知识与财富的链接
借助非线性有限元程序LS-DYNA,基于功能梯度材料的概念,改变蜂窝胞壁厚度,建立了具有密度梯度的内凹六边形负泊松比蜂窝材料模型.分析对比了均匀负泊松比蜂窝材料和梯度负泊松比蜂窝材料在不同面内冲击速度下的变形模式、动态响应和能量吸收特性.研究表明,梯度负泊松比蜂窝材料的动态响应和能量吸收能力受梯度、胞元内凹角度和冲击速度的影响.如果能适当选取各项参数,就可使材料在降低初始应力峰值的同时保持良好的能量吸收能力.因此,具有密度梯度的负泊松比蜂窝材料在结构防护方面具有良好的应用前景.
Based on the concept of functionally graded materials (FGM) and through changing the wall thickness of honeycombs cell,a model for density graded re-entrant auxetic honeycombs is established by using the nonlinear finite element program LS-DYNA.The deformation modes,dynamic response and energy absorption characteristics of both the homogeneous and graded auxetic honeycombs under different in-plane impact velocities are examined and compared.Results indicate that the dynamic responses and energy absorption ability of graded auxetic honeycombs change with the gradient,cell re-entrant angle and impact velocity.Given proper parameters,the initial peak stress can be decreased,but the energy absorption ability is still kept well.Therefore,auxetic honeycombs with density gradient and negative Poisson's ratio can be widely applied in structural protection areas.
