Comparison of the short beam shear (SBS) and interlaminar shear device (ISD) tests

Abstract

The Short Beam Shear (SBS) and Interlaminar Shear Device (LSD) tests are compared as methods for determining interlaminar shear strength of thermoplastic composite rings. The rings were manufactured using laser-assisted on-line consolidation and the interlaminar shear strength is taken as a measure of the quality of parts subjected to various processing conditions. Although a number of shear test methods have been developed for use with composite materials over the years, none provide pure uniform shear, or provide the entire stress-strain response to failure from a single specimen [Adams, D.F. and Lewis, E.Q., Current status of composite material shear test methods. SAMPE 31, 1994,6,32-401. Hence, a testing technique is required to provide efficient interlaminar shear strength results. Through the test results, it can be seen that a different mode of failure is acting in each of the tests. Finite Element Analyses (EEA) of the test procedures show that the stress state at the failure site for SBS is not interlaminar shear whereas it is the stress state in the failure zone of the ISD. Therefore, it is concluded that the ISD provides a better measure of the interlaminar shear strength of these specimens. 0 1997 Elsevier Science Limited