Inflow and the Fatigue of the LIST Wind Turbine

2002 ◽  
Author(s):  
Herbert J. Sutherland
Keyword(s):  
Test List ◽  
Vertical Component ◽  
Structural Response ◽  
Structural Data ◽  
Reynolds Stresses ◽  
Load Spectrum ◽  
Fatigue Load ◽  
Obukhov Length ◽  
Fatigue Loads

The Long-term Inflow and Structural Test (LIST) program is collecting long-term, continuous inflow and structural response data to characterize the spectrum of loads on wind turbines. A heavily instrumented Micon 65/13M turbine with SERI 8m blades is being used as the primary test turbine for this test. This turbine is located in Bushland, TX, a test site that exposes the turbine to a wind regime representative of a Great Plains commercial site. The turbine and inflow are being characterized with 60 measurements: 34 to characterize the inflow, 19 to characterize structural response, and 7 to characterize the time-varying state of the turbine. In this paper, the inflow and structural data from this measurement campaign are analyzed to determine the correlation of various inflow descriptors with fatigue loads. The inflow is described by various parameters, including the mean, standard deviation, skewness and kurtosis of the wind speed, turbulence intensity, turbulence length scales, Reynolds stresses, local friction velocity, Obukhov length and the gradient Richardson number. The fatigue load spectrum corresponding to these parameters is characterized as an equivalent fatigue load. A regression analysis is then used to determine which parameters are correlated to the fatigue loads. The results illustrate that the vertical component of the inflow is the most important of the secondary inflow parameters on fatigue loads. Long-term fatigue spectra illustrate that extrapolation of relatively short-term data to longer times is consistent for the data reported here.

Analysis of the Structural and Inflow Data From the List Turbine

2002 ◽  
Vol 124 (4) ◽  
pp. 432-445 ◽  
Author(s):  
Herbert J. Sutherland
Keyword(s):  
Test List ◽  
Vertical Component ◽  
Structural Response ◽  
Horizontal Wind ◽  
Reynolds Stresses ◽  
Load Spectrum ◽  
Fatigue Load ◽  
Horizontal Wind Speed ◽  
Fatigue Loads

The Long-term Inflow and Structural Test (LIST) program is collecting long-term, continuous inflow and structural response data to characterize the spectrum of loads on wind turbines. A heavily instrumented Micon 65/13M turbine with Phoenix 8m blades is being used as the test turbine for the first measurement campaign of this program. This turbine is located in Bushland, TX, a test site that exposes the turbine to a wind regime representative of a Great Plains commercial site. The turbine and inflow are being characterized with 60 measurements: 34 to characterize the inflow, 19 to characterize structural response, and seven to characterize the time-varying state of the turbine. In this paper, an analysis of the structural and inflow data is presented. Particular attention is paid to the determination of the various structural loads on the turbine, long-term fatigue spectra and the correlation of various inflow descriptors with fatigue loads. For the latter analysis, the inflow is described by various parameters, including the mean, standard deviation, skewness and kurtosis of the hub-height horizontal wind speed, turbulence intensity, turbulence length scales, Reynolds stresses, local friction velocity, Obukhov length, and the gradient Richardson number. The fatigue load spectrum corresponding to these parameters is characterized as an equivalent fatigue load. A regression analysis is then used to determine which parameters are correlated to the fatigue loads. The results illustrate that the vertical component of the inflow is the most important of the secondary inflow parameters with respect to fatigue loads. Long-term fatigue spectra illustrate that extrapolation of relatively short-term data to longer times is consistent for the data reported here.

Inflow and Fatigue Response of the NWTC Advanced Research Turbine

2003 ◽  
Author(s):  
Herbert J. Sutherland ◽  
Neil D. Kelley ◽  
M. Maureen Hand
Keyword(s):  
Test List ◽  
Structural Response ◽  
Synchronous Generator ◽  
Measurement Unit ◽  
Response Data ◽  
Extreme Loads ◽  
Sonic Anemometers ◽  
Planar Array ◽  
Fatigue Loads

The Long-term Inflow and Structural Test (LIST) program is collecting long-term inflow and structural response data to characterize the spectrum of loads on wind turbines. In one of the measurement campaigns being conducted under this program, the 42-m diameter, 600-kW NWTC Advanced Research Turbine (ART) was monitored. The turbine is an upwind, two-bladed teetered-hub machine. It has full span pitch control and a synchronous generator. The inflow was monitored with a planar array of five high-resolution sonic anemometers and supporting meteorological instrumentation located 1.5 diameters upwind of the turbine. The structural response of the turbine was measured using strain gauge circuits and an inertial measurement unit (IMU). The former were used to monitor root bending moments and the low-speed shaft torque, while the latter was used to monitor the motion of the tower and the nacelle. Auxiliary gauges measured blade pitch, rotor teeter, nacelle yaw and generator power. A total of 3299 10-minute records were collected for analysis. From this set, 1044 records are used to examine the influence of various inflow parameters on fatigue loads. Long-term fatigue loads and extreme loads are also examined.

Probabilistic Analysis of LIST Data for the Estimation of Extreme Design Loads for Wind Turbine Components*†

2003 ◽  
Vol 125 (4) ◽  
pp. 531-540 ◽  
Author(s):  
M. D. Pandey ◽  
H. J. Sutherland
Keyword(s):  
Wind Turbine ◽  
Sampling Error ◽  
Test List ◽  
Structural Data ◽  
Value Theory ◽  
Extreme Value ◽  
Sampling Errors ◽  
Extreme Loads ◽  
Design Loads

The robust estimation of wind turbine design loads for service lifetimes of 30 to 50 years that are based on limited field measurements is a challenging problem. Estimating the long-term load distribution involves the integration of conditional distributions of extreme loads over the mean wind speed and turbulence intensity distributions. However, the accuracy of the statistical extrapolation can be sensitive to both model and sampling errors. Using measured inflow and structural data from the Long Term Inflow and Structural Test (LIST) program, this paper presents a comparative assessment of extreme loads using three distributions: namely, the Gumbel, Weibull and Generalized Extreme Value distributions. The paper uses L-moments, in place of traditional product moments, with the purpose of reducing the sampling error. The paper discusses the effects of modeling and sampling errors and highlights the practical limitations of extreme value theory.

scholarly journals Fatigue Load Spectrum of Highway Bridge Vehicles in Plateau Mountainous Area Based on Wireless Sensing

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Li Rui ◽  
Xie Xiaoyu ◽  
Duan Xueyan
Keyword(s):  
Low Cost ◽  
Mineral Resources ◽  
Highway Bridges ◽  
Equivalent Model ◽  
Distribution Model ◽  
Mountainous Area ◽  
Wireless Sensing ◽  
Mountainous Areas ◽  
Load Spectrum ◽  
Fatigue Load

In Yunnan and other plateau mountainous areas, hydropower and mineral resources are abundant, and there are relatively many vehicles used for the transportation of large hydropower facilities. The widespread phenomenon of vehicle overload causes severe fatigue among the drivers. However, there is no reference vehicle load spectrum for fatigue analysis in the existing research. The application of wireless sensing technology to bridge health monitoring is favorable for the entire monitoring system’s low-cost and intelligent development. In this study, wireless sensors are used to collect sensing data in the measured area and perform preliminary filtering processing. The data collected by the sensing layer is aggregated at the TD gateway layer to realize local short-term storage of monitoring data, and 3G wireless transmission is used for the effective processing of the data. The clustering method is used to classify the vehicle models based on investigating the most representative expressway traffic flow information in Yunnan Province. Moreover, the weighted probability distribution model of different vehicle models is established through statistical analysis, which simplifies the composition’s fatigue intensity spectrum model. The selection of five vehicles of the equivalent model followed by a six-axle vehicle has the most significant impact on bridge damage as the standard fatigue vehicle. The research results establish a basis for the fatigue design of highway bridges in plateau and mountainous areas and provide data to establish vehicle fatigue load spectra in national highway regions.

An On-Going Monitoring Project of a New Timber Structure

2013 ◽  
Vol 778 ◽  
pp. 757-764 ◽  
Author(s):  
Francesca Lanata
Keyword(s):  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Environmental Conditions ◽  
Environmental Changes ◽  
Construction Material ◽  
Structural Response ◽  
Timber Structures ◽  
The Real ◽  
Structural Health

Structural design, regardless of construction material, is based mainly on deterministic codes that partially take into account the real structural response under service and environmental conditions. This approach can lead to overdesigned (and expensive) structures. The differences between the designed and the real behaviors are usually due to service loads not taken into account during the design or simply to the natural degradation of materials properties with time. This is particularly true for wood, which is strongly influenced by service and environmental conditions. Structural Health Monitoring can improve the knowledge of timber structures under service conditions, provide information on material aging and follow the degradation of the overall building performance with time.A long-term monitoring control has been planned on a three-floor structure composed by wooden trusses and composite concrete-wood slabs. The structure is located in Nantes, France, and it is the new extension to the Wood Science and Technology Academy (ESB). The main purpose of the monitoring is to follow the long-term structural response from a mechanical and energetic point of view, particularly during the first few service years. Both static and dynamic behavior is being followed through strain gages and accelerometers. The measurements will be further put into relation with the environmental changes, temperature and humidity in particular, and with the operational charges with the aim to improve the comprehension of long-term performances of wooden structures under service. The goal is to propose new improved and optimized methods to make timber constructions more efficient compared to other construction materials (masonry, concrete, steel).The paper will mainly focus on the criteria used to design the architecture of the monitoring system, the parameters to measure and the sensors to install. The first analyses of the measurements will be presented at the conference to have a feedback on the performance of the installed sensors and to start to define a general protocol for the Structural Health Monitoring of such type of timber structures.

Assessment of static and dynamic geodiversity in the Sesia Val Grande UNESCO Global Geopark: constraints for a sustainable use of related abiotic ecosystem services

2021 ◽  
Author(s):  
Cristina Viani ◽  
Luigi Perotti ◽  
Federico Tognetto ◽  
Ilaria Selvaggio ◽  
Marco Giardino
Keyword(s):  
Ecosystem Services ◽  
Environmental Changes ◽  
Sustainable Use ◽  
Structural Data ◽  
Western Alps ◽  
Landscape Resistance ◽  
Related Factors ◽  
Multitemporal Data ◽  
Geomorphological Evolution

<p>Geodiversity includes geological, geomorphological, hydrological and soil elements and processes. By analysing geodiversity we can offer static and dynamic views of abiotic landscapes on the Earth. The current state of geodiversity includes both relict, long-term features recalling the past of our planet earth and active landforms and processes whose monitoring is a key for interpreting relationships between geosphere, biosphere and human activities. If the long term geodiversity mainly represents distribution of litho-structural “static” constrains to environmental changes, recent and active environmental features may act as dynamic “proxies” for interpreting climate change.<br>Aim of this work is to analyse relevant examples of both static and dynamic geodiversity within the territory of the Sesia Val Grande UNESCO Global Geopark (Western Alps, Italy), in order to assess their role as georesources and to highlight possible sustainable use of related abiotic ecosystem services, including geoheritage. Geodiversity assessment has been performed by means of creation of geothematic maps and related factors analysed for better mountain environment understanding and management. <br>Starting with static geodiversity we collected, analysed and interpreted lithological and structural data in order to obtain information on distribution of georesources in the study area and to create a geothematic map on landscape resistance to erosion.<br>Thereafter we focused on two aspects related to dynamic geodiversity and their relationships with dramatic changes of the alpine landscape: glacial evolution and fluvial processes. On one hand, valley scale geomorphological evolution has been reconstructed by means of multitemporal data (e.g.: glacial landforms maps, glacier inventories) on evidences in the Sesia Valley. Obtained information crossed with national landslide inventory allowed to identify areas of strong glacial influence on slope stability (deep-seated gravitational slope deformation and landslides due to slope debutressing). Moreover, recent glacier withdrawal results in new glacier lakes increasing the hydrogeodiversity of the area and representing important potential georesources to be used. Finally, recent alluvial event (October 2020) has been considered for its high impact in reshaping fluvial environment and effects on both infrastructures and popular geosites along the Sesia river.<br>Results of this work are useful for the establishment of a proper Driver-Pressure-State-Impact-Response (DPSIR) framework related to environmental issues due to global change in order to support educational activities and sustainable development of alpine “tourism hubs” included in the Sesia Val Grande UNESCO Global Geopark by the “ArcticHubs” H2020-EU.3.5.1 project.</p>

Long-term Memory Upscales Volume of Postsynaptic Densities in the Process that Requires Autophosphorylation of αCaMKII

2019 ◽  
Vol 30 (4) ◽  
pp. 2573-2585 ◽  
Author(s):  
Małgorzata Alicja Śliwińska ◽  
Anna Cały ◽  
Malgorzata Borczyk ◽  
Magdalena Ziółkowska ◽  
Edyta Skonieczna ◽  
...  
Keyword(s):  
Dendritic Spines ◽  
Smooth Endoplasmic Reticulum ◽  
Structural Data ◽  
Long Term Memory ◽  
Brain Circuits ◽  
Hippocampal Area ◽  
And Function ◽  
And Storage ◽  
Old Mice

Abstract It is generally accepted that formation and storage of memory relies on alterations of the structure and function of brain circuits. However, the structural data, which show learning-induced and long-lasting remodeling of synapses, are still very sparse. Here, we reconstruct 1927 dendritic spines and their postsynaptic densities (PSDs), representing a postsynaptic part of the glutamatergic synapse, in the hippocampal area CA1 of the mice that underwent spatial training. We observe that in young adult (5 months), mice volume of PSDs, but not the volume of the spines, is increased 26 h after the training. The training-induced growth of PSDs is specific for the dendritic spines that lack smooth endoplasmic reticulum and spine apparatuses, and requires autophosphorylation of αCaMKII. Interestingly, aging alters training-induced ultrastructural remodeling of dendritic spines. In old mice, both the median volumes of dendritic spines and PSDs shift after training toward bigger values. Overall, our data support the hypothesis that formation of memory leaves long-lasting footprint on the ultrastructure of brain circuits; however, the form of circuit remodeling changes with age.

scholarly journals Further complexities on the pre-reversal vertical drift modeling over the Brazilian region: A comparison between long-term observations and model results

2020 ◽  
Vol 10 ◽  
pp. 20
Author(s):  
Jonas Sousasantos ◽  
Mangalathayil Ali Abdu ◽  
Angela Santos ◽  
Inez Batista ◽  
André Silva ◽  
...  
Keyword(s):  
Empirical Model ◽  
Bubble Formation ◽  
Vertical Component ◽  
Percentage Error ◽  
Ionospheric Scintillation ◽  
Additional Contribution ◽  
Plasma Bubble ◽  
Vertical Drift ◽  
Long Term Observation

The vertical component of the plasma drift, especially the evening-time pre-reversal drift, constitutes an important aspect of the nighttime electrodynamics of the equatorial ionosphere. Over the years, several studies using measurements and models have been performed to understand the characteristics of this process and its implications for the development of the instabilities leading to the plasma bubble formation and ionospheric scintillation. However, the Brazilian region presents some unique features that bring some difficulties for the vertical drift prognosis, which is required for the scintillation forecasting. These features are mainly related to the geomagnetic field lines topology that presents strong differences when compared to those of other equatorial longitudes. In this work, some of the difficulties for the pre-reversal vertical drift modeling and estimation are discussed; also, a dataset containing long-term observation (2001–2009) is compared with a widely used empirical model. The results show an intrinsic trend of underestimation by the model, which seems to be independent of latitude and seasonality thus suggesting an additional contribution arising from sources other than solely the geomagnetic topology. Also, the results indicate that the deviation can vary in the range of 0–40 m/s and the percentage error enhances with increasing values of pre-reversal vertical drift peak and reduces with increasing F10.7 values, thereby, indicating a clear possibility of meridional winds contribution which is not included in the empirical model used and may account for these differences.

scholarly journals Bridge Deck Load Testing Using Sensors and Optical Survey Equipment

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Hubo Cai ◽  
Osama Abudayyeh ◽  
Ikhlas Abdel-Qader ◽  
Upul Attanayake ◽  
Joseph Barbera ◽  
...  
Keyword(s):  
Sensor Network ◽  
Structural Integrity ◽  
Structural Response ◽  
Lessons Learned ◽  
Load Test ◽  
Load Testing ◽  
Deck Panels ◽  
Test Study ◽  
Deflection Analysis

Bridges are under various loads and environmental impacts that cause them to lose their structural integrity. A significant number of bridges in US are either structurally deficient or functionally obsolete, requiring immediate attention. Nondestructive load testing is an effective approach to measure the structural response of a bridge under various loading conditions and to determine its structural integrity. This paper presents a load-test study that evaluated the response of a prefabricated bridge with full-depth precast deck panels in Michigan. This load-test program integrates optical surveying systems, a sensor network embedded in bridge decks, and surface deflection analysis. Its major contribution lies in the exploration of an embedded sensor network that was installed initially for long-term bridge monitoring in bridge load testing. Among a number of lessons learned, it is concluded that embedded sensor network has a great potential of providing an efficient and accurate approach for obtaining real-time equivalent static stresses under varying loading scenarios.

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