Axial Crushing and Energy Absorption of Empty and Foam Filled Jute-glass/Epoxy Bi-tubes

Experimental work on the axial crushing of empty and polyurethane foam filled bitubular composite cone-tube has been carried out. Hand lay-up method was used to fabricate the bi-tubes using woven roving glass, jute and hybrid jute-glass/epoxy materials. The tubes were of 56 mm diameter, and the cones top diameters were 65 mm. Cone semi-apical angles of 5 degrees, 10 degrees, 15 degrees, 20 degrees and 25 degrees were examined. Height of 120 mm was maintained for all the fabricated specimens. Effects of material used, cone semi apical angle and foam filler on the load-displacement relation, maximum load, crush force efficiency, and the specific energy absorption and failure mode were investigated. Results show that the foam filler improved the progressive crushing process, increased the maximum load and the absorbed energy of the bitubes. The maximum crushing load and the specific energy absorption increased with increasing the cone semi apical angle up to 20 degrees for the empty bi-tubes and up to 25 degrees for the foam filled bi-tubes. Progressive failure mode with fiber and matrix cracking was observed at the top narrow side of the fractured bi-tubes as well as at the bottom surface of 20 degrees and 25 degrees cone semi-apical angle bi-tubes.