The Study Of Residual Stress Simulation And Elimination Based On Welding Thin Plate Of Cell Structure

In order to achieve the removal of material deformation and changes in materialproperties, various processing methods including non-traditional machining process are usedto produce the work piece in the mechanical manufacturing process, which will inevitablyproduce the residual stress during welding, stamping, casting and other process. The presenceof residual stress is harmful to the component in most cases. In recent years, VSR technologyis a new emerging technology to reduce the residual stress, which is remarkably efficient andenergy saving. However, this technology has its difficulties to apply widely in mechanicalindustry, and most enterprises has not bring into the formal process.The fundamental reason isthat its metal internal (crystal) micro mechanical characteristics and behavior is not clear, andit is impossible to understand its rules only depend on metal continuum model of macro. Thus,the micro VSR eliminate residual stress can be studied fundamentally by establishing themechanical model which is reflects the real crystal microstructure to reflect the internal micromechanical properties of metal crystal.This paper establishes the mechanical model of multi crystal metal for the surfacingrectangular thin plate, combining the numerical simulation with the experimentation to studywelding residual stress and VSR—a method of eliminating the welding residual stress.1. A kind of modeling method is proposed based on molecular dynamics modeling andmetal material micro structure, which can reflect the microstructure of real crystal mechanicsmodel, and bridge the gap between macro and micro research. The method of analysis ofdistribution of micro cell under macro stress can be constructed subsequently.2. The polycrystalline mechanical model and the element birth and death technology onfinite element method is used for the aluminum welded rectangular thin plate. The weldingprocess and the welding residual stress distribution is simulated according to the finiteelement heat theory. Materials changed for the residual stress distributions are researched,while the influence degree of elastic modulus, thermal expansion coefficient, specific heatcapacity and thermal conductivity on residual stress are discussed. The relationship betweenthe welding residual stress and elastic modulus through the theoretical analysis is built. Usingthe ANSYS finite element calculation software, the influence on residual stress for the naturalfrequencies of rectangular thin plate welding is verified for the welding residual stress, andthe residual stress on the polycystic mechanical model of atomic stress influence from themicroscopic point of view is analyzed.3. The influence of residual stress on the natural frequencies of rectangular thin platewelding and the material internal stress studied by using the ANSYS finite element software.4. Multi crystal mechanical model and harmonic response analysis technology in thefinite element method is used to simulate eliminating residual stress on the rectangular thin plate with welding residual stress. The influence of the vibration frequency, excitation forceand exciting point to eliminate residual stress is studied simultaneously, while the parametersof the method of eliminating residual stress such as the vibration frequency, the excitationpoint, and a dynamic stress selection principle is derived.5. The simulation results are verified by using the experiments, and it has been shownthat the simulation model and the research method for the metal material microstructure areestablished correctly.