IDENTIFICATION OF STIFFNESS AND DAMPING MATRICES OF HIGH DEGREE-OF-FREEDOM STRUCTURAL MODELS

A method to identify the stiffness and damping matrices of high degree-of-freedom structural models is described. The number of degrees of freedom is considered high if the state-space model of the correct dimension from force inputs to measured outputs becomes uncontrollable and cannot be identified from input-output measurements, thus rendering standard state-space based physical parameter identification methods unusable. This difficulty is overcome by identifying the physical parameters associated with each individual degree of freedom where controllability is not compromised. These parameters are aggregated to form the global stiffness and damping matrices of the entire structure.