Borovinšek Matej, Vesenjak Matej, Hokamoto Kazuyuki, Ren Zoran
Faculty of Mechanical Engineering, University of Maribor, 2000 Maribor, Slovenia.
Institute of Pulsed Power Science, Kumamoto University, 2-39-1 Kurokami, Kumamoto City 860-8555, Japan.
Materials (Basel). 2020 Apr 21;13(8):1949. doi: 10.3390/ma13081949.
The study presents the results of an experimental and computational study of the high-velocity impact of low-density aluminum foam into a rigid wall. It is shown that the aluminum foam samples deformed before hitting the rigid wall because of the high inertial forces during the acceleration. During the impact, the samples deformed only in the region contacting the rigid wall due to the high impact velocity; the inertial effects dominated the deformation process. However, the engineering stress-strain relationship retains its typical plateau shape until the densification strain. The experimental tests were successfully reproduced with parametric computer simulations using the LS-DYNA explicit finite element code. A unique computational lattice-type model was used, which can reproduce the randomness of the irregular, open-cell structure of aluminum foams. Parametric computer simulations of twenty different aluminum foam sample models with randomly generated irregular lattice structures were carried out at different acceleration levels to obtain representative statistical results. The high strain-rate sensitivity of low-density aluminum foam was also observed. A comparison of experimental and computational results during aluminum foam sample impact shows very similar deformation behavior. The computational model correctly represents the real impact conditions of low-density aluminum foam and can be recommended for use in similar high-velocity impact investigations.
该研究展示了低密度泡沫铝高速撞击刚性壁的实验和计算研究结果。结果表明，由于加速过程中的高惯性力，泡沫铝样品在撞击刚性壁之前就发生了变形。在撞击过程中，由于撞击速度高，样品仅在与刚性壁接触的区域发生变形；惯性效应主导了变形过程。然而，工程应力-应变关系在致密化应变之前保持其典型的平台形状。使用LS-DYNA显式有限元代码通过参数化计算机模拟成功再现了实验测试。使用了一种独特的计算晶格型模型，该模型可以再现泡沫铝不规则开孔结构的随机性。在不同的加速度水平下，对二十个具有随机生成的不规则晶格结构的不同泡沫铝样品模型进行了参数化计算机模拟，以获得具有代表性的统计结果。还观察到了低密度泡沫铝的高应变率敏感性。泡沫铝样品撞击过程中实验结果与计算结果的比较显示出非常相似的变形行为。该计算模型正确地反映了低密度泡沫铝的实际撞击条件，可推荐用于类似的高速撞击研究。
