Testing of In-Plane Shear Properties under Fatigue Loading

Abstract

A two-dimensional finite element analysis is performed in order to analyze and improve the performance of the three-rail shear test specimen as prescribed by the ASTM Standard Guide for testing of in-plane shear properties of composite laminates [1]. Of main interest is the location of high-magnitude stresses in the matrix direction that affect the fatigue life of the specimen. Through finite element analysis, the optimal specimen configuration is determined by inserting slots in the positions at which there are stress concentrations. This has the effect of transferring the location of high stress away from critical areas, thus increasing the fatigue life of the specimen. The results are verified by three-rail shear tests performed for both standard un-notched and new notched specimens. The notched specimens show great improvement in both static strength and fatigue life.