Explain what conditions would apply if plane strain can be assumed for analysis of the stress distribution
Conditions of plane strain apply when the loaded body is very long in the z direction and where there is no displacement in the z direction. The cross-sections are all under the same conditions. For such problems, γ_yz = 0, γ_xy = 0 and E_z = 0. Since σ_z = ν(σ_x + σ_y), the problem reduces to three unkowns, σ_x, σ_y, and Τ_xy.