نتایج جستجو برای: fatigue fracture
تعداد نتایج: 162207 فیلتر نتایج به سال:
A class of ultra-high-performance fibre-reinforced cementitious composites (UHPFRCC) has been developed at Cardiff university and registered under the trade name CARDIFRC. The method of its production and its mechanical and fracture properties were reported previously in a series of papers in Magazine of Concrete Research. Here the results of recent fatigue and shrinkage tests on this material ...
Bending fatigue failures OI cantilever type suction valve reeds occurred under operating conditions in a semi-hermetic refrigerant compressor during field trials. The finite element method (FEM) was applied to predict both the static and dynamic displacements and the resultant stresses of the reeds. The dynamic stresses in the location of the fracture exceeded the fatigue limit of the reed stee...
Fatigue is the progressive, localized, permanent structural change that occurs in materials subjected to fluctuating stresses and strains that may result in cracks or fracture after a sufficient number of fluctuations. Fatigue fractures are caused by the simultaneous action of cyclic stress, tensile stress and plastic strain. If any one of these three is not present, fatigue cracking will not i...
Compression-compression fatigue testing of metallic-glass foam is performed. A stress-life curve is constructed, which reveals an endurance limit at a fatigue ratio of about 0.1. The origin of fatigue resistance of this foam is identified to be the tendency of intracellular struts to undergo elastic and reversible buckling, while the fatigue process is understood to advance by anelastic strut b...
NASA has conducted an Airframe Structural Integrity Program to develop the methodology to predict the onset of widespread fatigue damage in lap-splice joints of fuselage structures. Several stress analysis codes have been developed or enhanced to analyze the lap-splice-joint configuration. Fatigue lives in lap-splicejoint specimens and fatigue-crack growth in a structural fatigue test article a...
In this study, we propose to approximate the a− n relation as well as the da/dn−∆K relation, in fatigue crack propagation, by using the Moving Least Squares (MLS) method. This simple approach can avoid the internal inconsistencies caused by the celebrated Paris’ power law approximation of the da/dn−∆K relation, as well as the error caused by a simple numerical differentiation of the noisy data ...
Steel plates with open holes are commonly used in structural assemblies. The fatigue properties of such details are influenced by bolted clamp-up and hole fabrication methods. The fracture surface, stiffness degradation and fatigue life of test specimens are investigated in detail and compared with the contemporary test data. The analysis results show that the presence of draglines greatly infl...
Recent advances in structural analysis technology such as the finite element method, improvements in the ability to model realistic sea loads, development of fatigue and fracture mechanics methods, development of reliability analysis methods, and the rapid advancements in computing technology, make it possible to develop methods to evaluate the structural strength of a ship, considering the req...
We present a theoretical study of the fatigue fracture of heterogeneous materials. A generic fiber bundle model is proposed, which provides a direct connection between the microscopic fracture mechanisms and the macroscopic time evolution of fatigue. In the model, material elements fail either due to immediate breaking or undergo a damage accumulating ageing process. On the macro-level the mode...
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