Weight Of Tower Research Articles

Nonlinear Finite Element Analysis of Tubular Steel Wind Turbine Towers near Man Door and Ventilation Openings to Optimize Design against Buckling

The safe and cost-effective design of wind turbine towers is a critical and challenging aspect of the future development of the wind energy sector. This process should consider the continuous growth of towers in height and blades in length. Among potential failure modes of tubular steel towers, shell local buckling due to static axial compressive stresses from the rotor, blades, and tower weight, as well as dynamic flexural compressive stresses from wind actions on the rotating blades and the tower itself, are dominant as thickness is optimized to reduce weight. As man door and ventilation openings are necessary for the towers’ operation, the local weakening of the tower shell in those areas leads to increased buckling danger. This is compensated for by tower manufacturers by the provision of stiffening frames around the openings. However, the cold-forming and welding of these frames are among the most time-consuming aspects of tower fabrication. Working towards the optimization of this design aspect, the buckling response of tubular steel towers near such openings is investigated by means of nonlinear finite element analysis, accounting for geometrical and material nonlinearity and imperfections (GMNIA), and also considering several wind directions with respect to the openings. The alternatives of stiffened and unstiffened openings are investigated, revealing that a thicker shell section around the opening may be sufficient to restore lost stiffness and strength, while the stiffener frame may also be eliminated, offering substantial benefits in terms of manufacturing effort, time and cost.

A Comparative Study on Lattice Tower Angle Member Capacities as Per Indian, American, and BSEN Standards

The transmission lines and Telecommunication networks are normally supported by lattice towers. Therefore, the reliability of these essentials depends much on the reliability of the towers and their foundations. In Both telecom and power transmission line sectors, the towers are mass-produced and generally based on optimized tower weight and foundation volumes. The weight of a tower is influenced to a great extent by the selection of tower configuration, choice of bracing patterns, choice of steel grade, and profile type. The towers in general are lattice types consisting of main legs, diagonals, horizontals, cross-arm members, and peak members. The telecommunication and power transmission line tower members are generally made of steel equal-angle sections. These tower members are modeled and analyzed as pin-jointed 3-dimensional space truss models and the members are subjected to axial forces, either axial compression or axial tension in nature. Estimation of member compression capacity is the most vital parameter in design as per respective local standards and proving those estimations during full-scale model tower testing if carried out. This paper presents the differences in axial compression capacity of angle members as per Indian, American, and European standards viz., IS: 802 (Part 1/Sec 2)-2016, IS 800-2007, ASCE 10-15 and BS EN 1993-3-1:2006.

Research of Turbine Tower Optimization Based on Criterion Method

Tower cost makes up an important part in the whole wind turbine construction especially for offshore wind farms. The main method to reduce tower cost is to reduce tower weight by optimum design. This paper proposes a two-level optimization criterion method for the optimal design of steel conical tower considering different structural reliability and uncertainty, along with the discreteness of design variables such as tower thickness and bolt type. In the first level, the tower shell geometry can be obtained by section design method; in the second level, bolted connections and flanges are designed based on the results of the first level. Then, summarized analysis and iterative calculation is performed to obtain optimum tower design with constant strength and rigidness. This method will play an important role in offshore customized turbine design.

Estimating the Optimum Weight for Latticed Power-Transmission Towers Using Different (AI) Techniques

The recent expansion of power-distribution networks has motivated many researchers to study how to minimize the costs of such projects. Although transmission towers present one of the main items in the network that greatly affect the project budget, there are no clear criteria or recommendations to select the optimum bracing system that minimizes the tower weight. This research presents recommendations to select the optimum configurations for latticed power-transmission towers, segment by segment, for certain loads, as well as the aspect ratio. The research started by generating a database with different segment configurations and their weights, and then three of the most famous AI techniques (GP, ANN and EPR) were used to generate models to calculate the weights of the segments. Studying these models led to the conclusion that K-shape bracing is better that X-shape bracing for segments with aspect ratios (H/B) less than 1.0. The generated models and conclusions were verified by using existing tower designs.

This paper illustrates the mechanical and physical properties of pure Cu and Cu-Ni (50-50 wt. %) alloy mixed with Al2O3 (1-4 wt. %) as micro-particles reinforcement materials. The attained composite alloy specimens' characteristics were estimated such as microstructure, relative density, electrical and thermal conductivity, hardness, and compression yield stress properties to adjust the suitable optimum percentage of reinforcing material which

The recent booming in the power network industry inspired a lot of researchers to develop models to estimate the optimum cost of transmission towers. Unlike previous researches which depended on design the tower from scratch, this research depends on collecting actual database from several projects around the globe and applying the well-known (GP) technique to develop a model to predict the tower weight. The accuracy of the developed formula was about 84%. The developed model could be used in early tender stage or to check design economy.

Nonlinear Buckling Analysis and Optimization Design of the Y‐Type Composite Insulator String

Under the action of extreme wind load, the overhead transmission line will lead to the fracture of the traditional V‐type insulator string, which greatly affects the safety of the power system. Compared with the V‐type insulator string, the Y‐type insulator string has better stability under the wind load. Therefore, the overhead lines in the mountainous areas of Anhui Province are taken as the research object, considering the combined effect of wind load and conductor dead weight, and through theoretical derivation, the calculation formula of insulator string wind deflection angle is obtained. Using numerical simulation software, the nonlinear mechanical analysis of Y‐type insulator strings is conducted, and under the action of different wind speeds, the windage yaw angle and unloading angle of the Y‐type insulator string are obtained. Compared with the calculation results of the V‐type insulator string, the stability of the Y‐type insulator string in the structure is better than that of the V‐type insulator string, and the Y‐type insulator string can make full use of the distance between layers and the gap margin of the tower head, reduce the length of the cross arm, and reduce the weight of the tower, which has obvious advantages. Combined with the results of theoretical analysis and numerical simulation, the optimal design method of the Y‐type insulator string is given. Under the condition of ensuring the safety and stability of insulators, the distance of the cross arm is shortened as much as possible and the weight of the transmission line tower is reduced. The research results will provide a theoretical reference for engineering design and improvement.

The role of learning style in engineering design thinking via project-based STEM course

ABSTRACT Engineering design thinking is at the core of engineering competence. Project-Based learning (PjBL) about Science, Technology, Engineering, and Mathematics (STEM), which is based on engineering design, has brought enormous success in students’ gaining and applying knowledge about STEM subjects. However, there are few studies on the perceived improvement in engineering design thinking and the possible role that learning style (LS) plays. We implemented PjBL-STEM classes to enable students to design and build a water tower using a truss tower structure that can withstand earthquakes. Constraints such as height, load weight, tower weight, and degree of earthquake withstanding were included. A total of 137 Taiwanese students participated in this course and employed a Gregorc learning style delineator to determine their learning preferences. A pre-test and post-test on perceived engineering design thinking performance was also undertaken. Students demonstrated significant improvements in their perceived engineering design thinking. Additionally, abstract-type learners had greater perceived improvement than concrete-type learners from the PjBL-STEM course. We suggest that different pedagogical methods should be utilized to provide equal opportunities for each student.

Resonance Investigation and its Effects on Weight Optimization of Tubular Steel Wind Turbine Towers

The dynamic behavior of tubular steel wind turbine towers is investigated, with emphasis on discussing how the effort to avoid resonance of the soil-foundation-tower system, by keeping its eigenfrequencies outside specific ranges around the rotor (1P) and blade-passing (3P) frequencies, influences tower optimization. For modern, tall towers avoidance of resonance becomes critical compared to other structural design checks, such as buckling and fatigue. Considering that the rotor and blades have predefined mass and rotation frequencies, the tower’s fundamental frequencies should be controlled considering the cross-sectional properties of the tower as well as the flexibility of its foundation. The objective of the optimization problem formulated in this work is to reduce tower weight, while satisfying the resonance and buckling criteria and considering restrictions pertaining to fabrication, transportation and erection. The vibration modes and frequencies of a 120m tall tower are determined via detailed as well as simplified finite element models, with the latter proving to be sufficiently accurate. The dependence of the tower’s vibration frequencies on the soil and foundation is also investigated. The numerical models are introduced into the high performance optimization computing platform (HP-OCP), to obtain an optimum distribution of tower shell thickness over the height.

Optimization Design of Transmission Tower Based on Intelligent Selection

In this work, the optimal design method for self-supporting transmission tower is put forward, whose procedure is that the tower body form is selected intelligently firstly and then the members types of tower are chosen. The case base of towers is established with application of object-oriented technology. Then, the knowledge of tower body is mined out with case based reasoning and data mining technology. At the same time, the structural regulations of tower in the standard are merged into the knowledge base. So, the intelligent selection system of tower structural scheme based on case reasoning and data mining is explored. A 500kV self-supporting tower is optimized according to above method and a real model test is conducted. Comparison between optimal tower and original tower indicates that weight of optimal tower is decreased by 3% and its ultimate bearing capacity is increased by 19%. Statistical analysis results of 20 optimal towers indicates that the weight is average reduced by 4.7%, the components of the optimal tower are stressed more uniformly and bearing capacity of the tower is enhanced 12% at least.

Topology design recommendations of transmission line towers to minimize the bolt slippage effect

Previous studies have recently demonstrated the importance of bolt slippage on the structural behavior of transmission line (TL) towers (CIGRE, 2009; Jiang et al., 2011; Ramalingam and Jayachandran, 2016; Jiang et al., 2017, just to name a few). In spite of these advances, this effect is still disregarded in the structural design, which is carried out through commercial computational packages that employ a linear or a geometrically nonlinear elastic analysis. Therefore, discrepancies between the model predictions and the actual tower behavior intrinsically occur. Moreover, its magnitude is highly dependent on the tower topology, a definition influenced by the engineer experience. Within this context, it is clear that the bolt slippage effect remains an open issue to treat on the engineering application point of view. Instead of including it in the mechanical model, a simpler alternative would be following a set of design topology recommendations able to minimize the connections’ influence on structural tower behavior. Hence, starting from a FEM model that includes the nonlinear bolt slippage and fits the CIGRE (2009) experimental measurements, 72 models to the same self-supporting 230 kV real structure with small differences in their elements configurations are constructed. These topology variations include the most common features employed by the industry. Because the effect of each one of them is isolated and assessed separately (qualitatively and quantitatively), topology design recommendations are provided, allowing the structural behavior becomes considerably closer to the linear one. Finally, a critical appraisal of each variation choice on the impact of the final tower weight is carried out.

Evaluation of Carbon Fiber Cables in Transmission Lines

This article aims to present a technical alternative to improve the electrical conductivity in Transmission Lines (TL) and provide greater energy efficiency by using an Aluminum Conductor Composite Core (ACCC) instead of the most common conductor, the Aluminum Conductor Steel Reinforced (ACSR RAIL). Designated as a simulation line in this article, an existing TL with 500 kV and 181 km in length was considered, in order to study the exchange of four ACSR RAIL conductors per phase. Initially, the physical characteristics of these two types of conductors were compared, and the advantages of the other types of ACCC cables were considered. The technical analyses carried out were the corona effect, electrical parameters, losses by the Joule effect, the increasing of ampacity and reduction in the tower weight. The main contribution of the present manuscript is to perform this study considering all the previously mentioned parameters simultaneously. In general, conductors with a carbon fiber core presented a great potential for energy efficiency; indeed, considering some specific parameters analyzed in this research, the conductor ACCC PRAGUE could achieve an energy efficiency of 48.5%.

Work specification for the construction of 33kv overhead lines across a lagoon using equal level dead-end lattice tower supports

Bare overhead distribution conductors are typically flexible and uniform in weight along their lengths. This weight causes the span to form a catenary (sag) which changes with conductor temperature, ice, wind loading and time. This catenary is capable of tripping circuits because it often results to short circuit and damage power system equipment with attendant loss of revenue to utility company. This paper presents a case study of 33kV overhead line construction crossing a 200m wide ‘Lagoon’ which requires minimum sag-tension design and estimation of Dead-End Lattice Tower weight specification that would determine weight of Tower foundation. These two parameters were obtained using the standard mathematical equations and the specifications for Aluminium Conductor Steel Reinforce (ACSR). The results of various Parameters evaluated in this research work are presented and discussed. The Sag and Tower weight results were applied to the proposed project which was successfully completed and commissioned. http://dx.doi.org/10.4314/njt.v37i1.28

Применение электронного тахеометра для обследования конструкций металлических башен сотовой связи

The availability and stability of cellular communication can be achieved with areas coverage by base stations. Base station cellular (metal tower) is a complex and massive engineering structure which is usually installed on different buildings. Weight of tower with equipment exceeds 1000 kg. For security purposes of objects with installed cellular base stations you need constantly determine the operating characteristics of towers. One of the important characteristics is the deviation of the tower from the vertical. In the regulations for the operation of towers various ways of determining the deviation of the tower from the vertical are discussed. In the instructions it is proposed to determine the deviation of the tower based on observations with three or four starting points, between which there must be mutual visibility. After all dimensions processing we will receive a deviation of the tower from the vertical. The paper proposes a more simple method of determining deviations of the tower from the vertical with the use of electronic total station. The software of the instrument will improve the quality of the work. Measurements are performed from one point in topocentric coordinates system. Independent observations from a different point improve accuracy and serve as a control. Error of the results does not exceed 5–7 mm.

A Mineral Biography of the City

For years, the skyscrapers in New York were firmly planted in Mid-town and down at the end of the island not by choice, but because there the dense Pegmatite-rich rock was exposed at the surface—Mica Schist strong enough to hold the weight of towers. This same type of rock inhabits the coast of Maine, vast areas of Scotland and Riverside Park along the Hudson. As a kid, I knew Mica from streets that glinted in the sun, playgrounds peopled by boulders that seemed made of silver and gold, rocks on the beach with layers you could peel open like pages in a book. A Mineralogy curator named Peter told me mineral samples of Mica are sometimes termed “books.” My mother remembers finding books of Mica in the alley next to the building where she grew up in Brooklyn. Edgar Allan Poe lived across from Riverside Park when he is rumored to have written The Raven. If you find a shimmering stone in the area and leave it on the granite plaque on West 83rd street, your book of Mica becomes part of a memorial to the Warsaw Ghetto Uprising. I imagine all these volumes together. A library composed of only rocks and minerals, every layer another narrative.

PREDICTING TELECOMMUNICATION TOWER COSTS USING FUZZY SUBTRACTIVE CLUSTERING

This paper presents a fuzzy subtractive modelling technique to predict the weight of telecommunication towers which is used to estimate their respective costs. This is implemented through the utilization of data from previously installed telecommunication towers considering four input parameters: a) tower height; b) allowed tilt or deflection; c) antenna subjected area loading; and d) wind load. Telecommunication towers are classified according to designated code (TIA-222-F and TIA-222-G standards) and structures type (Self-Supporting Tower (SST) and Roof Top (RT)). As such, four fuzzy subtractive models are developed to represent the four classes. To build the fuzzy models, 90% of data are utilized and fed to Matlab software as training data. The remaining 10% of the data are utilized to test model performance. Sugeno-Type first order is used to optimize model performance in predicting tower weights. Errors are estimated using Mean Absolute Percentage Error (MAPE) and Root Mean Square Error (RMSE) for both training and testing data sets. Sensitivity analysis is carried to validate the model and observe the effect of clusters’ radius on models performance.

The Advantage Analysis of Applying Steel Tube Tower in Large Span Engineering

With the operation of the power engineering, such as west-east electricity transmission, the outside sending of the three gorges, areas network and so on, many large span engineering emerged in different part of China. And among it, the key point of the whole subject is the design of the structure. This essay aims mainly at introducing the history and modern application of steel tube tower. Meanwhile do the analysis comparison for the modeling of the transmission tower according to angle steel tower and steel tube tower under the working condition of high winds. Steel tube tower is better because it is smaller in shape factor of wind load than angle steel tower, so it can reduce the tower weight and fundamental effort, the economical advantage is great.

The Research for Assembling Double Circuit Steel Tube Tower with New inside Pulling Wire

Double Circuit Steel Tube Tower has a large size structural and a heavy weight of components, so the construction of tower becomes more difficult. This article uses the Midas software to simulate the Process of Inside Pulling Wire for Double Circuit Steel Tube Tower erection in windy weather and no windy weather, Researching the influence of the new lifting system and the original lifting system on the whole of lifting system. Through the stress analysis and simulation formajor rigging, we can know which lifting ways can be used when the horizontal displacement of the derrick has or has not strict restrictions, or the lifting weight has been restricted when the Wind load is too strong. New lifting system can lift very heavy tower material and has little affect by windy weather, especially suite for assembling large size structural and heavy weight of components tower.

Analysis and Design of Integrated Optimization of 1.5MW Wind Turbine Tower

This paper uses Isight_FD 5.6 to integrate UG8.0 parametric modeling, ANSYS Workbench static analysis, modal analysis, and mathematical modeling of design optimization, by means of optimization algorithm, to meet strength and the stiffness of the tower, to realize the optimization of tower structure, so as to attain the expected target which reduces the weight of tower.

Response analysis of spar platform with wind turbine

Floating wind turbine platforms are the most economical means for deploying offshore wind turbines in deep waters. The merit of spar platform is the large range of topside payloads, favourable motions compared with other floating structures and minimum hull/deck interface. The main objective of this paper is to present the response analysis of the spar platform supporting a 5MW wind turbine, with taut mooring and with bottom keel plate in regular and random waves, studied experimentally and numerically. This paper presents the details of the studies carried out on a 16-m diameter and 100-m long spar buoy supporting a 90-m tall 5MW wind turbine with 3600-kN weight of nacelle and rotor and 3500-kN weight of tower. The weight of the ballast and the draft of the spar are adjusted in such a way so as to keep the centre of gravity below the centre of buoyancy. The mooring lines are divided into four groups, each of which has four lines. The studies on a 1:100 scale model of the spar with taut mooring configuration are carried out in regular and random waves. The operational significant wave height of 2.5 m and 10-s wave period and the survival significant wave height of 6 m and 18-s wave period at 300-m water depth are considered. The wind speed corresponding to the operational wave height is about 22 knots and this wind speed is considered to be the optimum wind speed for turbines. The heave and surge accelerations at the top of the spar platform were measured and are used for calculating the response, in both regular and random waves. The geometric modelling of the spar was carried out using MULTISURF and was directly exported to WAMIT for subsequent hydrodynamic and mooring system analysis. The numerical results were compared with experimental results and the comparison was found to be good.

Application of Recursion Algorithm Method in Design of a Chinese Transmission Tower’s Chord Member

Optimization method was designed via selecting a series of self calling functions on the basis of application of recursive algorithm method. An optimization method for unifying section of transmission tower’s chord member was testified from the example. The procedure to the feasible combination patterns for unifying section was put forward by recursion. Based on the hypothesis of static determination, the sections of the members in each pattern were shown, and the optimal design can be obtained by comparing existing patterns. Three different constraint inputs of transmission tower were checked by the recursion algorithm method in this paper. The comparison result shows that the design of unifying section save 123 Kg of steel after optimization under the condition of 5 division pattern of chord member. The number of possible combination of unifying section pattern was increased sharply, while the optimal weight of tower is decreased with the division of chord member.