Research Of Thin-wall Structures Dissimilar Material Assembly Precision Forcasting And Temperature Deformation

It is highly emphasized about accuracy and reliability in the industries like automotive, high-speed rail, aerospace etc., and effective prediction and control of the dimensional accuracy of assembly are important ways to achieve the quality requirements which have significant impacts on product performances. At the same time, the tendency of dissimilar materials assembly is so clear in the industries mentioned above due to kinds of reasons like lightweight, cost control, taking advantages of different materials etc., which will complicate the problem of prediction of dimensional accuracy. Therefore, it has very crucial significance to conduct dimensional accuracy prediction of dissimilar assembly including composite materisal.Currently, specific to dissimilar assembly, the main research contents are microstructure characteristics of connected region and process parameter optimization, which lack the research of assembly dimensions change characteristics. Basically, the impact on the assembly deviations because of material properties parameter fluctuations leaves out of consideration in models, accuracy and efficiency of calculation also need to be improved further. Lack of related research about assembly dimensional accuracy prediction of dissimilar materials with large discrepancy about physical and chemical properties due to thermal deformation caused by environment temperature change.In order to do precision prediction of dissimilar materials assembly dimensions, For the above shortcomings, things have been done as follows: Primarily, analysis of the assembly dimensional accuracy characteristics of dissimilar materials and study the differences comparing assembly of similar materials; followed by research on the influence of assembly dimensions accuracy because of material performance parameters fluctuations using FEA(finite element analysis) and computer program, providing a new fast pridiction method; Then conduct the law of the temperature effect of dissimilar materials assembly. Finally, conclusions will be used in case to verify. Main research contents are showed as bellows:(1) Assembly dimensional accuracy characteristics of dissimilar materialsFirst, establish effective FEA model, special to the assembly of dissimilar materials(including metal&metal, composite&composite, metal&composite), by contrast simulation data, conduct reasearch of assembly deviation law of dissimilar materials in the theoretical state and comparison with the same kind of material assembly dimensional accuracy characteristics as well.(2) Assembly precision forecast considering elastic modulus deviation fluctuation.Special to inevitable elastic modulus random fluctuation of metal or composite in the actual production process, research the effect of that to assembly deviation accuracy based on FEM. In this process, in order to improve research efficiency, based on part stiffness matrix of computational solid mechanics and formula derivation, combining traditional method of influence coefficient and computer programming, propose a method which can predict assembly deviation affect due to elasticity modulus fluctuation efficient effectively and quickly, wich has been validated.(3) Temperature deformation of dissimilar materials assembly dimensional accuracySpecial to experimental simulation structure, in the form of different manufacturing deviations, different boundary conditions, different materials combinations case, condcut comparison FEA, analyze influence of dimensional accuracy of dissimilar materials assembly due to the environmental temperature change though simulation data. During this process, consider the connection of the carbon fiber composite laminated plates&metal material and the influence of composite ply angle to assembly variation, particularly.(4) Application of automotive’s door impact beamTake door impact beam for case study, the temperature changes for error sources, FEA for analysis method, verify dimensional accuracy change characteristics of dissimilar materials assembly; Construct new hybrid materials assembly door impact beams to research on the differentiation between temperature effect to assembly dimensional of hybrid structure impact beam and that of the original door impact beam. This case verified the temperature deformation relevant conclusion and indirect explain the engineering significance of this research.