Researech On Fracture Prediction Of Control Of Deep Drawing Of Magnesium Alloy Variable Cruvature Plate Type Component

Aerospace,rail transportation,new energy vehicles and other areas of equipment components of lightweight manufacturing needs more and more urgent and urgent.Magnesium alloy as the lightest engineering metal material,in the satellite adapter cone barrel parts,compartment cover,body coverings and other shaped wall components to reduce the weight of the application of broad prospects.These components usually have large size,variable curvature and shaped deep cavity shape characteristics and service in the load/sub-load state,the use of magnesium alloy plate spinning,deep drawing forming is an important way to achieve its rapid low-cost integrated preparation,which is a multi-axial stress state deformation behavior.However,magnesium alloy is a dense row of hexagonal crystal structure,poor coordination of plastic deformation under complex stress state,narrow stable deformation interval,resulting in plastic deformation by the process conditions and deformation state strongly influenced by improper control is very easy to produce cracking defects,become an important factor to limit its development.In this paper,from the plastic deformation and fracture behavior of magnesium alloy,the fracture behavior and critical cracking criterion of twin-roll casting AZ31 magnesium alloy under multi-axial stress state are studied,as well as the damage distribution and rupture region tissue distribution state during deep drawing and forming,to provide guidance for the deep drawing and forming rupture of magnesium alloy.The deformation fracture behavior and fracture model of twin-roll casting AZ31 magnesium alloy were investigated by conducting tensile experiments without stress state and by considering the combined effects of temperature and strain rate.The test-finite element method was used to construct the critical cracking criterion.The finite element simulation method was used to study the failure behavior of materials under different fracture criteria in the physical tensile process,and to verify the applicability of each fracture criterion,which provided a basis for the prediction of crack initiation under multiaxial stress state,and the damage distribution analysis based on this fracture criterion was carried out,the fracture behavior and critical cracking criterion of cast-rolled magnesium alloys under multiaxial stress state are determined.Taking the seat front panel feature as an example,combined with the advantages of Autoform and Deform-3D simulation software,the fracture behavior of cast-rolling AZ31 magnesium alloy sheet in the deep drawing forming experiment was predicted by using the crack criterion constructed previously,which guides the industrial production of magnesium alloy complex shell parts.With the help of finite element analysis,Autoform is used to optimize the drawing process parameters,and the influence of metal flow,displacement field,stress/strain field,and temperature field distribution on the sheet metal in the drawing process is analyzed,the optimal forming process parameters during sheet metal deep drawing were determined.Secondly,to ensure the accuracy of deep drawing,the heat transfer coefficient(IHTC)in the process of heat transfer was calculated,and the damage distribution at room temperature and 523 K were analyzed by Deform-3D,the first fracture area of the sheet and the maximum forming height of the deep drawing are determined.The experimental verification of the deep drawing forming of twin-roll casting magnesium alloy and the analysis of the fractured state of the key area of deep drawing forming were carried out.The experimental verification of the deep drawing of twin-roll casting AZ31 alloy and the analysis of the fracture shape of the key area of deep drawing,and the cupping experiment method were used to further verify the fracture position and maximum forming of the deep drawing at room temperature and 523 K.Height,analyze the microstructure evolution of the sheet metal at high temperature in each area during the deep drawing process,and reveal the microstructure distribution state of the key forming area.