PSI - Issue 28

ScienceDirect Structural Integrity Procedia 00 (2019) 000–000 Structural Integrity Procedia 00 (2019) 000–000 Available online at www.sciencedirect.com Available online at www.sciencedirect.com ScienceDirect Available online at www.sciencedirect.com ScienceDirect

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

Procedia Structural Integrity 28 (2020) 1116–1124

© 2020 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 European Structural Integrity Society (ESIS) ExCo Abstract A common technique to reduce stress gradients in adhesive joints is to use the dual adhesive technique, which has proven to reduce peak stresses in single-lap joints. However, other joint configurations could benefit from this technique. This work experimentally and numerically evaluates stepped-lap dual-adhesive joints (DAJ) between aluminum adherends, for various overlap lengths ( L O ), and carries out a detailed comparison with stepped-lap single-adhesive joints (SAJ) with the same individual adhesives (Araldite ® AV138 and Araldite ® 2015). The joint behavior was predicted by cohesive zone modelling (CZM) with a triangular law. The analysis of the results is presented in the form of failure modes, stress analysis, maximum load ( P m ) and energy required to failure ( U ). It was concluded that, in general, CZM presented precise predictions and are a valuable tool for the design of both SAJ and DAJ. However, no significant increase in strength was achieved with DAJ, although using more ductile adhesive can promote better DAJ results. © 2020 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 European Structural Integrity Society (ESIS) ExCo Keywords: Adhesive joints; Stepped-lap joints; Cohesive zone models; Dual adhesive joints. 1. Introduction Adhesive bonding has been used in fields as diverse as aerospace (Désagulier 2011) and aeronautics (Hart-Smith 2011), defence, automotive (Burchardt 2011), electronics (Jung and Kim 2011), construction (Hartung and Boehm 2011), footwear (Martín-Martínez 2011), wood industry, marine (Davies 2011), railway (Suzuki 2011) and others. 1st Virtual European Conference on Fracture Bonded structures improvement by the dual adhesive technique C.L. Ferreira a , R.D.S.G. Campilho a,b *, R.D.F. Moreira a,b a Departamento de Engenharia Mecânica, Instituto Superior de Engenharia do Porto, Instituto Politécnico do Porto, Rua Dr. António Bernardino de Almeida, 431, 4200-072 Porto, Portugal. b INEGI – Pólo FEUP, Rua Dr. Roberto Frias, s/n, 4200-465 Porto, Portugal. Abstract A common technique to reduce stress gradients in adhesive joints is to use the dual adhesive technique, which has proven to reduce peak stresses in single-lap joints. However, other joint configurations co ld benefit from this tec nique. This work experimentally and numerica ly evalua es stepped-lap dual-adhesive joints (DAJ) betw en aluminum adherends, for vari us overlap lengths ( L O ), and rries out a de ailed comparison with stepped-lap single-adhesive joints (SAJ) with the same individual ad esives (Araldite ® AV138 and Araldite ® 2015). The joint b havior was predicted by cohesive zone modelling (CZM) with a triangular l w. The analysis of the results is presented in the form of failure modes, stress analysis, maxi um oad P m ) and energy req ired to failure ( U ). It was concl ded that, i general, CZM presented preci e p dictions and are a valuable tool for the design of both SAJ and DAJ. However, no significant i c ease in strength was a hi ved wi h DAJ, although sing m re ductile adhesive can promote better DAJ r sults. © 2020 The Authors. Published by ELSEVIER B.V. This is an open acce s article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review u der r ponsibility of e European Structural Integri y So i ty (ESIS) ExCo K ywords: Adhesive joints; Stepped-lap joints; Cohesive zone models; Dual adhesive joints. 1. Introduction Adhesive bonding has been used in fields as diverse as aerospace (Désagulier 2011) and aeronautics (Hart-Smith 2011), defence, automotive (Burchardt 2011), electronic (Jung nd Kim 2011), construction (H rtung and Boehm footwear (Martín-Martínez 2011), wood industry, marine (Davies , railway (Suzuki 2011) others. 1st Virtual European Conference on Fracture Bonded structures improvement by the dual adhesive technique C.L. Ferreira a , R.D.S.G. Campilho a,b *, R.D.F. Moreira a,b a Departamento de Engenharia Mecânica, Instituto Superior de Engenharia do Porto, Instituto Politécnico do Porto, Rua Dr. António Bernardino de Almeida, 431, 4200-072 Porto, Portugal. b INEGI – Pólo FEUP, Rua Dr. Roberto Frias, s/n, 4200-465 Porto, Portugal.

* Corresponding author. Tel.: +351 939526892; fax: +351 228321159. E-mail address: raulcampilho@gmail.com (R.D.S.G. Campilho). * Corresponding author. Tel.: +351 939526892; fax: +351 228321159. E-mail address: raulcampilho@gmail.com (R.D.S.G. Campilho).

2452-3216 © 2020 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 European Structural Integrity Society (ESIS) ExCo 2452-3216 © 2020 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 u der responsibility of t European Structural Integrity So i ty (ESIS) ExCo

2452-3216 © 2020 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 European Structural Integrity Society (ESIS) ExCo 10.1016/j.prostr.2020.11.126