Finite Element Analysis And Structure Optimization Of A Stake Fence Semi-trailer

With the development of the highway network and the semi-trailer industry in China,semi-trailer transport has become the main form of highway freight transportation with excellent cost-effectiveness.Therefore,the safety and cost of semi-trailers have been paid more and more attention.The study of semi-trailer was also becoming more and more thorough.In recent years,the finite element method has become the standard configuration in the study for automobile,but the application on the carriage of the stake fence semi-trailer was lacking.In this paper,the research object was a stake fence semi-trailer,finite element method was applied to statics analysis and free model analysis,and the strength and stiffness were checked,and the relevant parameters of free model was analyzed.Then,optimization on corresponding parts was carried out based on the study.The main research work is as follows:Firstly,The three-dimensional model of the semi-trailer was established with Pro/E software based on the drawings provided by the manufacturers after simplifying the model appropriately.Then,importing the three-dimensional model into the finite element software,extracting the mid-surface,cleaning up the geometry,meshing the model,establishing the connection and simulating the leaf spring so as to obtain the finite element model of the semi-trailer.Afterwards,determining the loads and boundary conditions according to the analysis and actual working conditions of the semi-trailer under the bending,twisting,emergency braking and turning conditions.Then statics analysis was carried out on the semi-trailer after applying loads and boundary conditions with Hyper Mesh/Opti Struct.Then the deformation and the Von Mises stress under the four typical conditions were calculated.In the process of checking the strength and stiffness,two problems were founded.One problem is that the strength of the joints of carriage's beams were insufficient.Another is that the material utilization rate of the major parts is not high.Next,we got the first sixteen natural frequencies and mode of vibrations by the free modal analysis.The shortcomings of the semi-trailer are obtained through analyzing of the relevant parameters.Finally,according to the problem that the strength of the connection of carriage's beams is insufficient,adopting inclined brace to optimize the design inconsideration of the experience of engineers and technicians.According to the problem that there is a great safety margin between the real strength values and the allowable stress values of the main parts,adopting a size optimization with Opti Struct after the definition of design variables,constraint conditions and objective functions.The final optimal design was obtained through the experience of design,the project design standards and the output of software.The problem about strength of the carriage's beams was solved and the mass of the semi-trailer was reduced effectively based on the optimal design.