不同泊松比蜂窝结构抗冲击性能数值分析

Numerical analysis of impact resistance of honeycomb structures with different Poisson's ratios

  • 摘要:
      目的  对不同泊松比蜂窝结构的抗冲击性能进行分析。
      方法  基于显式动力有限元方法,分析不同泊松比蜂窝结构在面内冲击载荷作用下的动态力学性能,探究蜂窝结构泊松比对其抗冲击性能的影响规律。选取3类具有负/零/正泊松比的典型蜂窝拓扑结构(内凹六边形、六边形和半内凹六边形),通过改变几何参数使其具有相同的相对密度和不同的泊松比(−2.76 ~3.63),分析结构在低/中/高速动态位移载荷作用下的动态力学性能。
      结果  结果显示:零泊松比半内凹六边形蜂窝在压缩变形时不产生横向变形,具有最好的结构稳定性;在不发生结构失稳的前提下,平台应力与泊松比的关联不大;致密应变会随泊松比绝对值的增大而增大;单位体积能量吸收EA随泊松比绝对值的增大而增大。在进行蜂窝结构设计时,如果需要平台应力较大(抵抗变形能力强)的结构,可以选择壁厚/壁长(t/l)较大、胞元倾斜角θ较小的负泊松比内凹六边形蜂窝结构;如果需要较强的EA,可以选择t/lθ均较小的正泊松比六边形蜂窝结构;如果需要结构有很好的稳定性,可以采用零泊松比半内凹六边形蜂窝结构。
      结论  所做研究可为舷侧抗冲击蜂窝结构的选型和几何参数设计提供参考。

     

    Abstract:
      Objectives  This papers aims to analyze the impact resistance of honeycomb structure with different Poisson's ratio.
      Methods  Based on the explicit dynamic finite element method, this paper analyzes the dynamic mechanical properties of honeycomb structures with different Poisson's ratios under in-plane impact load, and explores the influence laws of Poisson's ratios on their impact resistance. Three typical honeycomb structures with negative/zero/positive Poisson's ratios (reentrant hexagon, hexagon and semi-reentrant hexagon) are selected, their geometric parameters are changed to give them the same relative density and different Poisson's ratios (−2.76 – +3.63), and their dynamic mechanical properties under low/medium/high-speed dynamic displacement loads are analyzed.
      Results  The results show that the zero Poisson's ratio semi-reentrant honeycomb structure has the best structural stability without transverse deformation under compression deformation; without structural instability, the platform stress has little correlation with the Poisson's ratio; and the compact strain and total energy absorbtion increases with the absolute value of the Poisson's ratio. Negative Poisson's ratio honeycomb structures with large t/l and small θ are suitable for applications with high platform stress (strong deformation resistance), and negative Poisson's ratio honeycomb structures with small t/l and small θ are suitable for high total energy absorbtion applications, while zero Poisson's ratio semi-reentrant honeycomb structures are suitable for applications with high platform stress (strong deformation resistance).
      Conclusions  This study can provide references for the type selection and geometric parameter design of side impact honeycomb structures .

     

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