Determination of damage micromechanisms and fracture resistance of glass fiber/epoxy cross-ply laminate by means of X-ray computed microtomography

The onset and evolution of the damage in three dimensions was studied by X-ray computed micro-tomography (XCT) in a notched glass fiber/epoxy cross-ply laminate subjected to three-point bending. It was found that damage began by formation of intraply cracks in the 90° plies followed by intraply cracking the 0° plies. Fiber fracture in front of the notch tip occurred at 65% of the maximum load and finally fiber kinking and interply delamination took place under the loading point. Finite element (FE) simulations were carried out to understand crack initiation and the redistribution of stresses upon crack propagation. The crack area corresponding to each damage mechanism was quantified from the XCT images, and this information was used to determine the effective fracture resistance curve of the cross-ply laminate.