Truss Structure Optimization And Its Engineering Application Based On Improved Sine Cosine Algorithm

As a large space truss structure,the holding pole is often used in the erection of transmission towers.If the weight of the pole is too large,the manufacturing cost will increase,the transportation will be difficult and the tower assembly will have more safety risk.Therefore,the optimization design of truss structure like holding pole has great theoretical significance and engineering application value.In recent years,meta-heuristic algorithms have been widely used in the optimization of truss structures.This paper takes common trusses and the double rocker arm holding pole into consideration,and proposes an improved sine cosine algorithm（ISCA）to implement the size optimization,size and shape optimization,size shape and topology optimization for these structures.The main research contents and conclusions are as following:（1）The working principle and optimization idea of sine cosine algorithm（SCA）are introduced,and ISCA is proposed to treat the shortcomings of SCA,such as slow convergence speed and low convergence accuracy in truss structure and actual engineering optimization.Firstly,the main parameter（r₁）is changed from linear to nonlinear,which makes the algorithm search area more reasonable;secondly,Lévy flight is introduced into the position update formula to enhance the global search ability of the algorithm;then a new elite guidance strategy is introduced to enhance the local search ability of the algorithm;finally,the greedy selection strategy is adopted to keep more promising solutions.（2）The size,shape and topology optimization of four classical truss structures are carried out by using the SCA and the ISCA.The optimization results show that the ISCA can handle the truss structure optimization problems very well.Compared with the SCA and other algorithms,the ISCA can obtain better results with less calculation times,and more stable,and highly competitive in dealing with truss structure optimization problems.（3）The holding pole is analyzed under various classical load cases by finite element method.It can be seen from the analysis results that the wind direction,the unbalanced load and the horizontal rotation angle of the rocker arm have a great mechanical influence on the pole.The working condition,with the rocker arm horizontal rotation angle 45°,the wind direction 45°and the unbalanced load（4t,3t）,is dangerous condition.The non-working condition,with the rocker arm horizontal rotation angle 45°and wind direction0°,is dangerous condition.（4）Under dangerous working conditions,with the strength,stiffness and stability of the holding pole structure as constraint conditions,the optimization model is established,and the size optimization,size and shape optimization,size shape and topology optimization of the holding pole structure are carried out by using the SCA and the ISCA respectively.It can be observed in the results that the three optimization methods can effectively reduce the weight of the holding pole,and the optimization effects increase successively.The optimization result of size shape and topology optimization is the best.The finite element analysis results of the three kinds of optimized holding poles by the ISCA meet the design requirements.The ISCA can effectively solve the optimization design problem of large space truss like holding pole.