9713566 Bank This project will study the energy-absorption capacity of composite material tubes when loaded in bending. The ability to absorb energy in flexural deformation is required in framed structural systems. This flexural energy absorption capacity is a central tenant of the design philosophy of steel and reinforced concrete structures, since it allows these structures to develop "plastic-hinge" mechanisms prior to failure. Such "hinges" provide reserve capacity, overall ductility, and an all-important safeguard against catastrophic failure. It is the objective of this project to demonstrate that pseudo-plastic hinges can develop in composite material tubular beams, thus, imparting to composite structural frames an energy- absorption capacity analogous to that found in conventional steel or reinforced concrete frames. The mechanism by which a composite material tubular beam develops "stable" energy absorption is, however, very different from that of a steel or reinforced concrete beam. In these conventional beams, the energy absorption is obtained due to irreversible plastic strain in the elasto-plastic materials. It is the purpose of this study to show that in a composite material tubular beam, energy is absorbed in a stable manner by progressive "tearing failure" at the tube corners, and that this provides the beam with a behavior analogous to that of an elasto-plastic beam. Such a phenomenon has recently been reported but an in-depth study has not been conducted. This research will investigate the phenomenon in-depth, by use of experimentation and numerical modeling, and provide recommendations for design. ***
