Thermo-mechanical finite element study on deformation mechanics during radial scan line laser forming of a bowl shaped surface out of a thin sheet

摘要

Forming a smooth bowl shaped surface out of a flat circular sheet-blank requires tangential shrinkage which can be met well with radial laser scan lines placed in proper sequence as suggested by previous researchers. However, few studies look into the finite element analysis of laser forming of the entire bowl shaped surface from a flat circular thin sheet which could provide a better insight of the forming mechanism. Therefore, in this work the laser forming of a bowl shaped surface with radial laser scan lines has been investigated with the help of finite element simulation. This revealed that the bending of the sheet by radial scan does not take place only because of thickness increment at the radial scan tracks due to shrinkage, but also because of a localized buckling about the radial scan lines. Irregular meshing, reduced integration scheme and higher number of linear elements along the sheet thickness direction could provide a better matching of the simulation results with their experimental counterparts. Accuracy of prediction of the simulation results was also found to be sensitive to the tangent modulus of the assumed linear kinematic hardening model. (C) 2018 The Society of Manufacturing Engineers. Published by Elsevier Ltd. All rights reserved.