IS THE STANDARD FOR TENSILE TESTING OF UNIDIRECTIONAL COMPOSITES OPTIMAL?

Tensile tests allow for preliminary mechanical characterisation of composite materials, but the standard recommended specimens (ASTM and ISO) often fail improperly near the grip leading to underestimation of the tensile strength and conservative component design. Reliable results in tensile testing can be obtained by avoiding or reducing stress concentrations near the grips. To this aim, the present study exploits FE analysis to assess potential end tabs designs and find an optimal specimen configuration that yields the maximum failure strain. The optimal design results, with circle-shape end tabs, are compared with the experimental tests and numerical models of ASTM standard test specimen and two promising approaches in the literature, namely, continuous tab and butterfly specimens.