An experimental and analytical study of mode I fracture and crack kinking in thick adhesive joints

Ali Shivaie Kojouri; Javane Karami; Kalliopi-Artemi Kalteremidou; Jialiang Fan; Akash Sharma; Anastasios Vassilopoulos; Véronique Michaud; Wim Van Paepegem; Danny Van Hemelrijck

doi:10.1016/j.compositesb.2024.111695

An experimental and analytical study of mode I fracture and crack kinking in thick adhesive joints

Ali Shivaie Kojouri, Javane Karami, Kalliopi-Artemi Kalteremidou, Jialiang Fan, Akash Sharma, Anastasios Vassilopoulos, Véronique Michaud, Wim Van Paepegem, Danny Van Hemelrijck

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Abstract

This study investigates the fracture behavior of thick adhesive joints manufactured with composite adherends and bonded with an epoxy-based structural adhesive common to the wind turbine industry. For that purpose, double cantilever beam specimens with an adhesive thickness of approximately 10 mm and different pre-crack lengths are manufactured and tested under mode I loading. Analytical approaches are compared to assess the energy release rate, including the simple beam theory, modified beam theory, compliance calibration method, and beam on an elastic and elastic-plastic foundation. In order to evaluate the applicability of the analytical approaches, an in-situ measurement method based on Digital Image Correlation is also employed to determine the energy release rate of the thick adhesive joints. The crack propagation angle is determined theoretically using the second-order crack kinking theory. A good correlation is observed between the theoretical predictions and experimental results. Furthermore, it is demonstrated that due to the T-stress, the crack tends to deviate from the middle of the joint and propagate towards the interface. By comparing different data reduction methods to evaluate the energy release rate of thick adhesive joints, recommendations for their fracture analysis are made, pinpointing the beam on an elastic and elastic-plastic foundation as the most suitable model.

Original language	English
Article number	111695
Pages (from-to)	1-16
Number of pages	16
Journal	Composites Part B: Engineering
Volume	284
DOIs	https://doi.org/10.1016/j.compositesb.2024.111695
Publication status	Published - Sept 2024

Bibliographical note

Funding Information:
The authors acknowledge funding under the Lead Agency scheme from the Research Foundation - Flanders (FWO Vlaanderen) through the project grant G031020\u202FN and the Swiss National Science Foundation (SNF) through the project grant 200021E_18944/1 with the title \u201CCombined numerical and experimental approach for the development, testing and analysis of thick adhesive joints in large wind turbine blades\u201D. The authors also acknowledge Sika Technology AG for providing materials and support.

Funding Information:
The authors acknowledge funding under the Lead Agency scheme from the Research Foundation - Flanders (FWO Vlaanderen) through the project grant G031020N and the Swiss National Science Foundation (SNF) through the project grant 200021E_18944/1 with the title \"Combined numerical and experimental approach for the development, testing and analysis of thick adhesive joints in large wind turbine blades\u201D. The authors also acknowledge Sika Technology AG for providing materials and support.

Publisher Copyright:
© 2024 The Authors

Keywords

Mode I fracture
Energy release rate
J-integral
Thick adhesive joints
Crack kinking
Wind turbine blades

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10.1016/j.compositesb.2024.111695Licence: CC BY-NC

Final published versionFinal published version, 6.64 MBLicence: CC BY-NC

Cite this

@article{a30ab60809d74f14b452ca37f845ec04,

title = "An experimental and analytical study of mode I fracture and crack kinking in thick adhesive joints",

abstract = "This study investigates the fracture behavior of thick adhesive joints manufactured with composite adherends and bonded with an epoxy-based structural adhesive common to the wind turbine industry. For that purpose, double cantilever beam specimens with an adhesive thickness of approximately 10 mm and different pre-crack lengths are manufactured and tested under mode I loading. Analytical approaches are compared to assess the energy release rate, including the simple beam theory, modified beam theory, compliance calibration method, and beam on an elastic and elastic-plastic foundation. In order to evaluate the applicability of the analytical approaches, an in-situ measurement method based on Digital Image Correlation is also employed to determine the energy release rate of the thick adhesive joints. The crack propagation angle is determined theoretically using the second-order crack kinking theory. A good correlation is observed between the theoretical predictions and experimental results. Furthermore, it is demonstrated that due to the T-stress, the crack tends to deviate from the middle of the joint and propagate towards the interface. By comparing different data reduction methods to evaluate the energy release rate of thick adhesive joints, recommendations for their fracture analysis are made, pinpointing the beam on an elastic and elastic-plastic foundation as the most suitable model.",

keywords = "Mode I fracture, Energy release rate, J-integral, Thick adhesive joints, Crack kinking, Wind turbine blades",

author = "{Shivaie Kojouri}, Ali and Javane Karami and Kalliopi-Artemi Kalteremidou and Jialiang Fan and Akash Sharma and Anastasios Vassilopoulos and V{\'e}ronique Michaud and {Van Paepegem}, Wim and {Van Hemelrijck}, Danny",

note = "Funding Information: The authors acknowledge funding under the Lead Agency scheme from the Research Foundation - Flanders (FWO Vlaanderen) through the project grant G031020\u202FN and the Swiss National Science Foundation (SNF) through the project grant 200021E_18944/1 with the title \u201CCombined numerical and experimental approach for the development, testing and analysis of thick adhesive joints in large wind turbine blades\u201D. The authors also acknowledge Sika Technology AG for providing materials and support. Funding Information: The authors acknowledge funding under the Lead Agency scheme from the Research Foundation - Flanders (FWO Vlaanderen) through the project grant G031020N and the Swiss National Science Foundation (SNF) through the project grant 200021E_18944/1 with the title \{"}Combined numerical and experimental approach for the development, testing and analysis of thick adhesive joints in large wind turbine blades\u201D. The authors also acknowledge Sika Technology AG for providing materials and support. Publisher Copyright: {\textcopyright} 2024 The Authors",

year = "2024",

month = sep,

doi = "10.1016/j.compositesb.2024.111695",

language = "English",

volume = "284",

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AU - Shivaie Kojouri, Ali

AU - Karami, Javane

AU - Kalteremidou, Kalliopi-Artemi

AU - Fan, Jialiang

AU - Sharma, Akash

AU - Vassilopoulos, Anastasios

AU - Michaud, Véronique

AU - Van Paepegem, Wim

AU - Van Hemelrijck, Danny

N1 - Funding Information: The authors acknowledge funding under the Lead Agency scheme from the Research Foundation - Flanders (FWO Vlaanderen) through the project grant G031020\u202FN and the Swiss National Science Foundation (SNF) through the project grant 200021E_18944/1 with the title \u201CCombined numerical and experimental approach for the development, testing and analysis of thick adhesive joints in large wind turbine blades\u201D. The authors also acknowledge Sika Technology AG for providing materials and support. Funding Information: The authors acknowledge funding under the Lead Agency scheme from the Research Foundation - Flanders (FWO Vlaanderen) through the project grant G031020N and the Swiss National Science Foundation (SNF) through the project grant 200021E_18944/1 with the title \"Combined numerical and experimental approach for the development, testing and analysis of thick adhesive joints in large wind turbine blades\u201D. The authors also acknowledge Sika Technology AG for providing materials and support. Publisher Copyright: © 2024 The Authors

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N2 - This study investigates the fracture behavior of thick adhesive joints manufactured with composite adherends and bonded with an epoxy-based structural adhesive common to the wind turbine industry. For that purpose, double cantilever beam specimens with an adhesive thickness of approximately 10 mm and different pre-crack lengths are manufactured and tested under mode I loading. Analytical approaches are compared to assess the energy release rate, including the simple beam theory, modified beam theory, compliance calibration method, and beam on an elastic and elastic-plastic foundation. In order to evaluate the applicability of the analytical approaches, an in-situ measurement method based on Digital Image Correlation is also employed to determine the energy release rate of the thick adhesive joints. The crack propagation angle is determined theoretically using the second-order crack kinking theory. A good correlation is observed between the theoretical predictions and experimental results. Furthermore, it is demonstrated that due to the T-stress, the crack tends to deviate from the middle of the joint and propagate towards the interface. By comparing different data reduction methods to evaluate the energy release rate of thick adhesive joints, recommendations for their fracture analysis are made, pinpointing the beam on an elastic and elastic-plastic foundation as the most suitable model.

AB - This study investigates the fracture behavior of thick adhesive joints manufactured with composite adherends and bonded with an epoxy-based structural adhesive common to the wind turbine industry. For that purpose, double cantilever beam specimens with an adhesive thickness of approximately 10 mm and different pre-crack lengths are manufactured and tested under mode I loading. Analytical approaches are compared to assess the energy release rate, including the simple beam theory, modified beam theory, compliance calibration method, and beam on an elastic and elastic-plastic foundation. In order to evaluate the applicability of the analytical approaches, an in-situ measurement method based on Digital Image Correlation is also employed to determine the energy release rate of the thick adhesive joints. The crack propagation angle is determined theoretically using the second-order crack kinking theory. A good correlation is observed between the theoretical predictions and experimental results. Furthermore, it is demonstrated that due to the T-stress, the crack tends to deviate from the middle of the joint and propagate towards the interface. By comparing different data reduction methods to evaluate the energy release rate of thick adhesive joints, recommendations for their fracture analysis are made, pinpointing the beam on an elastic and elastic-plastic foundation as the most suitable model.

KW - Mode I fracture

KW - Energy release rate

KW - J-integral

KW - Thick adhesive joints

KW - Crack kinking

KW - Wind turbine blades

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U2 - 10.1016/j.compositesb.2024.111695

DO - 10.1016/j.compositesb.2024.111695

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SN - 1359-8368

VL - 284

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EP - 16

JO - Composites Part B: Engineering

JF - Composites Part B: Engineering

M1 - 111695

ER -

An experimental and analytical study of mode I fracture and crack kinking in thick adhesive joints

Abstract

Bibliographical note

Keywords

Access to Document

Other files and links

FWOAL970: Combined numerical and experimental approach for the development, testing and analysis of thick adhesive joints in large wind turbine blades

Cite this

An experimental and analytical study of mode I fracture and crack kinking in thick adhesive joints

Abstract

Bibliographical note

Keywords

Access to Document

Other files and links

Projects

FWOAL970: Combined numerical and experimental approach for the development, testing and analysis of thick adhesive joints in large wind turbine blades

Cite this