Study On The Properties Of Energy Absorption Of Porous NiTi Shape Memory Alloy

In recent years, porous NiTi shape memory alloy has gotten more and more attention due to its excellent biological mechanical properties and biocompatibility, at the same time, people found that porous NiTi shape memory alloy is a good energy absorption material while related application research is rare. In this paper, we are using ANSYS/LS-DYNA finite element software to study the round pore structure porous NiTi shape memory alloy in-plane impact energy absorption, and discussed the porosity, pore topology structure, impact speed and martensite transformation on the influence of the energy absorption. And further discuss porosity change of gradient on the influence of the energy absorption. The results of the study show that:(1) Through the in-plane impact finite element simulation of single porosity model, we found that model with different kinds of pile mode or different impact velocity, their stress strain curve are similar, they all consist of four distinct regions, which is the linear region, the collapse region, the transformation region and the densification region. One must note that the collapse region and transformation region are associated with stress and appear alternately throughout the whole process;(2) The impact velocity and pore topological structure alone has no influence on energy absorption, but with these two acting together, energy absorption effect of model with topological structure for square pile column is better as impact velocity is higher;(3) For the porosity gradient step increasing (LMH) or decreasing (HML) change model, the ways that porosity change (increasing or decreasing) has almost no effect on the energy absorption, and the energy absorption curve of this model is among the curves of the models that constitute its minimum and highest porosity;(4) The martensite transformation absorbed most of the energy during the impact process.