Analysis of Structural Vibrations of Vertical Axis Wind Turbine Blades via Hamilton’s Principle — Part 3: Pitch Angle and Equilibrium State

Pitch angle is one of the most important parameters of wind turbine blade. This study is aimed to investigate the effect of the pitch angle on the deformation of a VAWT. Lagrangian mechanics and Euler’s beam theory are used to derive the motion equations of linear structural vibration for straight blade vertical axis wind turbine blade with the pitch angle [Formula: see text]. The complete equations of motion take account of the 4-DOF deformation of flexural–flexural–torsion–extension as well as the material damping. Vibration analysis of generalized displacement about the equilibrium state (GDAES) is carried out with respect to the displacement of the equilibrium state (DOES), which is separated from the motion of vibration. After simplifying the equilibrium equation of 4-DOF into 1-DOF system, the exact solution of displacement [Formula: see text] of the equilibrium state is derived. The correction [Formula: see text] of [Formula: see text] due to the pitch angle and the characteristics of [Formula: see text] with constant linear speed are analyzed. Furthermore, we investigate the coupling effect of lateral bending and axial extension of the blade on [Formula: see text] is analyzed. Finally, the exact solution of [Formula: see text] is verified by the central difference method.

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Peningkatan Kekakuan Sudu Turbin Angin Vertikal Berbahan Komposit Serat Karbon Melalui Rekayasa Penampang Inersia

Jurnal Rekayasa Hijau ◽

10.26760/jrh.v2i3.2514 ◽

2018 ◽

Vol 2 (3) ◽

Author(s):

Marsono Marsono ◽

Ali Ali ◽

Alek P. Sembiring

Keyword(s):

Carbon Fiber ◽

Wind Turbine ◽

Turbine Blade ◽

Bending Strength ◽

Fiber Composite ◽

Turbine Blades ◽

Vertical Axis ◽

Wind Turbine Blade ◽

Vertical Axis Wind Turbine ◽

Carbon Fiber Composite

ABSTRAKPerubahan bentuk dan dimensi sudu akan menurunkan kinerja turbin angin. Perubahan bentuk dan dimensi sudu sangat dipengaruhi oleh kekakuan dan kekuatan sudu turbin tersebut. Pada kasus di lapangan, ditemui bahwa sudu turbin angin sumbu vertikal yang dibuat dengan bahan komposit serat karbon ternyata tidak memiliki kekakuan yang baik jika hanya dibuat dengan satu lapis (layer) serat karbon. Untuk mengatasi masalah kekakuan ini, maka dilakukan penambahan tulang penguat (stiffener rib) dari bahan yang sama pada sudu turbin angin. Pengujian yang telah dilakukan menunjukan bahwa penambahan tulang penguat pada sudu turbin angin sumbu vertikal telah menambah kekakuan sudu secara signifikan yang cenderung mengikuti grafik eksponensial. Kekakuan (K) sudu dengan tinggi tulang 6 mm adalah 0,0258 kg/mm. Kekakuan sudu dengan tinggi tulang 9 mm adalah 0,0740 kg/mm. Kekakuan sudu dengan tinggi tulang 12 mm adalah 0,2250 kg/mm. Di sisi lain, kekuatan lentur sudu turbin juga meningkat. Dengan penambahan tulang 6mm, kekuatan lentur maksimum (􀀀max) mencapai 4,008 kg/mm2, dengan penambahan tulang 9 mm kekuatan lentur mencapai 4,145 kg/mm2, dengan penambahan tulang 12 mm kekuatan lentur mencapai 4,544 kg/mm2.Kata kunci: sudu turbin angin sumbu vertikal, inersia penampang, kekakuan, kekuatan lentur.ABSTRACTChanges in shape and dimension of the blade will decrease the wind turbine performance. These change are strongly influenced by the stiffness and strength of turbine blade. It was found that vertical axis wind turbine blades which is made with carbon fiber composite did not have good stiffness if it was made with only one layer of carbon fiber. To overcome this stiffness problem, stiffener rib with the same material was applied on wind turbine blade. The test that has been done shows that the addition of the stifferner rib to the vertical axis wind turbine blade has significantly increased the stiffness that tends to follow the exponential graphic. The stiffness (K) of the blade with 6 mm rib height is 0.0258 kg/mm. The blade stiffness with 9 mm rib height is 0.0740 kg/mm. The blade stiffness with 12 mm rib height is 0.2250 kg/mm. On the other hand, the bending strength of the turbine blade is also increased. With the addition of 6mm rib, the maximum flexurall strength (smax) reaches 4,008 kg/mm2. With the addition of 9 mm rib, the strength reaches 4,145 kg/mm2. With the addition of 12 mm rib, the strength reaches 4,544 kg/mm2.Keywords: vertical axis wind turbine, inertia, stiffness, flexurall strength.

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