Lag-twist coupling sensitivity and design for a composite blade cross-section with D-spar

M. R. Amoozgar; A. D. Shaw; J. Zhang; C. Wang; M. I. Friswell

doi:10.1016/j.ast.2019.05.053

Lag-twist coupling sensitivity and design for a composite blade cross-section with D-spar

M. R. Amoozgar, A. D. Shaw, J. Zhang, C. Wang, M. I. Friswell

Research output: Contribution to journal › Article

Abstract

In this paper, the effect of various parameters of a specific rotor blade cross-section on the effectiveness of a twist morphing concept is investigated. Then, by considering different constraints, a cross-section consistent with this morphing concept with high lag-twist coupling and low extension-twist, is developed. This lag bending-torsion coupling is used to change the twist of the blade during the flight, while the high values of extension-twist coupling is avoided. To this end, a concentrated mass is added to the blade, where its chordwise location varies in flight. When the mass moves in the chordwise direction, a local lag bending is introduced into the blade. This in-plane bending moment then changes the blade twist distribution through lag-twist coupling induced through stiffness tailoring in the blade cross-section. Therefore, this coupling plays an important role in this morphing concept. The one-dimensional dynamics of the blade is modelled by using the geometrically exact fully intrinsic bean equations while the 2D cross-sectional stiffness values are determined by using the VABS software. First, a blade which resembles the BO-105 main rotor blade in the fundamental frequencies is designed. Then, the effect of various parameters of the cross-section on the fundamental frequencies, the lag-twist coupling, and the extension-twist coupling are determined. It is found that the skin of the spar has the highest contribution to both the extension-twist and the lag-twist coupling. Finally, a cross-section compatible with the proposed morphing concept is designed and it is demonstrated that the twist of the blade may be changed significantly.

Original language	English
Pages (from-to)	539-547
Number of pages	9
Journal	Aerospace Science and Technology
Volume	91
Early online date	24 May 2019
DOIs	https://doi.org/10.1016/j.ast.2019.05.053
Publication status	Published - 1 Aug 2019
Externally published	Yes

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Turbomachine blades

Composite materials

Rotors

Stiffness

Bending moments

Torsional stress

Skin

Cite this

Amoozgar, M. R., Shaw, A. D., Zhang, J., Wang, C., & Friswell, M. I. (2019). Lag-twist coupling sensitivity and design for a composite blade cross-section with D-spar. Aerospace Science and Technology, 91, 539-547. https://doi.org/10.1016/j.ast.2019.05.053

Amoozgar, M. R. ; Shaw, A. D. ; Zhang, J. ; Wang, C. ; Friswell, M. I. / Lag-twist coupling sensitivity and design for a composite blade cross-section with D-spar. In: Aerospace Science and Technology. 2019 ; Vol. 91. pp. 539-547.

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title = "Lag-twist coupling sensitivity and design for a composite blade cross-section with D-spar",

abstract = "In this paper, the effect of various parameters of a specific rotor blade cross-section on the effectiveness of a twist morphing concept is investigated. Then, by considering different constraints, a cross-section consistent with this morphing concept with high lag-twist coupling and low extension-twist, is developed. This lag bending-torsion coupling is used to change the twist of the blade during the flight, while the high values of extension-twist coupling is avoided. To this end, a concentrated mass is added to the blade, where its chordwise location varies in flight. When the mass moves in the chordwise direction, a local lag bending is introduced into the blade. This in-plane bending moment then changes the blade twist distribution through lag-twist coupling induced through stiffness tailoring in the blade cross-section. Therefore, this coupling plays an important role in this morphing concept. The one-dimensional dynamics of the blade is modelled by using the geometrically exact fully intrinsic bean equations while the 2D cross-sectional stiffness values are determined by using the VABS software. First, a blade which resembles the BO-105 main rotor blade in the fundamental frequencies is designed. Then, the effect of various parameters of the cross-section on the fundamental frequencies, the lag-twist coupling, and the extension-twist coupling are determined. It is found that the skin of the spar has the highest contribution to both the extension-twist and the lag-twist coupling. Finally, a cross-section compatible with the proposed morphing concept is designed and it is demonstrated that the twist of the blade may be changed significantly.",

keywords = "Concentrated mass, Cross-section design, Fully intrinsic equations, Lag-twist coupling, Twist morphing",

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Amoozgar, MR, Shaw, AD, Zhang, J, Wang, C & Friswell, MI 2019, 'Lag-twist coupling sensitivity and design for a composite blade cross-section with D-spar', Aerospace Science and Technology, vol. 91, pp. 539-547. https://doi.org/10.1016/j.ast.2019.05.053

Lag-twist coupling sensitivity and design for a composite blade cross-section with D-spar. / Amoozgar, M. R.; Shaw, A. D.; Zhang, J.; Wang, C.; Friswell, M. I.

In: Aerospace Science and Technology, Vol. 91, 01.08.2019, p. 539-547.

Research output: Contribution to journal › Article

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AU - Amoozgar, M. R.

AU - Shaw, A. D.

AU - Zhang, J.

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AU - Friswell, M. I.

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Y1 - 2019/8/1

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AB - In this paper, the effect of various parameters of a specific rotor blade cross-section on the effectiveness of a twist morphing concept is investigated. Then, by considering different constraints, a cross-section consistent with this morphing concept with high lag-twist coupling and low extension-twist, is developed. This lag bending-torsion coupling is used to change the twist of the blade during the flight, while the high values of extension-twist coupling is avoided. To this end, a concentrated mass is added to the blade, where its chordwise location varies in flight. When the mass moves in the chordwise direction, a local lag bending is introduced into the blade. This in-plane bending moment then changes the blade twist distribution through lag-twist coupling induced through stiffness tailoring in the blade cross-section. Therefore, this coupling plays an important role in this morphing concept. The one-dimensional dynamics of the blade is modelled by using the geometrically exact fully intrinsic bean equations while the 2D cross-sectional stiffness values are determined by using the VABS software. First, a blade which resembles the BO-105 main rotor blade in the fundamental frequencies is designed. Then, the effect of various parameters of the cross-section on the fundamental frequencies, the lag-twist coupling, and the extension-twist coupling are determined. It is found that the skin of the spar has the highest contribution to both the extension-twist and the lag-twist coupling. Finally, a cross-section compatible with the proposed morphing concept is designed and it is demonstrated that the twist of the blade may be changed significantly.

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