Sensor-based extraction of physical property matrices from realised state-space models

In some qualification such as damage detection, a more detailed representation including mass, stiffness, and damping property matrices plays a more pivotal role than an equivalent state-space model. In practice, estimating the modal parameters of the dominant modes in the signal records is superior to directly identifying the mass, stiffness, and damping matrices. In this paper, a novel technique is presented for deriving physical structural dynamics matrices from a balanced state-space realisation. In this approach, obtaining undamped modal parameters from the identified complex-valued modal parameters is not needed. Also there is no requirement for computing mass-normalised mode shapes. The only requirement of this technique is an accelerometer instrumentation of the degrees of freedom (DOFs) which are in mind for configuring the structural mode shapes. The structural state-space description is realised by eigen-system realisation algorithm with data correlation (ERA/DC). This procedure is validated with some simulations and the results are satisfactory.