Research On Cross-sections And Size Optimization Of Modern Telescopic Boom

Truck crane is widely used in various engineering fields because of its compact structure、 convenience mobility、flexible working conditions and site adaptability. Telescopic boom, as the bearing parts of truck crane is an important part among the design of the crane. The load it bears is very complex, which is mainly biaxial bending load. The form of cross-section and quality of boom directly determine the performance of the whole crane. Under the condition that the boom structure meets the strength, stiffness and stability requirements, the research of the form of boom sections and reduce its weight has great significance for improving the performance of the whole crane.With the continuous improvement of the level of design and widely use of new materials, truck crane is developing toward the large tonnage and large lifting height, which making the weight of boom also increasing. In order to reduce the boom weight and make full use of material properties, several cross-section forms are used, including the new ovalform cross-section. Because of the adoption of the arc slot board and skew web, this section form make the the anti-buckling capacity of boom structure greatly increased, the force more reasonable and the weight of whole crane lighter. The critical buckling load of the boom structure web has significantly increased, but new local stability problem emerges on the arc slot board. In this paper, the reseach is focused on the calculation method of local stability of the new elliptical cross-section telescopic boom, using the eigenvalue finite element method to modify the analytical method for cylinder shell buckling calculation, which is applied in the size optimization telescopic boom.The research of this paper is based on hexagon, octagon and a new ovalform cross-section telescopic boom. Considering the nonlinear bending of the boom structure, the mechanical model mechanical of the luffing plane and slewing plane is established, and mechanical constraints can be got. In programming, telescopic boom weight is made as the objective function, the sectional dimensions as design variables, and considering the impact of the sleeve length on the local stability. According to genetic algorithm which has good search performance, adaptability and high convergence speed, using the real value encoding method of Matlab software to program optimization procedure. The visualization software of the optimization of the telescopic performance and size is completed based on Matlab language. The crane performance parameters of QY70truck crane are applied to the optimization of three cross-section boom form, and getting the output of each iteration of the best individual. After the optimization calculation, the result shows that the weight of optimized hexagon, octagon and the new ovalform cross-section telescopic boom decreased by7.7%,9.2%,15.1%separately, compared with primary telescopic boom, which verify the feasibility of the program and the optimization effect.The research work provides reference for design of telescopic boom in practical engineering.