考虑声辐射特性的船舶板架结构动力优化设计

提出了一种基于导纳法和遗传算法的船舶板架结构动力优化设计方法,将板架结构分解成由薄板与梁在相应连接节点处耦合的组合结构,利用其导纳公式推导出带有隔振系统的板架结构在任意位置简谐力激励下的弯曲振动响应,并与边界元法相结合,分析计算板架结构的声辐射特性。数值计算表明,只需取较少的耦合节点即可得到较好的计算精度,避免了大量的有限元计算。在此算法的基础上,使用遗传算法进行考虑声辐射特性的板架结构动力优化设计。为提高优化收敛速度,针对船舶板架结构的特点,选取纵桁和强横梁剖面惯性矩作为设计变量,减少了设计变量的个数,并建立满足构件剖面尺寸搭配关系要求的、经过优选的剖面尺寸方案库,便于获得满足约束条件的离散优化解。一个船舶板架结构的动力优化实例验证了方法的有效性。

Structural Dynamic Optimization of Grillage Structures Considering Sound Radiation Characteristic

A dynamic optimization method based on admittance method and genetic algorithm was presented to optimize grillage structures considering their sound radiation characteristics.In the analysis,the grillage system was first separated into a plate and some discrete beams and then the admittance method was employed to calculate the dynamic response of the grillage system with vibration isolators,which was more efficient than one using the finite element method.And together with the boundary element method,the acoustic radiation power could be computed easily.The inertia moments of the beams were selected to be design variables in the study to reduce the number of optimal variables and the computational burden was greatly reduced accordingly.In order to obtain discrete optimal results a scheme database was constructed and from which the possible design scheme was selected based on the inertia moments of the beams that were determined by genetic algorithm.A numerical example showes that the dynamic response from the admittance method is well agreed with one obtained from the finite element method.A dynamic optimization example is also provided to demonstrate the validity and effectiveness of the proposed optimal method.