Im trying to model a rubber bushing which is basically natural rubber molded and bonded in some areas in a hollow metallic part (in red on the pic below), and correlate the FEA with experiments.
The rubber has an insert in it, and the test is basically going up and down with this insert to a required force, at a very low speed (20mm/min) so we could say the test is quasi-static
I have my rubber material properties which are an modelized with an Ogden 2 model, data is from experiment.
Im simulating the exact load deflection test with Abaqus/explicit (quasi static analysis)
Problem is when I plot the load/deflection curve of the insert, Im far far away from the experiment (not so much in extremum deflection values but I dont match the curve)
there is a knee point which I dont see in my FEA model
Where can this come from ? There are some parts which are unbounded so the rubber slides on the rigid parts, to model this I have an arbitrary coefficient of friction.
Any Ideas are very welcome ! best regards