复合材料面层-泡沫金属夹芯板的振动及吸能特性分析

Analysis of Vibration and Energy-absorption Characteristics of Sandwich Plates with Metallic Foam Cores and Composite Facesheets

在冲击载荷作用下,泡沫金属夹芯板沿厚度方向存在不可忽略的压缩和剪切变形,故经典层合板理论不适用于这类夹芯结构的分析,必须考虑芯层的横向压缩和剪切变形。利用高阶理论考虑芯层的横向剪切和正应变,应用Kirchhoff理论分析上下面层。采用哈密尔顿方程和加权伽辽金法获得夹芯结构振动方程;根据振动方程,边界条件和初始条件,利用4阶Runge-Kutta法,在冲击载荷作用下,求出复合材料面层-泡沫金属夹芯板在弹性变形阶段的横向动态位移,同时求出夹芯板的固有频率并与有限元计算结果进行比较,二者吻合很好。讨论不同复合材料面层铺设角、阻尼比及芯层厚度参数对夹芯结构振动特性的影响,结果表明:改变复合材料面层铺设角及芯层厚度,可改变夹芯结构的整体刚度,进而影响结构的振动特性;阻尼耗散结构能量,可加速结构振动的衰减。通过分析复合材料面层-泡沫金属夹芯板的能量吸收特性,得出了由于泡沫芯层承受横向压缩和剪切变形而具有良好吸能特性的结论。

The metallic foam core of lightweight composite sandwich plates undergoes significant deformation along the thickness direction under shock loading, and hence the transverse normal and shear compressions of the core must be considered. A higher-order theory is used to analyze the transverse normal and shear strains of the core, whilst the Kirchhoff theory is used to analyze the thin composite facesheets because of their high-stiffness. The Hamilton~ principle is used to obtain the equations governing the vi- bration performance of the sandwich plate. The extended Galerkin~ method is used to solve the governing equations to obtain the vibration equation of fourth-order Runge-Kutta method is employed the sandwich plate suitable for numerical anal to solve the transverse dynamic displacement of ysls. the The sandwich plate within the elastic range. The inherent frequency of the sandwich plate is compared with the re- suits of finite element method. Finally, the capacity to absorb energy of the sandwich plate is discussed by using the higher-order theory, and the influence of key system parameters is explored. The results show that the whole structural stiffness is affected by changing the ply angle of the facesheets and the thickness of the core, influencing the vibration characteristic of the sandwich composite ; the structural vi- bration is weakened as energy is dissipated by the material damp; and the metal foam core absorbs most of the energy due to the transverse normal and shear compressions.