Development of a robust structural health monitoring system for wind turbine foundations

The construction of onshore wind turbines has rapidly been increasing as the UK attempts to meet its renewable energy targets. As the UK’s future energy depends more on wind farms, safety and security are critical to the success of this renewable energy source. Structural integrity is a critical element of this security of supply. With the stochastic nature of the load regime a bespoke low cost structural health monitoring system is required to monitor integrity. This paper presents an assessment of ‘embedded can’ style foundation failure modes in large onshore wind turbines and proposes a novel condition based monitoring solution to aid in early warning of failure

Structural integrity monitoring of onshore wind turbine concrete foundations

Signs of damage around the bottom flange of the embedded ring were identified in a large number of existing onshore concrete foundations. As a result, the embedded ring experienced excessive vertical displacement. A wireless structural integrity monitoring (SIM) technique was developed and installed in the field to monitor the stability of these turbines by measuring the displacement patterns and subsequently alerting any significant movements of the embedded ring. This was achieved by using wireless displacement sensors located in the bottom of the turbine. A wind turbine was used as a test bed to evaluate the performance of the SIM system under field operating conditions. The results obtained from the sensors and supervisory control and data acquisition (SCADA) showed that the embedded ring exhibited significant vertical movement especially during periods of turbulent wind speed and during shut down and start up events. The measured displacement was variable around the circumference of the foundation as a result of the wind direction and the rotor uplift forces. The excessive vertical movement was observed in the side where the rotor is rotating upwards. The field test demonstrated that the SIM technique offers great potential for improving the reliability and safety of wind turbine foundations

Structural health monitoring for wind turbine foundations

The construction of onshore wind turbines has rapidly been increasing as the UK attempts to meet its renewable energy targets. As the UK’s future energy depends more on wind farms, safety and security are critical to the success of this renewable energy source. Structural integrity of the tower and its components is a critical element of this security of supply. With the stochastic nature of the load regime a bespoke low cost structural health monitoring system is required to monitor integrity of the concrete foundation supporting the tower. This paper presents an assessment of ‘embedded can’ style foundation failure modes in large onshore wind turbines and proposes a novel condition based monitoring solution to aid in early warning of failure. The most common failure modes are discussed and a low-cost remote monitoring system is presented

Building a Systematic Online Living Evidence Summary of COVID-19 Research

Throughout the global coronavirus pandemic, we have seen an unprecedented volume of COVID-19 researchpublications. This vast body of evidence continues to grow, making it difficult for research users to keep up with the pace of evolving research findings. To enable the synthesis of this evidence for timely use by researchers, policymakers, and other stakeholders, we developed an automated workflow to collect, categorise, and visualise the evidence from primary COVID-19 research studies. We trained a crowd of volunteer reviewers to annotate studies by relevance to COVID-19, study objectives, and methodological approaches. Using these human decisions, we are training machine learning classifiers and applying text-mining tools to continually categorise the findings and evaluate the quality of COVID-19 evidence

Structural integrity monitoring of onshore wind turbine concrete foundations

Signs of damage around the bottom flange of the embedded ring were identified in a large number of existing onshore concrete foundations. As a result, the embedded ring experienced excessive vertical displacement. A wireless structural integrity monitoring (SIM) technique was developed and installed in the field to monitor the stability of these turbines by measuring the displacement patterns and subsequently alerting any significant movements of the embedded ring. This was achieved by using wireless displacement sensors located in the bottom of the turbine. A wind turbine was used as a test bed to evaluate the performance of the SIM system under field operating conditions. The results obtained from the sensors and supervisory control and data acquisition (SCADA) showed that the embedded ring exhibited significant vertical movement especially during periods of turbulent wind speed and during shut down and start up events. The measured displacement was variable around the circumference of the foundation as a result of the wind direction and the rotor uplift forces. The excessive vertical movement was observed in the side where the rotor is rotating upwards. The field test demonstrated that the SIM technique offers great potential for improving the reliability and safety of wind turbine foundations

Structural health monitoring of wind turbine foundations using a wireless sensor network

Wind turbine foundations, that incorporate the 'embedded can' type tower/foundation connections, have been reported as showing significant evidence of vertical displacement at a number of wind farm sites. The 'embedded can' and connected tower sections in these reports have been observed to be moving up to 20mm or more in some instances. This poses a serious safety concern for the operator and action is needed to monitor and remedy the problem. There is currently no real-time, structural health monitoring system in place recording movement. The aim of the study was to develop and evaluate a novel wireless structural health monitoring system for an operator to facilitate monitoring of such movements, mapping and quantifying the displacement patterns and subsequently alerting any significant foundation events. Development of a novel displacement sensor array, connected to a wireless gateway and positioned in the bottom of an operational 2MW wind turbine offered a useful test article to evaluate the performance of the displacement sensors and the monitoring solution to track such movements. The results showed that the foundation was displacing vertically, especially during periods of significant gusting and during 'cut in' and 'cut out' periods. Results also show the effect of rotor acceleration and wind direction upon the level and pattern of displacement. This low cost monitoring solution would be easily 'retro- fittable' to track reliability and improve safety.Wind turbine foundations, that incorporate the 'embedded can' type tower/foundation connections, have been reported as showing significant evidence of vertical displacement at a number of wind farm sites. The 'embedded can' and connected tower sections in these reports have been observed to be moving up to 20mm or more in some instances. This poses a serious safety concern for the operator and action is needed to monitor and remedy the problem. There is currently no real-time, structural health monitoring system in place recording movement. The aim of the study was to develop and evaluate a novel wireless structural health monitoring system for an operator to facilitate monitoring of such movements, mapping and quantifying the displacement patterns and subsequently alerting any significant foundation events. Development of a novel displacement sensor array, connected to a wireless gateway and positioned in the bottom of an operational 2MW wind turbine offered a useful test article to evaluate the performance of the displacement sensors and the monitoring solution to track such movements. The results showed that the foundation was displacing vertically, especially during periods of significant gusting and during 'cut in' and 'cut out' periods. Results also show the effect of rotor acceleration and wind direction upon the level and pattern of displacement. This low cost monitoring solution would be easily 'retro- fittable' to track reliability and improve safety

Development of a low cost structural health monitoring system for wind turbine foundations

Paper describes the development of a low cost structural health monitoring system for wind turbine foundations

The effect of chemical and nanotopographical modifications on the early stages of osseointegration

PURPOSE: To investigate the effect of chemically modified implants with similar microtopographies but different nanotopographies on early stages of osseointegration. MATERIALS AND METHODS: Forty screw-shaped implants were placed in 10 New Zealand white rabbits. The implant surface modifications investigated in the present study were (1) blasting with TiO2 and further (2) fluoride treatment or (3) modification with nano-hydroxyapatite. Surface evaluation included topographical analyses with interferometry, morphologic analyses with scanning electron microscopy, and chemical analyses with x-ray photoelectron spectroscopy. Bone response was investigated with the removal torque test, and histologic analyses were carried out after a healing period of 4 weeks. RESULTS: Surface roughness parameters showed a slight decrease of the average height deviation for the fluoride-treated compared to the blasted (control) and nano-hydroxyapatite implants. Scanning electron microscopic images at high magnification indicated the presence of nanostructures on the chemically modified implants. Chemical analyses revealed the presence of titanium, oxygen, carbon, and nitrogen in all implant groups. The blasted-fluoride group revealed fluoride, and the blasted-nano HA group calcium and phosphorus with simultaneous decrease of titanium and oxygen. Removal torque values revealed an increased retention for the chemically modified implants that exhibit specific nanotopography. The histologic analyses demonstrated immature bone formation in contact with the implant surface in all groups, according to the healing period of the experiment. CONCLUSION: Chemical modifications used in the present study were capable of producing a particular nanotopography, and together with the ions present at the implant surface, may explain the increased removal torque values after a healing period of 4 weeks