Testing Methods for Energy Absorption of Composite Materials

A total of 20 flat-plate specimens and 6 tubes were crushed under quasi-static conditions. The energy absorbency of each specimen was measured resulting in a value of the specific sustained crushing stress (SSCS). The plates and tubes were all manufactured from 49/CYCOM 919 Kevlar/epoxy fabric and had the same layup providing a common laminate for comparison. In addition, the data were also compared with existing data from flat-plate and tube AS4/3501-6 graphite/epoxy specimens. Two different widths of flat plates were tested to determine the effect of the end conditions of the testing fixture on the observed energy absorbency. The flat-plate results indicate that the energy absorbency per unit thickness is independent of the specimen width which indicates no significant contribution to the energy absorbency by the edges of the testing fixture. Furthermore the results indicate that the tube geometry provides comparable energy absorption values to the flat-plate geometry energy absorption values.