Experimental Evaluation of Novel Foam-Filled Energy-Absorbing Composite Tubes

An experimental evaluation of a novel energy-absorbing device is presented. The device is composed of an angle-ply flexible matrix composite tube with a brittle foam filling. The device exhibits a large Poisson's contraction upon being loaded in tension due to high anisotropy of the composite shell material. Owing to this contraction, the foam filling inside the tube is radially crushed. The device exhibits multiple energy-absorbing mechanisms through foam crushing and damage in the composite shell. Energy-absorbing characteristics of crush tubes were experimentally evaluated by varying the fiber angle of the tube and the density of the foam. In the best case, a +/- 60-deg crush tube with 128 kg/m(3) foam exhibited a specific energy absorption of 13.9 J/g and a volumetric energy absorption of 8.10 MPa. The devices exhibit wide variations in force-displacement characteristics with changes in the parameters involved.