Comparison of the shear behavior in graphite-epoxy composites evaluated by means of biaxial test and off-axis tension test

Abstract Characterization of shear behavior in composite materials remains a not fully solved problem. In the last fifty years, many different approaches have been proposed to solve this problem (rail shear, thin-walled tube torsion, off-axis tensile, ±45° Arcan, Iosipescu, asymmetric four-point bend, plate twist, v-notched rail flexural, and frame), although none these achieved an unquestionable solution. For reason, proposals alternative methods comparison between experimental techniques are interest. present work, use cruciform samples with fiber oriented at 45° respect load directions, subjected tension-compression (creating pure stress state central part samples), is studied. The results compared tests (with 10°) for same material (AS4/8552), finding good agreement curves, especially initial curve, where modulus calculated. Nevertheless, strength value obtained by means specimen has shown be significantly lower than that using test. A Finite Element numerical model developed analyze field samples. Numerical there area specimens uniform developed, which suitable evaluation constitutive law material. It observed ( ? 22 ) concentration transition straight curved parts boundary geometry samples, explain some premature failures This failure could avoided tabs extended up beginning sample.