Elastic deformation is time-indipendent

[mech-eng]

"Elastic deformation is time-indipendent." What does this sentence refer to? It makes no sense to me.

Source: http://www.nobelyayin.com/sunumlar/malzeme/callister/ (page 11)

Thank you.

 

[Mapes]

Elastic deformation (which is an idealization of actual behavior) is instantaneous. That is, it occurs immediately upon application of the load and is unchanged thereafter. In that sense, it is independent of time.

 

[Bystander]

See "creep."

 

[Mapes]

Creep (i.e., permanent or plastic deformation over relatively long time scales) excludes elastic deformation but is one component of how all real materials actually behave.

 

[Nidum]

Elastic deformation is time-indipendent."

Elastic deformation is proportional to applied load . The final deformation only depends on the final load . Within some practical limits it does not matter how fast or how slow the load is applied - the final deformation will always be the same if the final load is the same . Elastic deformation is therefore time independent .

Creep is gradual continually increasing permanent deformation without increase of the applied load . A common problem with special aerospace alloys working at higher stress levels and higher temperatures .