research scientist, AdTech Systems Research,
In this study, the effect of loading frequency on delamination onset and growth characteristics of (30/−302/30/90)s IM6/3501-6 laminates, with and without an interleaf was studied. FM 300 adhesive layers, manufactured by American Cynamid, were placed at the 30/90 interface to study the influence of interleaf on the delamination characteristics of laminates. Quasi 3-D finite element analysis results indicate that the maximum interlaminar normal stress is lower in the laminate with the interleaf compared to the baseline laminate. Results also indicate that the presence of an interleaf reduces the Mode I component of strain energy release rate at the critical interface.
Experimental results indicate that the static delamination onset stress is greater in the interleafed laminate, but the ultimate failure strength of interleafed laminate is lower. The resistance to delamination growth is greater in the interleafed laminates under quasi-static loading. Under fatigue loading the delamination onset life and growth rate of both baseline and interleafed laminates were found to be frequency dependent.
Fractographic analysis of laminates reveals more hackles in interleafed laminates, indicating Mode II dominated failure. It was also noted that the matrix material exhibits greater ductility at lower loading frequencies in laminates with and without the interleaf.
Paper ID: CTR10529J