Готові списки джерел за темами / Effetto catenaria

Добірка наукової літератури з теми "Effetto catenaria"

Автор: Grafiati

Опубліковано: 14 березня 2023

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Статті в журналах з теми "Effetto catenaria"

Yao, Jiannan, and Xingming Xiao. "Investigation of Collision Behavior of Hoisting Catenaries during a Lifting Cycle in Coal Mines." Mathematical Problems in Engineering 2015 (2015): 1–16. http://dx.doi.org/10.1155/2015/640712.

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This investigation focused on the analyses of transverse vibrations of mine hoisting catenaries where collision between adjacent ropes is more likely to occur. To support the analyses of transverse vibrations of catenaries, theoretical correlation models for longitudinal tension and transverse vibration were first established. Based on a severe rope collision case, on-site measurements and numerical simulations were performed. The research results indicated that the external second-order excitation frequency induced by axial fluctuations of head sheave was the primary excitation frequency, which was closer to the resonance frequency. Furthermore, the effects of excitation amplitude and imbalanced tension were also investigated revealing that larger excitation amplitude contributes to larger response amplitude and the maximum response amplitude of a catenary is sensitive to imbalanced rope tension. Eventually, new solutions, which will facilitate hoisting catenary operation beyond the resonance frequency range, were proposed.

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TEICHMAN, J., and L. MAHADEVAN. "The viscous catenary." Journal of Fluid Mechanics 478 (March 10, 2003): 71–80. http://dx.doi.org/10.1017/s0022112002003038.

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A filament of an incompressible highly viscous fluid that is supported at its ends sags under the influence of gravity. Its instantaneous shape resembles that of a catenary, but evolves with time. At short times, the shape is dominated by bending deformations. At intermediate times, the effects of stretching become dominant everywhere except near the clamping boundaries where bending boundary layers persist. Finally, the filament breaks off in finite time via strain localization and pinch-off.

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Goela, J. S., N. Somu, R. Abedinzadeh, and R. Vijay Kumar. "Wind loading effects on a catenary." Journal of Wind Engineering and Industrial Aerodynamics 21, no. 3 (December 1985): 235–49. http://dx.doi.org/10.1016/0167-6105(85)90038-8.

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Zheng, Xue Xian, Xun Wang, Hong Bo Cheng, and Wen Hui Cao. "Lightning Protection Research and Simulation of High-Speed Railway Catenary." Advanced Materials Research 875-877 (February 2014): 1707–11. http://dx.doi.org/10.4028/www.scientific.net/amr.875-877.1707.

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The existing high-speed railway in China is erected on the viaduct. The traction power supply system of high-speed railway consists of catenary with auto-transformer (AT). The catenary above the rails is supported by towers besides the rails. As the increase of the height from top of towers to ground, the probability of the pilot discharging of lightning to catenary will increase. And the pilot striking distance to ground always remains constant. So the horizons shielding effects for catenary will decrese, and the whole catenary naked in the atmosphere extremely easily struck by thunderbolt. In the important places, e.g., substation and areas of frequent lightning, the lightning arrester is installed to limit lightning overvoltage. But the lightning arrester can limit local overvoltage only. In fact, high-speed railway struck by lightning has affected the safety of power supply system in China. So more reasonable lightning protection measures for Chinas high-speed railway will be studied in this paper.

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Chen, Guo, Yiren Yang, Yang Yang, and Peng Li. "Study on Galloping Oscillation of Iced Catenary System under Cross Winds." Shock and Vibration 2017 (2017): 1–16. http://dx.doi.org/10.1155/2017/1634292.

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This paper mainly aims at revealing the nature of the galloping oscillation of iced catenary system under cross winds. The aerodynamic force on the iced catenary system is assumed to be quasi-steady, and then the quasi-steady aerodynamic lift and drag coefficients are completed in FLUENT. By fitting the discrete simulation data, the expression of the vertical aerodynamic force is further obtained. According to the Den Hartog vertical galloping mechanism, the stability of iced catenary is discussed and the initial icing angle corresponding to the critical stability is obtained. On this basis, the dynamic model of the simple iced catenary system under cross winds is established. The partial differential vibration equation of the system is converted into the ordinary differential equation by the Galerkin method and then numerically solved. The condition of the unstable catenary motion in simulation is in agreement with that from theoretical stability analysis. In addition, the effects of structural damping, initial icing angle, and wind velocity on the system responses are investigated.

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Wang, Jiqiang. "Active Control of Contact Force for a Pantograph-Catenary System." Shock and Vibration 2016 (2016): 1–7. http://dx.doi.org/10.1155/2016/2735297.

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The performance of the high speed trains depends critically on the quality of the contact in the pantograph-catenary interaction. Maintaining a constant contact force needs taking special measures and one of the methods is to utilize active control to optimize the contact force. A number of active control methods have been proposed in the past decade. However, the primary objective of these methods has been to reduce the variation of the contact force in the pantograph-catenary system, ignoring the effects of locomotive vibrations on pantograph-catenary dynamics. Motivated by the problems in active control of vibration in large scale structures, the author has developed a geometric framework specifically targeting the remote vibration suppression problem based only on local control action. It is the intention of the paper to demonstrate its potential in the active control of the pantograph-catenary interaction, aiming to minimize the variation of the contact force while simultaneously suppressing the vibration disturbance from the train. A numerical study is provided through the application to a simplified pantograph-catenary model.

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Wang, Beining, Shaofang Wen, and Yongjun Shen. "LQR Active Control of Fractional-Order Pantograph-Catenary System Based on Feedback Linearization." Mathematical Problems in Engineering 2022 (October 21, 2022): 1–11. http://dx.doi.org/10.1155/2022/2213697.

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Fractional-order calculus has exclusive advantages in modeling the viscoelastic components with obvious fractional-order characteristics such as air springs and metal rubbers in the pantograph structure. In this paper, the air spring is tested, and fractional-order calculus is applied to the modeling of pantograph-catenary system of the high-speed train. The parameter identification method of fractional-order derivative is analytically derived. The traditional lumped mass model is improved and a coupling two-degree-of-freedom model of the fractional-order pantograph-catenary system is established. The fractional-order derivative term in the pantograph-catenary model is approximately calculated by the Oustaloup filter algorithm. Taking the time-varying nature into consideration, the catenary is treated as an extended variable to obtain an augmented model. On this basis, the system is linearized based on differential geometry theory, and an LQR controller is designed to control the pantograph-catenary system. The feedback linearized LQR control and PID control are used to control the same type of traditional pantograph, and the results are compared. Meanwhile, the control effects of feedback linearized LQR control under different pantograph parameters and at different train speeds are analyzed. The results show that the feedback linearized LQR control can present a much better control performance than PID control, and the pantograph-catenary contact force and pantograph head vibration amplitude are both reduced obviously. Even at different train speeds or under different pantograph parameters, it can also effectively reduce these control indexes and provide more robust control performance. These results help to put forward new control ideas and theoretical basis for the vibration control of the pantograph-catenary or similar dynamical system.

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Bryja, Danuta, and Adam Hyliński. "An influence of track stiffness discontinuity on pantograph base vibrations and catenary–pantograph dynamic interaction." Studia Geotechnica et Mechanica 42, no. 2 (June 30, 2020): 111–24. http://dx.doi.org/10.2478/sgem-2019-0035.

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AbstractIn this article, the computational methodology of the catenary–train–track system vibration analysis is presented and used to estimate the influence of vehicle body vibrations on the pantograph–catenary dynamic interaction. This issue is rarely referred in the literature, although any perturbations appearing at the pantograph–catenary interface are of great importance for high-speed railways. Vehicle body vibrations considered in this article are induced by the passage of train through the track stiffness discontinuity, being a frequent cause of significant dynamic effects. First, the most important assumptions of the computational model are presented, including the general idea of decomposing catenary–train–track dynamic system into two main subsystems and the concept of one-way coupling between them. Then, the pantograph base vibrations calculated for two train speeds (60 m/s, 100 m/s) and two cases of track discontinuity (a sudden increase and a sudden decrease in the stiffness of track substrate) are analyzed. Two cases of the railway vehicle suspension are considered – a typical two-stage suspension and a primary suspension alone. To evaluate catenary–pantograph dynamic interaction, the dynamic uplift of the contact wire at steady arm and the pantograph contact force is computed. It is demonstrated that an efficiency of the two-stage suspension grows with the train speed; hence, such vehicle suspension effectively suppresses strong sudden shocks of vehicle body, appearing while the train passes through the track stiffness discontinuity at a high speed. In a hypothetical case when the one-stage vehicle suspension is used, the pantograph base vibrations may increase the number of contact loss events at the catenary–pantograph interface.

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Jin, Mengzhe, Man Hu, Hao Li, Yixuan Yang, Weidong Liu, Qingyuan Fang, and Shanghe Liu. "Experimental Study on the Transient Disturbance Characteristics and Influence Factors of Pantograph–Catenary Discharge." Energies 15, no. 16 (August 17, 2022): 5959. http://dx.doi.org/10.3390/en15165959.

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The transient electromagnetic disturbance generated by arcing discharge between the pantograph and catenary can pose a significant risk to the safe operation of electrified railways. In order to better comprehend its properties, a pantograph–catenary discharge generating device is designed to simulate the discharge phenomenon with moving electrodes in this experimental investigation. The effects of the applied voltage, the gap distance, and the relative motion between the pantograph and catenary on the time- and frequency-domain features of the discharge current and electromagnetic field are investigated. The variation trends of pulse peak current, rise time, pulse repetition frequency, maximum amplitude, and characteristic frequency in the radiation spectrum are retrieved under varying experimental settings, and the effect mechanisms are derived from the physics of gas discharge. A dynamic discharge test is conducted in this study in order to further understand the effect of electrodes’ relative motion on discharge characteristics. The results indicate that lateral sliding motion of the pantograph along the track has a negligible effect on the transient discharge, whereas a faster vertical approaching motion between the pantograph and catenary generates a larger pulse current peak, a steeper rise front-edge, and a higher radiation intensity.

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Bocciolone, M., F. Resta, D. Rocchi, A. Tosi, and A. Collina. "Pantograph aerodynamic effects on the pantograph–catenary interaction." Vehicle System Dynamics 44, sup1 (January 2006): 560–70. http://dx.doi.org/10.1080/00423110600875484.

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Більше джерел

Дисертації з теми "Effetto catenaria"

Bridge, Christopher. "Effects of seabed interaction on steel catenary risers." Thesis, University of Surrey, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.431127.

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Schifter, Josh. "The effects of bending stiffness on the dynamics of catenary cables." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/10687.

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Iqbal, Naveed. "Analysis of Catenary Effect in Steel Beams and Trusses Exposed to Fire." Doctoral thesis, Luleå tekniska universitet, Byggkonstruktion och brand, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-26191.

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The goals of structural design are fundamentally different when designing structures at normal temperature or when designing them in a fire situation. While structures are primarily designed for normal temperature situations considering the different design limit states, in the fire design situation, however, the already designed structure is assessed for its resistance in the fire design limit state. The assessment of the structure in the fire limit state may lead to either active or passive fire protection measures. The assessment of the structure in fire may be done in several different domains such as its structural resistance, integrity of structural components to prevent spread of fire and insulation properties of materials. The focus of the thesis presented here is on the structural resistance of steel structural members particularly steel beams and trusses in fire situations.The Eurocodes permit designers to use either a simple prescriptive design procedure or a more complex performance based procedure for design of structures in fire. The prescriptive design is a simple choice regarding design of steel structures in fire due to their use of simple analytical equations; but through several studies it has been established that this approach might be conservative and in some situations it might not reflect the complexity of interaction between the heated structural members and its surrounding colder parts of the structure. The performance based approach has therefore been increasingly adopted in structural fire design, which, although more complex than the prescriptive approach, is closer to the real structural behaviour.Through a performance based approach, this thesis aims to establish that steel structural members are able to offer structural resistance in fire situations that are much higher than would be expected from a prescriptive approach. Two different types of structural members such as steel beams in multi-storey buildings and trusses in single storey buildings were considered here. It has been shown through extensive finite element analysis in both cases that actual resistance of these structural members in fire situations can exceed their primary resistance mechanism through flexure. Alternative load transfer mechanism through catenary action offers the added resistance at much higher temperatures than the conventional critical temperatures from prescriptive design. The thesis also proposes simplified calculation procedures that can be used to reasonably predict the structural resistance at elevated temperatures considering the catenary action.

Godkänd; 2016; 20160808 (naviqb); Nedanstående person kommer att disputera för avläggande av teknologie doktorsexamen. Namn: Naveed Iqbal Ämne: Stålbyggnad /Steel Structures Avhandling: Analysis of Catenary Effect in Steel Beams and Trusses Exposed to Fire Opponent: Professor Paulo Vila Real, Department of Civil Engineering, University of Aveiro, Aveiro, Portugal. Ordförande: Professor Milan Veljkovic, Avdelningen för byggkonstruktion och produktion, Institutionen för samhällsbyggnad och naturresurser, Luleå tekniska universitet, Luleå. Tid: Tisdag 6 september 2016, kl 10.00 Plats: F531, Luleå tekniska universitet

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Mwarage, Jessy Mbagara. "Simulation of the catenary effect under wind disturbances in anchoring of small boats." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/75670.

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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2012.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 47).
It has been conventional knowledge for as long as ships have existed that the catenary effect of an anchor line augments the efficiency of an anchoring system. This is achieved by making the anchor line as heavy as possible thus lowering the effective angle of pull on the anchor. This notion has, however, come under criticism in recent times. Many small boat owners have shifted to lighter tauter lines for anchoring. The argument in favor of this new method is the cost savings associated with lighter anchoring and the tension relief that comes with using lighter and more elastic anchor lines. The purpose of this study is to therefore compare the performance of long slack lines that form catenary shapes with that of shorter taut lines. An analysis is presented that describes the surge motion of a small anchored boat exposed to an input forcing function and various retarding forces and effects. The anchoring system used in the analytical model results in a non-linear but symmetrical restoring force, which resists the force-induced motion of the boat. Two main types of anchor lines are considered: uniform-material and two-material anchor lines. Each anchor line is evaluated both in catenary configuration and taut configuration in terms of its ability to minimize the motions of the boat and tension force in the anchor line due to wind disturbances.
by Jessy Mbagara Mwarage.
S.B.

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Pinto, Gabriela Martins. "Estudo paramétrico da atenuação de cargas estáticas em sistemas de ancoragem offshore." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2014. http://hdl.handle.net/10183/127882.

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As reservas de petróleo e gás estão localizadas cada vez mais longe da costa e em águas profundas e ultra profundas, o que faz necessário a utilização de estruturas flutuantes, as quais estão sujeitas às forças impostas por condições ambientais, tais como vento, ondas e correntes marítimas. É portanto relevante o estudo de sistemas de ancoragem de estrutura flutuantes, sendo estes responsáveis pelo posicionamento da plataforma, garantindo segurança às operações realizada. Este é o objetivo do presente trabalho, que diz respeito a um estudo numérico do comportamento do trecho enterrado da linha de ancoragem de plataformas flutuantes de extração, produção e/ou armazenamento de petróleo. O sistema de ancoragem estudado é do tipo taut-leg, recomendado para lâminas de água superiores a 1000m. Este tipo de ancoragem pode ser dividido em três partes, um trecho suspenso que vai da plataforma até o leito marinho, um trecho apoiado sobre o leito marinho e um terceiro segmento que penetra no solo junto com a âncora, o qual adquire a forma de uma catenária invertida. Este tipo de sistema chega ao leito marinho com inclinações entre 30 e 45° e é capaz de resistir a esforços horizontais e verticais. O objetivo deste estudo é analisar os parâmetros envolvidos, as forças atuantes e a configuração do trecho em catenária invertida, através de análise numérica para os experimentos realizados em laboratório em escala reduzida. Os ensaios experimentais realizados por Rocha (2014) consistiram na aplicação de um conjunto de forças no trecho da linha de ancoragem que simula o encontro da corrente com o leito marinho, medindo-se as cargas no ponto que representa o olhal onde a corrente é fixada à âncora. A configuração da linha no trecho enterrado era obtida através de um ultrassom. Neste trabalho foi feita retro-análise numérica dos resultados obtidos experimentalmente a fim de se determinar os parâmetros que definem o equilíbrio do trecho enterrado da linha de ancoragem. Esses parâmetros foram validados para diferentes carregamentos, respeitando as configurações do solo e da corrente, através de um conjunto de equações diferenciais e do software DIGIN. Com base nas análises são quantificados a atenuação do sistema e os parâmetros de capacidade de carga e adesão que controlam o processo de transferência de cargas.
Oil and gas reserves are located offshore, in deep and ultra deep waters and for this reason the use of floating structures becomes necessary. Those structures are subject to forces imposed by environmental conditions such as wind, waves and sea currents. It is therefore relevant to study the anchoring of floating structure systems, as it is responsible for positioning the platform and ensuring security operations. This is the aim of the present research efforts, which describes a numerical study of the behavior of the embedded portion of systems designed to anchor the floating platform during extraction, production and/or storage of oil. The taut-leg mooring system is the one studied herein, which is recommended for water depth beyond 1000m. This type of mooring system can be divided in three parts, one part that runs from the suspended platform to the seabed, a slice resting on the seabed and a third segment that penetrates the soil together with the anchor, which takes the form of a inverse catenary. This type of mooring system reaches the seabed at angles of 30° to 45 ° and is able to resist horizontal and vertical forces. The objective of this study is to analyze the parameters involved in the anchor system, the forces acting at the inverse catenary and its configuration through numerical analysis of small-scale laboratory experiments. Experimental tests conducted by Rocha (2014) consisted of applying a set of forces on the a chain that simulates the embedded portion of the anchor line, from the seabed to the shank attachment point, using a load cell located at a point that represents the lug throw in which the chain is connected to the anchor. The configuration of the embedded portion of anchor line was obtained through an ultrasound. In this study the experimental results were numerically back analyzed in order to determine the parameters that define the equilibrium of the embedded slice of the anchor line. These parameters were validated for various loads in compliance with both soil resistance and the configuration of the chain through a set of differential equations and DIGIN software. Based on this analysis, the attenuation of the system is quantified and the parameters controlling of load capacity and adherence are obtained.

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Jang, Yu-Song, and 鄭育淞. "Effect of Catenarin on Leukocyte Chemotaxis, Insulitis and Type 1 Diabetes in Non-obese Diabetic Mice." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/85586788151054631132.

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Частини книг з теми "Effetto catenaria"

Feng, Yang, Dan Song, and Minghui Li. "Fast Algorithm for Completion State Calculating of Wire Rope Cable Bridge." In Lecture Notes in Civil Engineering, 525–31. Singapore: Springer Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-1260-3_48.

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AbstractWhen determining the completion state of the main cable of a cableway bridge, although the catenary theory can accurately consider the nonlinear mechanical effect of the cable, the iterative calculation is cumbersome and not convenient for engineering applications. Although the calculation based on the parabola theory is simple, the calculation accuracy for long cables is low. In this paper, based on catenary theory and considering the calculation accuracy and avoiding iterative calculation, a fast algorithm for the completion state of the main cable of the wire rope cableway bridge is proposed. The results show that the bridge state can be quickly and accurately determined by approximating the horizontal component of the cable tension and avoiding multiple iterative calculations. The proposed algorithm can be used in engineering design and construction.

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Lim, Namyo Salim, Kang Hai Tan, and Chi King Lee. "Effect of Reinforcement Detailing on Catenary Action in 2-D RC Frame." In High Tech Concrete: Where Technology and Engineering Meet, 1740–49. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-59471-2_200.

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Kimiaei, M., and J. Liao. "Effects of different loading time histories on fatigue design of steel catenary risers using nonlinear riser-soil interaction models." In Frontiers in Offshore Geotechnics III, 399–404. CRC Press, 2015. http://dx.doi.org/10.1201/b18442-44.

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Тези доповідей конференцій з теми "Effetto catenaria"

Yong, KangLe, JiaWei Yan, ShiMing Huang, JianYe Nie, and Rongzhu zhang. "Thermal blooming effect of pulse vortex laser beam propagating through the atmosphere." In Micro- and Nano-Optics, Catenary Optics, and Subwavelength Electromagnetics, edited by Reinhart Poprawe, Bin Fan, Xiong Li, Min Gu, Mingbo Pu, and Xiangang Luo. SPIE, 2019. http://dx.doi.org/10.1117/12.2507386.

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Daocharoenporn, Siripong, Mongkol Mongkolwongrojn, Shubhankar Kulkarni, and Ahmed A. Shabana. "Pantograph/Catenary Wear Using Multibody System Dynamic Algorithms." In 2020 Joint Rail Conference. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/jrc2020-8006.

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Abstract In this investigation, computational multibody systems (MBS) algorithms are used to develop detailed railroad vehicle models for the prediction of the wear resulting from the pantograph/catenary dynamic interaction. The catenary wear is predicted for different motion scenarios that include constant-speed curve negotiation, and acceleration and deceleration on a tangent (straight) track. The effect of the vehicle vibration in these different motion scenarios on the contact force is further used to study the wear rates of the contact wire. The wear model used in this investigation accounts for the electrical and the mechanical effects. The nonlinear finite element (FE) absolute nodal coordinate formulation (ANCF), which is suitable for implementation in MBS algorithms, is used to model the flexible catenary system, thereby eliminating the need for using incremental rotation procedures and co-simulation techniques. The pantograph/catenary elastic contact formulation employed in this study allows for separation between the pantograph pan-head and the contact wire, and accounts for the effect of friction due to the sliding between the pantograph pan-head and the catenary cable. The approach proposed in this investigation can be used to evaluate the electrical contact resistance, contribution of the arcing resulting from the pan-head/catenary separation, mechanical and electrical wear contributions, and effect of the pantograph mechanism uplift force on the wear rate.

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Zhou, Tianfeng, Zhanchen Zhu, Jiaqing Xie, Qian Yu, Jia Zhou, and Xibin Wang. "Simulation and experimental study on the precision glass molding for microstructures on optical glass based on relaxation effect." In Micro- and Nano-Optics, Catenary Optics, and Subwavelength Electromagnetics, edited by Reinhart Poprawe, Bin Fan, Xiong Li, Min Gu, Mingbo Pu, and Xiangang Luo. SPIE, 2019. http://dx.doi.org/10.1117/12.2504777.

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Lardier, Julien, Torgeir Moan, and Zhen Gao. "Fatigue Reliability of Catenary Mooring Lines Under Corrosion Effect." In ASME 2008 27th International Conference on Offshore Mechanics and Arctic Engineering. ASMEDC, 2008. http://dx.doi.org/10.1115/omae2008-57360.

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Experiences show that mooring line failures have occurred due to crack propagation in chain links. Moreover, the crack propagation is accelerated by corrosion. To maintain the safety of floating structures in a long-term period of, say 20–30 years, it is therefore crucial that these chain links are properly designed as well as inspected and repaired during operation. The aim of this paper is to establish a reliability-based formulation for assessing mooring chains under the deterioration due to combined fatigue cracking and corrosion wastage. The crack growth in chain links has been modelled using the 2-dimensional Paris-Erdogan equation, which is validated by comparison with the SN data on a reliability basis. The corrosion is treated by considering the diameter reduction and the fatigue crack growth rate, using three zones of corrosion, namely the splash, catenary and bottom zones. A fatigue reliability case study of studless chain links is carried out considering various system models and proper correlation between links. The material correlation is modelled by splitting variables for the global and local effect. Accumulated failure probabilities of one year up to twenty years have been calculated to illustrate the effect of corrosion on fatigue reliability. A sensitivity study has been carried out on the initial crack size, the crack aspect ratio and the material correlation between links, when applying the fracture mechanics approach. Based on the case study, it has been found that the splash zone has an important effect on the failure probability of the entire mooring line, especially under corrosion of long time.

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Karakose, Ebru, and Muhsin Tunay Gencoglu. "An investigation of pantograph parameter effects for pantograph-catenary systems." In 2014 IEEE International Symposium on Innovations in Intelligent Systems and Applications (INISTA). IEEE, 2014. http://dx.doi.org/10.1109/inista.2014.6873641.

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van Gool, Richard M., Ryan A. Bradley, and Mitchell Gohnert. "Wind Loading on Catenary Domes." In IABSE Congress, New York, New York 2019: The Evolving Metropolis. Zurich, Switzerland: International Association for Bridge and Structural Engineering (IABSE), 2019. http://dx.doi.org/10.2749/newyork.2019.0585.

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<p>Catenary domes are a less conventional, but structurally efficient, alternative to traditional circular-profile domes. Unlike the more common circular forms, there is a dearth of wind loading information for catenary structures. This paper aims to provide some insight in this regard. A series of wind tunnel tests were undertaken to investigate the effects of geometry and Reynolds number on the mean pressure coefficient distributions over catenary domes in a turbulent boundary layer flow. A hemispherical dome was also assessed, and the results compared with that for the catenary shapes. These parameters were evaluated to elucidate their influence on the loading on these structures. Only the results relating to mean pressure coefficients are reported in this paper. An important finding was that the height to base radius (H/R) of the catenary dome had a substantial influence on the mean pressure coefficient distributions over the structure. Finally, the results of the investigation and their implications on the design of catenary domes are discussed. This may be of value to designers because at present no wind loading information exists for catenary domes</p><p>– at least to the author’s knowledge.</p>

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Guo, Shuangxi, Yilun Li, Min Li, Weimin Chen, and Yiqin Fu. "Dynamic Response of Floating Wind Turbine Under Consideration of Dynamic Behavior of Catenary Mooring-Lines." In ASME 2017 36th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/omae2017-61689.

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Recently, wind turbine has been developed from onshore area to offshore area because of more powerful available wind energy in ocean area and more distant and less harmful noise coming from turbine. As it is approaching toward deeper water depth, the dynamic response of the large floating wind turbine experiencing various environmental loads becomes more challenge. For examples, as the structural size gets larger, the dynamic interaction between the flexible bodies such as blades, tower and catenary mooring-lines become more profound, and the dynamic behaviors such as structural inertia and hydrodynamic force of the mooring-line get more obvious. In this paper, the dynamic response of a 5MW floating wind turbine undergoing different ocean waves is examined by our FEM approach in which the dynamic behaviors of the catenary mooring-line are involved and the integrated system including flexible multi-bodies such as blades, tower, spar platform and catenaries can be considered. Firstly, the nonlinear dynamic model of the integrated wind turbine is developed. Different from the traditional static restoring force, the dynamic restoring force is analyzed based on our 3d curved flexible beam approach where the structural curvature changes with its spatial position and the time in terms of vector equations. And, the modified finite element simulation is used to model a flexible and moving catenary of which the hydrodynamic load depending on the mooring-line’s motion is considered. Then, the nonlinear dynamic governing equations is numerically solved by using Newmark-Beta method. Based on our numerical simulations, the influences of the dynamic behaviors of the catenary mooring-line on its restoring performance are presented. The dynamic responses of the floating wind turbine, e.g. the displacement of the spar and top tower and the dynamic tension of the catenary, undergoing various ocean waves, are examined. The dynamic coupling between different spar motions, i.e. surge and pitch, are discussed too. Our numerical results show: the dynamic behaviors of mooring-line may significantly increase the top tension, particularly, the peak-trough tension gap of snap tension may be more than 9 times larger than the quasi-static result. When the wave frequency is much higher than the system, the dynamic effects of the mooring system will accelerate the decay of transient items of the dynamic response; when the wave frequency and the system frequency are close to each other, the displacement of the spar significantly reduces by around 26%. Under regular wave condition, the coupling between the surge and pitch motions are not obvious; but under extreme condition, pitch motion may get about 20% smaller than that without consideration of the coupling between the surge and pitch motions.

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Ma, Bowen, and Narakorn Srinil. "Numerical Prediction of 3-D Vortex-Induced Vibration of Catenary Riser In Planar and Non-Planar Flows." In ASME 2021 40th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/omae2021-61830.

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Abstract Vortex-induced vibration (VIV) is one of the most critical issues in deepwater developments due to its resultant fatigue damage to subsea structures such as risers, pipelines and jumpers. Although VIV effects on slender bodies have been comprehensively studied over decades, very few studies have dealt with VIV modelling and prediction of catenary risers in current flows with varying directions leading to complex fluid-structure interactions. This study advances a numerical model to simulate and predict 3-D VIV responses of a catenary riser in three flow orientations, relative to the riser curvature plane, including concave/convex (planar) and perpendicular (non-planar) flows. The model is described by equations of cross-flow and in-line responses of the catenary riser coupled with the hydrodynamic forces modelled by the distributed nonlinear wake oscillators. A finite difference method is applied to solve the coupled fluid-structure dynamic system. To consider the approaching flow in different directions, the vortex-induced lift and drag forces are formulated by accounting for the effect of flow angle of attack and the riser-flow relative velocities. Results show VIV features of a long catenary riser exhibiting a standing and travelling wave response pattern. VIV response amplitudes and oscillation frequencies are predicted and compared with experimental results in the literature for both straight and catenary risers. Overall results highlight the model capability in capturing the effect of approaching flow direction on 3-D VIV of the curved inclined flexible riser.

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Uche, Amarachi, and Franklin Okoro. "Effects of Seabed Topography on the Fatigue Life of Steel Catenary Risers." In SPE Nigeria Annual International Conference and Exhibition. Society of Petroleum Engineers, 2020. http://dx.doi.org/10.2118/203687-ms.

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Pargeter, Richard, David Baxter, and Briony Holmes. "Corrosion Fatigue of Steel Catenary Risers in Sweet Production." In ASME 2008 27th International Conference on Offshore Mechanics and Arctic Engineering. ASMEDC, 2008. http://dx.doi.org/10.1115/omae2008-57075.

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Steel catenary risers (SCRs) are commonly used for deepwater oil and gas developments and the most economic material of construction is generally carbon manganese (C-Mn) steel. These risers suffer cyclic loading principally due to vessel movements, and vortex induced vibration (VIV) from passage of marine currents. For this reason, close attention is paid to fatigue design and girth weld quality, and fatigue testing is commonly carried out on procedure test welds. A further advantage of C-Mn steel is that good quality welds can readily be made, and more importantly, freedom from defects can be assured by reliable ultrasonic inspection. In sweet corrosive environments, when significant hydrogen effects would not be anticipated, a range of environmental effects on fatigue could be envisaged under different conditions, and at different stages of fatigue crack growth. For example, in early stages of growth, corrosion could blunt crack tips, and therefore slow the growth rate, whereas under other circumstances, or later in life, corrosion could provide additional crack extension, and accelerate growth. It has been demonstrated in this programme of fatigue crack growth rate and endurance testing that the most aggressive conditions in terms of corrosivity may not give shortest fatigue lives in testing. The results of tests comparing behaviour in air and in a very highly corrosive aqueous environment at 60°C saturated with CO2 (conditions which could not be sustained in production) have been explained by reference to competing effects of fatigue and corrosion. Comparison has been made with other published data. Important safety implications surrounding conditions for project-specific corrosion fatigue testing for riser design are considered.

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Звіти організацій з теми "Effetto catenaria"

QUANTITATIVE EVALUATION OF EFFECT OF VARIOUS SPAN-TO-DEPTH RATIOS ON THE COLLAPSE PERFORMANCE OF PLANAR STEEL FRAMES. The Hong Kong Institute of Steel Construction, December 2022. http://dx.doi.org/10.18057/ijasc.2022.18.4.5.

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After the removal of a column caused by the unexpected extreme loading of the building structure, the remaining structure mainly relies on the double-span beams connected with the failed column to mitigate the progressive collapse, therefore, the span-to-depth ratios of the double-span beams has significant effects on the internal force redistribution among each story and the development of the anti-collapse mechanisms of the multi-story planar frames. To investigate the effect of span-to-depth ratios on the progressive collapse performance of steel frames, the collapse analysis of three-story steel frame models with various beam depths and beam spans was numerically studied. Firstly, the correctness of the numerical modeling method was verified by the collapse test results of a two-story sub-frame. Then, the refined modeling methods were applied to the analysis of progressive collapse performance of steel frames with various span-to-depth ratios. The load response, load distribution, deformation characteristic and load-resisting mechanisms of models are investigated in detail. The results showed that the resistances provided by flexural mechanism and catenary mechanism are mainly determined by span-to depth ratios and beam span, respectively. Through the principle of energy conservation, the different resistant contribution coefficients of each story are quantitatively obtained, and corresponding empirical formulas were proposed, which can be used as a reference for resistance evaluation before the design of structural anti-collapse.

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CAPACITY EVALUATION OF EIGHT BOLT EXTENDED ENDPLATE MOMENT CONNECTIONS SUBJECTED TO COLUMN REMOVAL SCENARIO. The Hong Kong Institute of Steel Construction, September 2021. http://dx.doi.org/10.18057/ijasc.2021.17.3.6.

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The extended stiffened endplate (8ES) connection is broadly used in the seismic load-resisting parts of steel structures. This connection is prequalified based on the AISC 358 standard, especially for seismic regions. To study this connection’s behaviors, in the event of accidental loss of a column, the finite element model results were verified against the available experimental data. A parametric study using the finite element method was then carried out to investigate these numerical models’ maximum capacity and effective parameters' effect on their maximum capacity in a column loss scenario. This parametric analysis demonstrated that these connections fail at the large displacement due to the catenary action mode at the rib stiffener's vicinity. The carrying capacity, PEEQ, Von-Mises stress, middle column force-displacement, critical bolt axial load, and the beam axial load curves were discussed. Finally, using the Least Square Method (LSM), a formula is presented to determine the displacement at the maximum capacity of these connections. This formula can be used in this study's presented method to determine the maximum load capacity of the 8ES connections in a column loss scenario.

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EFFECTS OF THE NUMBERS OF STORIES AND SPANS ON THE COLLAPSE-RESISTANCE PERFORMANCE OF MULTI-STORY STEEL FRAME STRUCTURES WITH REDUCED BEAM SECTION CONNECTIONS. The Hong Kong Institute of Steel Construction, June 2022. http://dx.doi.org/10.18057/ijasc.2022.18.2.10.

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The progressive collapse of a building structure under an accidental load involves a relatively complex mechanical behavior. To date, the collapse of single-story beam-column assemblies has been investigated extensively, revealing the resistance development of beams during progressive collapse. However, few studies of the progressive collapse behavior of multi-story frame structures have performed a systematic analysis of the Vierendeel action (VA) at a comprehensive level. It is difficult to convert quantitative analysis results accurately from the component level to the overall structure level to evaluate the collapse resistances of structures. To investigate the effects of the numbers of stories and spans on the collapse resistances of steel frame structures, a refined numerical simulation study of a multi-story frame model with different numbers of stories and spans was performed. First, the correctness of the finite element modeling method was verified by the collapse test results of a single-story and two-story frame. Then, the finite element modeling method was applied to study the collapse resistances of multi-story frame structures with different stories and spans. The load–displacement response, internal force development, deformation characteristics, and resistance mechanisms were analyzed, and the contributions of the flexural and catenary mechanisms of each story were separated quantitatively. The results illustrated that the VA can improve the load-carrying capacity to a certain extent in the small deformation stage, but can also cause the frame structures to undergo progressive collapse from the failure story to the top story. The bearing capacity of the multi-story frame did not have a simple multiple relationship with the number of stories. Increasing the number of spans can improve the collapse resistance in the large deformation stage, which is more obvious when the number of stories is smaller, and this accelerates the upward transmission of the axial tension force among the stories, although this effect is minimal for frames with few stories.

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