The gas turbine exhaust uptakes in the HALIFAX class frigates of the Canadian Navy have experienced thermally-induced fatigue cracking since soon after the commissioning of these ships. The uptake structure is heavily stiffened in order to meet shock resistance requirements. Unfortunately, the result has been that thermal expansion of the uptake shell is constrained, thus every flash-up and shu...

The objective of this study was to evaluate the influence of microstructure on the susceptibility to high-cycle fatigue (HCF) failure in Ti–6Al–4V following foreign-object damage (FOD), specifically by comparing a fine-grained bi-modal microstructure with a coarse grained lamellar microstructure. FOD was simulated by high-velocity impacts of steel spheres on a flat surface. This caused a marked...

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...

Submarine propulsion shafts have demonstrated acceptable reliability performance when inspected and refurbished at least every 6 years. Designers wish to extend the inspection interval to 12 years without sacrificing reliability. This interval is unprecedented, as no known submarine shafting system is currently operated with this inspection cycle, nor are any known commercial vessel shafts. Exp...

The high-resolution X-ray CT was applied to investigate the fatigue damage evolution of asphalt mixtures. detailed Xray images in centre samples were used characterise cracking and air voids increase at different vertical deformations. Air void content surface area distribution before after loading also analysed. results show that main failure mode mixtures low temperature is debonding interfac...

Recently, magnesium alloys have garnered a lot of interest as potentially useful material for applications involving biodegradable implants. Cracking or fracture metal-based implants under the combined action corrosion and mechanical stresses, namely stress cracking (SCC) is an obviously critical criterion before any new might be deployed occurs simultaneous stresses. This article gives review ...

In fact, in the welding process, there are many problems that arise. Such as cracking caused by excessive stress Residual can result a decrease mechanical properties of material such brittle fracture, fatigue, and cracking. The purpose this study was to determine comparison tensile strength ASTM plate welded joints A36 with variations single vee butt bevel knowing effects ofpost-weldd heat trea...

There has been a renewed interest of late in the mechanisms responsible for the in ̄uence of the load ratio, R, and the maximum stress intensity, Kmax, on the threshold for fatigue-crack growth, DKth. While mechanistic explanations in the past have largely focused on the role of crack closure, it is certainly not the only mechanism by which Kmax in ̄uences DKth. In this work, we examine the e€ect...

Fatigue tests have been conducted on an advanced disc Ni-based superalloy (Low Solvus, High Refractory (LSHR) alloy) at 650 C in air under three-point bend loading to investigate the role of orientation-dependent grain boundary oxidation in crack initiation and early propagation. It is found that crack initiation occurs mainly from bulged grain boundary oxides, and cracks then predominantly pro...

There is an increasing need to assess the service life of components containing defect which operate at high temperature. This paper describes the current fracture mechanics concepts that are employed to predict cracking of engineering materials at high temperatures under static and cyclic loading. The relationship between these concepts and those of high temperature life assessment methods is ...