Papers by Author: Peng Xiao Feng

Abstract: Flexible DCSF technology was put forward, and its forming character was described. The flexible DCSF machine was developed and related stretching experiment were carried out. The experimental photos show the DCSF technology is feasible and the DCSF machine is practicable. The FE model of flexible DCSF was set up, and extensive numerical simulations for spherical parts, saddle parts and S-type parts were carried out by Abaqus. The numerical results show that the longer the transitional length is, the more homogeneous the stretching strain and the thickness become. The smaller the friction coefficient is, the more homogeneous the stretching strain and the thickness become. The larger the clamp number is, the better the fit degree becomes. This work may provide useful guidance on the flexible DCSF process.

Abstract: In order to save the manufacturing cost and solve problems of stamping, a new type of flexible blank-drawer (FBD) forming device was presented by the authors based on the principle of flexible stretch-forming. It can be used with a variety of different sizes, different shapes of stamping die which can cut the manufacturing cost and shorten the development cycle of sheet metal forming largely. Extensive numerical simulations of the process for forming saddle parts were carried out and the forming results using FBD were compared with those using traditional blank-holder (TBH). By adjusting the value of blank-drawer force, good quality of saddle parts can be attained easily. Simulation results indicate that FBD forming can solve the shortages of TBH forming, inhibit wrinkle, prevent fracture, and form parts with small springback and uniform strain. This work can provide useful guidance in plastic forming technology for sheet metal.

Abstract: A new type of discrete clamp stretch forming machine based on flexible holding technology was developed to improve the performance of traditional rigid clamp stretch forming machine used for double-curvature metal sheet forming, and its forming characters were illuminated simply. The FE model of flexible discrete clamp stretch forming was set up, and extensive numerical simulations of spherical parts for both the flexible holding mode and the rigid holding mode were carried out by dynamic explicit finite element analysis. The numerical results show that the distribution of stress, strain and thickness were well-proportioned in the flexible holding mode. The larger the spherical radius is, the smaller the minimum transitional length of sheet metal is. The transitional length of 60mm is suitable for flexible discrete clamp stretch forming in the case of considering the forming quality and material utilization. Then, the stretch forming experiment proves that the flexible holding technology is feasible, and the error contrast illustrates the new type of discrete clamp stretch forming machine is practicable.

Abstract: Multi-roll stretch forming process is a new flexible manufacturing technique that the general idea of discretizing is put in use in the design of stretch forming machine. In the new process, the metal sheet can be more easily formed, and the flexibility can be much higher, which the traditional process cannot compare with. In this paper, in through extensive numerical simulations of the MRSF stretching process of toroidal saddle parts, A series of finite element simulations have done for the process of forming toroidal saddle parts using different lubricant and two kinds of rollers named damped rollers and ordinary rollers. The results show that the smaller the friction coefficient is, the easier the center of toroidal saddle part is stretched. Damped rollers can increase the stretching force and the ordinary rollers can increase the mobility of sheet metal. Arranging the damped rollers and ordinary rollers at a reasonable position can make the workpiece a more uniform stretching.

Abstract: In order to improve the performance of back drawing type of flexible multi-gripper stretch forming machine used for double-curvature metal sheet forming, back and down drawing type of flexible multi-gripper stretch forming machine was designed by finite element method (FEM), which has simple structure and cheap cost. The FE model of flexible multi-gripper stretch forming was established, and extensive numerical simulations of spherical parts for two kinds of flexible stretch forming machines were carried out. The variations of stress, strain, thickness and springback value of spherical parts for two kinds of drawing modes were analyzed. The numerical results show that the quality of spherical parts formed by the back and down drawing type of stretch forming machine is better than that by the back drawing type of stretch forming machine. This work provides a machine for developing the technology of stretch forming.