I am working on a simulation of an assembly that is tied down to a floor. I assumed a frictionless floor and applied a roller fixture to the entire base of the assembly. When I applied a substantial inertia load to the assembly against the tie-downs, I expect the case to want to lift off the floor somewhere just from deflection of the base. However, the base of the assembly remains totally flat, almost as if it were restrained from moving vertically up. I would expect the roller to restrain the face from moving vertically down, or penetrating the floor. I noticed the roller fixture symbol is a simple arrow whereas a fixed geometry symbol is an arrow with a base. This indicates to me that a roller restrains it in one direction on that axis whereas the fixture restrains in both directions on that axis.
Is my understanding of this type of fixture accurate?
Hi Adrian:
You are right that arrow symbol is deceiving. The restraint (when set to zero) is for both directions along the axis of the arrow. You might try the virtual wall type of support, or the "no penetration" type of contact, or the spring foundation support type. I believe the virtual wall will allow separation. I know the "no penetration" contact does (you can plot the "contact pressure" in the stress dialog and see little arrows showing where two surface are touching). And for the spring foundation, you could monitor the reaction on that for a value of zero to indicate when the assembly lifts away. Hope that helps a little. - Anthony