Numerical Study of Deflection and Stress Distribution on Composite Box Spar Structure – Application In Wind Turbine Blade

Putri Safina Ufaira (Department of Mechanical Engineering, Institut Teknologi Sepuluh Nopember)
Putu Suwarta (Department of Mechanical Engineering, Institut Teknologi Sepuluh Nopember)
Galih Bangga (Institute of Aerodynamics and Gas Dynamics, University of Stuttgart, 70569 Stuttgart, Germany)

JMES The International Journal of Mechanical Engineering and Sciences
Vol 6, No 1 (2022)

This paper present finite element analysis on the internal structure of wind turbine to examined the deflection and stress distribution. The structure was modeled as a cantilever box beam with constant cross section along the length. The dimension of the structure was set according to the original design of the 10 MW AVATAR (Advanced Aerodynamic Tools for Large Rotors) wind turbine. The proposed materials were unidirectional thin-ply TC35/Epoxy and M55/Epoxy carbon composites and standardthickness S−Glass 913/Epoxy composite. The fibre at the spar caps is oriented at 90o and at the shear webs at 0o. The deflection curve of the three composite materials showing non-linear behaviour with a maximum deflection of 2.618 m, 2.429 m, 4.175 m at the blade tip for S−Glass 913/Epoxy, T35/Epoxy, M55/Epoxy respectively which is less than the maximum deflection of an existing AVATAR beam. The critical stresses are located at the top outer surface of the spar cap which received the load directly and at the intersection between the spar caps and shear webs where stress transfer occurs. The deflection performance of the structure is dictated by the transverse Young’s Modulus (E22)  while the longitudinal Young’s Modulus (E11) plays an important role on stress distribution.