含金属内衬的复合材料缠绕壳结构应力场分析的混合状态Hamilton元半解析法

Stress and Failure Analysis of Composite Wound Shell Structures with a Metal Liner Using Semi-Analytical Hamiltonian Method

本文将基于Hellinger-Reissner广义变分原理,提出一种分析复合材料缠绕壳结构应力场分析的混合状态Hamilton元半解析法。该方法在周向面内采用有限元离散;而沿径向对状态方程进行解析求解。在求解过程中,采用了传递矩阵技术,以保证层间位移和应力的连续性,并建立了缠绕结构的内、外表面状态变量之间的关系。为此,不论缠绕结构的层数有多少,最后都归结为求解缠绕结构内、外表面未知量。同常规位移有限元法相比,此方法大大地降低了求解未知量的数目。文中还采用Chang F K提出的复合材料缠绕结构的破坏准则,对一在服役工况下具有金属内衬的复合材料缠绕壳典型结构进行了强度校核。

The composite wound high-pressure vessels with a metal liner is widely employed in aeronau- tics, astronautics industry, naval applications, civil structures, and automotive industry. As an experimental observation, the vessel appears in multi-failure modes during the service case, such as matrix microcracking, fibrous breakage and delamination et al. Therefore, an exact understanding of the characteristics and distribution of stress field is of importance in improving design of composite wound structures. For predicting the distribution and magnitude of such stresses the most of investigators have proposed some finite element models based on minimized potential energy principle. However the continuity conditions of inter-laminar stress field of neighboring layers along the interface can not be satisfied accurately for those models, an efficient finite element method based on rigorous elasticity theory is needed. An analysis of stress field was conducted on the basis of a systematic Hamiltonian elasticity theory in conjunction with semi-analytical finite element method. The set of first order ordinary differential vector equation was solved by precise integration method. From numerical result for a thick cylinder under uniform internal pressure as a benchmark example, it can be seen the efficiency and validity of present method. Finally, the failure analysis of a typical composite winding vessel with metal liner was carried out based on multi-failure rules developed by Chang F.K. The method and numerical conclusions should be of great value to engineers dealing with composite wound structures.