Over the past 50 years, the Sandwich panel has emerged as a particularly economical construction method. The combined materials always consist of two face sheets (depending on the application, rigid metallic face material or flexible face sheets such as thin aluminum, paper, or membranes) and a core insulating material.

Sandwich materials consisting of a low-density core and stiff face sheets offer significant potential for weight savings in panel applications, Where the main loads are based on bending. While Sandwich materials of interest for car and van body panels, seat shells, etc. include steel/plastic laminates, integrally foamed plastic shells, and fiberglass-reinforced polyester shells with foamed plastic cores.
We will discuss basic design formulas for the flexural stiffness and strength of such Sandwich materials and gives a method for designing optimum Sandwich structures at the lowest weight or cost.