A Alavi Nia - Associate professor, Bu-Ali Sina University
A Shirazi Beheshtiha - Master of Science Graduate, Bu-Ali Sina University

In this paper, effect of strain rate on mechanical behavior of aluminum thin-walled tubes with various section shapes (circular, hexagonal, square and triangular) are investigated both experimentally and numerically. Kinetic energy of impact mass is considered steady in order to obtain mean crushing force, initial peak load, crushing force efficiency, specific absorbed energy and maximum crushing distance in different strain rate. Non-linear finite element software LS-DYNA is used to analyze the axial compression behavior of thin-walled member under an impact load. To elucidate the effect of dynamic impact on the strain rate, the Cowper–Symonds equation is applied to analyze the plastic state of stress and the onset of dynamic yielding under different strain rates, such that the modeled deformation behavior of the member is consistent with the actual situation. Simulation and experimental data in all configurations show that crushing distance is decreased and mean crushing force and specific absorbed energy areincreased with rising strain rate. Also the results of simulation show that initial peak load is increased and crushing force efficiency is decreased in all of the figurations with rising strain rate.

thin-walled structures, impact load, axial strain rate, energy absorption