Telescopic Boom Optimization Research Based On The Nonlinear Bending

With good mobility and fast transfer characteristics, crane is widely used in the fields of construction, energy, chemistry, shipbuilding and so on. Telescopic boom works as an important component, whose weight takes up a large proportion of total weight of the crane and also has an important influence on the engine performance. It is of great importance to reduce the weight of the telescopic boom while the requirements of strength, stiffness, stability are met. Therefore, this paper conducts the optimized design of the telescopic boom based on the nonlinear bending theory, which is important, theoretically and practically.Telescopic boom is a typical thin-walled, large flexibility structure under biaxial bending. Nonlinear bending is an important factor, which must be considered in the design process. With gradual approximation method, the telescopic boom's deflection is analyzed. The analysis set up the foundation for telescopic boom optimization.In this paper, telescopic boom is optimized by the genetic algorithm.Among the optimization algorithms, the genetic algorithm is expert at good adaptability, global search without gradient calculation features;moreover it is suitable for settling multidimensional and multi-constrained engineering problems.With the requirement of the section, the optimal mathematical model is established. The objective function is the lightest weight of the telescopic boom, the design variables are the cross-section parameters, the constraints function are telescopic boom strength and structural design requirements.Then the penalty function is taken to conduct the mechanical constraints, and the real value code is used to improve the algorithm's accuracy and global search capability.Finally, the optimal program is compiled based on C++ Builder.The telescopic boom of QY70 truck crane is presented as the optimize example, of which the section parameter is optimized.Also average fitness of each generation and the corresponding weight of best fitness of each generation are analyzed, which show the validity of the termination code in the algorithm.The optimum solution and original scheme are compared and analyzed, that the results show that the optimized telescopic boom lower than before the weight of 12.6% (about 919kg) under the same constraints, with which the effectiveness of the program is verified.The research in this paper enhances the efficiency and level of the design, and also provides good references for the design of the telescopic boom of the truck crane.