It is generally accepted that residual stresses present in welded joints alter the conditions for fracture initiation by contributing to the crack-driving force. In this study, it is shown that weld residual stresses also alter crack-tip constraint, affecting fracture in an additional way. The fracture behavior of two crack geometries, a large pressure shell and a small fracture specimen, both ...

The fundamental requirement for the autonomous capsule-based self-healing process to work is that cracks need to reach the capsules and break them such that the healing agent can be released. Ignoring all other aspects, the amount of healing agents released into the crack is essential to obtain a good healing. Meanwhile, from the perspective of the capsule shapes, spherical or elongated capsule...

Effect of Cracks on Elastic Properties of Low Porosity Rocks by Terrence Patrick Todd Submitted to the Department of Earth and Planetary Sciences on May 1, 1973, in partial fulfillment of the requirements for the degree of Doctor of Philosophy Microcracks in terrestrial and lunar rocks significantly alter elastic, thermal, and mechanical properties. The degree to which microcracks alter physica...

This chapter is concerned with cracks . Real cracks in solids are complicated: they are thin cavities, their two faces may touch, and the faces may be rough. We consider ideal cracks. By definition, such a crack is modelled by a smooth open surface Ω (such as a disc or a spherical cap); the elastic displacement is discontinuous across Ω, and the traction vanishes on both sides of Ω (so that the...

Abstract Determination of S-N and Paris parameters form the two primary approaches as far fatigue testing is concerned. With many economic factors complexities involved in experimentation, these are not related to each other require implementation separate test standards for both them. In this work, an attempt made on interconvertibility experimental a numerical technique based virtual crack cl...

This paper describes algorithms for threedimensional dynamic stress and fracture analysis using the material point method (MPM). By allowing dual velocity fields at background grid nodes, the method provides exact numerical implementation of explicit cracks in a predominantly meshless method. Crack contact schemes were included for automatically preventing crack surfaces from interpenetration. ...

Failure analysis and fatigue life prediction are necessary and critical for engineering structural materials. In this paper, a general methodology is proposed to predict fatigue life of smooth and circular-hole specimens, in which the crack closure model and equivalent initial flaw size (EIFS) concept are employed. Different effects of crack closure on small crack growth region and long crack g...

In this work, XFEM is employed to obtain the stress intensity factors (SIFs) of a semi elliptical part through thickness axial crack. In XFEM, additional functions are employed to enrich the displacement approximation using partition of unity approach. Level set functions are approximated using higher order shape functions in the crack front elements to ensure the accurate modeling of the crack...