Adhesive (Bonding Layer)
To keep the faces and the core co-operating with each other the adhesive between the faces and the core, must be able to transfer the shear force between the faces and the core. The adhesive must be able to carry shear and tensile stresses. It is hard to specify the demands on the joints. A sample rule is that the adhesive should be able to take up the same shear stress as the core.