This is quick example for limit state, calculated with plastic card
This problem has simple analytical solution for limit moment
Mpl = Yield Stress * Plastic section modulus
Using CalculiX you can obtain numerical solution (the limit state when deflection is growing without load increment)
Get files and spreadsheet (LibreOffice with macros) at here
At some cases composite shell with many integration points should be used for limit state calculation.
See the example at here.