弹体水中自振特性的有限元分析  

Finite Element Analysis of Missile's Free-vibration Characteristics in the Water

作　　者：孙利民[1] 李凤琴[1] 张鹏[1] 

机构地区：[1]郑州大学工程力学系,郑州450001

出　　处：《淮阴工学院学报》2008年第3期1-4,共4页Journal of Huaiyin Institute of Technology

摘　　要：鱼雷及潜射导弹在水中的自振特性直接影响它们的水弹道,而其自振特性不仅受流体动压力的影响,还受不同水深下的静水压力的影响。为研究类似结构在水中的动态特性,将结构及其周围有限域内的流体组成一个耦合系统,依据流体力学、结构动力学及变分原理推导了结构-流体耦合系统的动力学方程,进而给出了考虑介质影响的结构动力特性的数值方法。建立了液体浸没弹体的有限元模型,利用非对称法分析了弹体结构的静水模态。结果显示静水模态的固有频率比干模态有较大下降,振型类似;用考虑初应力刚度的有限元方法计算了不同水深对导弹自振特性的影响,所得结果和方法可供流固耦合方面的研究参考。The channels of fish torpedo and missile＇s are influenced directly by their free -vibration characteristics in the water. The vibration characteristics of them are influenced not only by fluid dynamic pressure but also by static water pressure corresponding to different depth. To study structure ~ dynamic - characteristic such as submerging missile, an interaction system is constituted between structure and finite fluid in this paper. Based on the principles of fluid - mechanics, the dynamic of structure and the variation principle, dynamic equations for the interaction between the structures and the fluid have been deduced. Thus, it provides the feasibility to carry out numerical analyses of the dynamic characteristic of structure by considering addmass in the water. An FEM model adapting to submerged missile was built with general FEM software - ANSYS, and the missile~ calm -water modes were analyzed by using the unsymmetrical method in ANSYS structural modal analysis. Resulls demonstrate that the natural frequency of calm - water modes is much lower than dry modes＇, but the mode shape is similar. In terms of initial stress stiffness, the effects of the vibration characteristics of missile＇s model under different water depth are calculated with FEM. The results and method are of some reference values to the studies on fluid-solid interaction.

关 键 词：流固耦合 附连水质量 自振特性 有限元 

分 类 号：O3[理学—力学]