I make a thermal expansion simulation, and I want to make expand based on its mass center, so I need to minus the mass center displacement. I can get the displacement of the mass center in history output, but I have a problem, how abaqus calculate the mass center after the expansion or deformation(for expample, when an element expand, its density must change, In this case, how to calculate mass center), or how the displacement of the mass center was calculated? maybe some theory manul or user's manul can be recommend.Thanks
