End-grain balsa

Core material cut from balsa, a fast-growing tropical hardwood whose naturally cellular structure gives high compressive and shear strength for its weight. It is normally supplied as end-grain sheets or scrim-backed blocks, and as a renewable material it is often selected where sustainability is a factor.

The shear loading carried by the core of a sandwich panel as it bends, transferring load between the two face sheets. Core shear strength and shear modulus are primary selection properties for core materials, and core shear failure is a common design-limiting mode in sandwich structures.

A lightweight open-weave fabric used as a flexible carrier or stabiliser. In core materials it is bonded to one face of small core blocks so the sheet can drape over curved moulds, while in roofing membranes and coated fabrics a scrim acts as the reinforcing carrier that gives the sheet dimensional stability and tear resistance.