Dynamic Modeling of Structures with Bolted Joints The primary function of a joint in an engineering structure is to connect, usually stiffly, two (or more) separate substructures. Joints introduce two features to a structure: amplitude dependent stiffness and amplitude dependent damping. The analysis of modeling jointed structures can be briefly explained in three steps: The first step, the nonlinear static solve, is used to determine which nodes in the interface are stuck together, and which nodes are not expected to be in contact. In the second step, the problem is reduced slightly by assuming that nodes that are out of contact will remain out of contact during the analysis.