Work Done on Elastic Bars

Solids are often modeled as linear springs because under the action of a force they contract or elongate and when the force is lifted, the return to their original lengths, like s spring.

· As long as the force is in the elastic range, that is not large enough to cause permanent deformation. (plastic)

· Therefore, the equations used for elastic solid bars.

Alternately, we can determine the work associated with the expansion or contraction of an elastic solid bar by replacing pressure P by its counterparts in solids, normal stress σ_n= F/A in the work expression:

W_elastic=∫₁²F•dx = ∫₁²σ_n®·•A•dx (kJ) (2-30)