Library of geometric influences for SIF weight functions

Most researchers agree that the SIF is an important if not vital parameter in the assessment of defects prone to linear elastic fracture behaviour. Unfortunately the SIF is difficult to compute or measure, particularly if the crack is situated in a complex three-dimensional geometry or subjected to a non-simple stress state. Enormous developments in computing processing ability in the past few years has led to exciting Finite Element and Boundary Element approaches to the solution of SIFs in complex situations. These however, are likely to always remain the preserve of specialists. The need to provide quick robust and accurate SIF solutions for engineering defect assessment led to the development of a weight function approach to compose complex SIF solutions from simple constituent parts. These simple constituents make up a library that can be used with an appropriate composition algorithm to quickly build solutions for cracks in real engineering geometries. This paper describes the form of the "Library of Geometric Influences" for two dimensional symmetrical notch SIF Weight Functions. Future development of the approach to extend it to asymmetrical and three dimensional geometries is also discussed.