FRP composites have usually poor through thickness mechanical properties and thus are able to sustain more loads in tension than in compression and fails as a consequence of buckling. The through thickness reinforcement is carried out by stitching to improve the delamination strength and to reduce the in-plane crack growth rate. By preparing stitched and unstitched laminated plates using woven roving glass fibre mat and chopped strand glass fibre mat with polyester resin, the effect of stitching was studied. It is observed that stitching increases delamination strength to a great extent. There are losses in in-plane mechanical properties due to in-plane fibre damage and creation of resin rich pockets. The behavior of progressive crushing, triggering mechanism needed for progressive crushing and various energy absorbing modes during progressive crushing were studied both experimentally and theoretically. Analytical expressions for amount of energy absorbed in various modes, average crush stress were derived, and results thus obtained were compared with experiments.
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