Interpolation when y data is not strictly a function of x in a hysteresis behavior

hello all,

I'm trying to model an experimental hysteresis behavior of a certain component using OpenSEES and matlab, the hysteresis behavior is force-displacement. The output that i get from opensees has nearly 40000 sets of data however the experimental data only shows the amount of force at nearly 400 displacements, for me to calibrate my hysteresis model i need to find the forces of my model at the same displacements of the experimental data i tried using interpolation but it can't work since the behavior is hysteresis and force is not a direct function of displacement. Any Ideas?

[darova]

Add 3d parameter - arclength and interpolate x and y separately

See this answer