Numerical simulation and experiment of dimple for flexible clamp multi-point stretch forming of spherical part

Abstract

The structural character of flexible clamp stretch forming machine is introduced. The real stress and strain curve of Aluminium alloy 2024-O is tested by uniaxial tensile. Numerical simulation of dimple for spherical part with flexible clamp multi-point stretch forming (FCMPSF) is carried out by ABAQUS, and the generated result of dimple is elaborated. The effects of transitional length, sheet thickness and spherical radius on dimple are investigated by lots of numerical simulations, and the thickness strain of spherical part along the objective line ef with different forming suitation is extracted. Then polyurethane sheet is chosen as elastic cushion to depress dimple, and series of numerical simulations are put forward for spherical part of FCMPSF with different thicknesses of polyurethane sheet. Finally, FCMPSF experiment is done and forming precision is measured. Consequently, the spherical part has good forming shape and surface accuracy, which illustrates that the FCMPSF technology is feasible and practional to forming three-dimensional surface part.