Energy Absorption in Composite Tubes

The collapse characteristics and energy absorption of a variety of tubes made in glass, graphite and Kevlar fiber composites have been examined. Tubes made from glass or graphite fibers collapsed by a fracture mode. There was a critical range of tube geometry over which stable collapse occurred with high energy absorption; thinner wall tubes tended to collapse in an unstable manner with lower energy absorption. Changes in the lay-up which increased the modulus increased the energy absorption of the tube. Tubes made from, or including Kevlar fiber, tended to collapse in an unstable mode by buckling rather than by fracture, which led to low values for specific energy absorption.