Hi, I am brand new to these forums and fairly new to abaqus as well. I am doing a simple radial expansion on an axi-symmetric semicircle with a smaller semicircular hole in it. In order to do so, I created a datum CSYS that is cylindrical in nature but aligned with the global CSYS. In other words the R axis is the X axis and the T axis is the Y axis. After applying my displacement boundary condition to the inner semicircle to expand outward, I get the desired radial displacement, but I also get some varying motion of the nodes in the theta plane about 2 orders of magnitude lower than the radial displacement magnitude. Any idea on why that might be? My sides of the semicircle are constrained with a XSym boundary condition and my outer surface of the semicircle is encastred. Is this due to the compression of the elements? And if so, is it unavoidable? I wouldn't want to create another boundary condition preventing theta-plane displacement? I am uploading the input file as a .txt.