MrSamuel
Bioengineer
- Oct 13, 2011
- 45
I need to constrain the end of a wire to a solid. I'm using coupling. Here are the two methods for specifying the geometry I have tried and their short comings:
1. First select the end node of the wire, then specify the closet element node on the solid(I had to create a set for that element node). This method hasn't worked well as the wire seems to float around in space during the simulation and it takes a long time to solve.
2. First select the end node of the wire, then select the face on the solid body on which it lies. This method eliminates the floating around and it solves fast, but the face is very large and seems like a vague thing to attach the wire too. Does the solver just ensure that the end of the wire remains the same distance from all points on the surface that it was initially?
I need the precision of attaching to a node from method 1, but the quality and speed of attaching the wire to a face on the body from method 2. Any suggestions? Whats the best practice here?
Also, is coupling a good technique to join a wire with a solid, or is fixing better, or some kind of MPC constraint?
Those are my questions, here's a little more background information in case its helpful:
I'm attaching a ligament to a bone. The ligament uses an elastic material with compression turned off and a T3D2 element with two nodes. The bone is elastic with tetrahedral elements.
Thank you kindly,
Sam
1. First select the end node of the wire, then specify the closet element node on the solid(I had to create a set for that element node). This method hasn't worked well as the wire seems to float around in space during the simulation and it takes a long time to solve.
2. First select the end node of the wire, then select the face on the solid body on which it lies. This method eliminates the floating around and it solves fast, but the face is very large and seems like a vague thing to attach the wire too. Does the solver just ensure that the end of the wire remains the same distance from all points on the surface that it was initially?
I need the precision of attaching to a node from method 1, but the quality and speed of attaching the wire to a face on the body from method 2. Any suggestions? Whats the best practice here?
Also, is coupling a good technique to join a wire with a solid, or is fixing better, or some kind of MPC constraint?
Those are my questions, here's a little more background information in case its helpful:
I'm attaching a ligament to a bone. The ligament uses an elastic material with compression turned off and a T3D2 element with two nodes. The bone is elastic with tetrahedral elements.
Thank you kindly,
Sam