Butruille Thomas, Crone Joshua C, Portela Carlos M
Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139.
Physical Modeling and Simulation Branch, DEVCOM Army Research Laboratory, Aberdeen Proving Ground, MD 21005.
Proc Natl Acad Sci U S A. 2024 Feb 6;121(6):e2313962121. doi: 10.1073/pnas.2313962121. Epub 2024 Feb 2.
Ultralight architected materials enabled by advanced manufacturing processes have achieved density-normalized strength and stiffness properties that are inaccessible to bulk materials. However, the majority of this work has focused on static loading and elastic-wave propagation. Fundamental understanding of the mechanical behavior of architected materials under large-deformation dynamic conditions remains limited, due to the complexity of mechanical responses and shortcomings of characterization methods. Here, we present a microscale suspended-plate impact testing framework for three-dimensional micro-architected materials, where supersonic microparticles to velocities of up to 850 m/s are accelerated against a substrate-decoupled architected material to quantify its energy dissipation characteristics. Using ultra-high-speed imaging, we perform in situ quantification of the impact energetics on two types of architected materials as well as their constituent nonarchitected monolithic polymer, indicating a 47% or greater increase in mass-normalized energy dissipation under a given impact condition through use of architecture. Post-mortem characterization, supported by a series of quasi-static experiments and high-fidelity simulations, shed light on two coupled mechanisms of energy dissipation: material compaction and particle-induced fracture. Together, experiments and simulations indicate that architecture-specific resistance to compaction and fracture can explain a difference in dynamic impact response across architectures. We complement our experimental and numerical efforts with dimensional analysis which provides a predictive framework for kinetic-energy absorption as a function of material parameters and impact conditions. We envision that enhanced understanding of energy dissipation mechanisms in architected materials will serve to define design considerations toward the creation of lightweight impact-mitigating materials for protective applications.
先进制造工艺实现的超轻结构材料已具备整体材料无法企及的密度归一化强度和刚度特性。然而，这项工作大多集中在静态载荷和弹性波传播方面。由于力学响应的复杂性和表征方法的不足，对于结构材料在大变形动态条件下的力学行为的基本理解仍然有限。在此，我们提出了一种用于三维微结构材料的微观尺度悬板冲击测试框架，其中将超音速微粒加速到高达850米/秒的速度，使其撞击与基底解耦的结构材料，以量化其能量耗散特性。通过超高速成像，我们对两种结构材料及其组成的非结构整体聚合物进行了冲击能量的原位量化，结果表明在给定冲击条件下，通过采用结构设计，质量归一化能量耗散增加了47%或更多。在一系列准静态实验和高保真模拟的支持下，事后表征揭示了两种耦合的能量耗散机制：材料压实和颗粒诱导断裂。实验和模拟共同表明，特定结构对压实和断裂的抗性可以解释不同结构在动态冲击响应方面的差异。我们通过量纲分析对实验和数值研究进行补充，量纲分析为动能吸收作为材料参数和冲击条件的函数提供了一个预测框架。我们设想，对结构材料中能量耗散机制的深入理解将有助于确定设计考量因素，以创造用于防护应用的轻质减震材料。
