Yield strength

The maximum tensile stress a material can withstand before failure, determined by pulling a specimen to rupture in a tensile test. It is one of the most widely quoted mechanical properties on datasheets for metals, plastics, laminates and membranes.

The capacity of a material to undergo significant permanent deformation before fracture, as displayed by most metals and many thermoplastics. Ductile behaviour gives visible warning of overload and allows local stresses to redistribute.

The internal force carried by a material per unit of cross-sectional area. Stress may be tensile, compressive or shear, and comparing the applied stress with the material's strength is the basis of structural design.

The deformation of a material in response to stress, expressed as change in length divided by original length. Strain is dimensionless, often quoted as a percentage, and may be elastic (recoverable) or plastic (permanent).