Buckling

A mode of loading that shortens or squeezes a material. Compressive behaviour often limits composite structures because thin skins can buckle and fibres can microbuckle at stresses well below their tensile capability.

The resistance of a material or structure to elastic deformation under load, governed by the elastic modulus and by geometry. Stiffness is distinct from strength: a component can be stiff yet weak, or flexible yet strong, and the two must be considered separately in design.

A composite construction in which two thin, stiff skins are bonded to a thick, lightweight core such as foam, honeycomb or balsa. Separating the skins raises bending stiffness dramatically for very little added weight.