Investigation into design of a deformable metallic sandwich plate

Abstract

The metallic sandwich plate is composed of a relatively low-density core placed between two face sheets. Due to their lightweight characteristics and load-bearing properties with multi-functionality, metallic sandwich plates can be applied to diverse areas. They can be used with energy absorbers, thermal isolators, heat exchangers, sound dampers, catalyst supports, and current collectors. Despite many benefits, expanding their practically applicable areas remains a challenge. Sandwich plates cannot be deformed efficiently by commercial forming processes due to their low formability. The development of a deformable sandwich plate could not only expand the range of application, but also improve the bending characteristics due to the ability to prevent the local failures that weaken load-bearing resistance. In order to design a bendable sandwich plate, the axiomatic design theory is employed as a design methodology. The functional requirements were defined, and then the design parameters were established by the conceptualization process, numerical forming windows, analytic design maps, U-bending analysis, and 3-point bending analysis. A sandwich plate with a pyramidal truss core was determined as the object for a basic parametric study. An efficient method that employs the virtual equivalent projected model (VEPM) is introduced and formulated to simulate local failures in a sandwich plate. This approach is based on two-dimensional FE-analysis that uses the projected shapes of 3D pyramidal truss cores and utilizes virtual properties from the homogenized equivalent elastic-plastic properties of the original material and geometries. The results of simulations have shown that the load-displacement curves and deformed shapes with local failures of the VEPM are analogous to 3D pyramidal truss cores irrespective of the materials and core geometries. In addition, the computational time was greatly reduced. Numerical design procedures using the VEPM were carried out ...