However, there are issues preventing straightforward application of OMA to operational turbines, e.g. structure invariance during the test. The effect of rotor rotation manifests itself in the equation of motion with time-dependent coefficients. Formulating and solving eigenvalue problem lead to time-dependent eigenvalues and eigenvectors which become meaningless as modal parameters. Fortunatel...

This paper presents a comparative study of conventional Experimental Modal Analysis (EMA) and output-only Operational Modal Analysis (OMA) techniques for estimating the modal parameters of a moderately damped truck chassis. The OMA, without its need to measure input forces, would serve as a convenient methodology to test vehicle structures when response data alone is available. Data has been ac...

The field of Operational Modal Analysis (OMA) has recently become an emerging research interest. OMA, also known as Response-Only Modal Analysis, extracts the modal parameters by processing only the system response data. In many experimental measurement situations, the system’s output data series is short in length and buried under potentially correlated noise. In such cases, the separation of ...

Abstract Modal parameter estimation of randomly and ambient excited structures using output-only system identification techniques has become a recently essential issue for assessment of engineering structures, structural health monitoring and structural control. A number of mathematical models on the output-only identification techniques have been developed in the time domain, in the frequency ...

This paper investigates the dynamics of the engine driveline system for achieving accurate and online diagnostics of engine conditions using instantaneous angular speed (IAS). Based on a state space modelling approach and key structures of the system, a torsional vibration model is developed and its modal properties: modal frequency, damping ratio and shapes are evaluated. Then taking the outpu...