基于疲劳累积破坏机制的储罐结构动力可靠度分析

Analysis on dynamic reliability of storage tank structure based on fatigue cumulative failure mechanism

针对随机风载荷作用下储罐结构动力可靠性问题,以300 m 3的中小型立式低温储罐为研究对象,利用AR模型进行数值模拟得到风载荷的脉动风速时程与脉动功率谱密度函数。采用ANSYS建立储罐三维有限元模型,并对储罐进行动力学分析,计算出储罐结构的随机响应,进而求出随机风载荷作用下储罐结构动力可靠性所需全部数字特征,最后利用疲劳累积损伤机制计算得到储罐的动力可靠度。结果表明:假设结构强度不随时间退化,前5 a动力可靠度基本保持不变,随着使用年限的延长,动力可靠度下降速度明显增大。研究方法可为储罐的动力可靠性及寿命预测提供一定的理论依据。

For the dynamic reliability problem of storage tank structure under random wind load,a 300 m3 small and medium-sized vertical cryogenic tank was taken as the research object.The AR model was used to numerically simulate the pulsating wind speed time series and pulsating power spectral density function of wind load.The three-dimensional finite element model of the storage tank was established by ANSYS,and the dynamic analysis of the storage tank was carried out to calculate the random response of the tank structure,then all the digital features required for the dynamic reliability of the storage tank structure under random wind loads were obtained.Finally,the dynamic reliability of the tank was calculated by using the fatigue cumulative damage mechanism.The results showed that when assuming the structural strength did not degenerate with time,the dynamic reliability in the first five years remained basically unchanged.With the extension of the service life,the decrease speed of dynamic reliability increased significantly.This method can provide theoretical basis for the dynamic reliability and life prediction of storage tanks.