Vibration is usually caused by instability. Generally two causes for that, either values of beam spring and damp are out of range that works for given amount of beams and weight of nodes or there is some beams missing for stable structure. In your case, you need more beams between nodes, try to make each node to be supported by triangular formation of beams on all 3 axis. For example, your node n13 needs to be supported from below too as currently it is supported only from sides, you might place nodes between n13, n4 and nr7 as well as on other side, but decision of where to place beams depends how you want to share forces among the structure.
