Elastic recovery refers to the tendency of a material to partially return to its original shape after a load is removed, even if some plastic deformation has occurred. While the elastic portion of the deformation is fully recovered, any plastic deformation remains permanent. This behavior is observed in both purely elastic loading and in cases where the material has undergone plastic deformation, such as in bending or sheet metal forming.
In manufacturing, particularly in metal forming processes such as bending, stamping, and sheet metal forming, elastic recovery is commonly referred to as springback. Springback is more pronounced in materials with a lower modulus of elasticity (Young’s modulus), since they experience greater elastic strain relative to plastic deformation, leading to more elastic recovery after the forming force is removed.
Springback is a result of elastic recovery, which means that after plastic deformation, the material retains some elastic strain that causes it to return partially to its original shape. The amount of springback is influenced by both elastic and plastic deformation properties.
- Higher E (higher stiffness materials like steels and titanium alloys):
- A higher modulus of elasticity means the material is stiffer, so it resists elastic strain more, meaning less elastic strain accumulates in the elastic region.
- When plastic deformation occurs, less stored elastic energy is available to drive elastic recovery, so springback is relatively lower compared to materials with a lower E.
- Lower E (more compliant materials like aluminum and softer metals):
- A lower modulus of elasticity means the material experiences more elastic strain under the same stress before yielding.
- Because the elastic strain is larger, when the load is removed, the material experiences more elastic recovery, leading to greater springback.
References
Benson, Steve. “Bending Basics: The Hows and Whys of Springback and Springforward.” The Fabricator, July 9, 2014. Accessed January 24, 2025. https://www.thefabricator.com/thefabricator/article/bending/bending-basics-the-hows-and-whys-of-springback-and-springforward.