Multi-objective Lightweight Optimization Design Of A Dump Truck Compartment Under Multiple Working Condition

According to the national energy saving and emission reduction policy and the increasing emission standard of dump truck,the lightweight has become the focus of dump truck research field.Dump truck lightweighting research can not only reduce dump truck mass and cost,but also have a great improvement on fuel economy,power and safety of dump trucks.The mass of the carriage accounts for about 1/3 of gross weight of the dump truck,so the lightweight design of the dump truck carriage is crucial to the lightweight of the whole vehicle mass.In this paper,a multi-objective lightweighting study of dump truck carriages is conducted to reduce the mass of the carriages,improve the bending stiffness of the carriages,and shorten the carriage development cycle through a simulation study of the carriages.The main contents are as follows:(1)This paper firstly introduces the significance of dump truck lightweighting,the current development status and the status of domestic and foreign research,and reviews the domestic and foreign literature.Next,the solid model of the carriage is built using UG software and imported seamlessly into Hypermesh to pre-process the carriage and build the finite element model of the carriage.Improve the quality of the mesh by checking the mesh or changing the type of the mesh.The finite element model of the carriage after quality inspection is welded between the plates and the material properties are added to obtain the complete finite element model of the carriage.Finally,constraints are added to the carriage for various working conditions to lay the foundation for the analysis of different working conditions in the finite element model of the carriage.(2)Single-objective topology optimization of the carriage is performed with cell density as the design variable,strain and stress in the design region as constraints,and carriage volume as the objective function.The six working conditions of the carriage are simulated and analyzed under Optimization,and the strain distribution and stress distribution clouds for different working conditions of the carriage are obtained.According to the obtained cloud map data results and the enterprise requirements standards for comparison,to ensure that the carriage in different working conditions to work requirements,and simulation and analysis of the first eight orders of the carriage free mode.(3)Based on the simulation of various working conditions of the carriage,a comprehensive optimization analysis is carried out for the 0° lifting condition and the full load condition,and the multi-objective optimization design of the carriage is carried out with free mode,strain and stress as constraints.Under the Hypermesh module,the integrated model is seamlessly imported into Hyperstudy.A Latin hypercube experimental design(DOE)was used for the selection of design variables for the integrated model of the compartment,and the design variables were screened based on sensitivity analysis and sensitivity effects.Based on the Latin superliberal method,the Kriging,MLSM and RBF methods are compared and analyzed,and the RBF method is chosen to construct the approximate model of the carriage,and the accuracy of the carriage model is improved by changing the fitted values of the approximate model.A better multi-objective genetic algorithm is selected to optimize the design of the integrated model of the carriage for 36,000 iterations,and the most suitable optimization solution is selected in the Pareto solution set,and the optimization results are rounded and verified.(4)The reliability of the carriage is analyzed based on the normal distribution of the design variables,and the stress reliability of the carriage mass,0° lifting condition and full load condition is expressed in the form of probability.After the optimized rounding of the carriage,reinforcement bars are added in the dangerous area of the full load working condition,which reduces the value of strain and the area of the concentrated area and improves the safety performance of the carriage.With the minimum flexibility and minimum volume of the carriage floor as the optimization objectives and the maximum strain as the constraint,the variable density topology of the carriage floor assembly is optimized to improve the material utilization of the floor assembly.Comparing the carriage data before and after optimization,the mass was reduced by 20.54%,the bending stiffness was increased by 17.61%,and the strain concentration area under full-load working condition was greatly reduced,with significant optimization results,while meeting the enterprise stiffness and strength requirements.