Finite element modeling of laser bending of pre-loaded sheet metals

A new laser bending process of sheet metals with applied pre-stresses is put forward. Two different kinds of loading models are analyzed. The desired pre-stress distribution in the heated zone of sheet metal is obtained. A three-dimensional thermal–mechanical model is established. Using the thermal elastic–plastic finite element method (FEM), the laser bending process is simulated numerically and its forming mechanism is analyzed. The deformation of the sheet depends on the integration of the thermal stress and the pre-stress when the laser beam irradiates the sheet. The forming performance can be improved significantly under pre-stress, and the deformation direction can also be controlled easily by changing the direction and value of the pre-loading. The bending angles of the sheet metals increase remarkably with the increase of the pre-loading, and both are almost in exponential relationship.