Research On Hydromechanical Deep Drawing Of Cup With Stepped Geometires Based On Numerical Simulation

With the development of the aerospace, automotive and machineryindustries, new alloy materials have been applied widely. However, somelightweight alloy materials have poorer forming performance and othershortcomings and those restrict its development and application. The sheet metalhydromechanical deep drawing technology is a flexible processing technology,mainly used in alloy plate with poor plastic. It adopts hydraulic chamber ratherthan punch or concave die. Through filling on hydraulic chamber, the pressurecan perform on sheet metal properly. The flexible characteristics of the formingtechnology can improve the quality of forming sheet metal, which can form theparts with higher forming limit, smooth surface and less flaw.Double step cylinder deep drawing technology is based on plankhydromechanical deep drawing technology. It divides the process of formingdouble step, which makes double step cylinder parts reach higher forming limit.It can also solve the formation of impending area forming huge gap betweentools during a hydromechanical forming technology. In addition, it can helpweaken the reserved compression made by hydraulic chamber which can makethe plate become thinner in impending area in the early period. This method issuitable for forming the parts which possess the characteristics that exists hugedifference in bottom diameter and thin-walled complicated in shape.This paper conducted research on the double step cylinder parts of AA6111aluminum alloy material. Through adopting hydromechanical deep drawingtechnology and applying finite element numerical simulation method, it studiedon the influence of various parameters during the forming, analyzed several most influential parameters, and optimized them. In a set of optimal parameters of thesimulation, this paper analyzed the stress and strain condition during the processof forming. It concluded the dangerous section occurred in the instability ofdouble step cylinder. It summarized major factors of dangerous section in deepdrawing through stress value changing.Numerical simulation was made on forming parts through DYNAFORM, aapplication showing analysis software. Its service processing software analyzedthe pressure of hydraulic chamber, friction coefficient and tools coefficient ondistribution of the minimum thickness of double step cylinder parts. It made thelateral comparison on influential factors of various parameters of deep drawing.By analyzing the grid, it can detect the trace of typical points in every parts ofthe parts.Through the numerical simulation research of double step cylinderhydromechanical deep drawing technology, it found out that optimum hydraulicforming was the key factor of forming refined parts. It also analyzed stress andstrain in the process of deep drawing and summarized the reason of formingflaws of cracking and wrinkling. Through choosing typical points on the parts, itanalyzed the state of stress and strain. It revealed elastic-plastic deformation lawin the process of double step cylinder hydromechanical deep drawing technology.