Guys,
I have modelled a frame structure that is designed to be lifted by a single crane hook attaced to it by a two-leg slingset. I want to analyse the structure in a raised position.
I have set up a zero dof constraint at the crane hook location, and attached the constraint to the two lifting points on the structure by simulating the slingset using two point-to-surface rigid links. The rigid links are sonstrained at the lifting point surfaces with freedom in the vertical and horizontal (towards each other) directions.
I have set up a gravitational load in the -y vertical direction attached at the COG of the structure (which happens to be in free space).
The COG is not directly below the crane hook constraint, but its not too far away.
For me, this ought to be sufficiently constrained, as gravity is acting downwards away from the hook constraint.
However, CREO fails for being under constrained.
I have to add a constraint at the base limiting the freedom to the vertical direction to get the analysis to work. This isn't quite realistic though, as it doesn't allow the load to swing so that the COG is directly under the hook constraint.
How do you guys simulate a hanging load?