Abstract:

The technology of sheet metal flexible grippers stretch forming (FGSF) was introduced briefly, theoretic formula and calculation method of clamping force were given. A finite element model was established, and the numerical simulations of FGSF based on multipoint die were performed by a dynamic explicit algorithm for the cylindrical, spherical and saddle surface of different material with different thickness. The variation histories of the clamping force and its influencing factors were analyzed. The results indicate that the material and sheet metal thickness are very sensitive to the clamping force during sheet stretch forming, and the relatively large clamping force is needed if material is stiffer and sheet metal is thicker. The clamping force for forming workpiece of double curvature is obviously larger than that for forming workpiece of single curvature. The obtained results are significant for the optimal design of sheet metal FGSF equipments and the study of sheet metal practical forming process.

Key words: materials synthesis and processing technology, sheet metal forming, stretch forming, multipoint die, clamping force, numerical simulation