Generate softening curve

Hello,

I seek help from the forum regarding the following. Because I am very new to mechanics.

I have a continuum damage mechanics model with me. I have set up a problem of a typical three point bending test on a notched beam. The notch in the center of the specimen and extends from the bottom face up to the middle of the thickness. It is a plane stress problem. Now I want to simulate load-displacement curve obtained from the experiment (s).

The problem I find is none of the experimental papers that I have tells me what the displacement mean? That is at what location and Whether it is x or y or total displacement. Or is it too obvious where the displacement is typically measured in a typical 3 point bending test accordingly so that I could extract the modeling results.

Secondly, how do I draw a load-displacement curve? Specifically, how would one get the softening part of the load-displacement curve?

I would greatly appreciate if anyone could help me with this plotting.

Cheers,

Ram