This paper deals with a numerical investigation on the influence of residual stresses on fatigue crack growth in AA2024-T3 friction stir welded butt joints. The computational approach is based on the coupled usage of the finite element method (FEM) and the dual boundary element method (DBEM), in order to take advantage of the main capabilities of the two methods. Linear elastic FE simulations a...

A methodology is evaluated to predict the probability of specimen failure with subsequent fatigue, after a short surface crack has been detected in Al 2219-T851 alloy. Cracks are detected and tracked to failure using optical microscopy. Predictions of remaining lifetime distributions are made with a i~onte Carlo procedure in conjunction with growth laws which model the effect of grains of diffe...

The Paris power law, which relates fatigue-crack growth rates to the applied stress-intensity range, is an example of a scaling law with the inherent property of incomplete similarity. Previous considerations of dimensions and self-similarity have suggested that the assumed ‘materials constants’ in this law are also a function of specimen size. In this note, the question of the size-dependence ...

A newly developed microstructure‐sensitive extreme value probabilistic framework for fatigue variability based on computational polycrystal plasticity is exercised to compare the driving forces for fatigue crack formation (nucleation and early growth) at room temperature for four different microstructure variants of duplex a Ti‐6Al‐4V alloy. The aforementioned probabilistic framew...

In this paper, and its companion Part 2 [Dong and Atluri (2013b)], the Symmetric Galerkin Boundary Element Method (SGBEM), and the SGBEMFEM alternating/coupling methods, are compared with the recently popularized Extended Finite Element Method (XFEM), for analyzing fracture and fatigue crack propagation in complex structural geometries. The historical development, and the theoretical/algorithmi...

In this paper, rotating bending fatigue tests of 2024-T4 Al alloy with different oxide coatings were carried out. Compared to the uncoated and previously reported oxide coatings of aluminum alloys, the fatigue strength is able to be enhanced by using a novel oxide coating with sealing pore technology. These results indicate that the better the coating surface quality is, the more excellent the ...

Fatigue-crack-growth tests were conducted on compact, C(T), specimens made of D16Cz (clad) aluminum alloy under constant-amplitude loading, a single spike overload, and simulated aircraft spectrum loading. Constant-amplitude tests were conducted to generate crack-growth-rate data from threshold to near fracture over a wide range of stress ratios (R = Pmin/Pmax = 0.1–0.75) using the new compress...

The objective of this work is to provide a rationale approach to de®ne the limiting conditions for high-cycle fatigue (HCF) in the presence of foreign-object damage (FOD). This study focused on the role of simulated FOD in a€ecting the initiation and early growth of small surface fatigue cracks in a Ti±6Al±4V alloy, processed for typical turbine blade applications. Using high-velocity (200±300 ...

INTRODUCTION Stress fractures are common in athletes, military recruits, and Thoroughbred racehorses, and may occur as hip fractures in the elderly. All of these injuries, to some extent, depend upon the propagation of fatigue cracks. Therefore, it is important to characterize the rates at which fatigue cracks grow and how microstructural differences found in cortical bone influence the crack g...

Ultra High Cycle fatigue leads to a failure initiated in the bulk material of a material. Some results on the nodular cast iron are presented: initiation occurs from the defects, located at the surface or in the bulk. It has been shown that environment plays a major role that could explain the difference between fatigue lives, for the surface and internal initiation. The influence of the defect...