Plane elasticity in sectorial domain and the Hamiltonian system

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里卡提微分方程解的奇异性分析

本文处理有限长时间的里卡提微分方程。指出可以用区段混合能合并消元之法来得出它的解,在t_f处边界条件可以放在最后一步进行处理。这样就可以避免从奇点开始数值积分的困难。还可以据此分析t_f处的奇性。     

Finite element analysis for consolidation in interaction between structure and saturated soil foundation

The consolidation analysis of interaction between structure and saturated soil foundation is discussed. With the use of substructure technique, the structure is condensed onto the interface of the soil, and then the consolidation governing equations to describe the interaction between soil and structure are derived, The solution with non-iterative algorithm is proposed in this paper. The pressure Master-Slave relation method is used to deal with the non-permeability conditions on soil boundaries. A numerical example is illustrated. Based on this paper, the interactive consolidation analysis between large structure and soil has been more practical.     

ON S0ME PROBLEMS IN THE ASSEMBLING OF MULTILEVEL SUBSTRUCTURING

In this paper,some essential problems in the assembling ofmulti-level substructuring are discussed,which include thereferencing of superelements in the substructural module andrespective expression;the automatic formation of the nodesequence as well as the qualification number of these nodesin the substructural modules.All the ideas mentioned above have been implemented inthe general purpose structural analysis program JIGFEX.The assembling consideration is one of the most impor-tant practical problems in the structural analysis computerprogram design by the multi-level substructuring approach.In this paper these problems are discussed only from thetheoretical aspect and all the practical implementationand applications are neglected however.     

极限分析中新的上、下限定理

本文在文[1]的极限分析一般变分式的基础上,进行了发展,导出了极限乘子的新的上、下限定理。由本文上、下限定理决定的极限乘子的上、下限将比经典的上、下限定理给出的更为靠近准确解。然后又对于两种权因子得到的上、下限进行了比较。最后,在新的上、下限定理的基础上,建议了一套推求极限乘子的计算机算法。     

基于平面偶应力-Reissner/Mindlin板比拟的偶应力有限元

偶应力理论的有限元列式面临本质性的C1连续性困难. 平面偶应力理论和Reissner/Mindlin板弯曲理论之间的比拟关系表明这两个理论系统的有 限元的同一性，而R/M板有限元并不存在C1连续性困难. 因此，研究将R/M板单元转化为具有一般位移自由度的平面偶应力单元的一般方法. 根据这一方法，将典型的8节点Serendipity型R/M板单元Q8S转化为一个4节点12 自由度的四边形平面偶应力单元，数值结果表明该单元具有良好的精度和收敛性     

Numerical solutions of linear quadratic control for time-varying systems via symplectic conservative perturbation

Optimal control system of state space is a conservative system, whose approximate method should be symplectic conservation. Based on the precise integration method, an algorithm of symplectic conservative perturbation is presented. It gives a uniform way to solve the linear quadratic control (LQ control) problems for linear time-varying systems accurately and efficiently, whose key points are solutions of differential Riccati equation (DRE) with variable coefficients and the state feedback equation. The method is symplectic conservative and has a good numerical stability and high precision. Numerical examples demonstrate the effectiveness of the proposed method.     

多层层合板圣维南问题的解析解

将哈密尔顿体系理论引入到多层层合板问题之中，建立了一套求解该问题的横向哈密尔顿算子矩阵的本征函数向量展开解法，并成功地求解出圣维南问题的解析解．进一步显示了弹性力学新求解体系的有效性及其应用潜力     

用多层子结构与群论相结合的方法分析对称结构

本文采用多层子结构与群表示论相结合的方法,分析可承受任意荷载的、具有多种性质与形式的对称结构。按照这种方法,首先经凝聚消去内部自由度,然后再选择与各自的对称性相吻合的组合位移作未知数,使原问题分成一系列互不耦合的子问题,文末以工程计算实例来说明这种方法的有效性。本文的分析方法已在通用结构分析程序JIGFEX(Q)中实现。