I am trying to determine the best method for simulating an assembly with pinned joints and hydraulic cylinders that will give reasonable results with minimal run time. I have seen 4 different methods used and I wanted to get some advice and pros/cons for each one:
can you share with us the assembly? Maybe some pics with notes that show the zones where you want very clear results aor other things?
Unfortunately I can not share the model but I can tell you that it is a piece of heavy equipment. So think along the same lines as a wheel loader or excavator.
There are some examples of pin joints using weighted links, etc. in the community from the user skunks, within the last few months.
So far, my work concurs with your findings, that the local stress at the joints are best as contacts, they are just really time consuming. Some other methods with beams/beam releases or springs with low torsional stiffness are OK but they need weighted links (preferred) or rigid links to the expected contact areas (like a 90 degree segment of the pin cylinders). Also when trying as a bonded connection, it is more accurate to bond over the expected contact area, not 360 degrees of the pin. I tend to go with this bonded method as a good compromise.
There is another possible method which is the "free body diagram" method, for lack of a better term...
A: using rigid body mechanism dynamics to analyze and then transferring the loads to structure (loads-mechanism loads) to evaluate each link separately. Use bearing loads (or other non-uniform distribution) and inertia relief to get accurate stresses at the joints.
B: free body diagrams by hand and evaluate each component separately, again distributed loads and inertia relief for more accurate stresses at the boundary conditions. (St Venant's Principle does not apply in these areas)
I recognize that your assembly could be statically indeterminate, in which case a more complete model must be analyzed.
Does anyone think fastener idealization could be used to represent the pins?
I heard about using weighted links (or springs) instead of contact reagions to make modal analysies over parts clusters, not to make structural analyses. But it makes sense in order to improve the velocity (linear analysis with multi-thread instead of non-linear one with single thread).