A finite element model for analyzing curved surface sandwich panel forming

The article establishes a finite element (FE) model of sandwich panel (referred to as CSC FE model) using shell structure core and solid structure face sheet and provides a detailed derivation of the data transfer process between the shell structure and the solid structure in the FE model. In order to explore the application of CSC FE model in the curved surface sandwich panel forming, this paper studies the single curvature and double curvature sandwich panel forming in detail. Based on the maturity of the three-point bending theory, in order to facilitate theoretical verification, the article chooses the three-point bending process to study the single curvature sandwich panels forming. It is proved that the CSC FE model can be effectively applied to single curvature sandwich panel forming through three-point bending theory, numerical simulations and experiments of brazed aluminum honeycomb panel (BAHP). Low cost and efficient multi-point forming (MPF) process is used to analyze the double curvature sandwich panel forming. By MPF experiments and numerical simulations of saddle-shaped and spherical BAHPs, and with the help of 3D laser scanning technology, it is proved that the CSC FE model can accurately predict the curved surface shape of double curvature sandwich panel forming.