用杂交法改善应力解的新型复合材料层合板单元

A NEW DISPLACEMENT-BASED ELEMENT FOR THE ANALYSIS OF LAMINATED COMPOSITE PLATES WITH HYBRID-ENHANCED STRESS SOLUTIONS

本文给出一种基于一阶剪切变形理论(FSDT)新型的、无闭锁的位移型四边形复合材料层合板单元TMQ20的列式;并根据Hellinger-Reissner变分原理,针对位移型复合材料板单元提出了一种新型应力杂交化后处理方法来改善单元计算应力的能力,使位移型单元可以简单和正确地预测层合板的应力,特别是层间横向剪应力的解。数值算例表明,经过改善的TMQ20单元具有位移型和杂交型有限元的双重优点,它不仅自由度少,列式简单,而且对位移和应力都可以得到高精度的结果,适用于从薄到中等厚度的复合材料层合板的计算。本文所提出的杂交化后处理方法的概念适用于改善任何种类的位移型单元的应力解。

The formulation of a new simple displacement-based, quadrilateral 20 DOF (5 DOF per node) finite element based on the first-order shear deformation theory (FSDT) for analysis of laminated composite plates is presented in this paper. This new element, termed as TMQ20, is free of shear locking and has a proper rank. Moreover, a new simple hybrid procedure is also proposed to improve the stress solutions of such displacement-based elements. The new element TMQ20 possesses the advantages of both displacement and hybrid elements. Thus, excellent results for both displacements and stresses, especially the transverse shear stresses, can be obtained. Numerical examples show that the proposed element is a high performance element for moderately thick and very thin composite plates. Furthermore, the proposed hybrid-enhanced procedure is a general approach, which can be generalized to improve the stress solutions of displacement-based elements for all kinds of problems.