Operational Modal Analysis (OMA) is a technique of extracting modal parameters of a system from output responses only. It is an emerging field in structural dynamics and has been applied to complex structures that are often difficult to analyze using traditional Experimental Modal Analysis (EMA) techniques. Since the input information is unavailable in OMA, the technique makes use of certain as...

In the present contribution, the applicability of frequencydomain Maximum Likelihood (ML) identification techniques in the field of operational modal analysis is investigated. Attention is paid to the derivation of the spectral densities and noise information required for the ML estimator. The frequency-domain ML approach is applied to a real case study and confidence intervals are derived on t...

This paper deals with a model of a 3-bladed wind turbine and its identification. The linear, time-invariant state-space model has been developed at Fraunhofer IWES mainly for control engineering applications. Its parameters are obtained from an operational modal analysis carried out on a commercial 5MW turbine. The parameterised model is validated by comparison of estimated time series and meas...

Knowledge bases are currently being investigated by database researchers in order to extend the expressiveness of the relational model to include deductive capabilities in the form of rules. The motivation behind this paper is to present a formalism which extends the relational approach to homogeneous distributed databases to the knowledge base paradigm. The basis of our formalism of distribute...

Without affecting the integrity or stability of heritage monuments, vibration-based techniques provide useful solutions for acquiring global information about them. By studying dynamic response to suitable excitation sources, it is feasible define mechanical characteristics structures and identify locate defects in their behaviour. Laser Doppler vibrometry (LDV), which enables non-contact measu...

Smooth plant production is utmost expected by owners since any unplanned shutdown very much undesirable as it may incur loss of company’s profits and other repercussions. Critical operational assets such rotating machineries their components, e.g., motor, pump, compressor, turbines are crucial to be monitored in ensuring continuous operation the plant. Therefore, vibration being one elements pr...