贮液箱-支承结构体系的模态分析

MODAL ANALYSIS OF STORAGE TANK-SUPPORTING STRUCTURE SYSTEM

由贮液容器和支承结构组成的系统中,晃动的液体对支承结构的模态将产生重要影响。采用简化的理论方法,给出了矩形容器内液体晃动的等效力学模型参数,建立了贮液支承结构系统的运动方程,得到了系统的同步和异步频率算式;同时完成了液体-支承结构系统的自由振动试验,测得贮液结构系统的自由振动曲线,通过快速傅里叶(FFT)转换滤波分析得到系统的同步、异步频率与对应的阻尼比,频率实测值与理论计算结果吻合良好,表明所提出的简化计算模型及试验方法具有很好的适用性,可满足工程设计需求。

In a system composed of a liquid storage tank and a support structure,the sloshing liquid has an important influence on the vibration mode of support structure.The paper used a simplified theoretical method to obtain the parameters of equivalent model of sloshing liquid in a rectangular container.The motion equation was established for the structural system containing liquid tank.The in-phase and out-phase frequency formulae of the system were analytically obtained.The free vibration test of liquid-support structure system was conducted to measure the free vibration response curve of structural system.The in-phase and out-phase frequencies and the corresponding damping ratios were obtained by using the FFT filtering analysis method.The theoretical and measured frequencies agreed well.It was indicated that the proposed theoretical model and test method had a good applicability and could meet the engineering design requirements.