bilinear isotropic hardening for 2D plane stress

This code provides a 2D MATLAB example demonstrating bilinear (linear) isotropic hardening under plane stress conditions at a single Gauss point. Several options for strain excitation are included:

1. normal_x: strain excitation applied in the x-direction ($\varepsilon_\mathrm{xx} \neq 0$, $\varepsilon_\mathrm{yy} = 0$, $\gamma_\mathrm{xy} = 0$)
2. normal_y: strain excitation applied in the y-direction ($\varepsilon_\mathrm{xx} = 0$, $\varepsilon_\mathrm{yy} \neq 0$, $\gamma_\mathrm{xy} = 0$)
3. shear: strain excitation applied in the xy-direction ($\varepsilon_\mathrm{xx} = 0$, $\varepsilon_\mathrm{yy} = 0$, $\gamma_\mathrm{xy} \neq 0$)
4. combined: combined strain excitation applied in the x, y, and xy-direction ($\varepsilon_\mathrm{xx} \neq 0$, $\varepsilon_\mathrm{yy} \neq 0$, $\gamma_\mathrm{xy} \neq 0$)

The C++ version of this code has been implemented in GetDP (ONELAB) to simulate the elasto-plastic behavior of electrical machines. Nevertheless, it is also possible to calculate other geometries or models.

The workflow below presents the finite element analysis (FEA) solution methodology for bilinear isotropic hardening as implemented in GetDP:

The following workflow describes the algorithmic steps for bilinear isotropic hardening under plane stress conditions required at each Gauss point: