Mechanics of shock induced pore collapse in poly(methyl methacrylate) (PMMA): Comparison of simulations and experiments
Mechanics of shock induced pore collapse in poly(methyl methacrylate) (PMMA): Comparison of simulations and experiments
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DOI：
10.1016/j.jmps.2020.104075
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发表时间：
2020-10
影响因子：
5.3
通讯作者：
N. Rai;E. Escauriza;D. Eakins;H. Udaykumar
中科院分区：
文献类型：
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作者：
N. Rai;E. Escauriza;D. Eakins;H. Udaykumar
对透明材料聚甲基丙烯酸甲酯(PMMA)中冲击波驱动的孔塌进行了计算和实验数据的比较。模拟使用了SCIMITAR3D，这是一种欧拉尖锐界面的多材料程序，而平板碰撞实验则使用超高速X射线成像进行可视化。实验和模拟在广泛的加载条件下进行；从绝热剪切带占主导地位的低强度加载区域一直到预期的流体动力孔洞坍塌区域。PMMA的偏应力响应采用各向同性速率相关塑性模型，压力采用Tillotson状态方程。计算主要在2D中完成，以节省计算工作量，但也执行有限数量的3D计算来评估维度带来的差异。对于孔道形状的演化，二维计算结果与实验结果吻合较好。3D计算虽然计算量很大，但确实能与实验数据更好地吻合。在描述从强度为主向流体力学为主的孔洞坍塌转变的加载强度时，计算结果也与实验很好地吻合。这项工作使人们对欧拉尖锐界面计算技术在一系列加载条件下正确地表示和理解加载冲击波的多孔凝聚相材料的力学的能力充满信心。
Head-to-head comparisons are made between calculations and experimental data on shock-driven pore collapse in the transparent material, poly(methyl methacrylate) (PMMA). Simulations are performed using SCIMITAR3D, an Eulerian sharp-interface multi-material code, while plate impact experiments are visualized using ultra-high speed x-ray imaging. The experiments and simulations are conducted over a wide range of loading conditions; from low strength loading regimes where adiabatic shear banding predominates all the way up to the regime where hydrodynamic pore collapse is expected. PMMA is modeled using an isotropic rate-dependent plasticity model for the deviatoric stress response and a Tillotson equation of state for the pressure. Calculations are primarily done in 2D, to save computational effort, but a limited number of 3D calculations are also performed to assess the differences entailed by the dimensionality. The 2D calculations are in fairly good agreement with the experimental results, for the evolution of pore shape. 3D calculations, while quite computationally intense, indeed produce better agreement with experimental data. The computations also agree well with the experiments in delineating the loading strength at which a transition from the strength-dominated to hydrodynamics-dominated pore collapse occurs. This work provides confidence in the ability of Eulerian, sharp interface computational techniques to correctly represent and understand the mechanics of shock-loaded porous condensed phase materials over a range of loading conditions.