Structural dynamics studies the structural equilibrium over time among external forces, elastic forces, mass forces and viscous forces for a discrete structural system with points that are internally linked to each other and all linked to a fixed reference system. These internal links between points describing the structural system may be elastic or not. If they are not elastic, the behavior of the system of points is non-conservative and therefore the structural material has a nonlinear dissipative constitutive behavior. Additionally to this nonlinear behavior, there is also a nonlinear dissipative behavior due to the effects of the material viscosity that leads to viscous forces dependent on the system velocity. In simpler cases, the damping non linearity is due to the development of viscous forces proportional to the velocity; however, in more complex cases the viscosity term may be time-dependent. Also, the system’s non linearity can be observed in systems having large displacements and where the system works beyond its original geometric configuration, leading to a nonlinear kinematic behavior. Such non linearity is even more pronounced when large strain occurs along with large displacements, turning the solution of the structure’s dynamic problem more complex.