Lightweight Design Of Cargo Box Structure Of A Van

With the continuous promotion of national energy conservation and emission reduction strategy and the increasing shortage of oil resources,automobile lightweight design has become the focus of research.Van transport vehicles have the advantages of safety and environmental protection.At present,they have become the main vehicle in urban logistics.Vigorously developing van transport is the general trend of domestic logistics industry.As the main load-bearing component of transport vehicles,the weight of van container accounts for about 15% ～ 30% of the total weight of vehicles.Therefore,it is of great significance for relevant enterprises to study the lightweight technology of van container and develop a new type of container with a high degree of lightweight,so as to respond to market demand and improve product competitiveness.Firstly,based on the enterprise requirements and the existing research results in the field of lightweight,this paper formulated the design idea of the container,determined that the main components in the container will be made of aluminum alloy,and established the three-dimensional model of the container in the three-dimensional modeling software Solid Works.The three-dimensional model of the container is imported into the finite element software Hyper Mesh to assemble the frame,skid and other key components for the container.After pre-processing work such as geometric cleaning,meshing and leaf spring simulation,the finite element model of the container in the vehicle environment was obtained.Secondly,according to the requirements of enterprise standards,the static analysis conditions were determined,and the lateral load of goods on the box plate under different working conditions was calculated based on Coulomb earth pressure model and vehicle system dynamics theory.The static analysis of the container was carried out in the Optistruct solver,and the strength and stiffness of the container were checked.It was found that the container has insufficient strength and stiffness.Further,the free modal analysis of the container was carried out,and the natural frequencies and vibration modes of the first12 modes were extracted.By comparing the modal frequencies and external excitation frequencies,the shortcomings of the dynamic performance of the container were understood.Then,according to the problems found in the static analysis and modal analysis of the container,targeted improvements were made to the container structure: changed the cross-sectional shape of the cross beam at the bottom of the container,increased the cross beam support and stiffeners,locally strengthen the parts with concentrated stress,changed the connection form between the lower side beam of the front end face and the floor,and increased the skeleton on the top surface.The static and dynamic performance of the optimized container was analyzed again to verify the rationality of the optimized design.Finally,using experimental design,approximate model technology and multi-objective optimization method,a multi-objective optimization design method of corrugated plate geometric parameters based on RBF approximate model was proposed.Taking various geometric parameters of corrugated plate as test factors,the sample space was obtained through optimal Latin hypercube sampling,and the simulation test was carried out to obtain the output response,The RBF approximate model was established to replace the finite element simulation process.The NSGA-Ⅱ multi-objective genetic algorithm was used for optimization calculation to obtain the optimal solution of the geometric parameters of the corrugated plate.The results show that after the optimization of the corrugated plate,the weight of the container was reduced and the stiffness was improved.Further,the size of the container was optimized,the thickness of some parts in the container was taken as the design variable,and the minimum mass was defined as the optimization objective.The optimal thickness combination was obtained by solving and calculating in Optistruct,and the weight of the container was further reduced.Then the static and dynamic performance of the lightweight container was checked to determine that its performance meets the design requirements.