Dear FEAP users,
I want to analyze a body that rotates around an axis with a fixed radius at a certain constant rotational velocity. For the sake of simplicity let´s take a cube as geometry.
I figured out so far that one option is to use the <global, omega> command in a (quasi) static structural analysis. That way the centrifugal force is given respect to as the body forces are computed.
If you want to solve a transient structural analysis where you also capture the actual rotation of the body, my approach would be to define the constant rotational velocity with the <init,spin> command. I furthermore would define the coordinates of the nodes in the cylindrical system. (I am aware of the fact that finally the data has to be transformed into the cartesian system which is done by the <polar> command.) This I would do because theoretically this would be the form which allows you to give the boundary condition of a constant radius intuitively. In the example of the rotating cube I would want to set the radial DOF of all bottom nodes to be fixed.
To visualize what I am describing I attached an image of a cube. You look on the top of the cube (10mm x 10mm x 10mm) and you are able to see the coordinate system ~ 30 mm below the cube´s bottom surface. In my scenario the cube shall rotate around the 3rd axis.
My problem: In the input file, when I define the mesh in cylindrical coordinates then the boundary condition as <1,0,1> (meaning that the r- and z-coordinate shall be fixed) and then set the <polar> command the solution shows me that the boundary condition was interpreted as cartesian coordinates.
My question: How can I define this kind of boundary condition that the distance between a node and an axis should be constant?
Thank you for your help!
