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输电塔钢管构件易出现涡激振动引发的疲劳破坏。本文给出临界起振风速的确定方法,以避免疲劳破坏的发生。本文针对钢管构件两端铰支和两端固支这两种典型的支承条件,结合结构动力学理论,推导两种支承条件下钢管构件发生涡振时构件中部的最大振幅公式,并根据风洞试验数据进行验证,进而推导出构件最大弯矩公式。基于平均风速分布符合Weibull分布的假定,结合疲劳理论得出构件的容许应力幅公式。最后结合算例,得出构件的容许应力幅,并根据构件的最大弯矩公式结合焊缝分布形式计算法兰连接以及十字插板连接构件的焊缝应力幅,通过比较容许应力幅以及焊缝应力幅,给出疲劳寿命为50年的临界起振风速。
Transmission tower steel components prone to vortex induced vibration fatigue damage. This paper gives the method of determining the critical wind speed to avoid the occurrence of fatigue damage. In this paper, two kinds of typical support conditions of hinge and two ends fixed support of steel pipe members are deduced. Based on the structural dynamics theory, the maximum amplitude formula of the middle part of the steel tube members under vortex vibration is deduced. Test data to verify, and then derive the component maximum moment formula. Based on the assumption that the average wind speed distribution conforms to the Weibull distribution, the formula of the allowable stress amplitude of the component is obtained based on the fatigue theory. Finally, with the example, the allowable stress amplitude of the member is obtained, and according to the formula of the maximum bending moment of the member combined with the distribution of the weld, the stress amplitude of the weld of the flange connection and the cross-connecting plate member is calculated. By comparing the allowable stress amplitude and the weld Stress amplitude, given the fatigue life of 50 years of critical onset wind speed.