基于面心立方孔洞堆砌模型的泡沫铝准静态及动态压缩模拟研究

以有限元分析软件 ANSYS 的 Workbench 为平台,以高孔隙率面心立方孔结构(Face centered cubic, FCC)的泡沫铝模型为对象,进行了准静态压缩和落锤冲击的有限元模拟。高孔隙率泡沫铝特指孔隙率(Porosity, Pr)在85%~90%之间的泡沫铝。已有的实验结果表明,孔隙率为90%的泡沫铝的准静态压缩下屈服平台应力值为3 MPa,当冲击应变速率在900 s-1以上时,其屈服平台的应力值稳定在7 MPa 左右；模拟结果与实验结果一致,并发现当应变速率达到35342 s-1后,泡沫铝的屈服平台应力值会再次大幅升高,达到14 MPa。根据泡沫铝压缩模拟的应力云图,揭示了不同应变速率下泡沫铝的吸能能力和变形模式的对应关系,并从结构变形的角度解释了泡沫铝的抗冲击吸能性能优于其准静态压缩的原因。

FEM Simulation Investigation on Al-foam Quasi-static and Dynamic Compression by Using FCC Pore Distribution Based Model

Based on Workbench of ANSYS,finite element method simulation software,the quasi-static and dy-namic compression behaviours of Al-foam with high porosity (Pr=85%-90%)were simulated by using a high poro-sity Face Centred Cubic distributed pore model.The previous experiment results show that the yielding plateau stress is about 3 MPa for the Al-foam under the quasi-static compression,and it stays about 7 MPa without significant in-crease for the impact with a strain rate over 900 s-1 .The simulation results not only match the experiment results, but also show the yielding plateau stress will increase to 14 MPa when the strain rate is up to 35342 s-1 .According to the comparison among different stress clouds of the Al-foam models,the deformation mode and the energy absorption ability are relevant to the compression strain rate.From the view of structure deformation,the different deformation modes can explain the fact that the Al-foam under dynamic compression can absorb more energy than those under the quasi-static compression.