PSI - Issue 42

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ScienceDirect

Procedia Structural Integrity 42 (2022) 382–389 Structural Integrity Procedia 00 (2019) 000–000 Structural Integrity Procedia 00 (2019) 000–000

www.elsevier.com / locate / procedia www.elsevier.com / locate / procedia

© 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the scientific committee of the 23 European Conference on Fracture – ECF23 Abstract During the manufacturing process of adhesive bonds di ff erent faults can occur, leading to a loss of structural integrity of the entire structure. This requires a thorough study of the connection behaviour in the presence of faults and localisation of such faults. For this purpose, double cantilever beam specimens were manufactured with and without predefined gaps. A soft, rubber-like adhesive system (Sikaflex ® -521 UV) was investigated. The experimental investigations include several measurement methods to identify the deflection of the adherend beams and to calculate the J-Integral in situ during testing. Optical measurement techniques such as digital image correlation and shearography are compared to backface strain measurement by optical fibres. In addition to quantifying of the e ff ects of certain defects on Mode I fracture behaviour, the applicability of the selected test methods and their respective limitations are discussed. All measurement methods are suitable for detecting gaps with di ff erent advantages and disadvantages. For example, it is possible to evaluate the J-integral from the backface strain and digital image correlation measurement with the deflection curve approach. 2020 The Authors. Published by Elsevier B.V. his is an open access article under the CC BY-NC-ND license (http: // creativec mmons.org / licenses / by-nc-nd / 4.0 / ) er-review under responsibility of 23 European Conference on Fracture – ECF23 . Keywords: optical measurement techniques; hyperelastic adhesive joints; double cantilever beam 23 European Conference on Fracture – ECF23 On the localisability of gaps in adhesive joints loaded in mode I Dennis Domladovac a, ∗ , Christian Wolf b , Igor Kryukov b , Martin Kahlmeyer b , Stefan Bo¨hm b , Stephan Marzi a a Technische Hochschule Mittelhessen, Wiesenstraße 14, 35390 Gießen, Germany b Universita¨ t Kassel, Kurt-Wolters-Straße 3, 34125 Kassel, Germany Abstract During the manufacturing process of adhesive bonds di ff erent faults can occur, leading to a loss of structural integrity of the entire structure. This requires a thorough study of the connection behaviour in the presence of faults and localisation of such faults. For this purpose, double cantilever beam specimens were manufactured with and without predefined gaps. A soft, rubber-like adhesive system (Sikaflex ® -521 UV) was investigated. The experimental investigations include several measurement methods to identify the deflection of the adherend beams and to calculate the J-Integral in situ during testing. Optical measurement techniques such as digital image correlation and shearography are compared to backface strain measurement by optical fibres. In addition to quantifying of the e ff ects of certain defects on Mode I fracture behaviour, the applicability of the selected test methods and their respective limitations are discussed. All measurement methods are suitable for detecting gaps with di ff erent advantages and disadvantages. For example, it is possible to evaluate the J-integral from the backface strain and digital image correlation measurement with the deflection curve approach. © 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http: // creativecommons.org / licenses / by-nc-nd / 4.0 / ) Peer-review under responsibility of 23 European Conference on Fracture – ECF23 . Keywords: optical measurement techniques; hyperelastic adhesive joints; double cantilever beam 23 European Conference on Fracture – ECF23 On the localisability of gaps in adhesive joints loaded in mode I Dennis Domladovac a, ∗ , Christian Wolf b , Igor Kryukov b , Martin Kahlmeyer b , Stefan Bo¨hm b , Stephan Marzi a a Technische Hochschule Mittelhessen, Wiesenstraße 14, 35390 Gießen, Germany b Universita¨ t Kassel, Kurt-Wolters-Straße 3, 34125 Kassel, Germany

1. Introduction 1. Introduction

During the manufacturing process of adhesive bonds in industrial applications, voids and gaps can occur, leading to a degradation of the joints performance. This requires studies into both the connection behaviour in the presence of gaps with regard to the mechanical properties and about the localisability of such faults. To the authors’ knowledge, only few publications deal with fracture mechanics of adhesive joints containing gaps, cavities or improper adhesion. Heide-Jørgensen et al. (2017) and Heide-Jørgensen et al. (2018) focus on thin adhesive layers of rather large sti ff ness and derived new models based on Euler-Bernoulli beam and Winkler elastic foundation During the manufacturing process of adhesive bonds in industrial applications, voids and gaps can occur, leading to a degradation of the joints performance. This requires studies into both the connection behaviour in the presence of gaps with regard to the mechanical properties and about the localisability of such faults. To the authors’ knowledge, only few publications deal with fracture mechanics of adhesive joints containing gaps, cavities or improper adhesion. Heide-Jørgensen et al. (2017) and Heide-Jørgensen et al. (2018) focus on thin adhesive layers of rather large sti ff ness and derived new models based on Euler-Bernoulli beam and Winkler elastic foundation

∗ Corresponding author. Tel.: + 49-641-309-2151; fax: + 49-641-309-2911. E-mail address: dennis.domladovac@me.thm.de ∗ Corresponding author. Tel.: + 49-641-309-2151; fax: + 49-641-309-2911. E-mail address: dennis.domladovac@me.thm.de

2452-3216 © 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the scientific committee of the 23 European Conference on Fracture – ECF23 10.1016/j.prostr.2022.12.048 2210-7843 © 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http: // creativecommons.org / licenses / by-nc-nd / 4.0 / ) Peer-review u der responsibility of 23 European Conference on Fracture – ECF23 . 2210-7843 © 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http: // creativecommons.org / licenses / by-nc-nd / 4.0 / ) Peer-review under responsibility of 23 European Conference on Fracture – ECF23 .