Recently, I modeling the rack server in order to do the drop test simulation by using Ansys ls-dyna. But I am very confusing about share topology. And I searched the information on the website, they shows their model was not share topology. But in my experience, the model always need share topology in Ansys APDL which means the model has conformal mesh. Therefore, could anybody tell me why we need to share topology? and what if I don't share topology and use bonded instead of share topology, the result is still ok or not? if I can't, what's the different between share topology and bonded? I attach the image of my model and the image from website which didn't share topology.