Structural transverse cracking mechanisms of trailing edge regions in composite wind turbine blades

Miao, Xiangshui; Xiao, Chen

doi:10.1016/j.compstruct.2023.116680

“…They have also been considered to calculate peel stresses in a trailing edge adhesive joint [6]. Buckling as another geometrically nonlinear effect was found to be a possible driver for trailing edge damages [7]. However, to the best knowledge of the authors, there is no publication available on the effect of IPCD on the aerodynamic or aeroelastic behavior of the blade.…”

Section: Introductionmentioning

confidence: 99%

Impact of shell structure stiffness on aero-structural coupling in wind turbine rotor blades

Balzani,

Gebauer

2023

IOP Conf. Ser.: Mater. Sci. Eng.

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Wind turbine rotor blades are heavily loaded composite structures that experience a mixture of aerodynamic, inertial, gravitational, and gyroscopic forces during their operation life. Due to the high loads, the cross-sections of the blades are subjected to in-plane and out-of-plane deformations. The out-of-plane deformations are referred to as shear warping while the in-plane deformations are also called blade breathing. Blade breathing depends on the magnitude of the mechanical loads, which are expressed by means of internal forces and moments, and the stiffness of the blade shell. In this work, the relationships between in-plane cross-sectional deformations and internal loads are investigated. For the quantification of the deformation, a reference blade is studied via 3D finite shell element simulations for different loading scenarios. The cross-section of interest is located at the radial position of maximum chord. To compare the shape of the cross-sections in the undeformed and the deformed configurations, a procedure is proposed to relate the positions of nodes associated with the cross-section of interest in both configurations to a joint coordinate system. The shape of the deformed cross-section is then extracted and compared with the undeformed configuration. The comparison is executed for the individual internal forces and moments, namely flapwise and edgewise bending moments, normal force, shear forces, and torsion moment, respectively. The deformation patterns are discussed and it is addressed how these may influence the aerodynamic behavior of the cross-section under consideration.

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Asynchronous Ring Opening of Cyclic Carbonate and Glycidyl Ether Induced Phase Evolution Towards Heat‐Free and Rapid‐Bonding Superior Epoxy Adhesive

Niu,

Li,

Zhu

et al. 2024

Angewandte Chemie

0

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Structural adhesives that do not require heating are in high demand in the automotive and electronics industries. However, it remains a challenge to develop robust adhesives that rapidly achieve super adhesion near ambient temperature. Herein, a room‐temperature curable, fast‐bonding, and super strong epoxy‐based structural adhesive was designed from the perspective of cross‐scale structure, which lies in threefold pivotal aspects: (i) high branching topology of glycerol carbonate‐capped polyurethane (PUGC) increases the kinetics of the ring‐opening reaction, contributing to fast crosslinking and the formation of abundant urethane and hydroxyl moieties; (ii) asynchronous crosslinking of epoxy and PUGC synergistically induces phase separation of PUGC within the epoxy resin and the resulting PUGC domains surrounded by interpenetrated shell serves to efficiently toughen the matrix; (iii) abundant dynamic hydrogen bonds including urethane and hydroxyl moieties, along with the elastomeric PUGC domains, dissipate energy of shearing force. As a result, the adhesive strength rapidly grows to 16 MPa within 4 hours, leveling off to 21 MPa after 7 hours, substantially outperforming commercial room‐temperature curable epoxy adhesives. The results of this study could advance the field of high‐performance adhesives and provide valuable insights into designing materials for efficient curing at room temperature.

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Asynchronous Ring Opening of Cyclic Carbonate and Glycidyl Ether Induced Phase Evolution Towards Heat‐Free and Rapid‐Bonding Superior Epoxy Adhesive

Niu,

Li,

Zhu

et al. 2024

Angew Chem Int Ed

1

0

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Structural adhesives that do not require heating are in high demand in the automotive and electronics industries. However, it remains a challenge to develop robust adhesives that rapidly achieve super adhesion near ambient temperature. Herein, a room‐temperature curable, fast‐bonding, and super strong epoxy‐based structural adhesive was designed from the perspective of cross‐scale structure, which lies in threefold pivotal aspects: (i) high branching topology of glycerol carbonate‐capped polyurethane (PUGC) increases the kinetics of the ring‐opening reaction, contributing to fast crosslinking and the formation of abundant urethane and hydroxyl moieties; (ii) asynchronous crosslinking of epoxy and PUGC synergistically induces phase separation of PUGC within the epoxy resin and the resulting PUGC domains surrounded by interpenetrated shell serves to efficiently toughen the matrix; (iii) abundant dynamic hydrogen bonds including urethane and hydroxyl moieties, along with the elastomeric PUGC domains, dissipate energy of shearing force. As a result, the adhesive strength rapidly grows to 16 MPa within 4 hours, leveling off to 21 MPa after 7 hours, substantially outperforming commercial room‐temperature curable epoxy adhesives. The results of this study could advance the field of high‐performance adhesives and provide valuable insights into designing materials for efficient curing at room temperature.

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Structural transverse cracking mechanisms of trailing edge regions in composite wind turbine blades

Cited by 8 publications

References 28 publications

Impact of shell structure stiffness on aero-structural coupling in wind turbine rotor blades

Impact of shell structure stiffness on aero-structural coupling in wind turbine rotor blades

Asynchronous Ring Opening of Cyclic Carbonate and Glycidyl Ether Induced Phase Evolution Towards Heat‐Free and Rapid‐Bonding Superior Epoxy Adhesive

Asynchronous Ring Opening of Cyclic Carbonate and Glycidyl Ether Induced Phase Evolution Towards Heat‐Free and Rapid‐Bonding Superior Epoxy Adhesive

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