Reliability Analysis And Optimum Design Of A Semi-trailer Frame

With the progress of society and the rapid development of economy and technology,the requirements of the machinery industry are getting higher and higher.In order to comply with the national policy and be in a dominant position in the market competition,the design and improvement of semi-trailers should conform to the general trend.Now the quality and reliability of semi-trailers are required to be higher.Therefore,lightweight design and improvement of semi-trailers should be carried out.It is very important to ensure the reliability of the frame.This paper expounds the background and significance of the research on semi-trailer according to the relevant policies of our country,the requirements of semi-trailer in the market and the development trend of semi-trailer,collects and collates a lot of literature on semi-trailer analysis and optimization,and analyses and collates the status of semi-trailer research technology at home and abroad.Then a reliability analysis document is compiled with APDL for the frame of a semi-trailer.The finite element modeling of the longitudinal beam of the semi-trailer and the reliability analysis of the PDS module in ANSYS are carried out by using Monte Carlo method.The reliability of the design of the semi-trailer is verified,which provides a theoretical basis for the design and reliability analysis of the semi-trailer.In order to be more in line with the analysis of the semi-trailer model,a topology optimization model is established based on the original model of the frame.The model takes the cross-beam area of the frame as the region of the topology optimization design on the premise of keeping the longitudinal beam unchanged,uses the variable density method of the degeneration method to optimize the frame topology,takes the minimum overall flexibility of the semi-trailer as the objectivefunction,and takes the volume fraction of the design area as the volume fraction.As a constraint condition,in order to meet the use requirements of semi-trailer,this paper simulates the four working conditions which have the greatest impact on semi-trailer,applies corresponding boundary conditions and carries out analysis in the process of finite element analysis and optimization design.According to the data of topology optimization under four working conditions,the model after topology optimization is rationalized to make it easy to process.Then the model after topology optimization is analyzed by finite element method.The stiffness,strength and quality of the model after topology optimization are compared with that of the original model.It is concluded that the model after topology optimization has higher stiffness and strength and better quality than the original model.To alleviate,the rationality of topology optimization is obtained.Because the stiffness and strength of the model after topology optimization are increased,there is still some room for optimization of the model after topology optimization.OptiStruct module in HyperWorks is used to optimize the size of the model after topology optimization according to the size optimization criterion,and the original model is also optimized.In the optimization,the objective function of the optimization model is the quality of the frame,and the constraints are set.For stress and deformation,the state variable is the thickness of components in the frame for size optimization.It is concluded that the weight of semi-trailer is reduced by 18.31%after topology optimization than by size optimization only.The vibration of semi-trailer during transportation will be greatly affected by ground excitation.The original model,the model after topology optimization and the model after size optimization are analyzed in free state.The results of the first ten order which have the greatest impact on semi-trailer are extracted by BLOCK LANCZOS method.The model can be seen from the vibration pattern and natural frequency.To meet the safety requirements of semi-trailer,according to the vibration pattern and natural frequency obtained from the analysis,it can be seen that the topology optimization and size optimization also have a certain impact on the modal,and the topology optimization has a greater impact on the modal of the model than thesize optimization,which provides a certain theoretical basis for the Modal Research of the frame in the future.