Статті в журналах: "Ice-wind loads"

1

Krishnasamy, Samy, and S. Kulendran. "Combined wind and ice loads from historical extreme wind and ice data." Atmospheric Research 46, no. 1-2 (April 1998): 123–29. http://dx.doi.org/10.1016/s0169-8095(97)00055-0.

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2

Sun, Yu, and Xiu Li Wang. "Extreme Weather Loading Risk Model of Overhead Transmission Line." Advanced Materials Research 383-390 (November 2011): 2005–11. http://dx.doi.org/10.4028/www.scientific.net/amr.383-390.2005.

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Power grid suffers tremendous economic loss in extreme ice disaster weather, suggesting that it lacks immediate precautionary system. On the basis of the standards of Q/GDW179-2008 and IEC60826-2003, the curve of transmission line design loads is built up. In view of ransom character for load-strength of transmission line, according to load-strength interference theory, a short-term wind and ice loading risk model is established, which is a time-dependent wind and ice loading model, and can be calculated unreliability probability and fault rate, showing risks about cluster fault and common fault. Furthermore, wind and ice loads are divided into five states, which show risk margin of loads. It also can provide precautionary information for operator, and can present risk measurement on time scale.

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3

Zhou, Li, Shifeng Ding, Ming Song, Junliang Gao, and Wei Shi. "A Simulation of Non-Simultaneous Ice Crushing Force for Wind Turbine Towers with Large Slopes." Energies 12, no. 13 (July 7, 2019): 2608. http://dx.doi.org/10.3390/en12132608.

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When the offshore wind energy industry attempts to develop in cold regions, ice load becomes the main technological challenge for offshore wind turbine foundation design. Dynamic ice loads acting on wind turbine foundations should be calculated in a reasonable way. The scope of this study is to present a numerical model that considers the non-simultaneous ice crushing failure acting on the vertical structure of a wind turbine’s foundation. The local ice crushing force at the contact surface between the ice sheet and structure is calculated. The boundary of the ice sheet is updated at each time step based on the indentation length of the ice sheet according to its structure. Ice loads are validated against two model tests with three different structure models developed by other researchers. The time series of the ice forces derived from the simulation and model tests are compared. The proposed numerical model can capture the main trends of ice–wind turbine foundation interaction. The simulation results agree well with measured data from the model tests in terms of maximum ice force, which is a key factor for wind turbine design. The proposed model will be helpful for assisting the initial design of wind turbine foundations in cold regions.

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4

Wahba, Yohanna M. F., Murty K. S. Madugula, and Gerard R. Monforton. "Limit states design of antenna towers." Canadian Journal of Civil Engineering 21, no. 6 (December 1, 1994): 913–23. http://dx.doi.org/10.1139/l94-097.

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The Canadian Standard CAN/CSA-S37-M86 “Antennas, towers and antenna supporting structures” follows a quasi-limit states approach in which the member forces determined for specified loads are multiplied by a unified factor and compared with factored resistances given in CAN3-S16.1-M84. This results in designs basically the same as those resulting from a working stress design with a factor of safety of 5/3. Such structures exhibit a non-linear structural behaviour even under service loads. Thus the effect of ice accretion and direct interaction between wind and ice does not permit the load factors specified in CAN/CSA-S16.1-M89 “Limit states design of steel structures” to be directly applied to antenna supporting structures.In this study, 41 different towers (representing various heights and designed for different ice classes and wind pressures) were analyzed under specified loads and then under a set of factored loads. From the comparison of the design forces in the towers with those calculated according to the existing standard, a set of partial load factors was derived. The new load factors to be used in the 1993 edition of S37 are presented and justified. Key words: antenna towers, guyed towers, ice and wind loads, limit states design, self-supporting towers, working stress design.

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5

Ye, Kehua, Chun Li, Fudong Chen, Zifei Xu, Wanfu Zhang, and Junwei Zhang. "Floating Ice Load Reduction of Offshore Wind Turbines by Two Approaches." International Journal of Structural Stability and Dynamics 18, no. 10 (October 2018): 1850129. http://dx.doi.org/10.1142/s0219455418501298.

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The offshore wind turbines (OWTs) constructed at the northern sea areas under cold climate are frequently subjected to floating ice loads. It is imperative to reduce the damage owing to the floating ice with some appropriate approaches. The purpose of this paper is to ascertain the effectiveness of the tuned mass damper (TMD) and the ice-breaking cone for reducing floating ice loads on OWTs. The National Renewable Energy Laboratory's (NREL) 5 MW OWT, which is treated as a multibody system with rigid and flexible parts, is adopted as the example model here. The multiple loads taken into consideration in the fully coupled simulation include floating ice and turbulent wind. The aerodynamic load acting on the blades is solved by the blade element momentum method based on a full-field turbulent wind farm generated by the Kaimal spectrum. The Matlock model and the Ralston model are adopted for evaluating the floating ice loads on the cylindrical and conical structures, respectively. The TMD system in the nacelle and the ice-breaking cone on the tower at the mean sea level are the two load reduction approaches of concern in this paper. A weak aeroelastic simulation of the OWT model is conducted. The solution of flexibility effectiveness depends on some accurate mode shapes by the linear modal representation. Finally, Kane's method is used for predicting the motion of the whole OWT. The relevant results reveal some positive effectiveness of the TMD system and the ice-breaking cone for reducing the floating ice load. The displacement of tower top decreases significantly with the utilization of the two approaches. The TMD system has a better performance for the side-side displacement than the fore-aft displacement. By switching the ice failure mode from crushing to bending, the ice-breaking cone reduces the floating load more effectively than the TMD system. It affects equally significantly the fore-aft and side-side displacements.

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6

Braun, Moritz, Alfons Dörner, Kane F. ter Veer, Tom Willems, Marc Seidel, Hayo Hendrikse, Knut V. Høyland, Claas Fischer, and Sören Ehlers. "Development of Combined Load Spectra for Offshore Structures Subjected to Wind, Wave, and Ice Loading." Energies 15, no. 2 (January 13, 2022): 559. http://dx.doi.org/10.3390/en15020559.

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Fixed offshore wind turbines continue to be developed for high latitude areas where not only wind and wave loads need to be considered but also moving sea ice. Current rules and regulations for the design of fixed offshore structures in ice-covered waters do not adequately consider the effects of ice loading and its stochastic nature on the fatigue life of the structure. Ice crushing on such structures results in ice-induced vibrations, which can be represented by loading the structure using a variable-amplitude loading (VAL) sequence. Typical offshore load spectra are developed for wave and wind loading. Thus, a combined VAL spectrum is developed for wind, wave, and ice action. To this goal, numerical models are used to simulate the dynamic ice-, wind-, and wave-structure interaction. The stress time-history at an exemplarily selected critical point in an offshore wind energy monopile support structure is extracted from the model and translated into a VAL sequence, which can then be used as a loading sequence for the fatigue assessment or fatigue testing of welded joints of offshore wind turbine support structures. This study presents the approach to determine combined load spectra and standardized time series for wind, wave, and ice action.

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7

Song, Ming, Wei Shi, Zhengru Ren, and Li Zhou. "Numerical Study of the Interaction between Level Ice and Wind Turbine Tower for Estimation of Ice Crushing Loads on Structure." Journal of Marine Science and Engineering 7, no. 12 (December 1, 2019): 439. http://dx.doi.org/10.3390/jmse7120439.

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In this paper, the interaction between level ice and wind turbine tower is simulated by the explicit nonlinear code LS-DYNA. The isotropic elasto-plastic material model is used for the level ice, in which ice crushing failure is considered. The effects of ice mesh size and ice failure strain on ice forces are investigated. The results indicate that these parameters have a significant effect on the ice crushing loads. To validate and benchmark the numerical simulations, experimental data on level ice-wind turbine tower interactions are used. First, the failure strains of the ice models with different mesh sizes are calibrated using the measured maximum ice force from one test. Next, the calibrated ice models with different mesh sizes are applied for other tests, and the simulated results are compared to corresponding model test data. The effects of the impact speed and the size of wind turbine tower on the comparison between the simulated and measured results are studied. The comparison results show that the numerical simulations can capture the trend of the ice loads with the impact speed and the size of wind turbine tower. When a mesh size of ice model is 1.5 times the ice thickness, the simulations can give more accurate estimations in terms of maximum ice loads for all tests, i.e., good agreement between the simulated and measured results is achieved.

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8

Fu, Ping, and Masoud Farzaneh. "Simulation of the ice accretion process on a transmission line cable with differential twisting." Canadian Journal of Civil Engineering 34, no. 2 (February 1, 2007): 147–55. http://dx.doi.org/10.1139/l06-109.

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Cable rotation caused by ice accretion was specifically modelled and simulated for this paper. Both ice loads and wind-on-ice loads were taken into account during the modelling, and the quantity for the wind-on-ice loads was obtained by integrating air pressure and air shear along the airflow boundary. Air pressure and air shear were both evaluated through time-dependent airflow computations. Two types of overhead transmission line cables, namely, the Bersimis cable and an overhead ground wire, were examined using the new model, and a number of conclusions were drawn. The validity and reliability of the modelling methods were confirmed by comparing the simulation results with those obtained from experimental measurements.Key words: airflow computation, cable rotation, ice accretion, computer modelling, simulation.

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9

Alshannaq, Ammar A., Lawrence C. Bank, David W. Scott, and Russell Gentry. "A Decommissioned Wind Blade as a Second-Life Construction Material for a Transmission Pole." Construction Materials 1, no. 2 (July 7, 2021): 95–104. http://dx.doi.org/10.3390/constrmater1020007.

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This paper demonstrates the concept of adaptive repurposing of a portion of a decommissioned Clipper C96 wind turbine blade as a pole in a power transmission line application. The current research program is aimed at creating a path towards sustainable repurposing of wind turbine blades after they are removed from service. The present work includes modelling and analysis of expected load cases as prescribed in ASCE 74 and NESC using simplified boundary conditions for tangent pole applications. Load cases involving extreme wind, concurrent ice and wind, extreme ice, differential ice, broken conductor, and broken shield have been analyzed and governing load cases for bending, shear, and torsion have been examined. Relative stiffnesses of different parts forming the wind blade’s cross section (i.e., shell, web, and spar cap) are determined. The corresponding stresses associated with each part under the governing loads are compared to allowable strength values which are determined from composite laminate theory and modelling of the known laminate structure of the E-Glass FRP material. Stresses and deflections obtained are compared with governing reliability-based design criteria and code requirements. The results of the structural analysis indicate that the wind blade can resist the expected loads with reasonable safety factors and that the expected deflections are within permissible limits. Recommendations are provided for detailing and modification of the wind blade for a power pole application in which crossarm and davit connections are highlighted, and foundation details are emphasized.

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10

Krishnasamy, S. Samy G., and M. Tabatabai. "Wind loads on bare and ice-covered overhead conductors." Journal of Wind Engineering and Industrial Aerodynamics 36 (January 1990): 171–80. http://dx.doi.org/10.1016/0167-6105(90)90302-s.

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11

Savadjiev, Konstantin, and Masoud Farzaneh. "Probabilistic model of combined wind and ice loads on overhead power line conductors." Canadian Journal of Civil Engineering 30, no. 4 (August 1, 2003): 704–10. http://dx.doi.org/10.1139/l03-026.

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There is evidence that extreme ice loads combined with moderately high winds may cause catastrophic damage to overhead power lines and prolonged periods of electrical power outage. In this paper, a probabilistic model for combined wind and ice loads was developed for establishing realistic and conservative criteria for design and normalization. The proposed model combines icing of extreme thickness with a moderate wind speed, Vice, reduced by a reduction factor, kr, with respect to the extreme wind speed, Vmax. The evaluation of kr, which is the main purpose of this paper, is done by means of statistical analysis of samples taken from the same initial distribution of hourly wind speeds, Vh. The size of samples corresponds to the average annual icing persistency period, Tipp, observed in the climatic conditions of Quebec. This period, which was established in an earlier study by the authors using statistical analysis of data from the Hydro-Québec passive ice meter (PIM) network, is evaluated to be on average 144 h/year. It was found that kr ranges from 0.4 to 0.7, mainly as a function of the coefficient of variation (COV) of the initial distribution of wind speeds and the return period prescribed for extreme climatic loads.Key words: combined wind and ice loads, probabilistic model, overhead transmission lines.

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12

Wahba, Yohanna M. F., Murty K. S. Madugula, and Gerard R. Monforton. "Combined wind and ice loading on antenna towers." Canadian Journal of Civil Engineering 20, no. 6 (December 1, 1993): 1047–56. http://dx.doi.org/10.1139/l93-135.

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The present study contains an analysis of the recorded and predicted values of ice accretion for the meteorological stations in Canada; also, the value of the wind pressure associated with the maximum ice accretion is studied. The values were compared with those specified in CAN/CSA S37-M86. Changes to the ice map of Canada are proposed based on the climatic data analyzed, and this map is compared with the one specified in the 1991 edition of the Ontario Highway Bridge Design Code. Also, some modifications to the method of calculating radial ice thickness are recommended to include the size of the member. Key words: antenna towers, environmental loads, guyed towers, ice loads, self-supporting towers.

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13

Chen, Jun Qi, and Wei Wang. "Analytical Study on Wind-Induced Vibration of Ice Coating Transmission Line Systems." Advanced Materials Research 383-390 (November 2011): 3657–62. http://dx.doi.org/10.4028/www.scientific.net/amr.383-390.3657.

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Transmission line systems are vulnerable to winds and storms, particularly in cold climate regions where atmospheric ice accretes on network equipment. This paper describes a method for analyzing wind-induced vibrations of ice coating transmission towers coupled with power lines. An ice coating model of transmission line systems is introduced. Wind loads on ice coating transmission line systems are also presented. The time histories of wind speed acting on transmission line systems are simulated with the harmony superposition method. Finally, the responses of ice coating transmission line systems under different thickness of ice and different wind velocity are discussed. The results show that the displacement and unbalanced tension increase rapidly with the thickness of ice and wind velocity increasing. The value of the unbalanced tension increases significantly when the ice coating on conductors is nonuniform.

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14

Kolerski, Tomasz, Parisa Radan, and Dariusz Gąsiorowski. "Ice Load Characteristics on Floating Photovoltaic Platform." Energies 14, no. 9 (April 26, 2021): 2466. http://dx.doi.org/10.3390/en14092466.

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Nowadays, based upon human needs and preferring perpetual types of energy, photovoltaic system (PV) is a suitable alternative and more frequently used in northern countries, which are recently more attracted by solar power. The new floating type of the structure is installed in the water bodies instead of land. One of the main elements in floating photovoltaic structures is the forces imposed on the panels. In the northern regions, the dominant load is considered to be ice interaction with the structure. This study aims at identifying the loads imposed on a floating PV structure located in the Łapino Reservoir on the Radunia River, which are produced by the wind action on the ice cover. The wind velocity varying between 10 and 26 m/s is implemented, and also the reduction of the pool level was studied. Wind direction plays an important role in the inclination and expansion of ice accumulation. Moreover, the magnitude of wind velocity is a determinative factor in the maximum thickness emerged in various spot of the area. Changes in pool level reduction is not able to cause noticeable changes in ice cover expansion and maximum ice thickness. Additionally, the shoving mechanism is able to originate abrupt changes in ice thickness by means of rising wind velocity.

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15

Xu, Wen Jun, Hong Ming Yang, Ming Yong Lai, and Shuang Wang. "The Probabilistic Method of Failure Analysis to Transmission Facilities under Ice Storms." Applied Mechanics and Materials 37-38 (November 2010): 1525–28. http://dx.doi.org/10.4028/www.scientific.net/amm.37-38.1525.

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Based on Extreme Value Theory (EVT), the Generalized Pareto Distributions (GPDs) of meteorological variables wind speed and freezing precipitation is simulated. Considering the dependence of them, a joint probability distribution is calculated by the Copula function. Further more, the probability distributions of ice loads and wind loads on transmission lines are analyzed, and the failure probability of broken lines and collapsed towers under ice storms is calculated. The accuracy and validity of this analytical method is demonstrated with comparison between numerical results and the historical datas of Chen Zhou power transmission systems.

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16

Ibrahim, Galal M., Kevin Pope, and Yuri S. Muzychka. "Transient atmospheric ice accretion on wind turbine blades." Wind Engineering 42, no. 6 (June 15, 2018): 596–606. http://dx.doi.org/10.1177/0309524x18780380.

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This article aims to predict ice loads on a wind turbine blade section at 80% of blade span, using FENSAP ICE. Using low and high liquid water content conditions of stratiform and cumuliform clouds, different icing events are simulated. Ice accretion predictions with single-shot and multi-shot approaches are presented. Blade surface roughness is also investigated, as well as the relationships between ice mass, liquid water content, median volume diameter, and temperature.

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17

Musatay, Zh M., and I. M. Polyakova. "DETERMINATION OF LOADS FOR CALCULATION OF STRENGTH CHARACTERISTICS OF STRUCTURAL ELEMENTS OF FACADES." Bulletin of Kazakh Leading Academy of Architecture and Construction 81, no. 3 (September 30, 2021): 125–37. http://dx.doi.org/10.51488/1680-080x/2021.3-16.

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This article discusses the possible loads that will affect the elements of the facade coatings of buildings. Various types of facade slabs, claddings, ice, wind loads, loads from various types of guides for fastening the slabs are considered. The standard and design loads were determined, taking into account the Eurocodes, the loads for the calculations were selected.

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18

Liu, Chun Cheng, and Jiao Liu. "Ice Accretion of Glaze Loads Model on Wires of Power Transmission Lines." Advanced Materials Research 189-193 (February 2011): 3225–29. http://dx.doi.org/10.4028/www.scientific.net/amr.189-193.3225.

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In connection with the process of glaze ice, prediction models about height and thickness of ice coating under uniform and non-uniform ice accretion of wire are presented by taking into account local collision efficiency, freeze coefficient and collection coefficient based on the existing model at home and abroad. The time-dependent ice models on the conditions of different median volume diameter of super-cooled droplets, wind speed and wire diameter are analyzed. Compared with the existing model, the proposed ice accretion model performed well in predicting ice’s weight and thickness. At the same time, it can give some lights on ice disaster and anti-icing design for power transmission lines.

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19

Huang, Shuai, Yuejun Lyu, Liwei Xiu, and Haijun Sha. "Seismic performance analysis of a wind turbine tower subjected to earthquake and ice actions." PLOS ONE 16, no. 3 (March 31, 2021): e0247557. http://dx.doi.org/10.1371/journal.pone.0247557.

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Sea ice is one of the main loads acting on a wind turbine tower in areas prone to icing, and this threatens safe working life of the wind turbine tower. In our study, a simplified calculated model of ice, wind turbine tower, and water dynamic interaction under earthquake action was proposed, which could avoid to solve a large number of nonlinear equations. Then, the seismic behaviour of the wind turbine tower with and without the influence of sea ice was investigated, and we found that the influence of the greater mass of the sea ice on the seismic response of a wind turbine tower should be considered when the wind turbine tower is designed in an area with thick ice. With the influence of the most unfavourable ice mass, the deformation and energy dissipation capacity of the wind turbine tower are decreased, and the wall thickness or stiffening rib thickness should be increased to improve the seismic performance and ductility of the wind turbine tower; the shear force and bending moment increased significantly on the wind turbine tower, and the shear force changes at the bottom of the wind turbine tower and position of action of the sea ice: attention should be paid to the wind turbine tower design at these positions. Finally, we conducted the shaking table test, and verified the rationality of our proposed simplified model.

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20

Gantasala, Sudhakar, Narges Tabatabaei, Michel Cervantes, and Jan-Olov Aidanpää. "Numerical Investigation of the Aeroelastic Behavior of a Wind Turbine with Iced Blades." Energies 12, no. 12 (June 24, 2019): 2422. http://dx.doi.org/10.3390/en12122422.

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Wind turbines installed in cold-climate regions are prone to the risks of ice accumulation which affects their aeroelastic behavior. The studies carried out on this topic so far considered icing in a few sections of the blade, mostly located in the outer part of the blade, and their influence on the loads and power production of the turbine are only analyzed. The knowledge about the influence of icing in different locations of the blade and asymmetrical icing of the blades on loads, power, and vibration behavior of the turbine is still not matured. To improve this knowledge, multiple simulation cases are needed to run with different ice accumulations on the blade considering structural and aerodynamic property changes due to ice. Such simulations can be easily run by automating the ice shape creation on aerofoil sections and two-dimensional (2-D) Computational Fluid Dynamics (CFD) analysis of those sections. The current work proposes such methodology and it is illustrated on the National Renewable Energy Laboratory (NREL) 5 MW baseline wind turbine model. The influence of symmetrical icing in different locations of the blade and asymmetrical icing of the blade assembly is analyzed on the turbine’s dynamic behavior using the aeroelastic computer-aided engineering tool FAST. The outer third of the blade produces about 50% of the turbine’s total power and severe icing in this part of the blade reduces power output and aeroelastic damping of the blade’s flapwise vibration modes. The increase in blade mass due to ice reduces its natural frequencies which can be extracted from the vibration responses of the turbine operating under turbulent wind conditions. Symmetrical icing of the blades reduces loads acting on the turbine components, whereas asymmetrical icing of the blades induces loads and vibrations in the tower, hub, and nacelle assembly at a frequency synchronous to rotational speed of the turbine.

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21

Getz, David, and Jose Palacios. "Design procedures and experimental verification of an electro-thermal deicing system for wind turbines." Wind Energy Science 6, no. 5 (October 6, 2021): 1291–309. http://dx.doi.org/10.5194/wes-6-1291-2021.

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Abstract. There has been a substantial growth in the wind energy power capacity worldwide, and icing difficulties have been encountered in cold climate locations. Rotor blade icing has been recognized as an issue, and solutions to mitigate accretion effects have been identified. Wind turbines are adapting helicopter rotor and propeller ice protection approaches to reduce aerodynamic performance degradation related to ice formation. Electro-thermal heating is one of the main technologies used to protect rotors from ice accretion, and it is one of the main technologies being considered to protect wind turbines. In this research, the design process required to develop an ice protection system for wind turbines is discussed. The design approach relies on modeling and experimental testing. Electro-thermal heater system testing was conducted at the Adverse Environment Rotor Test Stand at Penn State, where wind turbine representative airfoils protected with electro-thermal deicing were tested at representative centrifugal loads and flow speeds. The wind turbine sections tested were half-scale models of the 80 % span region of a generic 1.5 MW wind turbine blade. The icing cloud impact velocity was matched to that of a 1.5 MW wind turbine at full power production. Ice accretion modeling was performed to provide an initial estimate of the power density required to de-bond accreted ice at a set of icing conditions. Varying icing conditions were considered at −8 ∘C with liquid water contents of the cloud varying from 0.2 to 0.9 g/m3 and water droplets from 20 µm median volumetric diameter to 35 µm. Then, ice accretion thickness gradients along the span of the rotor blade for the icing conditions were collected experimentally. Given a pre-determined maximum power allocated for the deicing system, heating the entire blade was not possible. Heating zones were introduced along the span and the chord of the blade to provide the required power density needed to remove the accreted ice. The heating sequence for the zones started at the tip of the blade, to allow de-bonded ice to shed off along the span of the rotor blade. The continuity of the accreted ice along the blade span means that when using a portioned heating zone, ice could de-bond over that specific zone, but the ice formation could remain attached cohesively as it is connected to the ice on the adjacent inboard zone. To prevent such cohesive retention of de-bonded ice sections, the research determined the minimum ice thickness required to shed the accreted ice mass with the given amount of power availability. The experimentally determined minimum ice thickness for the varying types of ice accreted creates sufficient tensile forces due to centrifugal loads to break the cohesive ice forces between two adjacent heating zones. The experimental data were critical in the design of a time sequence controller that allows consecutive deicing of heating zones along the span of the wind turbine blade. Based on the experimental and modeling efforts, deicing a representative 1.5 MW wind turbine with a 100 kW power allocation required four sections along the blade span, with each heater section covering 17.8 % span and delivering a 2.48 W/in.2 (0.385 W/cm2) power density.

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22

Ji, Shunying, and Dongbao Yang. "Ice loads and ice-induced vibrations of offshore wind turbine based on coupled DEM-FEM simulations." Ocean Engineering 243 (January 2022): 110197. http://dx.doi.org/10.1016/j.oceaneng.2021.110197.

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23

Bęc, Jarosław. "Aerodynamics of guyed masts." Budownictwo i Architektura 1, no. 1 (December 11, 2007): 103–18. http://dx.doi.org/10.35784/bud-arch.2304.

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Guyed masts response to wind action, ice load and thermal action has been analysed in this paper. Computational model of wind action based on quasi-steady theory has been applied. It has been assumed that nodal displacements may be expressed as a linear combination of representative mode shapes. Special computer program has been made to allow analysis of such structures. It has been found that the selection of representative mode shapes is very influential on the calculations outcome. The obtained results have been compared with the ones calculated according to patch loads method presented in Eurocode 3. The dynamic part of forces calculated with own method are about half of the ones coming from the standard.

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24

Hann, Richard, Adriana Enache, Mikkel Cornelius Nielsen, Bård Nagy Stovner, Jeroen van Beeck, Tor Arne Johansen, and Kasper Trolle Borup. "Experimental Heat Loads for Electrothermal Anti-Icing and De-Icing on UAVs." Aerospace 8, no. 3 (March 18, 2021): 83. http://dx.doi.org/10.3390/aerospace8030083.

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Atmospheric in-flight icing on unmanned aerial vehicles (UAVs) is a significant hazard. UAVs that are not equipped with ice protection systems are usually limited to operations within visual line of sight or to weather conditions without icing risk. As many military and commercial UAV missions require flights beyond visual line of sight and into adverse weather conditions, energy-efficient ice protection systems are required. In this experimental study, two electro-thermal ice protection systems for fixed-wing UAVs were tested. One system was operated in anti-icing and de-icing mode, and the other system was designed as a parting strip de-icing system. Experiments were conducted in an icing wind tunnel facility for varying icing conditions at low Reynolds numbers. A parametric study over the ice shedding time was used to identify the most energy-efficient operation mode. The results showed that longer intercycle durations led to higher efficiencies and that de-icing with a parting strip was superior compared to anti-icing and de-icing without a parting strip. These findings are relevant for the development of energy-efficient systems in the future.

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25

Jeong, Dae Il, Alex J. Cannon, and Xuebin Zhang. "Projected changes to extreme freezing precipitation and design ice loads over North America based on a large ensemble of Canadian regional climate model simulations." Natural Hazards and Earth System Sciences 19, no. 4 (April 17, 2019): 857–72. http://dx.doi.org/10.5194/nhess-19-857-2019.

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Abstract. Atmospheric ice accretion caused by freezing precipitation (FP) can lead to severe damage and the failure of buildings and infrastructure. This study investigates projected changes to extreme ice loads – those used to design infrastructure over North America (NA) – for future periods of specified global mean temperature change (GMTC), relative to the recent 1986–2016 period, using a large 50-member initial-condition ensemble of the CanRCM4 regional climate model, driven by CanESM2 under the RCP8.5 scenario. The analysis is based on 3-hourly ice accretions on horizontal, vertical and radial surfaces calculated based on FP diagnosed by the offline Bourgouin algorithm and wind speed during FP. The CanRCM4 ensemble projects an increase in future design ice loads for most of northern NA and decreases for most of southern NA and some northeastern coastal regions. These changes are mainly caused by regional increases in future upper-level and surface temperatures associated with global warming. Projected changes in design ice thickness are also affected by changes in future precipitation intensity and surface wind speed. Changes in upper-level and surface temperature conditions for FP occurrence in CanRCM4 are in broad agreement with those from nine global climate models but display regional differences under the same level of global warming, indicating that a larger multi-model, multi-scenario ensemble may be needed to better account for additional sources of structural and scenario uncertainty. Increases in ice accretion for latitudes higher than 40∘ N are substantial and would have clear implications for future building and infrastructure design.

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Akhmedova, Olga, and Anatoly Soshinov. "Analysis of Ice Melting System." Applied Mechanics and Materials 698 (December 2014): 710–15. http://dx.doi.org/10.4028/www.scientific.net/amm.698.710.

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The problem of preventing icing accidents in electric networks of power systems is relevant in many regions of Russia. Disruptions of overhead lines, caused by intensive icing and icing and wind loads are most severe in their effects. However, the devastating effect of icing is not fatal. This is confirmed by the experience of power systems, systematically carrying on a struggle against ice. Prevention of icing accidents is based on the use of an integrated system of activities in a systematic manner.

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Wang, Hong Wei, Gan Zhou, and Mei Juan Zhou. "The Strength Analysis of Pre-Tightening Force on Covering Pipe-Ear." Applied Mechanics and Materials 741 (March 2015): 171–74. http://dx.doi.org/10.4028/www.scientific.net/amm.741.171.

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The covering pipe-ear is one of the important components of the overhead contact line system (OCS) for supporting loads. The finite element model of covering pipe-ear was established, as the pre-tightening force, wind load and ice load all have effect on it, the stress distribution law were simulated under 12 kinds of loading conditions. The results show that the pre-tightening force has remarkable influence on covering pipe-ear and 2500N pre-tightening force is appropriate for the aluminum alloy covering pipe-ear. It is useful for the catenary components static strength reliability design.

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28

Vacev, Todor, Stanko Brčić, Andrija Zorić, Miloš Milić, Ivan Nešović, and Slobodan Ranković. "Static and dynamic approach to the analysis of wind gusts in case of a tower H=110 m." Gradjevinski materijali i konstrukcije 64, no. 3 (2021): 201–5. http://dx.doi.org/10.5937/grmk2103201v.

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Steel lattice towers have large application in meteorology, and are regularly exposed to loads difficult to determine reliably, like wind and ice, and especially wind gusts and accompanied structural vibrations. EN 1993-3-1 treats such structures and requires checking of vibrations, but does not supply methodology for it, neither allowed values for deformation and vibrations. The paper presents analysis of a tower 110 m high using the Finite Element Method (FEM), in case of wind gust, for iced and non-iced structure, both statically and dynamically. The results were compared and recommendations for future treatment of such sensitive structures were given.

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Alhrshy, Laurence. "Implementation of Variable Blade Inertia in OpenFAST to Integrate a Flywheel System in the Rotor of a Wind Turbine." Energies 14, no. 10 (May 12, 2021): 2783. http://dx.doi.org/10.3390/en14102783.

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In this paper, the integration of the dynamic behavior of the flywheel system into the load simulation tool OpenFAST is presented. The flywheel system enables a wind turbine to vary the inertia of its rotor blades to control the power production and, most importantly, to affect the vibratory behavior of wind turbine components. Consequently, in order to simulate the behavior of a wind turbine with a flywheel system in its rotor, the variable blade characteristics need to be considered in the load simulation tool. Currently, computer-aided engineering tools for simulating the mechanical loads of wind turbines are not designed to simulate variable blade inertia. Hence, the goal of this paper is to explain how variable inertias of rotor blades are implanted in such load simulation tools as OpenFAST. OpenFAST is used because of it is free, publicly available, and well documentation. Moreover, OpenFAST is open source, which allows modifications in its source code. This add-on in the load simulation is applied to correct rotor mass imbalance. It can also be applied in many cases related to the change in the inertia of wind turbine rotor blades during its operation as, for example, atmospheric ice accretion on the blades, smart blades, etc.

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30

Panteleev, V. I., and А. V. Maleev. "System monitoring intensity of glaze-clear ice generation on wires of overhead transmission lines." Omsk Scientific Bulletin, no. 174 (2020): 74–80. http://dx.doi.org/10.25206/1813-8225-2020-174-74-80.

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Improving the reliability and efficiency of power supplying by reducing accidents in electrical networks caused by intense ice and wind loads is an important comprehensive task. The solution of this problem consists of several mainly stages: timely detection of the onset of ice formation, impact on the device for removing ice and frost deposits and efficiency of removing of ice monitoring. This article discusses a system for detecting ice formation based on a fundamentally new technique using the technology of «machine vision». The developed system of ice formation makes identify the thickness of ice wall and indirectly, by the angle of deviation of the wire relative to the horizontal position, to determine the mass of ice deposits and wire sag. Considered monitoring system is located on support in close proximity from the wire and consists of the following mainly elements: an electronic unit, an optical sensor, a solar panel and GSM antenna

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Cucuzza, Raffaele, Marco Martino Rosso, Angelo Aloisio, Jonathan Melchiorre, Mario Lo Giudice, and Giuseppe Carlo Marano. "Size and Shape Optimization of a Guyed Mast Structure under Wind, Ice and Seismic Loading." Applied Sciences 12, no. 10 (May 11, 2022): 4875. http://dx.doi.org/10.3390/app12104875.

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This paper discusses the size and shape optimization of a guyed radio mast for radiocommunications. The considered structure represents a widely industrial solution due to the recent spread of 5G and 6G mobile networks. The guyed radio mast was modeled with the finite element software SAP2000 and optimized through a genetic optimization algorithm (GA). The optimization exploits the open application programming interfaces (OAPI) SAP2000-Matlab. Static and dynamic analyses were carried out to provide realistic design scenarios of the mast structure. The authors considered the action of wind, ice, and seismic loads as variable loads. A parametric study on the most critical design variables includes several optimization scenarios to minimize the structure’s total self-weight by varying the most relevant parameters selected by a preliminary sensitivity analysis. In conclusion, final design considerations are discussed by highlighting the best optimization scenario in terms of the objective function and the number of parameters involved in the analysis.

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Gregow, E., B. Bernstein, I. Wittmeyer, and J. Hirvonen. "LAPS–LOWICE: A Real-Time System for the Assessment of Low-Level Icing Conditions and Their Effect on Wind Power." Journal of Atmospheric and Oceanic Technology 32, no. 8 (August 2015): 1447–63. http://dx.doi.org/10.1175/jtech-d-14-00151.1.

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AbstractThe wind power industry is highly sensitive to weather, and there is a clear impact on turbine efficiency associated with icing, which can cause significant power losses and even result in the total shutdown of wind farms. Therefore, accurate analyses and forecasts of wind- and icing-related meteorological variables are of great importance. To this end, the Local Analysis and Prediction System (LAPS)–LOWICE system has been developed to produce real-time, hourly estimates of the presence, intensity, and impacts of icing on wind power production. As part of this development, it became clear that power losses did not correlate well with measured icing loads but correlated reasonably well with the time history of icing rate in combination with ice loss due to melting, sublimation, and shedding.

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33

Tsavdaridis, Konstantinos Daniel, Andreas Nicolaou, Anand Dipak Mistry, and Evangelos Efthymiou. "Topology optimisation of lattice telecommunication tower and performance-based design considering wind and ice loads." Structures 27 (October 2020): 2379–99. http://dx.doi.org/10.1016/j.istruc.2020.08.010.

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34

Dar’enkov, Andrey, Elena Sosnina, Andrey Shalukho, and Ivan Lipuzhin. "Economy Mode Setting Device for Wind-Diesel Power Plants." Energies 13, no. 5 (March 10, 2020): 1274. http://dx.doi.org/10.3390/en13051274.

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The article is devoted to the problem of reducing fuel consumption in a diesel generator set (DGS) as a part of a wind-diesel power plant (WDPP). The object of the research is a variable speed DGS. The goal is to develop the WDPP intelligent control system, providing an optimal shaft speed of an internal combustion engine (ICE). The basis of the intelligent control system is an economy mode setting device (EMSD), which controls the fuel supply to the ICE. The functional chart of EMSD has been presented. The main EMSD blocks contain a controller and an associative memory block. The associative memory block is a software model of an artificial neural network that determines the optimal shaft speed of the ICE. An algorithm for the WDPP intelligent control system has been developed and tested using the WDPP Simulink model. The EMSD prototype has been created, and its research has been conducted. Dependences of the change in specific and absolute fuel consumption on the load power have been obtained for two 4 kW DGS: with constant rotation speed and variable rotation speed DGS with EMSD. It has been established that the use of EMSD in the mode of low loads allow one to reduce fuel consumption by almost 30%. The error in determining the optimal engine speed using EMSD prototype is not more than 15%.

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35

Tian, Li, and Yujie Zeng. "Parametric Study of Tuned Mass Dampers for Long Span Transmission Tower-Line System under Wind Loads." Shock and Vibration 2016 (2016): 1–11. http://dx.doi.org/10.1155/2016/4965056.

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A parametric study of tuned mass dampers for a long span transmission tower-line system under wind loads is done in this paper. A three-dimensional finite element model of transmission tower-line system is established by SAP2000 software to numerically verify the effectiveness of the tuned mass damper device. The wind load time history is simulated based on Kaimal spectrum by the harmony superposition method. The equations of motion of a system with tuned mass damper under wind load excitation are proposed, and the schematic of tuned mass damper is introduced. The effects of mass ratio, frequency ratio, damping ratio, the change of the sag of transmission line, and the robustness of TMD are investigated, respectively. Results show that(1)the change of mass ratio has a greater effect on the vibration reduction ratio than those of frequency ratio and damping ratio, and the best vibration reduction ratio of TMD is not the frequency ratio of 1;(2)the sag-span ratio has an insignificant effect on the vibration reduction ratio of transmission tower when the change of sag-span ratio is not large; and(3)the effect of ice should be considered when the robustness study of TMD is carried out.

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36

Bladyko, Yu V. "Mechanical Calculation of Flexible Wires of Spans with Different Tensioning Insulator Strings." ENERGETIKA. Proceedings of CIS higher education institutions and power engineering associations 63, no. 1 (February 7, 2020): 55–65. http://dx.doi.org/10.21122/1029-7448-2020-63-1-55-65.

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In design activities, technical solutions are practiced, which provide for the use of different tension strings of insulators in a single span. The present paper considers the calculation of the sag and load factors for a span with two different tensioning insulator strings that are of identical suspension heights. The system of “the first tension insulators string – the wire – the second tension insulators string” was described by the equations of a parabola. A relationship has been established between the sag increase factor and the coefficients that take into account the presence of tensioning insulators strings. The resulting compact formula for sag increase is generally suitable for any combination of strings in a span. The coincidence of the calculation is shown for particular cases known from the literature. The formula for calculating the load factor for the equation of state was derived, taking into account the presence of different strings in the span. The reliability of the formula has been proved by the coincidence of results for particular cases of the arrangement of strings. The obtained expressions can be used both for vertical (weight and ice) loads and for horizontal (wind) ones. In the case of loads in two planes, the equation of state must take into account all the components when calculating the resulting reduced load on the wire along the inclined plane. Calculations were performed for different lengths of spans of switchgear with different wires and strings of insulators. A span with one and two tensioning strings of insulators, with the same suspension heights, in the absence of wind and ice is considered. The curves of the sagging wires to different strings have been plotted. It is demonstrated that when calculating sags and tensions, the difference between strings must not be neglected.

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37

Lundquist, J. E. "The Relative Influence of Diseases and Other Small-Scale Disturbances on Fuel Loading in the Black Hills." Plant Disease 91, no. 2 (February 2007): 147–52. http://dx.doi.org/10.1094/pdis-91-2-0147.

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Disturbances that kill trees in forests often co-occur in time and/or space. This process results in changes in the fuel loading for wildfire. Determining specific causes of changing fuel loads can be complex. Path analysis was used to estimate the relative importance and the strength of interaction of each of nine small-scale disturbances affecting forest stands in the Black Hills. Different disturbances were partitioned according to their indirect and direct effects on fuel loads. Fire and wind had the greatest indirect effects; stem rots had the smallest. Root rots had the largest direct effects. Root rots, strong wind, stem rots, suppression, human disturbances, and tree cutting all caused fuel loads to increase. Treeless meadows, stem cankers, fire, ice/snow damage, failed regeneration, and shallow soil were associated with decreasing fuel loads. Grazing, lightning, bark beetles, and competition had null impacts. Disease control has two aims: reducing fire hazard and enhancing restoration. Understanding the biology and ecology of the agents that create dead wood is as fundamental to restoration ecology as it is to forest pathology. Management and control both begin by first determining the cause.

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38

Lagdani, O., M. Tarfaoui, M. Nachtane, M. Trihi, and H. Laaouidi. "Numerical Simulation of the Impact ofIce Accumulation on a Composite Wind Turbine Blades located in a Cold Climate." E3S Web of Conferences 229 (2021): 01052. http://dx.doi.org/10.1051/e3sconf/202122901052.

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The blades of wind turbines placed in cold climate regions are exposed to the risk of icing phenomena which impact their lifetimes. This paper proposes a numerical model to simulate 50 mm ice thickness localized on the tip side of a horizontal wind turbine blade, and to study its mechanical behavior. The wind turbine blade wasmodeled with the finite element method (FEM)in ABAQUS software taking into account aerodynamic, centrifugal and inertial loads under the conditions of service of the blade.Numerical tests haveevaluated the behavior of different composite materials and compared with each other. Damage mode based on the Hashin criteria was defined. Carbon fibers were considered to be the most rigid material which results in thinner, stiffer and lighter blades.

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39

Goryachev, M. P., M. F. Sadykov, and D. A. Yaroslavskiy. "Method for control the mechanical parameters of overhead power lines based on improved inclinometry." Power engineering: research, equipment, technology 21, no. 3 (November 29, 2019): 160–71. http://dx.doi.org/10.30724/1998-9903-2019-21-3-160-171.

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Structural elements of overhead power transmission lines are experiencing both horizontal and vertical loads. Wires and cables are elements of the overhead power line, on which changes in mechanical loads are observed to a greater degree. This occurs due to the change in the tension force of the wire/cable depending on the temperature and the formation of icy-rime deposits on it, as well as fluctuations in wind gusts. The article describes the most common systems and methods for determining the mechanical loads on an overhead power transmission line. A method is proposed for calculating the mechanical loads on an overhead transmission line based on mathematical models of a flexible wire, rope and a model for determining ice deposits on wires, taking into account the rotation of the wire/cable around its axis. A comparison of the improved inclinometry method with the method developed earlier for the case of formation of ice deposits on the S-50 cable has been carried out. A comparison was made on the error in determining the tension of the S-50 ground-wire protection cable using the method developed to control the mechanical parameters of overhead power lines, which takes into account the wire/cable rotation around its axis and the method for determining icy-rime deposits developed earlier. The developed method allows determining the elongation of the wire/cable in the span with one anchor support, as well as the strength of its tension with greater accuracy. However, additional clarification is required due to the influence of the wind, the formation of icy-rime deposits of various shapes, as well as the structural limitations of the wire/cable rotation when attaching it to the support.

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40

Szilder, Krzysztof, Edward P. Lozowski, and Gerhard Reuter. "A Study of Ice Accretion Shape on Cables Under Freezing Rain Conditions." Journal of Offshore Mechanics and Arctic Engineering 124, no. 3 (August 1, 2002): 162–68. http://dx.doi.org/10.1115/1.1488932.

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The influence of atmospheric conditions (specifically precipitation rate and external heat flux) on the freezing rain ice accretion forming on a non-rotating, horizontal cylinder is studied, using an analytical model based on a simple form of the equations for conservation of mass and heat balance. In keeping with the freezing rain application, but in order to simplify this first step, we have assumed vertical incidence of precipitation (no wind) and no dripping from the accretion (hence light to moderate precipitation rates with relatively low air temperatures). The initial ice accretion shape and the location of its center of mass are examined as a function of the ratio of the precipitation mass flux to the total heat flux lost from the ice surface. An increase in the flux ratio leads to a quantifiable downward displacement of the accretion center of mass. We complement this analysis with numerical simulations, using an improved, two-dimensional version of the Szilder-Lozowski morphogenetic model that predicts the evolution of the accretion shape. For the first time, the freezing probability, which is the critical model parameter, is expressed as a function of location and atmospheric conditions for an accretion shape evolving with time. Using the morphogenetic model, we examine the influence of atmospheric conditions on the accretion shape and ice load. In particular, we address the question of what gives rise to extreme ice loads by identifying the range of atmospheric conditions that tends to maximize (or minimize) the ice load for a given amount of precipitation. The results of this research are applicable to predicting ice formation on overhead transmission lines.

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41

Shen, Zhao Wei, Wei Liang Jin, and Xiao Hong Wang. "Reliability of the Offshore Jacket Platform Based on Load Combination." Applied Mechanics and Materials 405-408 (September 2013): 1415–19. http://dx.doi.org/10.4028/www.scientific.net/amm.405-408.1415.

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Offshore jacket platforms under complicated and changeful ocean environments are subjected to various stochastic actions such as actions of wave, current, wind, ice, earthquake and their combinations. This paper presented the approach to calibrate of the reliability of the offshore jacket platform, and suggested all kinds of associated load cases. The combination of loads were mainly investigated. As an example, the reliability of offshore jacket platform of QK18-1 in Bohai Bay was verified. The result shows that the reliability of the offshore jacket platform related to 25-year reference period is between 2.7 and 3.39, which is close to the conclusion of some existing researches. This method would be used more widely for the design of offshore jacket platforms.

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42

Song, Ziqiu, Jizhen Liu, Yang Hu, Yi Cheng, and Fanghui Tan. "Real-Time Performance Analyses and Optimal Gain-Scheduling Control of Offshore Wind Turbine Under Ice Creep Loads." IEEE Access 7 (2019): 181706–20. http://dx.doi.org/10.1109/access.2019.2959648.

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43

刘, 泽青. "Failure Probability Assessment Method for Overhead Transmission Lines under Ice and Wind Loads considering Blowing Sand Wear." Smart Grid 09, no. 03 (2019): 101–11. http://dx.doi.org/10.12677/sg.2019.93011.

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44

Valenzuela, Alex, Carlos Barrera, and Esteban Inga. "Electrical assessment of georeferenced distribution network due to electric vehicles deployment." I+D Tecnológico 16, no. 1 (January 28, 2020): 61–68. http://dx.doi.org/10.33412/idt.v16.1.2441.

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Several cities worldwide are focused to reduce the environmental degradation based on the deployment and integration of renewable energies and electric vehicles (EV) into the distribution network. The first one replaces electricity produced by fossil fuels with solar, wind or hydro power plants, whilst the second one is a feasible alternative to substitute internal combustion engine (ICE) vehicles with eco-friendly vehicles. Set in this context, this paper proposes an examination about the main effects in a georeferenced distribution system when non-linear loads are connected to the grid. The distribution network model contemplates georeferenced data from customers, where unbalanced currents due to the customer’s consumption in each distribution transformer is evaluated using a variety of coefficient for commercial and residential load models. Voltage unbalance, harmonics and load flow analysis is performed in PowerFactory to determine the impacts of EVs to the grid.

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45

Bobryashov, Viktor V., Viktor M. Bobryashov, Anastasiya Bobryashova, and Nikolay Bushuev. "Faultlessness of composite enclosing structures with thin-sheet linings and effective thermal insulation." E3S Web of Conferences 97 (2019): 04068. http://dx.doi.org/10.1051/e3sconf/20199704068.

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Fencing composite structures with thin-sheet metal cladding and effective thermal insulation are widely used. They are especially effective in hard to reach, remote, seismic areas, in areas with harsh climates. There is a problem of estimating the real random loading of snow, wind, ice, temperature loads and others according to Roshydromet, when the strength, heat engineering, dielectric, and other structural parameters are random and changes in which from the allowable area lead to failures.The paper provides an assessment of the reliability of enclosing structures of buildings based on quantitative signs of impacts (wind, snow and permanent), as well as the results of statistical evaluation of factory acceptance tests. This paper discusses to exhaust the resource - the strength of the middle layer of the structure during shear.

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46

Bladyko, Yu V. "Accounting for Spacers in the Mechanical Calculation of Flexible Wires for Overhead Lines and Switchgears." ENERGETIKA. Proceedings of CIS higher education institutions and power engineering associations 62, no. 3 (June 3, 2019): 219–31. http://dx.doi.org/10.21122/1029-7448-2019-62-3-219-231.

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The mechanical calculation of flexible wires of overhead lines and switchgears, in which in-phase or phase-to-phase spacers are installed, is under consideration. Spacers are considered as concentrated loads acting on the split phase. The formulas for determining the sag are given for a different number of spacers as a function of their number and the coefficient of concentrated forces. This takes into account the difference in suspension heights, tension insulators strings, wind and ice loads. These formulas, being presented in a form that is convenient for consumers, can be used for computer execution of the mechanical calculation of flexible wires in different climatic regimes, both in the presence and in the absence of phase splitting. The errors of replacing the spacers with a distributed load are demonstrated. Formulas are proposed that give the smallest error when replacing spacers with a distributed load. The greater the value of the concentrated forces from the tap-off lines and loops, the greater the error in calculating the sag of the switchgears wires. Therefore, it is not possible to replace them with a distributed load obtained by simply dividing the total load by the length of the span in the presence of the tap-off lines and loops.

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47

Tian, Li, Liulu Guo, Ruisheng Ma, Xia Gai, and Wenming Wang. "Full-Scale Tests and Numerical Simulations of Failure Mechanism of Power Transmission Towers." International Journal of Structural Stability and Dynamics 18, no. 09 (September 2018): 1850109. http://dx.doi.org/10.1142/s0219455418501092.

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Full-scale tests are conducted to investigate the load-bearing capacity and failure mechanism of power transmission towers subjected to various loading patterns (broken lines, wind and ice). Detailed finite element models of power transmission towers are established based on these experimental prototypes. To capture the member instability, the integral stability coefficients are obtained from different specifications and introduced into a user-defined material model. Subsequently, the failure analysis of power transmission towers is carried out using an explicit algorithm, and good agreement is found in comparison with experimental results. The results show that the proposed procedure is effective in simulating the power transmission tower failure process. The full-scale test and numerical simulation studies can provide a valuable database for the design of power transmission towers subjected to various loads.

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48

Ahmad, Samir, and Izhar-ul-Haq. "Wind Blade Material Optimization." Applied Mechanics and Materials 66-68 (July 2011): 1199–206. http://dx.doi.org/10.4028/www.scientific.net/amm.66-68.1199.

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In recent years the wind turbine blade has been the subject of comprehensive study and research amongst all other components of the wind turbine. As our appetite for renewable energy from the wind turbine continues to increase, companies now focus on rotor blades which can go up to 80m in length. The blade material not only have to face large aerodynamic, inertial and fatigue loads but are now being designed to endure environmental effects such as Ultraviolet degradation of surface, accumulation of dust particles at sandy locations, ice accretion on blades in cold countries, insect collision on blades and moisture ingress. All this is considered to ensure that the blades complete its designated life span. Furthermore exponential increase in composite blade manufacturing is causing a substantial amount of unrecyclable material. All these issues raise challenges for wind blade material use, its capacity to solve above mentioned problems and also maintain its structural integrity. This paper takes on this challenge by optimizing from the properties, merits, demerits and cost of different possible competing materials. Then the material is checked for its structural integrity through Finite Element Analysis simulation using standards like IEC-61400-1.This paper also shows the future direction of research by elaborating the influence nanotechnology can have in the improvement of the wind blade.

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49

Adakole Okpe, Samuel, and Joseph Ejelikwu Edeh. "Analysis, design and construction of gravity offshore structure; state-of-the-art." International Journal of Advanced Engineering, Sciences and Applications 3, no. 1 (February 1, 2022): 12–17. http://dx.doi.org/10.47346/ijaesa.v3i1.74.

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Abstract: Offshore platforms are divided into many types which are mainly categorized according to waterdepth in the installation location. However, the design differs for each type to accomplish the target of the operation. But for some case of sea waterdepths and an aggressive environment such as the North Sea, steel ones are not suitable, so the heaviest type called gravity platform having enormous mass is used. This type of platform has its special requirements and procedures for construction and needs special types of construction materials in order to resist the climate factors applied due to the aggressive environment. The paper carefully illustrates how the principal Environmental loads (wind and wave), current forces, loads from ice and loads from earth-quake for (earth-quake prone zones) are deployed to archive the design and construction of offshore concrete gravity platforms. Two design methods (Analysis and Design of Shell structures) and the Tangent Modulus Methods of design of Offshore Concrete Gravity platforms are discussed

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Chen, Bo, Wei-hua Guo, Peng-yun Li, and Wen-ping Xie. "Dynamic Responses and Vibration Control of the Transmission Tower-Line System: A State-of-the-Art Review." Scientific World Journal 2014 (2014): 1–20. http://dx.doi.org/10.1155/2014/538457.

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This paper presented an overview on the dynamic analysis and control of the transmission tower-line system in the past forty years. The challenges and future developing trends in the dynamic analysis and mitigation of the transmission tower-line system under dynamic excitations are also put forward. It also reviews the analytical models and approaches of the transmission tower, transmission lines, and transmission tower-line systems, respectively, which contain the theoretical model, finite element (FE) model and the equivalent model; shows the advances in wind responses of the transmission tower-line system, which contains the dynamic effects under common wind loading, tornado, downburst, and typhoon; and discusses the dynamic responses under earthquake and ice loads, respectively. The vibration control of the transmission tower-line system is also reviewed, which includes the magnetorheological dampers, friction dampers, tuned mass dampers, and pounding tuned mass dampers.

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