Experimental characterization of the effects of stacking sequence on the transverse crack behavior in quasi-isotropic interleaved CFRP laminates

Transverse crack behavior in quasi-isotropic interleaved CFRP laminates was observed by an optical microscope and a soft X-ray radiography system. Seven symmetric laminates composed of the same combination of ply orientations were tested to clarify the effect of stacking sequence on transverse crack behavior in 90 degrees plies. The thickness of 90 degrees plies and the modulus of adjacent plies were found to be most influential in their effect on transverse cracking behavior. To model the experimental results, damage mechanics analysis was used. The predictions of transverse crack evolution based on both energy and average stress criteria were compared with the experimental results. The validity of the present analysis was confirmed. The advantage of this analysis was its applicability to general laminate configuration, once the critical values were determined.