Hi, i am running a static structural analysis to simulate a crash of a glider. I need to simulate a rigid wing connecting two bulkheads with mass of each wing at some point along the length of the two wings. How can simulate this? any idea will be appreciated. I tried using RBE2 Elements but always get dependent dof constrained error. Also is there a possibility to define a shell structure as completely rigid so i can use such a structure to model the wing.?