size, and crack growth rather than crack initiation was found to take up the major portion of the fatigue lifetime in these tests. The results could therefore be analyzed on the basis of the following constitutive relation for fatigue crack growth. da/dN=A(ΔKeff‐ΔKeffth)2This analysis was simplified since the influence of transients in the crack growth rate induced upon change in load level was found to be minimal. The approach provides a rational basis for dealing with load‐sequence effects.
A STUDY OF FATIGUE AND CREEP BEHAVIOUR OF FOUR HIGH TEMPERATURE SOLDERS
Authors: Liang J. , Gollhardt N. , Lee P. S. , Schroeder S. A. , Morris W. L. 
Published: April 2007

AbstractCreep and cyclic deformation behavior of two lead‐free high temperature solder alloys, 95Sn‐5Ag and 99Sn‐1.0Cu, a high lead alloy 97.SPb‐1.SAg‐1.0Sn, and an Ag‐modified eutectic alloy 62.SSn‐36.1Pb‐1.4Ag, were studied. Room temperature and high (100°C and 150°C) temperature fatigue tests (with cyclic strain amplitude up to 6.0%) for the four solders were conducted, with the fatigue lives ranging from a few cycles to more than 100,000 cycles. It is shown that among the alloys studied, 62.SSn‐36.1Pb‐1.4Ag (the modified Sn‐Pb eutectic alloy) has the lowest fatigue resistance in term of low cycle fatigue life (strain controlled). The high lead alloy, 97.SPb‐1.5Ag‐1.0Sn, has the highest strain fatigue resistance in the large strain region (Δ > 2.0%). Temperature has a significant effect on alloys 95Sn‐5Ag and 99Sn‐1.0Cu, but has a negligible effect on the Ag modified Sn‐Pb eutectic alloy 62.5Sn‐36.1Pb‐1.4Ag and 97.5Pb‐1.5Ag‐1.0Sn. Creep studies show that these alloys generally have a very significant primary creep regime (up to 20%); thus, any realistic constitutive relation has to take such a primary creep phase into consideration. Cyclic deformation of alloy 95Sn‐SAg was simulated by using a constitutive relation built upon a 2‐cell model, which covers both primary and secondary creep. This model provides a good estimate of the peak stresses (the minimum stress and the maximum stress in each cycle); it agrees with experimental results when the applied cyclic strain is small and/or the applied strain rate is very low.
STATIC AND CYCLIC FRETTING FATIGUE BEHAVIOUR OF SILICON NITRIDE
Authors: Okane M. , Mutoh Y. , Kishi Y. , Suzuki S. 
Published: April 2007

AbstractA cyclic fretting fatigue test machine was constructed. The piezoelectric bimorphs were used as actuators for cyclic loading and fretting motion at the resonance frequency of the system. Fretting fatigue tests under static and cyclic loading conditions were carried out using HIP‐sintered silicon nitride. From the experimental results, it was found that fretting fatigue strengths under the two test conditions were identical and hence the effect of cyclic loading on fretting fatigue strength of silicon nitride was almost negligible. A fretting crack initiated in a very early stage of the fatigue life at the position of the maximum frictional stress in the contact area. Fretting fatigue life prediction based on fracture mechanics was also carried out. The predicted lives were in good agreement with the experimental results.
A TEST METHOD FOR MODE II FATIGUE CRACK GROWTH RELATING TO A MODEL FOR ROLLING CONTACT FATIGUE
Authors: Otsuka A. , Sugawara H. , Shomura M. 
Published: April 2007

Abstract— From fractographic observations of specimens that have failed due to rolling contact fatigue, it has been concluded that the first stage of damage is the formation of mode II fatigue cracks parallel to the contact surface due to the cyclic shear stress component of the contact stress. Although these initial subsurface cracks, in both metals and ceramics, are produced in a direction parallel to the cyclic shear stress, cracks eventually grow in a direction close to the plane of the maximum tensile stress if we apply a simple mode II loading to them. The difference between crack growth in simple mode II loading and crack growth due to rolling contact fatigue is, we suppose, whether or not there is a superimposed compressive stress. Based on this hypothesis, we developed an apparatus to obtain the intrinsic characteristics of mode II fatigue crack growth, and developed a simplified model of subsurface crack growth due to rolling contact fatigue.Some results in terms of da/dN versus ΔKII relations have been obtained using this apparatus on specimens of steel and aluminum alloys. Fractographs of the mode II fatigue fracture surfaces of the various materials are also provided.
VARIABLE AMPLITUDE LOADING OF SMALL FATIGUE CRACKS IN 6261‐T6 ALUMINIUM ALLOY
Authors: James M. N. , de los Rios E. R. 
Published: April 2007

Abstract— Constant and variable amplitude (VA) loading fatigue studies were carried out on a 6261 aluminium alloy using cylindrical plain hour‐glass specimens. Crack growth was monitored via surface replication using cellulose acetate.Crack growth results at constant amplitude loading show the typical intermittent high and low periods of growth rate associated with crack‐microstructure interactions. Acceleration in growth rate during an overload block depends on crack length and stress amplitude ratio. It appears to pass through a maximum at a crack length corresponding to the first microstructural barrier. Microstructural‐based modelling is therefore required for small fatigue cracks, rather than solely closure‐based modelling. The Navarro‐de los Rios model of short fatigue crack growth appears able to provide good indications of crack growth rates under VA block loading, and gives reasonable life predictions.For short cracks (surface length < 80 μm) and a small overload ratio (6.7%), crack growth may show severe retardation during the overload block. This is ascribed to crack tip blunting being more important than the increase in stresses when closure is low. It appears from a Miner's rule type exercise, that VA block loading has its major effect on growth at a surface crack length of 20 μm. This means that the crack initiation period cannot be ignored in life prediction models for small fatigue cracks.
NUCLEATION OF INTERGRANULAR CRACKS DURING HIGH TEMPERATURE LOW CYCLE FATIGUE OF SUS316 STAINLESS STEEL
Authors: Nishino S. , Sakai W. , Yamada K. 
Published: April 2007

Abstract—Fundamental behaviour of intergranular cracking of SUS316 stainless steel which characterises the high temperature low cycle fatigue process has been studied with a special emphasis on the interaction between oxidation and a grain boundary sliding. Two types of specimens were prepared for fatigue experiment to extract a sole effect of surface oxidation on crack nucleation. One was heat‐treated in air and the other was in vacuum so that the specimens had the same history of heat treatment except oxidation to the surface. Results of fatigue tests of these specimens well explain the relationship between oxidation and surface cracking as follows. The morphology of the oxidised surface of the specimen subjected to low‐cycle fatigue at 700°C is quite different from that of the oxidised surface caused by simply holding at the same temperature in air for several hours with no applied stress. Localised oxidation along the grain boundary is a characteristic feature for the specimen fatigued at 700°C, while no localised oxidation was observed when the specimens were simply held at the same 700°C, i.e. with no fatigue loading. Accordingly, intergranular cracking in high temperature low cycle fatigue in air occurs when grain boundary sliding due to cyclic loading is accelerated by localised oxidation along the grain boundary.
OVERLOAD EFFECTS IN ENVIRONMENTAL HYDROGEN INDUCED FRACTURE
Authors: Gao H. , Yang X. , Cao W. , De Los Rios E. R. 
Published: April 2007

Abstract—A study has been made of the effect of short periods of overloading on the environmental hydrogen induced fracture (HIF) life of 0.42% C, 0.87% Cr, 0.2% Mo steel tested in a 0.5 mol/L H2SO4 solution under continuously hydrogen charging conditions. Experimental results showed that when the overloading was applied during the early or middle stage of the test, the HIF life was longer than that obtained at constant stress; however, if the overloading was applied during the later stages, a shortened HIF life was obtained. It is important to note that the processes of HIF (including hydrogen absorption, transportation and accumulation, crack initiation and propagation) depend not only on the electrochemical condition, but also on both stress‐strain state and stress history. In view of the above considerations, effects of plasticity induced closure, residual compression stress, dislocation shielding and overload damage, which control HIF life, are discussed.
INFLUENCE OF SHOT‐PEENING ON SHORT CRACK BEHAVIOUR IN A MEDIUM CARBON STEEL
Authors: Natkaniec‐Kocada D. , Kocada S. , Miller K. J. 
Published: April 2007

Abstract—The results of research into short fatigue crack behaviour in shot peened, medium carbon steel specimens under reversed torsion are presented. Characteristic features of short crack growth were established on the basis of optical and electron‐optical observations of the replicas and micro‐sections of the samples. Surface crack growth analysis, supported by plots of crack development, crack growth rate and crack length distributions against cycle ratio show that significantly slower crack growth and lower crack densities occur in shot peened specimens than in non‐treated samples. That results can be linked to the effect of grain distortion, the packing of laminar grains, a high dislocation density in the plastically deformed surface layer and the introduction of compressive residual stresses. A fractographic analysis of the fracture surfaces has assisted an understanding of the mechanisms of fracture in shot peened specimens.
MICROCRACK PROPAGATION AND MICROSTRUCTURAL PARAMETERS OF FATIGUE DAMAGE
Authors: Beretta S. , Clerici P. 
Published: April 2007

Abstract— Modern approaches to microstructural analysis of fatigue in metallic materials consider the density and the total length per unit area of propagating surface microcracks as useful indicators of fatigue damage. Such parameters, when observed on a carbon steel studied in a previous paper, have a dispersion similar to that of fatigue life and they are linearly correlated with fatigue endurance.The aim of this paper is to extend the research on fatigue damage in the already studied carbon steel and to examine the scatter of crack propagation rate together with the evolution of surface cracks during fatigue life. The final aim of this work is to study how these two factors are correlated with fatigue life distribution in order to evaluate the effectiveness of damage detection methods.
CYCLIC FATIGUE OF Al2O3 AND Al2O3‐Al2TiO5 COMPOSITES IN DIRECT PUSH‐PULL
Authors: Bartolomé J. F. , Requena J. , Moya J. S. , Li M. , Guiu F. 
Published: April 2007

Abstract— A reaction sintering route is developed to produce, “in situ”, composites of alumina‐aluminium titanate using alumina and titania as starting powders. Aluminium titanate, can be formed by a solid state reaction between Al2O3 and TiO2 at temperatures above the eutectoid temperature of 1280°C. These composites have different grain sizes of alumina matrix and a different quantity and distribution of aluminium titanate according to the heating cycle used.In the present work direct push‐pull tests under cyclic loads have been carried out with both monolithic alumina and alumina‐aluminium titanate composites. It has been found that all the samples show a decrease in tensile strength with the number of applied cycles of loading when plotted in graphical form but the slopes of these graphs for both Al2O3‐Al2TiO5 composites are lower than for the alumina specimens. The role of aluminium titanate and the alumina matrix grain size in fatigue crack growth resistance has been studied during push‐pull tests, where failure occurs by catastrophic propagation of small surface cracks after a very short regime of subcritical crack growth. These results have been compared with measurements of slow stable fatigue crack growth rates in Al2O3‐Al2TiO5 composites carried out elsewhere with pre‐notched specimens of the compact tension type. These latter tests provide information about the behaviour of significantly long cracks, i.e. cracks that are several millimetres long.
LOW CYCLE FATIGUE BEHAVIOUR OF STRUCTURAL STEEL MEMBERS AND CONNECTIONS
Authors: Ballio G. , Calado L. , Castiglioni C. A. 
Published: April 2007

Abstract— An experimental study was carried out to investigate the low‐cycle fatigue behaviour of steel beam and beam‐column members, as well as of steel connections, with particular emphasis on beam‐to‐column joints. Several full‐scale specimens were tested, in a multi‐specimen testing program, using constant‐amplitude displacement histories, to develop a cumulative‐damage model. Variable amplitude tests were carried out in order to verify the validity of the proposed model.It is shown that the S‐N curves given by codes for high‐cycle fatigue can be used to interpret the low‐cycle fatigue behaviour of steel members and connections. Miner's rule can be used, together with the previously defined S‐N curves and with a cycle counting method to define a unified cumulative damage model valid for both high and low cycle fatigue. A general failure criterion is proposed which considers the actual energy dissipation through plastic deformation.
International Banking Facilities Revisited
Authors: Moffett Michael H. , Stonehill Arthur 
Published: April 2007

AbstractThe creation of International Banking Facilities (IBFs) in 1981 was an attempt by U.S. banking regulators to allow U.S.‐based banks and their offshore customers to have access to the Euromarket in a U.S. political and legal jurisdiction, operating in a U.S. time zone. The expected benefits were as follows: 1. the cost of capital for U.S.‐based banks (both U.S. and foreign‐owned) and their offshore customers, particularly multinational firms, would be reduced due to lower political risk, no reserve requirements, and no Federal Deposit Insurance Corporation requirements; 2. Banks could potentially reduce their operating costs to die extent that IBFs replaced offshore shell branches; 3. Additional bank employment would be created in the U.S.; 4. although IBFs would not be subject to U.S. Federal taxes, a geographical shift of bank assets to the U.S. might create a higher Federal tax revenue due to a reduction in foreign tax credit claimed by the banks.In retrospect the performance of IBFs has shown mixed results. With respect to cost of capital, the IBFs must have been cost effective because there has been an impressive growth in IBF assets and loans, coincident with a stagnation in the offshore bank shell branches. However, die largest benefit of this growdi has accrued to foreign‐owned IBFs. With respect to lower operating costs, the IBFs have not caused the offshore shell branches to close since they are needed to do business with U.S. residents. With respect to employment, bank employment in the U.S. has gone up marginally, although not nearly as much as originally predicted. The impact of IBFs on Federal tax revenues was not investigated in this study.Public policy impacts of IBF operations have also been less than expected in that IBFs have not eliminated the need for offshore shell‐branches in the Caribbean, although they have significantly stifled growth in these financial centers. The entrance of the Japanese Offshore Market in December 1986 and the potential that other countries may enter the competition could well have long term negative impacts on the growth potential of U.S. IBFs.
International Tax Issues Surrounding Cross‐Border Security Investments, Including Implications of Recent Revisions of the U.S. Tax Code
Authors: Hammer Richard M. , Crawford Charles T. 
Published: April 2007

AbstractThis article demonstrates how international tax considerations can affect international security investments. The investor who ignores international tax factors puts himself at a disadvantage relative to those who are atuned to international tax developments. Similarly, financial managers interested in successfully raising funds in foreign capital markets would do well to examine the tax implications of their international security offerings from the target investor's viewpoint.