Extrapolation techniques at short gauge lengths based on the weakest link concept for fibres exhibiting multiple failure modes

Abstract

In order to extrapolate the tensile strength of ® bres at short gauge lengths corresponding, for instance, to the mean fragment length in a fragmentation test or the so-called load-transfer length for unidirectional composite failure models, four types of extrapolation techniques have been reviewed. The ability of these models to describe the tensile strength of ® bres is checked on E-glass ® bres exhibiting multiple modes of failure. It is shown that Weibull unimodal statistics as well as the bimodal Weibull cumulative distribution function model lead to underestimated results. The double box approach provides values having a physical meaning but remaining phenomenological. The need for modelling to take a trimodality into account is emphasized.

Strength of silicon wafers: fracture mechanics approach

“…To accurately describe the distribution of strength of a material with more than one failure mode, a multimodal (mixed) Weibull (Zinck et al 1999;Wolstenholme 1995) distribution can be used. For a typical brittle material such as silicon, the following three failure modes can be distinguished: bulk, surface, and edge mode (see Fig.…”