简化的舱段船壳模型试验模态分析

The experimental modal analysis of model of the simplified hull in the cabin section

工厂加工的试验模型与设计模型有时存在一定的差异,致使试验模型的动态特性与设计模型的动态特性不一致,本文中用于振动主动控制实验研究的舱段船壳模型就属于这种情况.而舱段船壳模型的动态特性对于其振动主动控制研究是很重要的.应用锤击激励法和LMS,CADA-X结构动态测试与分析软件对简化的舱段船壳模型上部平板进行模态试验,得到了前六阶固有频率、阻尼和振型,经模态置信准则检验,所测试验模态参数真实有效.将试验模态参数与有限元计算模态参数比较分析,找出了试验模型的加工缺陷,即船壳模型上部平板存在初挠度,致使试验模态与有限元计算模态的某些阶模态参数存在很大差别.

The difference between the experimental model produced by the factory and the design model causes the difference in dynamic characteristics between the experimental model and the design model,and the dynamic characteristics of the cabin section hull model are very important to the research on active control of vibration,and the modal parameters of the simplified cabin section hull model’s upper plate are obtained using hammering excitation.The test of MAC matrix proves that the experimental modal parameters measured are true and valid.It is found out by comparing the experimental modal parameters with the calculated parameters obtained using the finite element method that the initial deflection of the hull model’s upper plate,a processing defect in the experimental model,caused the large difference between the experimental modal parameters and some calculated parameters obtained using the finite element method.