Hello everyone,

I am studying the case of a disc impacting a surface. In this work, I have continuously encountered issues with the mesh on the disc twisting and deforming for no apparent reason. I have typically encountered this issue with hexahedral elements in 3D models and quadrilateral elements in plane strain models. The issue persists regardless of whether distortion control or hourglass control, though I am still relatively new to using these. Attached is a before and after picture of the disc and how it deformed during simulation without any interaction with surrounding bodies.

Has anyone had experience with this type of deformation? Is there any insight for how it arises and how I may avoid it?

Edit (more information):

This is an explicit dynamic analysis using a plane strain model. The disc pictured is meshed with quadrilateral elements. It has no boundary conditions imposed upon it and it is suspended in space until gravity and an impulse act on it later in the simulation. Both before and after shots are prior to any forces or boundary conditions acting on the disc and the deformation shown occurs while the disc is suspended without contact with anything around it. Before and after is just denoting before and after the mesh becomes distorted.

Thank you.