Dynamic Behavior and Impact Tolerance of Elastomeric Foams Subjected to Multiple Impact Conditions
Dynamic Behavior and Impact Tolerance of Elastomeric Foams Subjected to Multiple Impact Conditions
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DOI：
10.1007/s40870-022-00340-z
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发表时间：
2022-06-08
影响因子：
1.7
通讯作者：
Kokash, Y.
中科院分区：
文献类型：
--
作者：
Koohbor, B.;Youssef, G.;Kokash, Y.
超弹性泡沫是一类理想的冲击缓解材料，应用于可能存在不止一个冲击载荷事件的场合。然而，用于表征经受多种冲击条件的超弹性泡沫的冲击耐受性的方法和方案是有限的，并且提供的关于材料的冲击承载功效的信息不足。在这项工作中，我们提出了一个全面的实验方法，允许调查的动态行为和耐冲击性的一种新的弹性体聚脲泡沫。所提出的方法包括传统的实验技术，例如，冲击力分析，辅以全场应变测量和泡沫的应变相关泊松比的评价作为额外的指标，使详细的研究泡沫的宏观动态行为的演变，在响应多个冲击与可变的冲击能量。实验测量与细观有限元分析和变形后的显微组织观察相结合。本文获得的结果表明，内部损伤形成的可能性，作为影响缓解功效略有下降的主要来源。具体而言，泡沫中高度拉伸的聚脲细胞壁被确定为微观永久性损伤的来源。尽管在多次冲击加载期间产生了显著的损害，但泡沫保持了有效水平的总体冲击能量减缓能力。
Hyperelastic foams are an ideal class of impact mitigating materials in applications where more than a single impact loading event may exist. However, methods and protocols used to characterize impact tolerance in hyperelastic foams subjected to multiple impact conditions are limited and provide insufficient information about the impact load-bearing efficacy of the material. In this work, we present a comprehensive experimental approach that allows for investigating the dynamic behavior and impact tolerance of a novel elastomeric polyurea foam. The proposed approach includes conventional experimental techniques, e.g., impact force analyses, supplemented by full-field strain measurements and the evaluation of strain-dependent Poisson's ratio of the foam as additional metrics that enable a detailed study of the evolution of the macroscopic dynamic behavior of the foam in response to multiple impacts with variable impact energies. The experimental measurements are coupled with mesoscale finite element analyses and post-deformation microstructural observations. Results obtained herein indicate the possibility of internal damage formation as the primary source of the slight decrease in impact mitigation efficacy. Specifically, the highly stretched polyurea cell walls in the foam are identified as the source of microscopic, permanent damage. Despite the significant damage developed during the multi-impact loading, the foam retains an effective level of overall impact energy mitigation capacity.