Development And Optimization Design Of All Alurminum Semi-Trailer Frame

With the rapid development of the transportation industry and the stricter regulations on energy saving and emission reduction in the global market,it is of great significance to promote the process of light weight in the automobile field,and the application of aluminum alloy in the automobile is one of the important ways to realize the light weight of the automobile.Based on a fully aluminum van semi-trailer,this paper has carried out various aspects of optimization design research on the basis of the frame structure design.The main research contents are as follows:First of all,according to the relevant national standards and the design requirements of the company,the structure design of the frame is carried out.In view of the characteristics of aluminum alloy,this new material has changed the structure of traditional steel frame and gained a brand-new design scheme of lightweight frame.Secondly,in view of the cracking problem of the welded joints of the frame of the same series of semi-trailers,the mechanical properties of the welded joints of aluminum alloy are tested.Under the same shape and size,the strength difference between the welded specimen and the parent specimen is studied.The strength limit of the weld seam under the high stress condition is quantitatively analyzed,which provides a certain reference for the finite element analysis and optimization design of the frame.Thirdly,using the Hypermesh and Nastran software,the finite element simulation of the frame is carried out,and some weak points of the frame are found,such as the front end beam lock support and the front assembly support,which have a serious stress concentration phenomenon.This paper redesigns the hidden parts of the structure,puts forward several optimization schemes,and uses the simulation comparison to determine the final design scheme of the frame structure,and avoids the problem of low local strength before the optimization.Using the Optistruct module of Hypermesh software,the bolt arrangement in the connection between the frame beam and the longitudinal beam is topologically optimized,and a new form of spiral hole arrangement is obtained,and the stress concentration around the bolt hole is improved.Finally,on the basis of the finite element method and response surface method,the thickness of the main structure is redesigned on the premise of the shape of the cross section of the frame.The bending stiffness,torsional stiffness and the weight of the frame are optimized.The bending stiffness and torsional stiffness of the frame are ideal at the same time as the weight of the frame is reduced.It is proved that the response surface method is effective in the design of the key components of the frame in the case of multi-objective optimization.The results show that The yield strength and tensile strength of weld specimens were significantly reduced,from 120Mpa and 203.51Mpa to 75Mpa and 129Mpa,respectively.And the stress value of the frame risk point is reduced from 280Mpa to about 110Mpa,and the frame's bending stiffness and torsion stiffness are unchanged,and the frame quality is reduced by 35kg and the decrease is 3%.It not only makes the frame meet the requirements of stiffness and strength,but also achieves the purpose of lightweight.The research methods in this paper provide some guidance for the wide application of aluminum alloy on semi-trailers.