Laser forming of doubly curved plates using minimum energy principle and comprehensive strain control

Forming complex shapes is an important process for many heavy industries such as shipbuilding. The traditional forming method is line heating method, which relies on the worker experience. This paper presents a method of mechanical and thermal forming based on the minimum energy principle and comprehensive strain control. The doubly curved plate is developed into the singly curved shape using finite element method and minimum energy principle based on nonlinear deformation theory. The strain distribution can be obtained through the optimized development process and the laser heating paths are planned according to the comprehensive strain obtained from in-plane and out-of-plane strains. The heating condition is determined using geometrical difference between the doubly curved and the developed singly curved shapes based on the deformation database. The overall methodology is experimentally validated through two kinds of doubly curved surfaces.