夹层板结构层间应力数值分析

夹层板由两块高强度表层板和较软的中间夹心层组成，表层剪切刚度大，夹层剪切刚度小．这些特点将会给夹层板层间应力分析增加难度．为此推导了角铺设1，2—3高阶剪切变形理论，这一理论满足层间位移、应力连续条件和自由表面条件，并且未知量个数独立于夹层板的层数．基于此理论建立了满足C^1连续条件的三节点三角形单元并用于夹层板结构层间应力分析．计算结果表明：根据推导的三角形单元，由求得的应变可以精确计算层问横向剪切应力和面内应力，进一步地，采用平衡方程后处理方法可以准确地计算层间法向应力．

Numerical analysis of sandwich plate's interlaminar stress

The sandwich plates are composed of two very stiff surface sheets and a comparatively flexible core material. The bending analysis of the sandwich plates is difficult to carry out due to the abrupt variation of strain components between the the 1,2-3 double-superposition theory proposed, surface and the core regions of the plate. Based on a global-local higher-order theory for angle-ply laminated plates is derived. This theory fully satisfies the free surface conditions and the geometric and stress continuity conditions at interfaces. The number of unknowns of the higher-order theory is independent of the layer numbers of the composite laminate. Based on the higher-order theory, a three noded triangular element is presented. This element satisfies the interelement C^1 continuity conditions. Numerical results show that in-plane stresses and transverse shear stresses can be accurately calculated by the direct constitutive equation approach. In order to obtain transverse normal stresses, the equilibrium equation approach is employed.