双壁厚蜂窝铝芯的共面冲击力学性能

IN-PLANE IMPACT PROPERTIES OF ALUMINUM DOUBLE-WALLED HONEYCOMB CORES

参考文献[1],加入孔壁的剪切和伸缩变形精确推导了双壁厚蜂窝铝芯的共面弹性模量公式,并给出了其静态峰应力、密实化应变和单位体积密实化应变能的计算公式。建立了双壁厚蜂窝铝芯7×7的单元阵列有限元分析模型,分析了冲击速度在3～252m/s时双壁厚蜂窝铝芯的冲击性能。随着冲击速度的增加,双壁厚蜂窝铝芯在x1和x2方向上先后表现出三种变形模式,变形模式的转换速度与（t/l）^1/2成线性关系。双壁厚蜂窝铝芯的弹性模量与冲击速度成二次曲线关系,峰应力和单位体积密实化应变能与冲击速度的平方成线性关系,它们的相关拟合系数与t/l成二次曲线关系。根据壁厚在0.05～0.3mm间的模拟结果,给出了描述以上关系的经验公式。

The accurate formulas for calculating the in-plane elastic moduli elastic moduli in consideration of the shear and extension deformation of cell edges and the theoretical expressions of plateau stress, densification strain and densification strain energy per unit volume of the aluminum double-walled honeycomb cores are derived. The in-plane impact finite element model of aluminum double-walled honeycomb cores with seven-by-seven cells is established, and their impact properties under the impact velocities between 3 and 252m/s are analyzed. With the increase of impact velocity, three deformation modes in direction x1 or x2 are observed, and the transition velocities of deformation modes are proportional to the square root of t/l. The elastic moduli are in quadric relation to the impact velocities. The Plateau stress and densification strain energy per unit volume are proportional to the square of impact velocities, and their fitting parameters are also in quadric relation to t/l. The related empirical formulas about deformation modes, elastic modulus, plateau stress and densification strain energy per unit volume are suggested in terms of the analysis results with wall thickness from 0.05 mm to 0. 3mm .