SOLIDWORKS Motion is a great tool for analyzing kinematic motion of assemblies. When problems arise, discovering why is difficult at times. I had a particular case of this recently.
I was analyzing a complex mechanism, and the behavior of it moved to the left at the beginning of the motion, which was unexpected. It became a case of determining the root cause. What didn't I understand? Was is a motor applied in the wrong place? Was it bad modeling and mates?
I went through everything. Modeling. Setup. Materials. Double check. Triple check. Nothing seemed to be wrong. I took a break and moved on to some other work for the time being.
While working on another project, I was checking for interference. Then it hit me, maybe the software was resolving an interference between components with a contact defined. Sure enough, the hunch was right. Interference was being resolved at the first time step causing a force to be produced. Remating the component removed the interference and fixed the problem, producing the behavior I expected.
Before starting a Motion project, I highly recommend running an interference detection to help you prevent additional forces from developing in your model. If you have unexpected behavior with SOLIDWORKS Motion, interference detection is a good place to start.
By: Brandon Donnelly, Simulation Applications Engineer