Ansys13: Clever way to apply moment (rotation) to solid 187

[countryroad]

Hi all,

I learned a clever way to apply a moment (pure rotation) for a cylinder meshed by Solid187. However, there is one thing I do not understand. It seems this way will squeeze the cylinder fist then recovered judged by the animation (please watch the video).

My have some questions
1). How can this happen? How to avoid this?
2). This cylinder is used to create a pure rotation (moment) for other part. Will this be a problem or just video effect?
I included the simplified code that applied this rotation (or moment). Please help me out.

3)Does anyone have a clever way to apply the moment (or pure rotation)

!-----------The simplified part to apply this the moment (or pure rotation)---------------------------------------

rotangle=60

*do,i,1,no_node,1
*get,min_node,node,,num,min !start the smallest node number
*get,x_pos,node,min_node,loc,x !get x
*get,y_pos,node,min_node,loc,y !get y
*set,r,(sqrt(x_pos**2+y_pos**2)) !get the circle (for the moment)
*set,q,((atan2(y_pos,x_pos))-rotangle*3.14/180) !rotate 60 degrees
*set,new_x,(r*cos(q)) !set x
*set,new_y,(r*sin(q)) !set y
d,min_node,ux,(new_x-x_pos) !apply ux
d,min_node,uy,(new_y-y_pos) !apply uy
nsel,u,node,,min_node !unselect the min and move to next (bigger) number of node
*enddo
!-----------------------------------------------------
Help is highly appreciated.

Thanks.

Steve