Fatigue and Fracture of Engineering Materials and Structures
8756-758X
1460-2695
Anh Quốc
Cơ quản chủ quản: WILEY , Wiley-Blackwell Publishing Ltd
Lĩnh vực:
Materials Science (miscellaneous)Mechanics of MaterialsMechanical Engineering
Phân tích ảnh hưởng
Thông tin về tạp chí
Fatigue & Fracture of Engineering Materials & Structures (FFEMS) encompasses the broad topic of structural integrity which is founded on the mechanics of fatigue and fracture, and is concerned with the reliability and effectiveness of various materials and structural components of any scale or geometry. The editors publish original contributions that will stimulate the intellectual innovation that generates elegant, effective and economic engineering designs. The journal is interdisciplinary and includes papers from scientists and engineers in the fields of materials science, mechanics, physics, chemistry, etc.
Các bài báo tiêu biểu
Bauschinger effect of alloys and plasticity‐induced crack closure: a finite element analysis The effect of overloads, underloads and stress ratio on plasticity‐induced crack opening level is examined for different ‘model’ materials. This study is focused on the consequences of the Bauschinger effect on the crack opening level. Various finite element analyses were conducted using ABAQUS to test these effects, involving the Chaboche constitutive equations that take into account both the Bauschinger effect of the material and its cyclic hardening or softening. The cyclic plastic behaviour of the material is found to strongly affect the crack behaviour after an overload or an underload. The experimental data obtained on a 0.4% carbon mild steel confirm the numerical results.
Tập 23 Số 2 - Trang 129-139 - 2000
EFFECT OF SPECIMEN GEOMETRY ON FATIGUE CRACK GROWTH IN PLANE STRAIN—II. OVERLOAD RESPONSE Abstract— Overload tests were performed on compact tension (CT) and centre cracked panel (CCP) specimens made from 6082‐T6 aluminium alloy and BS4360 50B structural steel. The specimens were sufficiently thick for plane strain conditions to apply. Consistently greater retardation was observed in the CCP geometry than in the CT geometry. The effect of geometry is understood in terms of the T ‐stress and its effect on the overload plastic zone size. This was confirmed by biaxial tests in which the T ‐stress was varied independently of K. The action of machining off the side faces of an overloaded specimen did not eliminate the retardation; thus overload retardation is not due to a propping open by the surface regions of the specimen. Discontinuous closure was observed after overloads in the aluminium alloy and steel, as predicted by finite element calculations.
Tập 13 Số 3 - Trang 297-310 - 1990
Very high‐cycle fatigue behaviour of shot‐peened high‐carbon–chromium bearing steel ABSTRACT Effect of shot‐peening on fatigue behaviour in the gigacycle regime was investigated in order to clarify the duplex S–N curve characteristics. Cantilever‐type rotary bending fatigue tests were performed in laboratory air at room temperature by using hourglass‐shaped specimens of high‐carbon–chromium bearing steel, JIS SUJ2. Fatigue crack initiation site changed from the surface of untreated specimen to the subsurface of the specimen because of hardening and compressive residual stress with shot‐peening in the region of high‐stress amplitude. On the other hand, no difference in fatigue life controlled by the subsurface crack initiation between untreated specimen and shot‐peening one was observed in high‐cycle region. It was suggested that the S–N curve corresponding to the internal fracture mode is inherent in the material, as compared with the S–N curve of surface fracture mode, which is affected by surface conditions, environmental conditions and so on. Subsurface crack initiation and propagation behaviour were discussed under the detailed measurement of crack initiation area and shape of the fish‐eye fracture surface.
Tập 25 Số 8-9 - Trang 813-822 - 2002
FINITE ELEMENT ANALYSIS OF SPECIMEN GEOMETRY EFFECTS ON FATIGUE CRACK CLOSURE Abstract— Elastic‐plastic finite element analysis is used to study fatigue crack closure at three different crack length to width ratios for three plane stress specimen geometries: center‐cracked plate, single‐edge‐cracked plate (tension), and single‐edge‐cracked plate (bend). The maximum stress to flow stress ratio, Smax /σO , which successfully describes closure results in many center‐cracked plate configurations, does not correlate the effect of different geometries on the normalized opening stress, S open /S max . Crack opening stresses for different geometries and crack lengths are successfully correlated by a normalized stress intensity parameter, K max /K 0 , where K 0 =σ0 φa. The quality of the correlation is very high at small K max /K 0 , and gradually deteriorates as K max /K 0 increases beyond the small‐scale yielding regime.
Tập 17 Số 8 - Trang 861-872 - 1994
INFLUENCE OF AN OVERLOAD ON THE FATIGUE CRACK GROWTH IN STEELS Abstract— This study is concerned with the influence of a single‐peak overload and the overload ratio on the subsequent rate of growth of a fatigue crack in steels. Retardation increases with increasing overload ratio.The crack opening load was also measured during all tests. It is shown that the Elber's crack closure concept is not able to explain the effect of overloads. The importance of the material yield stress was evaluated by testing steels of different strength. It seems that the residual stress state induced by the overload is the major factor causing retardation. Two models are analyzed.
Tập 6 Số 1 - Trang 1-13 - 1983
INFLUENCE OF A NEGATIVE <i>R</i> RATIO ON THE CREEP‐FATIGUE BEHAVIOUR OF THE N18 NICKEL BASE SUPERALLOY Abstract— Crack growth rate measurements, performed on smooth specimens during creep‐fatigue testing of the N18 nickel base superalloy at 650°C, reveal a strong detrimental effect of the compressive part of the loading cycle. This effect is attributed to the residual stresses in the wake of the crack, which promote early crack opening. A finite element analysis is conducted in order to predict the evolution of the opening stress level as a function of the stress ratio. Good agreement is found between numerical and experimental results. The influence of the constitutive equation of the material on the crack closure level is tested and the effects of kinematic hardening and viscosity are more specifically examined. An engineering simplified method is proposed to determine the opening stress intensity factor as a function of crack length, stress ratio and maximum stress. This method, developed for cracks in smooth specimens, is then applied to small cracks growing from a notch root. Good agreement is found between the results given by the engineering simplified method and the result of the finite element analysis.
Tập 20 Số 1 - Trang 93-107 - 1997
A literature survey on the stability and significance of residual stresses during fatigue ABSTRACT Many manufacturing processes can induce residual stresses in components. These residual stresses influence the mean stress during cyclic loading and so can influence the fatigue life. However, the initial residual stresses induced during manufacturing may not remain stable during the fatigue life. This paper provides a broad and extensive literature survey addressing the stability of surface and near‐surface residual stress fields during fatigue, including redistribution and relaxation due to static mechanical load, repeated cyclic loads, thermal exposure and crack extension. The implications of the initial and evolving residual stress state for fatigue behaviour and life prediction are addressed, with special attention to fatigue crack growth. This survey is not a critical analysis; no detailed attempt is made to evaluate the relative merits of the different explanations and models proposed, to propose new explanations or models or to provide quantitative conclusions. Primary attention is given to the residual stresses resulting from four major classes of manufacturing operations: shot peening and related surface treatments, cold expansion of holes, welding and machining.
Tập 30 Số 3 - Trang 173-205 - 2007
FATIGUE OF THICK‐SECTION COLD‐EXPANDED HOLES WITH AND WITHOUT CRACKS Abstract— Fatigue tests under spectrum loading were conducted to evaluate hole cold‐expansion in thick‐section open‐hole aluminium alloy specimens, some of which contained residual fatigue cracks before cold expansion. Cold expansion resulted in an increase in life by a factor of about 7. Small residual fatigue cracks did not inhibit the effectiveness of the cold‐expansion process, indicating that it may not be essential to remove such cracks prior to hole cold‐expansion. The increase in life is primarily associated with a reduced crack propagation rate compared with that for cracks from non‐cold‐expanded holes. Cold‐expanded hole fractures displayed a marked disparity in crack depths adjacent to the two faces of the specimens. Considerable differences were evident in crack depths and fatigue crack areas at failure between cold‐expanded and non‐cold‐expanded hole specimens. These findings have ramifications in the damage tolerance assessment of aircraft structures.
Tập 12 Số 6 - Trang 553-567 - 1989
FATIGUE CRACK GROWTH IN RESIDUAL STRESS FIELDS: EXPERIMENTAL RESULTS AND MODELLING Abstract— The paper discusses the results of fatigue crack growth rate tests conducted in the presence of residual stresses. Three different residual stress distributions, obtained by laser welds, were employed in order to characterize the crack propagation behaviour under different conditions, producing either an increase or a reduction of the stress intensity factor due to external loads. Test results are analysed by means of a non‐linear numerical model (based on the weight function method) and a knowledge of the fatigue crack growth properties of the base material, free from residual stresses. The results of the analysis are discussed with reference to experimental trends, in order to clarify the predictive capabilities of the method and aspects needing further investigation.
Tập 17 Số 12 - Trang 1433-1444 - 1994
FINITE ELEMENT ANALYSIS OF CLOSURE BEHAVIOUR OF FATIGUE CRACKS IN RESIDUAL STRESS FIELDS Abstract An elastic‐plastic finite element analysis with high order elements is performed to examine closure behaviour of fatigue. cracks in residua1 stress fieids and the numerical results are then compared with experimental results. The finite element analysis, performed under plane stress using 8‐node isoparametric elements, can predict fatigue crack closure behaviour through residual stress fields very well. The crack opening and closing behaviour through a compressive residual stress field is found to be complicated and influenced by the applied load magnitude and the location of the crack tip. Three different types of crack opening behaviour, namely, normal, unsymmetric partial and symmetric partial crack opening behaviour are observed through a compressive residual stress field. The partial crack opening stress intensity factor including the partial crack opening effect is recommended for the prediction of fatigue crack growth through a compressive residual stress field.
Tập 18 Số 1 - Trang 105-117 - 1995