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Sara Fogelström

Publications and source records attributed to Sara Fogelström.

2 recordsLinked to original sources

Optimal preventive maintenance scheduling for wind turbines under condition monitoring

We suggest a mathematical model for computing and regularly updating the next preventive maintenance plan for a wind farm. Our optimization criterium takes into account the current ages of the key components, the major maintenance costs including eventual energy production losses as well as the available data monitoring the condition of the wind turbines. We illustrate our approach with a case study based on data collected from several wind farms located in Sweden. Our results show that preventive maintenance planning gives some effect, if the wind turbine components in question live significantly shorter than the turbine itself.

math.OC↗

Local Analysis of Nonlinear Oscillations of Thin Accretion Disks

We calculated the coupling coefficients for non-linear, quasi-local oscillatory modes of thin accretion disks. We found that several of them are non-zero. Mode coupling is a necessary condition for a resonance, and thus our results may be relevant for the recently discussed QPO resonance model.

astro-ph↗