A new approach for reduced order modeling of mechanical systems using vibration measurements

This study investigates the possibilities of obtaining reduced order mass-damping-stiffness models of mechanical systems using state space realizations identified via dynamic tests. It is shown that even when the system is insufficiently instrumented with sensors and actuators, it is still possible to create physically meaningful reduced order mass-damping-stiffness models that incorporate measured and unmeasured degrees of freedom. It is further discussed that certain assumptions, such as having a diagonal mass matrix or having classical damping in the system, allow one to develop alternative reduced order representations with different physical interpretations. The theoretical presentation is supplemented by a numerical example that illustrates the applications of the formulations developed herein.