# Plane Strain

The 2D simplification option models the problem using a plane strain assumption. The displacement in one of the directions is negligible compared to the other two.

The plane strain assumption is valid when the following conditions occur:
• One of the dimensions is much larger than the other two.
• In-plane forces do not vary along the largest dimension.
• Forces acting normal to the section plane are negligible.

The figure shows a thick solid under uniform loads. The dimension in Y is much larger than the X and Z dimensions. To model the problem, you create a section plane parallel to the XZ plane, specify the thickness, and apply the loads and fixtures to the edges.

You can create multiple 2D bodies using a section plane and define contact conditions between them.

The following simplifications are valid for the simulation results.

 Displacement, Load, and Temperature Displacement and temperature do not vary along the thickness. For the thick solid: where u is the displacement vector. Also, uy = 0, where P is the load vector. Also, Py=0, and where T is the temperature. Stress All stress components are nonzero. However, out-of-plane stress components exist because of the Poisson's effect and are not critical for the analysis. Strain Out of plane strain components are zero. Only in-plane strain components exist. For the thick solid: where ε represents normal strain and γ represents shear strain.