A NEW COMPRESSION TEST METHOD FOR THICK COMPOSITES

A test method was developed for determination of compressive properties of thick composite materials. A new fixture was designed and built based on the concept of transmitting the initial load through the tabs by shear loading and thereafter engaging the ends to apply the additional load to failure by end loading. This fixture was used to measure the longitudinal compressive properties of thick composite materials. It is shown that longitudinal compressive strengths of 1660 MPa (240 ksi) are obtainable experimentally for thick composites. Several factors were found to affect the results of these compression tests. They include alignment, specimen geometry, stress concentrations, specimen end-crushing, and timing of end-loading engagement.