Stress And Strain Analysis And Optimization Design Of A School Bus Body Skeleton

In recent years,safety,energy conservation and environmental protection are still the main problem that is need to be solved urgently in automotive industry,structural static analysis and lightweight design are the main directions of the current car researches.With the development of the social economy,school buses are becoming the main means of transport increasingly for urban and township students and have a very broad future market.However,frequent school bus accidents are warning the community with the cost of of the children 's life that solving the security problem of school bus is imminent.Therefore,National Standardization Management Committee,Ministry of Industry and Information Technology organize National Automotive Standardization Technical Committee to revise the national standard for school bus safety with the "safety first,in line with national conditions" principle after seeking the views of the community widely,the new standard puts a higher strength requirements on the large and medium-sized school bus body skeleton structure.This paper used finite element method to do the structural analysis and the modal analysis about vehicle skeleton with the "special school bus safety technical conditions"requirements,also adopted size optimization design which is belonging to structural optimization methods to make the vehicle to achieve the goal of lightweight designing.Taken a large domestic semi-loaded school bus as our research target,built a 3Dmodel of the vehicle frame by using software CATIA,imported the CATIA geometry into Hyperworks software,used the two-dimensional shell element to build the finite element model of the school bus vehicle body skeleton based on the Hypermesh software,analyzed the method of applying load and the constraint which are included in finite element.Conducted the simulation analysis on the full loaded school bus under five typical working conditions,studied the stress distribution and deformation of the bus body skeleton under the five typical working conditions.Designed the static strength experiment of school bus based on computerized electrical measurement,analyzed the stress and strain of the body skeleton through the experimental data,verified the correctness and reliability of the finite element model of the vehicle body frame.On the basis of the above work,this paper used the size optimization technique to optimize the size of the local skeleton and the left and right side of the frame,utilized the finite element method to do analysis on the optimized model under the two typical workingconditions(bending of full load condition,torsion of full load condition),by compared with the pre-optimization model,When the body frame was lightweight,the new school bus body frame reduced quality by 69.73Kg when it was relative to the original body skeleton,the body structure strength has been maintained basically and the structural stiffness has been increased slightly by compared with the original body skeleton,achieved the purpose of optimization,gained a better lightweight effect,showed that the optimization design has the reliability and practical significance.