Discussion Forum

Hi all,

I am a new comsol user and have a small query which I hope someone can help me with. I am working with comsol 4.2 model involving circuit and current modules. The objective is to find out voltage distribution in a 3D assembly. The geometry is quite simple; just two half-toroids wrapped around each other (like a contact of two links in a chain). The dimensions are such that there is no gap between two half-toroids. (mph file is attached for the reference)
To find out the potential distribution, we can define one of the ends of one of the half-toroids as terminal 1 and the end of other half-toroid as ground. Now there are two steps in the problem:
1. Find out potential distribution by combining both parts and treating it as a single object.
2. Find out potential distribution by assuming a contact resistance between the parts.
For the first step, comsol forms the union but somehow fails to treat both parts as a single entity. If we look at the mesh closely we can see that the nodes at the curve of contact (two semicircles in saddle shape) do not match. As the two parts are not in contact after meshing, the model fails go generate solution.
How can I make the nodes at the contact overlap? Shouldn't the mesh be uniform after union? I tried meshing some simple objects in contact and they give nice common nodes at the contact (whether it be contact surface or contact line)
Also, is there a way to circumvent this issue and define a contact resistance between the two mating surfaces?

Any help is much appreciated!!!

Thanks
Vaibhav