This work uses the non-linear finite element software LS-DYNA to analyze the axial compression behavior and energy absorption of a high-strength thin-walled member under an impact load. The stressstrain curve of high-strength steel is determined by performing static uniaxial tensile tests. To elucidate the effect of dynamic impact on the strain rate, the Cowper-Symonds equation is adopted during the plastic stage to calculate the dynamic yield strength under various strain rates, such that the modeled deformation behavior of the member is consistent with the actual situation. This work initially compares thinwalled members made of mild steel and dual phase steel. Under the condition that the components are made of different materials but have equal sectional areas, an analysis confirms that the high-strength steel thin-walled component outperforms the mild steel thin-walled component. Accordingly, thin-walled tubes made of high-strength steel are studied using a series of tests.
Industrial progress and energy shortages have caused auto-makers to prioritize the manufacture of lighter vehicles. In the process of weight reduction, however, structural safety under impact loading is ensured by using light materials whose ultimate strength can be readily and by using thin-walled members as energy absorbing components to increase the impact durability of the structure. Many scholars have developed various models for analyzing the axial bucking property of thin-walled members based on plastic hinge theory, experimentation or numerical simulation. Alexander (1960) observed the accordion-like axi-symmetrical deformation pattern of a cylinder under plastic buckling during an experiment, and proposed the concept of the static plastic hinge. Based on observations of the destruction pattern of the cylinder under axial compression, he proposed the model for energy absorption, which is still adopted by most of the scholars in the field because its computation is simple and its results are consistent with experimental outcomes.
