A METHOD BASED ON CLASSICAL LAMINATION THEORY TO CALCULATE STIFFNESS PROPERTIES OF CLOSED COMPOSITE SECTIONS
Structural deformation of composite wind turbine blades affect the aerodynamic performance of the rotor. To design better blades in terms of efficiency, aerodynamic performance and load mitigation, it is crucial to understand how blades act under operational loads. An interdisciplinary research should be conducted including composite structures and aerodynamics to analyze this interaction. This article focuses on the structural part and explains an easy to apply method to define sectional properties of a closed composite section. The method is based on Classical Lamination Theory (CLT) and it is assumed that the blade is a thin walled structure. Stress concentration and warping effects are ignored. During preliminary design phase, this method is useful to calculate bending and torsional stiffness values based on different lamination parameters and materials, it can also be used to investigate bending-torsion coupling effects. This article also includes parametric studies on NACA profiles using the method explained. This is the first phase of a study investigating aero-structure interaction in wind turbine blades and its effects on rotor performance.
 Kaw, A. K., (2006) “Mechanics of Composite Materials”, Taylor & Francis, 2nd Edition.
 Daniel, I. M. and Ishai, O., (1994) “Engineering Mechanics of Composite Materials”, Oxford University Press.
 Kollar, L. P. and Springer, G. S., (2003) “Mechanics of Composite Structures”, Cambridge University Press.
 Vasiliev, V.V. and Morozov, E. V., (2001) “Mechanics and Analysis of Composite Materials”, Elsevier.
 Librescu, L. and Song, O., (2006) “Thin-walled composite beams: theory and application”, Springer.
 Karaolis, N.M., Jeronimidis, G., Musgrove, P. J., (1989) “Composite wind turbine blades: coupling effects and rotor aerodynamic performance”, EWEC 1989 Proceedings.
 Armanios, E. A. and Badir, A. M., (1995) “Free Vibration Analysis of Anisotropic thin walled closed section beams”, AIAA Journal, Vol. 33, No. 10, pp. 1905-1910.
 Chandra, R. and Chopra, I., (1992) “Structural behavior of two-cell composite rotor blades with elastic couplings”, AIAA Journal, Vol. 30, No. 12, pp. 2914-2921.
 Lee, A. ve Flay, R., (1998). “Compliant blades for wind turbines”, IPENZ Transactions, 1999, Vol. 26, No. 1/EMCh.
 Lobitz. D. W. and Veers, P. S., (1998), “Aeroelastic Behavior of Twist-Coupled Hawt Blades”, Sandia National Laboratories, Albuquerque, New Mexico 87185-0439.
 Ong, C. H. and Tsai, S. W. (1998), “Elastic Tailoring of a Composite D-Spar”, Sandia National Laboratories, Report No: SAND98-1750.
 Volovoi V.V. and Hodges D.H., (2000) “Theory of anisotropic thin-walled beams”, J. Applied Mechanics; 67(3):453–459.
 Volovoi V.V. and Hodges D.H., (2002) “Single and multi-celled composite thin-walled beams”, AIAA J;40(5):960–6.
 Volovoi, V. V., Hodges, D. H., Cesnik, C. E. S., Popescu, B., (2001). “Assessment of Beam Modeling Methods for Rotor Blade Applications”, Mathematical and Computer Modelling 33 (2001) 1099-1112.
 Maheri, A., Noroozi, S., Toomer, C., Vinney, J., (2006). “WTAB, a computer program for predicting the performance of horizontal axis wind turbines with adaptive blades”, Renewable Energy 31 (2006) 1673–168.
 Maheri, A., Noroozi, S., Vinney, J., (2007), “Combined analytical/FEA-based coupled aero structure simulation of a wind turbine with bend–twist adaptive blades”, Renewable Energy 32 (2007) 916–930, Elsevier.
 Maheri, A., Noroozi, S., Vinney, J., (2007), “Application of combined analytical/FEA coupled aero-structure simulation in design of wind turbine adaptive blades”, Renewable Energy 32 (2007) 2011-2018.
 Maheri, A., Noroozi, S., Vinney, J., (2006), “Decoupled aerodynamic and structural design of wind turbine adaptive blades”, Renewable Energy 32 (2007) 1753-1767, Elsevier.
 Chen, H., Yu, W., Capellaro, M., (2009), “A critical assessment of computer tools for calculating composite wind turbine blade properties”, Wind Energy, (2009), DOI: 10.1002/we.372.
 Park, A. J., Jung, S. N., (2009), “General Purpose Cross-section Analysis Program for Composite Rotor Blades”, International Journal of Aeronautical & Space Sciences, Volume 10, No:2, November 2009.
 Tingrui, L. ve Yongsheng, R., (2010), “Vibration and flutter of wind turbine blade modeled as anisotropic thin-walled closed-section beam”, Mechanical & Electronical Institute, Shandong University of Since & Technology, Qingdao, China
 Jeong, M., Yoo, S., Lee, I., (2011), “Aeroelastic Analysis for Large Wind Turbine Rotor Blades”, 52nd AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference 19th, 4 - 7 April 2011, Denver, Colorado.
 Lee Y., Jhan Y., Chung C., (2012), “Fluid–structure interaction of FRP wind turbine blades under aerodynamic effect”, Composites Part B: Engineering, Volume 43, Issue 5, 2012, Pages 2180–2191.
 Jeon M., Lee S. and Lee S., (2014), “Unsteady vortex lattice method coupled with a linear aeroelastic model for horizontal axis wind turbine”, J. Renewable Sustainable Energy 6, 042006.
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