Effect of Z-pins distribution on mode Ⅰ delamination toughness ofZ-pinned laminated double cantilever beam specimens

With less than 5 % volume f raction of through2thickness Z-pins insertion , the delamination toughness ofZ-pinned laminates can be improved significantly and the delamination area induced by low-energy impact can also bereduced greatly. Based on the currently available Z-pin micro-model , a Z-pin element was developed and a beam element model for Z-pinned double cantilever beam (DCB) specimens was proposed in this paper to study the effect ofZ-pins dist ribution on the mode Ⅰdelamination toughness of Z-pinned DCB specimens. A contact element is also int roduced to the proposed model to avoid the unrealistic penet ration of the two subst rate beams at the delaminationcrack tip. The numerical results show that the Z-pin distribution has an insignificant effect on the mode Ⅰdelaminationtoughness of the Z-pinned laminated DCB specimens.