Study On The Structural Optimization Design Of The Semi-trailer Towing Vehicle Fifth Wheel

With the vigorous development of China’s road transport industry, semi-trailer towing vehicle as the current logistic in the main models get more and more attention. As the key component of the fifth wheel on the semi-trailer towing vehicle,it not only plays a role of connecting the tractor and semi-trailer, but also hosts a variety of vehicle operating conditions impact loads. With the continuous improvement of tractor transport speeds, the fifth wheel to withstand dynamic load. In order to save energy and improve the competitiveness of enterprises,the optimization design of the fifth wheel is studied. It has very important theoretical and practical significance.Firstly, the QD9020 fifth wheel is treated as research object,in according with its size parameters, and 3D solid model is established in CREO software, after appropriately simplified import ANSYS software to establish the fifth wheel of the finite element model. The strength and stiffness of the fifth wheel are calculated under the condition of compression, braking and tension. According to the analysis of the stress and strain of the fifth wheel to verify whether the relevant requirement. According to the theory of structural dynamic, the fifth wheel is constrained by modal analysis,and the first 10 natural frequencies and mode shapes are gotten to determine whether the fifth wheel resonance phenomena occur. Then, according to the actual conditions of our country, the dynamic load is obtained through the combined simulation of the MATLAB and ADAMS when the fifth wheel is excited in the C grade road, after it is applied on structural surface, the transient dynamics analysis is done. The research results showed that the static and dynamic performance of the fifth wheel to meet the requirement, and structural quality of redundancy is serious, and larger space is optimized. Based on the analysis results of static and dynamic, the multi-objective optimization modal of the fifth wheel is established with the quality and the first order natural frequency as the objective function, and its size is optimized by target layering method. Finally, optimal solution of fifth wheel is gotten,and the static and dynamic performance of the optimized fifth wheel is verified. In ANSYS n Code Designlife platform, combined with the fifth wheel in the vehicle suffered during transport loads, fatigue type and material parameters, the nominal stress method and Miner cumulative damage rule are chosen based on the optimized traction fatigue analysis to verify the reliability of their fatigue.The results show that when satisfying the constraints, the quality of the fifth wheel is reduced by 48.74 Kg, and the natural frequency is increased to 4.2Hz, and the fifth wheel achieves a lightweight and security, and provides a theoretical basis for the design and development of fifth wheel.