When the yield stress of the material is 100 mpa calculate

Question

A force 12 kN is gradually applied and then removed at the end of an elastoplastic bar. When the yield stress of the material is 100 MPa, calculate plastic strains and tip displacement after removing the applied force.

Use the following material properties: E = 100 GPa and H = 10 GPa. The crosssectional area of the bar is A = 1.0 10^-4 m² and the length of the bar is L₀ = 1 m.