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

[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/l和θ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。

[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 semireentrant 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 semireentrant 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.