In this work, fracture behavior of multilayered unidirectional graphite/epoxy composite (T800/3900-2) materials is investigated. Rectangular coupons with a single-edged notch are studied under geometrically symmetric loading configurations and impact loading conditions. The notch orientation parallel to or at an angle to the fiber orientation is considered to produce mode-I or mixed-mode (mode-...

An alternating method, in conjunction with the finite element method and a newly developed analytical solution for an elliptical crack in an infinite solid, is used to determine stress intensity factors for semi-elliptical surface flaws in cylindrical pressure vessels. The present finite element alternating method leads to a very inexpensive procedure for routine evaluation of accurate stress i...

A three-dimensional extended finite element method (X-FEM) coupled with a narrow band fast marching method (FMM) is developed and implemented in the Abaqus finite element package for curvilinear fatigue crack growth and life prediction analysis of metallic structures. Given the level set representation of arbitrary crack geometry, the narrow band FMM provides an efficient way to update the leve...

A symmetric-Galerkin boundary element framework for fracture analysis with frictional contact (crack friction) on the crack surfaces is presented. The algorithm employs a continuous interpolation on the crack surface (utilizing quadratic boundary elements) and enables the determination of two important quantities for the problem, namely the local normal tractions and sliding displacements on th...

In this paper, in order to predict the crack growth trajectory and to evaluate the SIF under mixed modes (I & II), one proposes a new finite element program for crack growth using the source code written in FORTRAN. The fin ite element mesh is generated using an advancing front method, where the generation of the background mesh and the construction of singular elements are also added to this d...

The diffraction of SH waves by a finite plane crack is studied. The classical Sommerfeld solution for a semi-infinite straight reflecting screen is used as a building block to calculate the diffracted field generated by a finite crack. The solution is derived from the analysis of the behaviour of diffracted waves. These waves, which are first generated at the edges of the crack, travel along th...

BACKGROUND Despite the multitude of public health and community harms associated with crack cocaine use, little is known about factors associated with smoking crack in public and related risks such as rushed public crack smoking. METHODS Data were derived from two prospective cohort studies of people who use illicit drugs in Vancouver, Canada between 2010 and 2014. Multivariable generalized e...

This paper focuses on the analysis of the partial differential equations arising from a new approach to modeling brittle fracture based on an extension of continuum mechanics to the nanoscale. It is shown that ascribing constant surface tension to the fracture surfaces and using the appropriate crack surface boundary condition given by the jump momentum balance, leads to a sharp crack opening p...

Title: Crack Growth During Brittle Fracture in Compression. Author: Bartlett W. Paulding, Jr. Submitted to the Department of Geology and Geophysics February 9, 1965 in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology. Photoelastic analysis of several two-crack arrays predicts that compressive fracture is initiated at cra...

In this paper, we’ll answer several abstract, formal questions about the nature of crack growth and nucleation. Bringing a field theory point of view to fracture illuminates things in what I hope will be an entertaining way. Formally, what is the crack nucleation rate? Fracture is an instability of elastic theory under tension. For thermally nucleated cracks, there is an analogy with supercoole...