Double beam shear (DBS) as a new test method for determining interlaminar shear properties of composite laminates

We have developed a new test method, the DBS, at Loughborough University for determining interlaminar shear (ILS) properties in a single test. Overcoming the shortcomings of SBS and Iosipescu standards, the DBS method guarantees ILS failure at one of two pure ILS sections by promoting the dominance of ILS stresses. Extensive experimental validations of the DBS have been conducted along with SBS, using different types of composite material systems, involving different lay-ups. DBS ILS strengths are accurate, reliable and significantly greater in magnitude than SBS values. In particular, the DBS method is able to produce ILS failure in some composite laminates, which are unable to fail in delamination, using the SBS standard.