ANALYTICAL AND EXPERIMENTAL COMPARISON OF TEST METHODS TO DETERMINE INTERLAMINAR SHEAR STRENGTH OF COMPOSITES

摘要

Test methods to accurately determine the interlaminar shear strength of composite materials has been a topic of controversy for over 30 years. Various methods have been applied to organic matrix composites, ceramic matrix composites and carbon/carbon composites. The primary methods utilized are Three Point Flexure, Four Point Flexure, Double Notched Shear, and to a lesser extent Tube torsion and Iosipescu. Detailed finite element analysis of the stress state in the Four Point Flexure and the Double Notched Shear configurations is presented. These are the two methods that are currently most widely applied. The finite element meshes are highly refined to highlight the areas of stress concentration in each configuration. Studies were conducted on the effects of mesh density in the initial phases of the study. Areas of stress concentration for Double Notched Shear tests are adjacent to the notches, whereas for the flexure tests it is the regions of support and load application.