输电塔-线体系的风致动力稳定

结合增量动力分析法和弧长法有限元分析了安徽某输电塔-导地线结构的风致动力稳定,通过杆塔顶侧移比、底层受压侧主材应力和导线挂线点反力、张力和振幅的变化规律分析了塔-线相互作用及结构动力失稳前、后的受力特征。根据非线性静力与动力失稳塔顶侧移比相等原则得到了不水平档距塔-线结构动力失稳临界平均风速。研究结果表明,塔-线结构动力失稳过程主要为杆塔挂线点杆件屈服、塔身底部受压侧主材屈服、塔顶侧移比增大、塔底主材压屈；随着水平档距增加,塔顶侧移比增大,挂线点反力增大,导地线张力减小,导地线振幅增大,动力失稳临界平均风速减小；输电塔的风致稳定性设计应考虑动力效应及塔-线相互作用的影响。

Dynamic stability analysis on transmission tower-line systems under wind-induced loading

The dynamic stability of transmission tower-line system in Anhui under wind load is studied utilizing incremental dynamic analysis combining with arc length method in this paper. To reveal the pre- and post-instability behaviors of transmission tower-line, the developments of top drift ratio, Mises stress of bottom structural elements, hanging reaction forces, tensions and amplitudes of conductors are investigated. The critical wind speeds of dynamic instability of various span length transmission tower are captured by the principle of equal top drift ratio of tower. The analysis results indicate that the characteristics of dynamic instability of transmission tower include the plastic developing of wire hanging position, column yielding and top drift ratio increasing. Increasing the span length increases the top drift ratio, the hanging reaction force, the amplitude of conductor, and decreases conductor tension and the critical wind speed of tower. The influences of dynamic responses and interactions between tower and wires on the instability of transmission tower shall be taken into account in the design.