Abstract: Numerical simulation and experiment were performed to study the bending-forming process of bidirectional trapezoidal sandwich panel with different deformation degrees. The deforming characteristics, regularity and main forming defects of the panel were investigated. The results show that the stress and strain of the weld region between the face sheet and the core plate are obviously less than that of the suspended area. The strain and equivalent stress of the top face sheet in the weld region are respectively 15.2% and 76.2% of that in the suspended region. The strain and equivalent stress in weld region of the bottom face sheet are respectively 11.5% and 67% of that in the suspended region. Each cell of the core is mainly deformed by changing the angle between the inclined plane and the bottom plane. Moreover, the deformation of the core cell is mostly converged in the transition curved region. The depression, straight plane and wrinkle are the main forming defects in the forming process of the sandwich panel. Face sheet thickness and deformation degree are the main factors affecting the forming defects. The characteristics of the formed part of the sandwich panel are tested by multi-point bidirectional bending test, and the correctness of numerical simulation of the forming defects is verified.

Key words: materials synthesis and processing technology, sandwich composite panel, numerical simulation, cylinder forming, forming defects