Research On Springback Technology For Cold Stretch Forming Of Titanium Alloy With Hyperbolic Skin

At present,the shape structure of domestic civil aircraft tends to be internationalized,the performance improvement is relatively high,the complex parts of the outer skin are more,the forming difficulty is relatively large,and the application of titanium alloy skin is a developing trend.At present,the general processing method is used for the engineering of skin parts,but titanium alloys generally use thermal forming or superforming.Due to equipment and size limitations,tensile processes are used,but the process parameters lack theoretical support.And the production cycle is long,difficult and expensive,we need to solve the problem of titanium alloy tensile technology difficulties.Therefore,in this paper,the tensile process of titanium alloy thin plate is discussed and studied in depth,and ABAQUS finite element forming simulation software is used as an auxiliary platform to study the forming technology of titanium alloy skin parts,and to discuss its reasonable design.Stretching performance analysis,rebound control,compensation analysis,cutting technology for feasibility analysis,the main contents of the paper are as follows:Through the combination of theoretical analysis,numerical simulation and process test,the precise manufacturing process,subsequent cutting parameters,forming rules and die design of ARJ21 aircraft titanium alloy body skin were studied in detail.It is proposed to use ABAQUS and other simulation software to simulate product forming,explore key process parameters and optimize the relationship between them,and combine the forming of typical parts to record parameters,compare results,correct parameters,and combine theory and practice to produce qualified typical parts.Provide technical support for mass production.By analyzing the control of rebound defects in the process of sheet metal forming,the die surface or die structure is corrected to overprocess the stretch part.Based on the trend and law of material rebound,the actual shape of t he shell is similar to the theoretical shape.Optimizing the forming process,changing the stress state of the sheet metal during forming,or making the sheet metal fully plastic deformation,to inhibit the occurrence of rebound deformation.In practical e ngineering,two kinds of methods can be used together to achieve the best results.In order to determine the feasibility of the tensile forming of titanium alloy,the numerical simulation of parameter simulation and composite forming is carried out in ABAQUS finite element forming simulation software.In this paper,we use the method of compensation to eliminate the geometrical error of the workpiece caused by rebound.The method of compensation is to correct and repair the shape of the workpiece based on the different amount of rebound and distribution area.The shape of the part after forming meets the basic requirements of the theoretical shape.In practical engineering,the size distribution of the rebound volume is not easy to measure.Therefore,how to use numerical simulation to predict the amount of rebound and reduce the geometric error of the parts.Through the research of this project,it is proposed to solve the problem that the cold forming technology of the sheet metal of the titanium alloy can not meet the requirements of production assembly.At the same time,on the basis of meeting the requirements of aircraft design,high-quality qualified parts are processed.It has laid the foundation for our forming technology in all aspects of titaniu m alloy parts in the future.