基于试验模态分析的原油储罐损伤识别研究

Research on Damage Identification of the Crude Oil Storage Tank Based on Experimental Modal Analysis

基于试验模态分析的基本原理,对立式拱顶钢制原油储罐模型进行应变模态试验,考察了模态参数对原油储罐模型损伤程度和损伤位置的识别能力。试验分析表明,罐体结构在损伤位置相同的情况下,损伤程度越大,频率的衰减增大,但相对变化率的变化规律不甚明显;位移振型不能给出损伤的位置信息,振型差曲线可以识别出罐体损伤位置;随着模型内充水高度上升,结构频率呈下降趋势,反映了附加质量和附加阻尼的作用;罐内液体存在对损伤位置识别影响不大。

According to the basic principle of the experimental modal analysis,the strain modal of the vertical steel crude oil storage tank model with doom roof were tested.The ability of identifying the damage degree and location of the crude oil tank model using modal parameters were observed.Experimental analysis shows that the more damage of the tank body exists in the same location,the higher frequency is reduced,but the changing regulation of the relative changing rate of the natural frequency is not pronounced.The train modal shape cannot give information on the damage location,but the curves of modal shape difference can be used to identify the damage location.The frequencies tend to decrease as the liquid height inside the model tank rises,which reflects the effect of the additional mass and additional damping.It is also shown that capacity of liquid inside the model tank does not have much effect on the identification of the damage location.