Unit resilience is the amount of elastic energy stored in a unit volume of a material by the time yield strength is reached. Higher unit resilience is, for example, associated with superior spring performance.
Ultimate resilience (also called unit rupture work) is the amount of energy absorbed per unit volume of material as it is taken from zero load to rupture, in tension. In the context of a tensile stress-strain curve, ultimate resilience is the area under the curve.
Ultimate resilience is useful in estimating the impact absorption performance of a material. It is also associated with erosion resistance, as a more resilient material requires the fluid-borne erosive particles to have more kinetic energy in order to dislodge a part of the material's surface.
ASTM testing standards include D2632 and D7121. ISO standards include 4662 and 8307.