The structure's response is based on a subset of the modes of the system, which must first be extracted in a frequency step. The immediately preceding step must be a linear perturbation procedure. Modal dynamic steps do not carry over the initial conditions from the results of the preceding step. You can choose to include the effects of material damping in a modal dynamic step. Damping models the energy loss in a nonconservative system due to material nonlinearity, internal material friction, or external (mostly joint) frictional behavior. | ||||||||||||