水下复杂应力结构的固有频率研究

发布时间：2018-07-21 15:58

【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。
[Abstract]:The influence of the complex stress state of underwater structure on the natural frequency of the structure is studied, which overcomes the limitation that only the uniform distribution of stress is considered in previous studies. Underwater structures are often in complex stress state because of the special external environment. The interaction of complex stress and fluid-structure coupling makes the natural frequency solution of the structure become a coupled nonlinear eigenvalue problem. The previous methods for fluid-solid coupling are no longer suitable for this kind of problems. The finite element method can also deal with this kind of problems, but there are some disadvantages such as complicated processing process and large calculation, which can not clearly explain the essential physical relation between the stress and dynamic characteristics of the structure, and so on. Firstly, based on the theory of Fl 眉 gge shell and considering the fluid-solid coupling, the free motion equations of complex stress structures are established by using the orthogonality between specific modes. Then the method of polynomial approximation and quadratic matrix linearization is used to solve the natural frequency of this kind of structure. In a numerical example, the natural frequencies of an underwater cylindrical shell are calculated, and the effects of different types of complex stresses on the natural frequencies of underwater structures are compared and analyzed.
【作者单位】：上海交通大学船建学院海洋工程重点实验室;中船重工第七0二研究所上海分部;
【分类号】：TB12

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