加筋板的双重非线性分析

本文综合工程实际的需要,对船体加筋板结构进行了双重非线性有限元分析。采用Prandtl-Reuss流动理论,具体导出了加筋板在双重非线性状态下理想弹-塑性和强化材料的单元刚度矩阵;用增量切线刚度法-迭代法相结合的混合解法来提高求解精度;对单剛、等效节点力的计算,均采用Gauss积分法和进行分层精度判别来节约机时和内存。

ANALYSIS OF THE DOUBLE NONLINEARITY OF STIFFENED PLATE

An analysis is made of the double nonlinearity of stiffened plate of ship hull by FEM to meet the requirements of engineering practice. The ideal elastic-plastic and hardened material's element stiffness matrices are derived for stiffened plate in double nonlinear state by means of PrandtlReuss's flow theory. The accuracy of solution is enhanced by combining the Incremental Tangential Stiffness Method with the Iterative Method. The calculation of element stiffness and equivalent nodal point internal force is performed by Gauss integration and laminated accuracy judgement to save computer time and memories.To check the correctness of theoretical inference and programming, we have carried out calculations of the linear elastic and geometric nonlinear plate and unidirectional stiffened plate. The results obtained are in good agreement with those of analytical and series of analysis are made of various nonlinear states of the unidirectional and double direction stiffened plates, revealing the process of evolution and laws concerning the stiffened plate's plate and beam that enter different nonlinear states with the load being gradually increased. A theoretical basis is thus provided for approximate calculations of engineering structures in future.