TESTING OF INPLANE SHEAR PROPERTIES UNDER FATIGUE LOADING

A two-dimensional finite element analysis is performed in order to ana lyze and improve the performance of the three-rail shear test specimen as prescribed by the ASTM Standard Guide for testing of in-plane shea r properties of composite laminates [1]. Of main interest is the locat ion of high-magnitude stresses in the matrix direction that affect the fatigue life of the specimen. Through finite element analysis, the op timal specimen configuration is determined by inserting slots in the p ositions 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 ver ified by three-rail shear tests performed for both standard un-notched and new notched specimens. The notched specimens show great improveme nt in both static strength and fatigue life.