SCALING OF ENERGY ABSORBING COMPOSITE PLATES

The energy absorption response and crushing characteristics of geometr ically scaled graphite-Kevlar epoxy composite plates were investigated . Two different trigger mechanisms including notch, and steeple geomet ries were incorporated into the plate specimens to initiate crushing. Sustained crushing was achieved with a new test fixture which provided lateral support to prevent global buckling. Values of specific sustai ned crushing stress (SSCS) were obtained which were lower than values reported for tube specimens from previously published data. Two sizes of hybrid plates were fabricated; a baseline or model plate, and a ful l-scale plate with in-plane dimensions scaled by a factor of two. The thickness dimension of the full-scale plates was increased using two d ifferent techniques: the ply-level method in which each ply orientatio n in the baseline laminate stacking sequence is doubled, and the subla minate technique in which the baseline laminate stacking sequence is r epeated as a group. Results indicated that the SSCS has a small depend ence on trigger mechanism geometry. However, a reduction in the SSCS o f 10-25% was observed for the full-scale plates as compared with the b aseline specimens, indicating a scaling effect in the crushing respons e.