Simon Ambühl
Aalborg University
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Publication
Featured researches published by Simon Ambühl.
Proceedings of the Institution of Mechanical Engineers, Part O: Journal of Risk and Reliability | 2015
Simon Ambühl; Laurent Marquis; Jens Peter Kofoed; John Dalsgaard Sørensen
Inspection and maintenance costs are a significant contributor to the cost of energy for wave energy converters. There are different operation and maintenance strategies for wave energy converters. Maintenance can be performed after failure (corrective) or before a breakdown (preventive) occurs. Furthermore, a helicopter and boats can be used to transport equipment and personnel to the device, or the whole device can be towed to a harbour for operation and maintenance actions. This article describes, among others, a risk-based inspection and maintenance planning approach where the overall repair costs including costs due to lost electricity production are minimized. The risk-based approach is compared with an approach where only boats are used and another approach where the target is to minimize the downtime of the device. This article presents a dynamic approach for total operation and maintenance costs estimations for wave energy converter applications including real weather data and damage accumulation. Furthermore, uncertainties related with costs, structural damage accumulation, inspection accuracy and different maintenance strategies can be included. This article contains a case study where different maintenance strategies are applied for the Wavestar device, and the influences of the different parameters, for example, failure rate, inspection quality and inspection interval, are evaluated for the overall costs and the number of repairs needed during its lifetime.
ICASP12: 12th International Conference on Applications of Statistics and Probability in Civil Engineering | 2015
Simon Ambühl; Morten Kramer; John Dalsgaard Sørensen
Wave energy converters (WECs), which harvest energy from the waves and transfer them to electricity, are a new technology, where structural standards need to be developed. An important step towards standardization is the calibration of partial safety factors. A methodology for calibration of partial safety factors for design of welded details for wave energy converter applications is presented in this paper using probabilistic methods. The paper presents an example with focus on the Wavestar device. SN curves and Rainflow counting are used to model fatigue without considering inspections. The influence of inspections is modelled using a fracture mechanics approach, which is calibrated by the SN curve approach. Furthermore, the paper assesses the influence of the inspection quality. The results show that with multiple inspections during the lifetime of the device and by applying a good inspection quality, the safety factor can be significantly reduced.
Energies | 2014
Francesco Ferri; Simon Ambühl; Boris Fischer; Jens Peter Kofoed
International Journal of Marine Energy | 2015
Simon Ambühl; Francesco Ferri; Jens Peter Kofoed; John Dalsgaard Sørensen
International Journal of Marine Energy | 2014
Simon Ambühl; Martin Sterndorff; John Dalsgaard Sørensen
Energies | 2014
Simon Ambühl; Morten Kramer; John Dalsgaard Sørensen
Ocean Engineering | 2014
Simon Ambühl; Jens Peter Kofoed; John Dalsgaard Sørensen
Energies | 2017
Simon Ambühl; John Dalsgaard Sørensen
European Wave and Tidal Energy Conferenceeuropean Wave and Tidal Energy Conference | 2015
Simon Ambühl; Morten Kramer; John Dalsgaard Sørensen
Journal of Ocean and Wind Energy | 2015
Simon Ambühl; Jens Peter Kofoed; John Dalsgaard Sørensen