KR367: I am working in the global cylindrical coordinate system (CYS=1). I am able to create the geometry in this coordinate system. I'd like to apply a displacement constraint on an area in the theta direction. I tried setting UY=0 for this area but this seems to take effect in the global cartesian coordinate system (from looking at the symbols that appear in the graphics window). How do I apply a displacement constraint in the theta direction in the cylindrical coordinate system?
Constraints are applied to the nodes, which are in the nodal coordinate system. The nodal coordinate system is ALWAYS Global Cartesian. What you
will need to do it to 'rotate the nodes into the active coordinate system' using the NROTATE command. If your active coordinate system is cylindrical, NROTATE will rotate them so that y will be the tangential direction for each node. Here is an example:
nsel,s,loc,x,5 !select nodes on curve
nplo !See that y constraints are all pointing in the global y direction
nrot,all !Rotate nodes into the active coordinate system
nplo !Now see that the constraints are what you wanted