负刚度蜂窝材料的机械设计

负刚度蜂窝材料的机械设计(中文5600字,英文3700字)
Dixon M Correa1, Carolyn Conner Seepersad1*和Michael R Haberman1,2。
文摘
当一个机械系统需要减少施用力以产生位移时，它的刚度是负的。负刚度特性对振动声阻尼材料、隔振机理和机械开关有一定的应用价值。这种非直观的机械响应可以通过横向加载合适的几何形状的弯曲梁结构来引出，可以设计出一个或两个稳定的位置。目前的研究工作是研究蜂窝结构，其单元单元是由弯曲梁结构产生的，其设计是为了提供负刚度的行为和一个稳定的位置。这些特性使得蜂巢能够在稳定的高原压力下吸收大量的机械能，就像传统的蜂巢一样。然而，与传统的蜂巢不同，吸能行为的机理是弹性屈曲而不是塑性变形，这使得负刚度的蜂窝可以从大变形中恢复。因此，对于那些需要分散多重影响的应用程序来说，它们是引人注目的候选者。对单元格设计的详细探索表明，负刚度的蜂巢可以被设计成可以在相对密度较低的情况下，以与传统蜂窝结构相比较的数量来消耗机械能。此外，他们独特的细胞几何结构允许设计者在密度、应力阈值和能量吸收能力之间进行权衡。本文描述了这些权衡和基础分析。
关键词:蜂窝;负刚度;双稳性;能量吸收;弹性刚度;压力阈值

Abstract
A mechanical system exhibits negative stiffness when it requires a decrease in applied force to generate an increase in displacement. Negative stiffness behavior has been of interest for use in vibro-acoustic damping materials, vibration isolation mechanisms, and mechanical switches. This non-intuitive mechanical response can be elicited by transversely loading a curved beam structure of appropriate geometry, which can be designed to exhibit either one or two stable positions. The current work investigates honeycomb structures whose unit cells are created from curved beam structures that are designed to provide negative stiffness behavior and a single stable position. These characteristics allow the honeycomb to absorb large amounts of mechanical energy at a stable plateau stress, much like traditional honeycombs. Unlike traditional honeycombs, however, the mechanism underlying energy-absorbing behavior is elastic buckling rather than plastic deformation, which allows the negative stiffness honeycombs to recover from large deformations. Accordingly, they are compelling candidates for applications that require dissipation of multiple impacts. A detailed exploration of the unit cell design shows that negative stiffness honeycombs can be designed to dissipate mechanical energy in quantities that are comparable to traditional honeycomb structures at low relative densities. Furthermore, their unique cell geometry allows the designer to perform trade-offs between density, stress thresholds, and energy absorption capabilities. This paper describes these trade-offs and the underlying analysis.

Keywords: Honeycombs; Negative stiffness; Bistability; Energy absorption; Elastic stiffness; Stress threshold