For monotonic loading, obtaining the strain energy density data is straightforward: calculating the area under the stress-strain curve.
However, obtaining the same for cyclic loading appears to be tricky. Do I have to calculate differently for the loading and unloading curves? I tried this but I get unusual curves.
Any idea on the correct method of obtaining the strain energy density data for cyclic loading? I will appreciate it. I need this data to model the Mullins effect.
Thanks in advance,