Mesh size, computation time, and lining up nodes

[mglover]

Hello. Computer engineer and Pynite newbie here.

I'm repairing and old home-built trailer. I'm working out what reinforcements I need where the bed mates to the frame, and trying to model this in Pynite.

I've added the frame rails as members, and the plywood bed as a mesh.

I'm applying supports for the frames, and forces on the bed, using loops like in the Rectangular Tank Wall example.

I'm calling merge_duplicate_nodes() to join the bed to the frame.

In order for the nodes to merge, they need to be close to one another, but the locations are oddly spaced. I'm trying to figure out the best way to get the mesh nodes to line up with the beam nodes.

I've tried using a smaller than necessary mesh size. This made computation time unacceptable.

I'm currently fudging the numbers so that everything lines up on a 4in mesh. This is...not good?

I could increase the matching distance (currently default), but I'm concerned about unintended consequences later.

Is there some other strategy I should consider?

Also, is it possible to merge nodes conditionally?

Tambien, thank you for a really nice tool!

-mg

[JWock82]

The rectangular mesh object accepts control points. Use the ‘x_control’ and ‘y_control’ mesh attributes to specify lists of control points you want it to mesh to. These control points are specified in the mesh’s local coordinate system. For example ‘my_rectmesh.x_control = [1.3, 5, 10]’.

Small meshes greatly increase the computation time. They also increase the solution’s accuracy. One of the biggest challenges of finite element analysis is balancing solution speed vs accuracy.

There isn’t a conditional node merge option.

[mglover]

Thank you. 'x_control' is what I was looking for.