I'm wondering how can give a torsional torque to a rod which is fixed in a specified position. I mean imagine two rods that are connected by a universal joint, one by angle of another, and they stay in that position for all times while one of them receiving torque. The main problem I faced with is differences in the interfaces between torque and a rod and I don't know how to fix.
Any information would be useful.
Can you give more details? It's hard to answer this in the abstract. You should be able to add a Torque block from the mechanics library or put a torque across any of the joints. If you post a simple model, and specify where you want the torque, we can be more helpful.