analyze is very common in engineering applications. A
complicated rotor system is divided into several kinds of
basic elements: rigid disk, bearing (usually linear modeled),
flexible shaft segments, couplings, squeeze-film
dampers, and so on. The equations of motion for each of
these components were developed using the appropriate
force-displacement and force-velocity relations and the
momentum principles or other equivalent dynamic relations.
Then, the system equations were assembled using
geometric displacement constraints that guaranteed the
connectivity of the components.