基于滞回非线性基座结构的舰船低频线谱重构试验研究

Low frequency line spectrum reconstruction tests of ship vibration based on hysteretic nonlinear base structure

针对舰船振动噪声低频(100 Hz以下)线谱重构问题,提出了一种含半主动作动元件(磁流变阻尼器)的滞回非线性基座结构,并给出了基于MRD(magnetrokeological damper)电流调节的舰船振动低频线谱重构方法。首先,基于Bouc-Wen滞回非线性模型建立起了新型基座结构的运动方程并开展数值仿真分析,发现MRD的引入在使基座振动出现了分岔、混沌特征,这为舰船振动线谱重构奠定了理论基础;为进一步验证所提滞回非线性基座的低频线谱重构效果,搭建了缩比模型试验平台并开展了线谱重构试验。试验结果表明:40组工况中线谱幅值降低效果平均达到49.8%,最大可达90.7%。

Here,aiming at the problem of low frequency(below 100 Hz)line spectrum reconstruction of ship vibration and noise,a hysteretic nonlinear base structure with semi-active actuator(magnetorheological damper,MRD)was proposed,and a method of low frequency line spectrum reconstruction of ship vibration based on MRD current regulation was presented.Firstly,based on Bouc-Wen hysteretic nonlinear model,the dynamic equation of the new base structure was established and the numerical simulation analysis was performed.It was found that introduction of MRD makes the base vibration have bifurcation and chaos characteristics,this lays a theoretical foundation for reconstruction of ship vibration line spectrum.In order to further verify the low-frequency line spectrum reconstruction effect of the proposed hysteretic nonlinear base,a scaled model test platform was built and line spectrum reconstruction tests were conducted.The test results showed that the reduction effect of line spectrum amplitude reaches 49.8%on average and 90.7%on the maximum in 40 working conditions.