Sandwich Composite
A sandwich composite is made of two outer skins bonded to a core.
The skins or facings are thinner, stiffer, and
stronger compared to the core.
The core is usually lighter to reduce the overall
mass and has a high shear modulus of elasticity to resist sliding of skins.

Use sandwich composite when higher resistance to bending loads is required.
The stiff and strong skins are located on the outside so that they take
maximum stress. The core is usually much thicker to reduce the stresses
observed under bending.
Related Topic
Composite Shells