Recent high-cycle fatigue (HCF) related failures of gas-turbine jet engines have prompted a re-examination of the design methodologies for HCF-critical components, such as titanium alloy turbine blades. As foreign-object damage (FOD) from ingested debris is a key concern for HCF-related failures of such blades, the current study is focused on the role of simulated high velocity FOD in affecting...

In previous work, fatigue-crack-growth tests were conducted on middle-crack tension, M(T), and compact, C(T), specimens made from the same D16Cz (clad) aluminum alloy sheet. These tests were conducted over a wide range of stress ratios (R = Pmin/Pmax = 0.5 to 0.75) to generate crack-growth-rate data from threshold to near fracture. These tests were used to generate the effective stress-intensit...

The inspection of various structures often detects a fatigue cracks developed during long service life. These fatigue cracks significantly reduce remaining fatigue life and fatigue strength. Influence of the initial fatigue cracks size in non-load-carrying fillet-welded one-sided transverse attachment joints on the remaining fatigue life and fatigue strength is considered in this paper. A compu...

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...

This paper reports the potential drop technique as an imaging tool for the clear identification and sensitive evaluation of very small surface cracks. The distributions of d-c potential drop around the surface cracks are obtained by scanning the closely coupled probes potential drop sensor, and a methodology for evaluating a 3-D crack from the potential drop profiles measured across and along t...