If you need to really model the rivet, then you need to build the composite in solid layers, and then made a solid rivet, but if it's just location, then there are a few reference guides, such as aircraft design by michael nue.
If you need to model the connecting element and not just equivalence, then you can do it this way. usually it's done using 2 RBE2 elements with a spring connecting, or without the RBE elements.
