TY - CONF A1 - Stengel, Dominik A1 - Mehdianpour, Milad A1 - Clobes, M. ED - Bucher, C. T1 - Böenbeanspruchung von Freileitungsseilen - Naturmessungen, Windkanalversuche und numerische Simulationen N2 - Im Rahmen eines Forschungsprojekts zur Tragverhaltensstudie von Freileitungsseilen unter Böenbeanspruchung soll durch die Kombination von Naturmessungen, Windkanalversuchen und numerischen Simulationen versucht werden, das mechanische Verhalten von Freileitungsseilen und turbulenter Windbeanspruchung genauer abzubilden. Die Unsicherheiten bei der Modellierung dieses Zufallsprozesses sollen durch Windkanalversuche und Naturmessungen auf ein Minimum reduziert werden. Im vorliegenden Beitrag werden Ergebnisse von Simulationen mit den Beobachtungen aus den Naturmessungen verglichen und bewertet. Ziel des Forschungsvorhabens ist die Bewertung der aktuellen Bemessungsvorschriften für die Berücksichtigung von Wind auf Leiterseile. T2 - 13. Dreiländertagung D-A-CH 2013 CY - Wien, Austria DA - 10.10.2013 PY - 2013 SN - 3-928909-12-6 N1 - Serientitel: WtG-Berichte – Series title: WtG-Berichte VL - 13 SP - 37 EP - 47 AN - OPUS4-29316 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stengel, Dominik A1 - Mehdianpour, Milad A1 - Clobes, M. A1 - Thiele, K. ED - Cunha, A. ED - Caetano, E. ED - Ribeiro, P. ED - Müller, G. T1 - Numerical simulation of an overhead power line section under wind excitation using wind tunnel test results and in-situ measured data N2 - Overhead transmission lines are very sensitive structures in regards to wind action. The cables, spanning over a few hundred meters contribute in particular to the overall action on the suspension towers. These slender structures incorporate both structural nonlinearities from the large deformation of the cables and aerodynamic nonlinearities which need to be accounted for when it is to estimate the system response to strong wind events. In this work, a finite element procedure is presented to model an existing power line section using nonlinear cable elements. The wind force is assumed quasi-steady with force coefficients determined in wind tunnel test on a conductor section. Further, aerodynamic damping is incorporated by considering the relative velocity between cable nodes and oncoming wind flow. The results are compared with on-site measurements of the cable’s support reaction. The results show a significant effect of damping since almost no resonant amplification is visible both in observation and simulation. In addition, wind tunnel tests approved aerodynamic damping to be large for the system of sagging cables, but nonlinear in its nature. It is concluded, that the dynamic response of overhead transmission line cables has to be modeled with care, considering all sources of nonlinearities. That is of particular interest in case of random excitation such as wind because the peak response depends on the probability distribution of the system's response. T2 - EURODYN 2014 - 9th International conference on structural dynamics CY - Porto, Portugal DA - 2014-06-30 KW - Overhead transmission lines KW - Cable dynamics KW - Aerodynamic damping KW - Wind tunnel KW - In-situ measurements PY - 2014 SN - 978-972-752-165-4 SN - 2311-9020 SP - Paper MS07, 1 EP - 6 AN - OPUS4-30993 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stengel, Dominik A1 - Clobes, M. A1 - Mehdianpour, Milad ED - Schlünzen, K.H. T1 - Overhead transmission line cables under wind gust loading - measurements and numerical simulations N2 - Overhead transmission lines with conductor cables spanning over a few hundred meters are highly sensitive to the action of wind. Particularly wind acting on the cables signifies a major load on the suspension towers. In order to identify critical loading parameters and the load-response mechanism of those structures, measurements are carried out along a high voltage overhead transmission line capturing the acting wind field as well as the structural response of the cables. A finite element model of the structure is built and used to simulate the system's response. A method is presented which allows generating a complete wind field for all the model’s nodes incorporating measured wind velocities and estimated parameters of the acting wind. The full scale measurements of both action and reaction will be compared to the numerical results. T2 - CWE 2014 - 6th International symposium on computational wind engineering CY - Hamburg, Germany DA - 2014-06-08 PY - 2014 SP - Article 0158_0016, 1 EP - 8 AN - OPUS4-30860 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mehdianpour, Milad A1 - Schmid, Wolfgang A1 - Clobes, M. T1 - MOSYTRAF - Monitoringsystem zur Tragverhaltensstudie von Freileitungen unter Böenbeanspruchung N2 - MOSYTRAF steht für ein Monitoringsystem zur Tragverhaltensstudie von Freileitungen unter Böenbeanspruchung. Die Tragverhaltensstudie dient der Entwicklung eines realitätsnahen Berechnungsmodells zur Abschätzung der Mastbeanspruchung infolge Starkwindeinwirkung auf die Leiter. T2 - Messen im Bauwesen 2011 CY - Berlin, Germany DA - 01.03.2011 KW - Monitoring KW - Freileitungen KW - Wind KW - Naturmessung PY - 2011 SP - 89 EP - 100 AN - OPUS4-23331 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stengel, Dominik A1 - Thiele, K. A1 - Clobes, M. A1 - Mehdianpour, Milad T1 - Aerodynamic damping of nonlinear movement of conductor cables in laminar and turbulent wind flow N2 - It is widely accepted that aerodynamic damping is a decisive parameter influencing the dynamic response of overhead transmission line conductors in turbulent wind flow. But anyway, methods of how to account for the effects of aerodynamic damping differ significantly and so might do the results. In this work, the source of aerodynamic damping shall be revised leading to the well-known formulation for a linear pendulum being the result of the relative velocity between the structure and wind flow. Based on wind tunnel tests and validated by simulations, the differences to a pendulum movement of a sagging cable are shown. The reasons for that deviation are the large deflections, resulting in a movement non parallel to the acting wind flow. For some analysis, in particular those in frequency domain, it is practically not possible to incorporate aerodynamic damping implicitly by fluid structure interaction. If the dynamic movement can be linearized at a working point of the mean deflection, a modification to the linear approach is suggested. This approach is validated by simulation with a finite element model of an existing overhead transmission line, calibrated with onsite measurements for wind velocities at lower levels. Further accent is put on the different possibilities to incorporate aerodynamic damping in time step analysis, such as Rayleigh damping or modal damping. The differences between both approaches are emphasized and modal damping is shown to be the most adequate representation of aerodynamic damping. T2 - ICWE14 - 14th International conference on wind engineering CY - Porto Alegre, Brazil DA - 21.06.2015 KW - Aerodynamic damping KW - Conductor cables KW - Overhead transmission lines KW - Wind tunnel experiments KW - Nonlinear finite element simulation PY - 2015 SN - 978-85-66094-07-7 SP - 1 EP - 9 AN - OPUS4-33612 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stengel, Dominik A1 - Clobes, M. A1 - Thiele, K. T1 - Investigation on the dynamic behavior of an OHL conductor bundle with light and heavy ice accretion N2 - Under a variety of possible cable vibrations which overhead line conductors can suffer, galloping identifies by large amplitudes at rather low frequencies. Changes of the cross-section as by ice-accretion provide the basis for such vibrations through an aerodynamic instability of drag and lift responses under wind excitation. Two different types of light and heavy ice bodies attached to a quad bundle conductor are analysed in wind tunnel tests. The results of aerodynamic drag and lift coefficients are investigated by means of a finite element model under turbulent wind excitation. It was found that instability can be well simulated for the heavy ice accretion but not for the case of lightly iced conductors. T2 - 8th International Colloquium on Bluff Body Aerodynamics and Applications CY - Boston, MA, USA DA - 07.06.2016 KW - wind turbulence KW - overhead transmission line KW - bundle conductors KW - ice accretion KW - dynamic behaviour PY - 2016 SP - Paper 116, 1 EP - Paper 116, 8 AN - OPUS4-36554 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stengel, Dominik A1 - Thiele, K. A1 - Clobes, M. A1 - Mehdianpour, Milad T1 - Aerodynamic damping of nonlinear movement of conductor cables in wind tunnel tests, numerical simulations and full scale measurements N2 - Aerodynamic damping is a decisive parameter influencing the dynamic response of overhead transmission line conductors. Methods of how to account for the effects of aerodynamic damping differ significantly and so might do the results. In this work, the source of aerodynamic damping being the result of the relative velocity between the structure and wind flow will be revised. Based on wind tunnel tests and validated by simulations, the differences of linear movement compared to a pendulum movement of a sagging cable are shown. The reasons for that Deviation are the large deflections, resulting in a movement non-parallel to the acting wind flow. For analysis in frequency domain, it is not possible to incorporate aerodynamic damping implicitly by fluid structure interaction. If the dynamic movement can be linearized at a working point of the mean deflection, a modification to the linear approach is suggested. This approach is validated by simulation with a finite element model of an existing overhead transmission line, calibrated with full scale measurements. Aerodynamic damping is incorporated in time step analysis by Rayleigh damping and modal damping. The differences between both approaches are emphasized and modal damping is shown to be the most adequate. KW - Aerodynamic damping KW - Overhead transmission lines KW - Conductors KW - Nonlinearities PY - 2017 U6 - https://doi.org/10.1016/j.jweia.2017.07.002 SN - 0167-6105 SN - 1872-8197 VL - 169 SP - 47 EP - 53 PB - Elsevier AN - OPUS4-41028 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -