settlement of supports in polar coordinate system 1

[jiligeo]

Hi,
How can I define settlement of supports in polar coordinate system?
I have to define the settlement in a tunnel (it is 2 cm in radial direction).
I can define that as ux and uy but they have different values according to the location of joints and I am looking for to use polar Coordinate system to define u(r), and u(teta)?
Thank you very much for your help
Jili

 

[Drej]

Switch the coordinate system to cylindrical using the csys command (or go to: Utility Menu>WorkPlane>Change Active CS to>Global Cylindrical). Make sure your workplane is in the correct place, as your cylindrical origin will be at the workplane origin (go to Workplane>Display Working Plane to see where this is). If your workplane's in the wrong place, you'll have to move it using one the workplane commands (workplane>offset wp to...).

Cheers,

-- drej --

 

[jiligeo]

Thank you for your tip. I find that I have also use nrotat comand .
best wishes
jalil

 

[Drej]

No problem, but be careful as your question is possibly asking two things:

1) How to define the nodes in a cylindrical coordinate system
2) How to define displacement of the nodes in a cylindrical coordinate system

While global and local coordinate systems locate geometry items, the nodal coordinate system orients the degree of freedom directions (Ux, Uy, etc.) at each node. Each node has its own nodal coordinate system, which, by default, is parallel to global Cartesian (REGARDLESS of the active coordinate system in which the node was defined). If you need to ROTATE THE NODES INTO A COORDINATE SYSTEM, you can do this, like you say, using the NROTAT command. This will ensure all displacements of these nodes occur in this coordinate system. If you switch using CSYS and then create the nodes, the nodes will displace in the default cartesian system, even though you defined them in a different system.

Sorry to labour the point, but this is important.

Cheers,

-- drej --