Simulation And Experimental Research On The Technology Of Repetitive Bulging Of Spherical Parts

Sheet metal forming is widely used in aerospace, automotive, marine and other vehicle manufacturing industry and civil industry. How to delay the failure and improve the forming limit is the main development direction of sheet metal forming. Repeated forming is a special forming,which can effectively inhibit the part of the wall thickness of the forming parts and improve the forming limit of sheet metal forming. In this paper, the method of finite element simulation and experimental study is used to study the forming process of spherical parts.Using Marc finite element software, the finite element simulation of a spherical part of one time bulging and repeated bulging(two times, three times and four times) forming is carried out, through which stress strain distribution, the curves of stress-strain and the variation curves of wall thickness in each phase of forming process were obtained and contrastively analyzed. Combining with two times of repeated bulging forming simulation, We divide the process into different stages and study the stress and wall thickness of each stage. Research results show that after repeated deformation, the stress and strain distribution can be effectively improved, and the local thinning of the sheet is suppressed, and the forming limit is improved.Experimental research of repeated bulging process and one time bulging were performed via Sheet forming testing machine. Through which the curves of load-displacement were obtained. Comparing with the simulation results, we find the trend of these curves is basically the same. By measuring the wall thickness of the workpieces, we know the thickness of the wall thickness decreases gradually with the increase of the number of repetitive times.Measure the thickness of forming parts via Grid strain measurement, then you can get the distribution of strain,thickness,Thinning rate and Forming Limit Diagram. Comparing these figures with the simulation results, experimental results were exactly the same as the simulation results, which further validated the feasibility of technology and the correctness of the simulation.