Cohesive-zone models have been used to study the effects of strength and toughness on the delamination of beam-like geometries. The conditions under which linear-elastic interfacial mechanics provide a good frame-work for predicting failure of such systems have been studied. It has been determined that the phase angle derived from LEFM calculations provides an excellent description of the parti...

The fatigue resistance of aerospace structures is degraded by the presence corrosion damage. This work characterizes micro-scale (<50 µm) morphologies and underlying microstructure AA7050 that impact crack formation. Corroded specimens were cycled to failure using a fracture surface marking spectrum. Pre-test characterization, fractography EBSD performed. No damage or metric independently corre...

Serial mechanical sectioning and high resolution X-ray tomography have been used to study the three-dimensional morphology of small fatigue cracks growing in a 12 Cr tempered martensitic steam turbine blade material. A range of surface conditions has been studied, namely polished and shot peened (with varying levels of intensity). In the polished (unpeened) condition, inclusions (alumina and ma...

For many fracture problems of practical engineering importance, the three-dimensional effects are significant and a three-dimensional analysis for the problems is thus required. In this paper, an endochronic theory coupled with anisotropic damage is first established, which is actually an elasto-plastic damage theory coupled with isotropic-nonlinear kinematic hardening. The ductile damage evolu...

The welding heat input has a great influence on the weldments properties. This paper describes the influence of welding heat input on the weld metal toughness of high-carbon steel surface welded joint. The steel is surfaced with self-shielded wire, with three different heat inputs (6.5; 10.5 and 16 kJ/cm). Total impact energy, as well as crack initiation and crack propagation energies, are esti...

Modelling quasi-static crack growth with interface elements is a widely accepted technique [1-2]. Interface elements are inserted into the finite element mesh along possible crack paths. The interface elements are characterised by a traction-displacement curve. When a specific maximum stress is reached, the interface element undergoes a softening process until the critical fracture energy has b...

An understanding of the evolution of toughness is essential for the mechanistic interpretation of the fracture of cortical bone. In the present study, in vitro fracture experiments were conducted on human cortical bone in order to identify and quantitatively assess the salient toughening mechanisms. The fracture toughness was found to rise linearly with crack extension (i.e., rising resistance-...

A two dimensional finite model with inclined crack at different crack angles are being analyzed in mixed mode condition using photo elasticity method for the determination of Stress Intensity Factors. The well-known Sih’s equation and three points deterministic approach is used for the determination of stress intensity factors. The effects of biaxial load factor, crack angle, size factors were ...

The purpose of this research is to determine the resistance to the stress corrosion cracking (SCC) of three unidirectional (pultruded) E-glass/polymer composites based on modified polyester, epoxy and vinyl ester resins. The composites have been subjected to a nitric acid solution of pH 1.2 in a newly designed four-point bend fixture. The stress corrosion process was initiated on the as supplie...

PURPOSE The aim of the present study was to assess the influence of pre-treatments of zirconia by sandblasting and/or heat treatment on the flexural strength of zirconia and debonding/crack-initiation strength of porcelain-veneered zirconia ceramic. MATERIALS AND METHODS Zirconia ceramic specimens were divided into four groups according to treatment (grinding as controls, sandblasting, heat t...