강한 전단 해류 환경에서 동적 전력케이블의 VIV 피로해석 절차에 관한 기초 연구
A Fundamental Study of VIV Fatigue Analysis Procedure for Dynamic Power Cables Subjected to Severely Sheared Currents
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The subsea power cables are increasingly important for harvesting renewable energies as we develop offshore wind farms located at a long distance from shore. Particularly, the continuous flexural motion of inter-array dynamic power cable of floating offshore wind turbine causes tremendous fatigue damages on the cable. As the subsea power cable consists of the helical structures with various components unlike a mooring line and a steel pipe riser, the fatigue analysis of the cables should be performed using special procedures that consider stick/slip phenomenon. This phenomenon occurs between inner helically wound components when they are tensioned or compressed by environmental loads and the floater motions. In particular, Vortex-induced vibration (VIV) can be generated by currents and have significant impacts on the fatigue life of the cable. In this study, the procedure for VIV fatigue analysis of the dynamic power cable has been established. Additionally, the respective roles of programs employed and required inputs and outputs are explained in detail. Demonstrations of case studies are provided under severely sheared currents to investigate the influences on amplitude variations of dynamic power cables caused by the excitation of high mode numbers. Finally, sensitivity studies have been performed to compare dynamic cable design parameters, specifically, structural damping ratio, higher order harmonics, and lift coefficients tables. In the future, one of the fundamental assumptions to assess the VIV response will be examined in detail, namely a narrow-banded Gaussian process derived from the VIV amplitudes. Although this approach is consistent with current industry standards, the level of consistency and the potential errors between the Gaussian process and the fatigue damage generated from deterministic time-domain results are to be confirmed to verify VIV fatigue analysis procedure for slender marine structures.
Abstract
The subsea power cables are increasingly important for harvesting renewable energies as we develop offshore wind farms located at a long distance from shore. Particularly, the continuous flexural motion of inter-array dynamic power cable of floating offshore wind turbine causes tremendous fatigue damages on the cable. As the subsea power cable consists of the helical structures with various components unlike a mooring line and a steel pipe riser, the fatigue analysis of the cables should be performed using special procedures that consider stick/slip phenomenon. This phenomenon occurs between inner helically wound components when they are tensioned or compressed by environmental loads and the floater motions. In particular, Vortex-induced vibration (VIV) can be generated by currents and have significant impacts on the fatigue life of the cable. In this study, the procedure for VIV fatigue analysis of the dynamic power cable has been established. Additionally, the respective roles of programs employed and required inputs and outputs are explained in detail. Demonstrations of case studies are provided under severely sheared currents to investigate the influences on amplitude variations of dynamic power cables caused by the excitation of high mode numbers. Finally, sensitivity studies have been performed to compare dynamic cable design parameters, specifically, structural damping ratio, higher order harmonics, and lift coefficients tables. In the future, one of the fundamental assumptions to assess the VIV response will be examined in detail, namely a narrow-banded Gaussian process derived from the VIV amplitudes. Although this approach is consistent with current industry standards, the level of consistency and the potential errors between the Gaussian process and the fatigue damage generated from deterministic time-domain results are to be confirmed to verify VIV fatigue analysis procedure for slender marine structures.
참고문헌 (27)
- Cigre, inc., "Recommendations for mechanical testing of submarine cables for dynamic applications", Cigre technical brochure 862 (Cigre TB 862), ~ (2022)
- Fu, S., "VIV of flexible cylinder in oscillatory flow", Proceedings of the ASME 2013 32nd International Conference on Ocean, Offshore and Arctic Engineering, pp.1~14 (2013)
- Jaiswal, V., "VIV response prediction for long risers with variable damping", Proceedings of the 26th International Conference on Offshore Mechanics and Arctic Engineering, pp.901~909 (2007)
- Jhingran, V., "Incorporating the higher harmonics in VIV fatigue predictions", Proceedings of the 26th International Conference on Offshore Mechanics and Arctic Engineering, pp.891~899 (2007)
- 김유철, "Cross flow response of a cylindrical structure under local shear flow", International Journal of Naval Architecture and Ocean Engineering, 1(2), pp.101~107 (2009), 대한조선학회
- Lekkala Malakonda Reddy, "Fatigue damage assessment of offshore riser subjected to vortex-induced vibrations by SHEAR7", International Journal of Naval Architecture and Ocean Engineering, 14, pp.1~17 (2022), 대한조선학회[DOI]
- Maincon, P., "Towards a time-domain finite element analysis of vortex induced vibrations", Proceedings of the ASME 2011 30th International Conference on Ocean, Offshore and Arctic Engineering, pp.415~425 (2011)
- Marcollo, H., "Traveling wave response in full-scale drilling riser VIV measurements", Proceedings of the ASME 2011 30th International Conference on Ocean, Offshore and Arctic Engineering, pp.523~537 (2011)
- Passano, E., "A Procedure to include slip damping in a VIV analysis of an umbilical", Proceedings of the ASME 2016 35th International Conference on Ocean, Offshore and Arctic Engineering (2016)
- Passano, E., "VIV of free spanning pipelines: comparison of response from semi-empirical code to model tests", Proceedings of the ASME 2010 29th International Conference on Ocean, Offshore and Arctic Engineering, pp.567~577 (2010)
- Pagnini, L. C., "VIV regimes and simplified solutions by the spectral model description" (2020), Journal of Wind Engineering & Industrial Aerodynamics
- Rao, Z., "VIV excitation competition between bare and buoyant segments of flexible cylinders", Proceedings of the ASME 32nd International Conference on Offshore Mechanics and Arctic Engineering (2013)
- Schiller, R. V., "Vortex induced vibrations of deep water risers: sensitivity to current profile, shear and directionality", Proceedings of the ASME 2014 33rd International Conference on Ocean, Offshore and Arctic Engineering (2014)
- User Guide for SHEAR7 Version 4.11, "MIT", MIT, ~ (2021)
- 심천식, "동적 파워 케이블의 해양운용환경 내구성 검증시험에 관한 연구", 대한조선학회 논문집, 58(1), pp.49~57 (2021), 대한조선학회[DOI]
- SESAM White Paper Helica. Cross section analysis of compliant structures – flexibles, umbilicals and cables. DNV GL Report, "Skeie, G.", ~ (2016)
- Sodahl, N., "Consistent VIV fatigue analysis methodology of umbilicals", Proceedings of the ASME 2011 30th International Conference on Ocean, Offshore and Arctic Engineering, pp.439~447 (2011)
- Soni, P.K., "Vortex pattern comparison for periodic and harmonic combined cross-flow & in-line forced oscillations", Proceedings of the ASME 2009 28th International Conference on Ocean, Offshore and Arctic Engineering, pp.853~867 (2009)
- Srinil, N., "Vortex-induced vibration of catenary riser: Reduced-order modeling and lock-in analysis using wake oscillator", Proceedings of the ASME 2009 28th International Conference on Ocean, Offshore and Arctic Engineering, pp.1404~1414 (2009)
- Sung, Y.B., "Power Cable Design and Dynamic Analysis for a Hybrid Platform", The 29th International Ocean and Polar Engineering Conference (2019)
- Vandiver, J. K., "Revealing the effects of damping on the flow-induced vibration of flexible cylinders", pp.29~54 (2018), Journal of Sound and Vibration
- Vandiver, J. K., "Fatigue damage from high mode number vortex-induced vibration", Proceedings of the 26th International Conference on Offshore Mechanics and Arctic Engineering, pp.803~811 (2006)
- Wu Hao, "Experimental study on the tension of cables and motion of tunnel element for an immersed tunnel element under wind, current and wave", International Journal of Naval Architecture and Ocean Engineering, 13, pp.889~901 (2021), 대한조선학회[DOI]
- Wu, J., "VIV responses of riser with buoyancy elements:forced motion test and numerical prediction", Proceedings of the ASME 2017 36th International Conference on Ocean, Offshore and Arctic Engineering (2017)
- Wu, J., "VIV force identification using classical optimal control algorithm", Proceedings of the ASME 2009 28th International Conference on Ocean, Offshore and Arctic Engineering, pp.559~570 (2009)
- Zhang, C., "Experimental investigation on the VIV of a slender body under the combination of uniform flow and top-end surge", Ocean Engineering, 216, pp.108094~ (2020)
- Zheng, H., "Vortex-induced vibration analysis (VIVA) based on hydrodynamic databases", Proceedings of the ASME 2011 30th International Conference on Ocean, Offshore and Arctic Engineering, pp.657~663 (2011)