Analysis of core shear stress in welded deformable sandwich plates to prevent de-bonding failure during U-bending

In this work, a multi-point resistance welding process was employed as a bonding mechanism for deformable sandwich plates with sheared dimple cores to improve productivity. During U-bending, a de-bonding failure occurred due to the shear deformation of the core. An analytic study that investigated the bending mechanism was carried out to determine the control parameter of core shear stress. The analytic estimation revealed that the shear stress of the core could be reduced drastically by increasing the clearance. In addition, from the analysis of the de-bonding failure, the de-bonding behavior with respect to clearance could be effectively predicted. The fabricated sandwich plates could be bent without failure when the clearance was larger than the thickness of the sandwich plate by three times.