Dynamic impact response and energy absorption performance of conch shell-inspired cross-laminated metamaterials
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摘要: 针对传统体心立方晶格在动态冲击下极易发生全局灾难性失效的缺陷,受天然海螺壳交叉层状微观结构启发,本文旨在开发兼具极端轻量化与高效动态吸能特性的新型防护材料。基于高韧性树脂材料,设计了引入节点约束梯度的单层仿生结构与结合正交堆叠策略的三层仿生交叉层状超材料,并以传统体心立方晶格为基准对照组。采用落锤冲击试验系统开展了低速动态冲击实验,同步结合高速摄影技术与显式动力学有限元仿真,系统对比分析了三种拓扑结构在动态加载下的形变响应、应力波传递规律及失效演化过程。研究结果表明,传统晶格表现出迅速贯穿的全局剪切带与破坏性的刚性触底现象;单层仿生结构通过力学异质性显著提升了初始抗冲承载力,但大变形后期仍存在整体软化;三层仿生结构通过层间正交旋转构筑了宏观人工界面,成功激发了界面阻断效应,极大增加了裂纹扩展的空间曲折度。研究得出结论:多维仿生协同设计使三层超材料的失效模式彻底蜕变为以跨层变形滞后为特征的渐进式粉碎机制,该结构有效消除了触底尖峰并在极限压缩内维持了漫长稳定的载荷平台,展现出极致的冲击动能耗散表现,为先进轻质抗冲击吸能结构的设计提供了全新的范式。
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关键词:
Abstract: Addressing the inherent defects of traditional body-centered cubic (BCC) lattices, which are highly prone to rapid, global catastrophic failure and dangerous stress localizations under dynamic impact, and profoundly inspired by the naturally occurring, highly toughened cross-layered microstructures found in seashells, this paper aims to develop a novel class of protective metamaterials that seamlessly combine extreme lightweight characteristics with highly efficient dynamic energy absorption capabilities. Based on the utilization of advanced high-toughness resin materials, a single-layer bionic structure featuring node-constrained spatial gradients and a sophisticated three-layer bionic cross-layered metamaterial employing an orthogonal stacking strategy were meticulously designed, with the traditional uniform BCC lattice serving as the baseline control group. Low-velocity dynamic impact tests were rigorously conducted using an advanced drop-weight impact testing system. This experimental approach was systematically combined with in-situ high-speed photography and highly detailed explicit dynamic finite element simulations to comprehensively compare and analyze the complex deformation responses, stress wave propagation patterns, and progressive failure evolution processes of the three distinct topologies under transient dynamic loading. The multifaceted results reveal that the traditional lattice exhibited rapidly penetrating global shear bands and highly destructive rigid bottoming phenomena, severely limiting its protective utility; the single-layer bionic structure significantly enhanced the initial impact-bearing capacity through engineered mechanical heterogeneity, but an overall structural softening still inevitably occurred in the later stages of large deformation; conversely, the three-layer bionic structure, precisely through interlayer orthogonal rotation, successfully constructed a macroscopic artificial interface, effectively triggering a profound interface-blocking effect and greatly increasing the tortuosity of crack propagation pathways. The study concludes that this multidimensional bionic collaborative design fundamentally transforms the failure mode of the three-layer metamaterial into a highly desirable progressive crushing mechanism, distinctly characterized by a beneficial interlayer deformation lag. Ultimately, this hierarchical structure effectively eliminates hazardous bottoming peaks and reliably maintains a prolonged, stable load plateau even under extreme compression, exhibiting exceptional impact kinetic energy dissipation performance and providing a robust new paradigm for the future design of advanced, lightweight impact-resistant and energy-absorbing structural systems. -
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