水下复杂应力结构的固有频率研究  

Natural frequencies of underwater complex stress structures

作　　者：杨念[1] 陈炉云[1] 易宏[1] 刘勇 

机构地区：[1]上海交通大学船建学院海洋工程重点实验室,上海200240 [2]中船重工第七〇二研究所上海分部,上海200011

出　　处：《振动与冲击》2016年第22期92-100,共9页Journal of Vibration and Shock

摘　　要：研究水下结构物的复杂应力状态对结构固有频率的影响,克服以往研究中只考虑整体均匀分布应力的局限性。水下结构因外部环境特殊常常处于复杂应力状态,复杂应力与流固耦合的共同作用使结构的固有频率求解变为一个耦合非线性特征值问题,以往求解流固耦合的方法不再适用于此类问题。有限元方法也能处理此类问题,但存在处理过程复杂、计算量大、不能明确说明结构应力与动力特性之间的本质物理联系等缺点。针对该问题用理论方法进行了分析,首先基于Flügge壳体理论、考虑流固耦合作用、利用特定模态之间的正交性建立复杂应力结构自由运动方程,然后采用多项式近似结合二次型矩阵线性化的方法对此类结构的固有频率进行求解。在数值算例中,计算了某水下圆柱壳的固有频率,并对比和分析了不同类型的复杂应力对于水下结构固有频率的影响特点。The influence of the complex stress in underwater structure on its natural frequency was discussed and the limitation of the assumption of overall uniform stress distribution in former studies was revealed：the stresses in underwater structures are often very complex because of their working environment.The coaction of complex stress and fluid-structure coupling offers a nonlinear eigenvalue problem which is difficult to solve.An underwater cylindrical shell was taken as an example and based on the Flugge shell theory,considering the fluid-structure interaction and making use of the orthogonality of specific order modes,the dynamic equation of the structure was derived.The stress-caused coupled fluid structure modes were calculated by means of the polynomial approximation and quadratic matrix linearization.In the case study,the natural frequencies of structures with different types of stresses were calculated and the influence characteristics of different types of stresses were analysed and compared.

关 键 词：复杂应力 流固耦合 结构振动 固有频率 

分 类 号：TB535[理学—物理]