High Strength Aluminum Alloy Friction Stir Welding And Aging Forming On Integration Simulation Research

High strength aluminum alloy has high strength,low density and good processing performance,so large aircraft usually use high strength aluminum alloy by aging forming to make the aircraft's wings,panels and skin.These panels and panels parts are generally large size and have high requirements for manufacturing and transportation equipment.If the welding sheet plate is used as the aging forming raw material,the size of the raw material can be significantly reduced.Friction stir welding is a new non-melting welding method through the friction of the stir head producting heat quantity.Friction stir welding has small welding deformation and small residual stress,so it is very suitable for the connection process of aluminum alloy materials.Therefore,the continuous process of friction stir welding and aging forming need to be studied.First,the simulation study of high strength aluminum alloy friction stir welding and aging forming is conducted.At present,this research is still in the exploration stage,and the integration research of friction stir welding and aging forming is less reported.In terms of numerical simulation of friction stir welding,parameters uncertainty of heat source model still exist.In terms of numerical simulation of aging forming,the creep model doesn't consider the mutual relationship between welding residual stress and two-phase particles.In the integrated simulation study of friction stir welding and aging forming,the influence of aging temperature and time on creep strain and welding residual stress have not been seen.Based on the above,this article studies the following content.Based on the heat production principle of friction stir welding,the three-dimensional heat source model of high strength aluminum alloy is established.The geometric parameters of heat flow density are determined,and studies the law of uncertainty.Then,the heat source model uncertainty parameters are verified by the temperature field example of the high-strength aluminum alloy friction stir welding,and an accurate heat source model is obtained.The finite element model of friction stir welding is established,and realizes the welding residual stress and deformation simulation of high strength aluminum alloy by the heat change material model,lower pressure and heat source model.The results verify the accuracy of the heat-stress coupling model by comparing test and numerical simulation.Establishing a creep finite element model of high-strength aluminum alloy considers the relationship of stress and two-phase particles.The model takes into account the effects of welding residual stress on precipitate evolution,initial stress and pre-strain on stress relaxation,and the connection among microstructure,strength,and stress relaxation.Further through differential equation discretization and programming,subprograms are successfully developed for numerical simulation of aging forming and for integrated simulation of friction stir welding and aging forming.Based on the heat source model,heat-stress coupling model,and creep model,the finite element model of friction stir welding and aging forming is established,integrated simulation of friction stir welding and aging forming,comparing the rebound experiment and simulation data of friction stir welding and aging forming.Based on these,the effects of aging time and temperature on creep strain and stress are studied.Research,on the integrated automatic simulation system of friction stir welding and aging forming,develops the hexahedral transition mesh automatic division of flat workpieces,and develops the integrated automatic simulation system based on VS,Fortran and Python.