Topology Optimization Of UHV Transmission Tower

Nowadays, the study on ultra-high voltage power transmission and transformation lines test project is being done widely in domestic. The transmission towers who get wide spans, large heights and heavy weights cost a lot in this project. And the whole investment of the transmission line is mostly determined by the structure design of the towers. Hence, it is of great practicality and economical to reduce the cost of steel by optimizing structure, which is conditioned by satisfying the national design criterion.The project 1000kV Hanjiang long span transmission project is researched as the engineering background, and the crossing tower in this project is the highest and the heaviest in all of the towers as well as the most technical at the same time. By the topology optimization of this crossing tower under dynamic constraints, the structural weight is obviously reduced which not only guarantees the safety of the ultra-high voltage transmission tower but also makes a remarkable reduction of its cost. The main achievements run as follows.First of all, according to the transmission tower-line system, a precise truss for analysis is modeled by finite element method. And the wind load is simulated based on harmonic synthesis method. Based on the balanced equation of the ultra-high voltage transmission tower forced by the simulated wind load, the vibratory response of this tower is calculated by the precise time integration method (PTI), and the PTI satisfies the precision with random time increment is proved well by comparing the results. Therefore, the PTI method is applicable in the further precise study of the vibratory response of the transmission tower-line system.Secondly, a method of optimizing the transmission tower is proposed as follows. In the first place, the section optimization is carried out by changing the inner and external diameters of the cylindrical steel tube. After that, the shape optimization is achieved by the movement of the node in the foot of the tower. Afterwards, topology optimization is accomplished by the topology theory brought forth advanced in the article. Based on adaptive genetic algorithms (AGA), the optimization program is compiled to automatically search the best section, to find the optimal location of the node, to choose the most adaptive number of the nodes and the assistant material, as well as the cross braces. Compared result of the topology optimization with that of the shape and section optimizations, the conclusion is obviously showed that topology optimization method is much better than shape and section optimizations. In addition, a pilot research on the complicated topology optimization has been done to seek the optimal structure automatically, combining the complicated structure optimization method with the topology optimization method.Thirdly, the topology optimization under the constraint of vibratory responses is conducted based on the AGA, which programming considered the coupling of topology, shape and section optimizations. In comparison with result of the topology optimization under the simulated static wind load, the calculation result shows that topology optimization under the constraint of vibratory responses guarantees the safety of the ultra-high voltage transmission tower as well as a visible reduction of its cost.