This study mainly develops a simulation algorithm to analyze the stresses and deformation behavior of aluminum sheet metal (A5052P-H32) going on U-shape bending in a circular die cavity using ABAQUS finite element programs. The diameter of the round die is 60 mm, depth of U-shape bending is 50.8 mm, and the thickness of sheet material is 1/32" (0.794 mm). The variables considered for bending simulation include different width of sheet metal ranging from 20 mm to 50 mm, two average punching speeds (63 mm/sec and 151 mm/sec), and with or without using stripper under the bottom surface of sheet metal during punching. In this study, we choose single crank type press to proceed a set of bending experiments, and use dynamometer (Kistler 9257B) to measure the varying punching forces for the purpose of comparison with present simulation results. The simulation results are very close to experimental results, and they show some features as follows: (1) When punching without using stripper, the bottom side of finished U-shape part warps more as the sheet blank increases its width, iii e.g. as the blank is 50 mm wide, the warping may reach approximately 6 mm high. (2) After retracting punch, the springback angle of U-shape part increases as the blank decreases its width, e.g. for 20 mm blank width, the springback angle is up to about 10.3 degrees. (3) The warping phenomenon and springback angle can be effectively improved or reduced when bending with stripper. (4) It can improve springback angle if we use higher punch speed.