Study on energy absorption characteristics of expansion tube with light magnesium alloy

This paper proposed a lightweight magnesium alloy expansion energy-absorbing structure. The structure adopts lightweight materials, which can greatly reduce its own weight on the basis of ensuring energy absorption performance. Firstly, the geometric model of structure is designed and the corresponding physical prototype is processed. The theoretical model of magnesium alloy expansion tube is studied, and the main mechanical response is analyzed. Then the structural mechanical properties are studied by quasi-static compression test. Combined with the theoretical model, several typical deformation stages in expanding are analyzed. The effects of geometric parameters on the energy absorption performance are studied. The results show that with the increase of die angle, die expansion size and tube thickness, the maximum peak force, average force, energy absorption and specific energy absorption increase. Then the test results are compared with the corresponding theoretical steady force to verify the applicability of the theoretical model. The theoretical values are basically in good agreement with the experimental values. The error of all results is within 10%. Finally, comparing the characteristics of magnesium alloy, aluminum alloy and steel energy absorbing tube with the same quality, it is concluded that the specific energy absorption of magnesium alloy structure is 31.6% and 4.1% higher than that of steel and aluminum respectively, and magnesium alloy tube has higher specific energy absorption.