含剪切自由度的厚薄通用三角形层合板单元

基于一阶剪切变形理论（FSDT），构造了一种新型的消除剪切闭锁的三角形层合板单元，简记为CDST-S6单元。该单元剪应变场及单元转角场由结点包含有两个剪切自由度的DST-S6单元理论确定，不需要借助减缩积分、假设应力或应变等辅助数学手段，也不会产生对稳定性带来影响的附加零能模式，较好地解决了厚薄板单元的剪切闭锁难题，且其公式推导过程和最终的表达式比目前能考虑剪切变形的绝大多数层合板单元更为简单，可方便地进行有限元数值求解分析。数值算例表明，CDST-S6单元有较高的精度和收敛性，是一种厚薄通用的优质层合板单元。

A New Laminated Plate Element CDST S6 for Thin or Thick Plates

Based on the first-order shear deformation laminated plate theory (FSDT), a new three node triangular laminated plate element, labeled here as CDST-S6, is proposed. The transverse shear strains and rotations of the element are the same with DST-S6 (Discrete Shear Triangular element with 6 extra Shear degrees of freedom). The proposed CDST-S6 can eliminate the shear locking, without any numerical expediencies such as the reduced integration, the use of assumed strains/stresses, or the need for the stabilization of the attendant zero energy mode. The expression of the CDST-S6 is simple in formulation and easy to be implemented by using finite element method. Numerical examples indicate that the element has high accuracy and high convergence rates for the solving of both thin and thick laminated plates.