PSI - Issue 68

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Procedia Structural Integrity 68 (2025) 358–364 Structural Integrity Procedia 00 (2024) 000–000 Structural Integrity Procedia 00 (2024) 000–000

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European Conference on Fracture 2024 Dual-actuator mixed-mode bending tests on adhesive joints of di ff erent thickness European Conference on Fracture 2024 Dual-actuator mixed-mode bending tests on adhesive joints of di ff erent thickness Ihssane Kididane a , Kamila Koza´kova´ b,c , Stephan Marzi a, ∗ a Institute of Mechanics and Materials, Technische Hochschule Mittelhessen, 35390 Gießen, Germany b Institute of Physics of Materials CAS, Zˇizˇkova 513 / 22, Brno, Czech Republic c Faculty of Mechanical Engineering, Brno University of Technology, Technicka´ 289 / 2, Brno, Czech Republic Ihssane Kididane a , Kamila Koza´kova´ b,c , Stephan Marzi a, ∗ a Institute of Mechanics and Materials, Technische Hochschule Mittelhessen, 35390 Gießen, Germany b Institute of Physics of Materials CAS, Zˇizˇkova 513 / 22, Brno, Czech Republic c Faculty of Mechanical Engineering, Brno University of Technology, Technicka´ 289 / 2, Brno, Czech Republic Abstract In this work, fracture mechanics test results on adhesive joints of di ff erent thicknesses in mixed mode I + II are presented. While established test setups commonly apply constant mode-mixity and therefore provide a single data point of the fracture envelope, dual-actuator mixed-mode bending tests are intended to determine the entire fracture envelope in a single test. This circumstance significantly reduces the number of experiments required to obtain a fracture envelope with many support points. A modification of the experimental setup enables a Single-Leg Bending (SLB) configuration and thus opens up the possibility of a comparison with reference measurements from the literature. © 2025 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 ECF24 organizers. Keywords: Adhesive joints; Mixed-mode I + II testing; Fracture envelope; J -Integral Abstract In this work, fracture mechanics test results on adhesive joints of di ff erent thicknesses in mixed mode I + II are presented. While established test setups commonly apply constant mode-mixity and therefore provide a single data point of the fracture envelope, dual-actuator mixed-mode bending tests are intended to determine the entire fracture envelope in a single test. This circumstance significantly reduces the number of experiments required to obtain a fracture envelope with many support points. A modification of the experimental setup enables a Single-Leg Bending (SLB) configuration and thus opens up the possibility of a comparison with reference measurements from the literature. © 2025 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 ECF24 organizers. Keywords: Adhesive joints; Mixed-mode I + II testing; Fracture envelope; J -Integral © 2025 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 ECF24 organizers

1. Introduction 1. Introduction

In the area of fracture mechanics testing of adhesive joints in mixed-mode loading, a lot of e ff ort was put into developing suitable testing arrangements and evaluation methods. The main focus in literature is on a combination of peel stress (mode I) and in-plane shear stress (mode II). Marzi (2023) provides a comprehensive overview of established methods and recent developments. What most of the established methods have in common is that they load the sample under conditions of constant mode-mixity. As a result, a specific value of the critical energy release rate (ERR) is obtained for a specific mode-mixity and quite a lot of experimentation is required to obtain a fracture envelope with a su ffi cient number of support points. If the influence of certain joint parameters (e.g. layer thickness) on the mixed-mode fracture behavior is of interest, a possible variation of the mode-mixity within a single test would be an excellent alternative. In the area of fracture mechanics testing of adhesive joints in mixed-mode loading, a lot of e ff ort was put into developing suitable testing arrangements and evaluation methods. The main focus in literature is on a combination of peel stress (mode I) and in-plane shear stress (mode II). Marzi (2023) provides a comprehensive overview of established methods and recent developments. What most of the established methods have in common is that they load the sample under conditions of constant mode-mixity. As a result, a specific value of the critical energy release rate (ERR) is obtained for a specific mode-mixity and quite a lot of experimentation is required to obtain a fracture envelope with a su ffi cient number of support points. If the influence of certain joint parameters (e.g. layer thickness) on the mixed-mode fracture behavior is of interest, a possible variation of the mode-mixity within a single test would be an excellent alternative.

∗ Corresponding author. E-mail address: stephan.marzi@me.thm.de ∗ Corresponding author. E-mail address: stephan.marzi@me.thm.de

2452-3216 © 2025 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 ECF24 organizers 10.1016/j.prostr.2025.06.066 2210-7843 © 2025 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 ECF24 organizers. 2210-7843 © 2025 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 ECF24 organizers.