In situ observation of interactive failure modes in a single-edge notched symmetric cross-ply laminate using synchrotron X-ray tomography

Abstract

Interactive failure mechanisms of a single-edge notched (SEN) symmetric cross-ply laminate subjected to tensile loading are studied in situ using synchrotron X-ray tomography and a DIC technique at the micro- and macro- scales. The SEN configuration guarantees the repeatability and consistency of the progressive and interactive failure behavior at the two different scales. The evolution of various fracture modes in different layers is observed through synchrotron radiation CT images. Due to the geometrically asymmetric configuration, all the initial cracks sequentially occurring near the notch tip can be captured in a narrow field of view. Stress relaxation due to the subsequent fracture initiations is indirectly captured by measuring the crack lengths and opening displacements from the 3D CT images at different loading steps. The stress relaxation is directly measured by DIC analysis using the macro-scale test data. DIC results show strains relaxed in the region between existing and emerging transverse cracks.