Definition of Strain Energy
When a piece of bar is subjected to a tensile or a compressive load, P, then there is a change in length which is proportional to the load P within elastic limit. It is said that work is done and is stored in the form of strain energy within a bar or material. On removal of the loading, the material returns to its original position due to release of stored energy.
It may be defined as
The work done by the load in straining material or bar. It is denoted by U.
Strain energy per unit volume stored in a material is called resilience.
Strain energy at elastic limit in a material or bar is known as Proof Resilience.
Strain energy is measured in Newton meter or Joule.