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) 1950–1962

© 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 Adhesive bonding has become a fundamental manufacturing technology in the railway industry by allowing lightweight design of structures, which is beneficial in terms of energy, environmental and cost efficiency. Due to the polymeric nature of adhesive materials, the presence of stress multiaxiality has a strong effect on their mechanical behaviour under static and fatigue conditions. The present work deals with an investigation of the multiaxial behaviour of an elastic (polyurethane-based) and a structural (epoxy based) adhesive for railway applications. Samples with different stress multiaxialities (butt joint, scarf joint, and thick adherend shear test joint) were tested under static and fatigue conditions. The stress multiaxiality was defined as the ratio between the hydrostatic stress ( p ) and the von Mises equivalent stress ( q ). Finite Element Analysis showed that the mechanical properties of adhesives have a strong influence of the stress multiaxiality distribution of joints with elastic adhesive reaching higher levels of stress multiaxiality. Static tests revealed that elastic adhesive joints are more sensitive to multiaxiality (i.e. higher hydrostatic stresses) than their structural counterparts, especially in samples with larger hindering of lateral contraction. From fatigue test results of both adhesives, namely SN curves, it was demonstrated how multiaxial p-q fatigue diagrams can be constructed. One of the main advantages of this approach is the possibility of predicting the fatigue lifetime of joints regardless of their multiaxial stress state. © 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: elastic adhesive; structural adhesive; static analysis; fatigue analyis; multiaxialiy; railway application; stress analysis. adhesives for railway applications Vinicius Carrillo Beber a,b *, Markus Brede a a Fraunhofer-Institute for Manufacturing Technology and Advanced Materials IFAM, Wiener Straße 12, D-28359, Bremen, Germany b University of Bremen, Faculty 04 – Pr duction Engi e ring, Badgasteiner Straß 1, D-28359, Bremen, Ger a y Abstract Adhesive bonding has become a fundamental manufacturing technology in the railway industry by allowing lightweight design of structures, which is ben ficial in terms of energy, envi o m ntal and cost effic enc . D e to the p lymeric nature of adhesive materials, the presenc of stress multiaxiality has a strong effect on their mechanical behaviour under static and f igue con itions. The present wo k deals with an investigation of the multiaxial behaviou of an elastic (polyuretha e-ba ed) and a s ructural (ep xy bas d) adhesive for rail ay pplications. Samples with different stress multiaxial ties (b tt joi t, sc rf joi t, nd thick adherend shear test joint) were tested under static and fatigue conditio s. The stress mult axiality was defined as the ratio between the hydrostatic stress ( p ) and the von Mises equivalent stress ( q ). Finite Element Analys s sho ed that the mec anical properties of adhesives hav a strong influence of the stress multiaxiality distribution of joints with elastic ad esiv rea ing higher l vel stres multi xiality. Stat c tests revealed that elastic adhesive jo nts are more sens iv to multiax ality (i.e. higher hydrostatic es) th n their structural count rparts, especially in samples with large hindering of lateral contract on. From fatigue test results of both adhe ives, namely SN cu ves, it was demonstrated how multiaxial p-q fatigue diagrams c n be constructed. One of the main advantag of this pproach is the possibility of predicting the fatigue l fetime of joints reg rdless of their multiaxial stress state. © 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 K ywords: elastic adh sive; structural ad esive; static analysis; fatigue analyis; multiaxialiy; railway application; stress analysis. 1st Virtual European Conference on Fracture Multiaxial static and fatigue behaviour of elastic and structural adhesives for railway applications Vinicius Carrillo Beber a,b *, Markus Brede a a Fraunhofer-Institute for Manufacturing Technology and Advanced Materials IFAM, Wiener Straße 12, D-28359, Bremen, Germany b University of Bremen, Faculty 04 – Production Engineering, Badgasteiner Straße 1, D-28359, Bremen, Germany 1st Virtual European Conference on Fracture Multiaxial static and fatigue behaviour of elastic and structural

* Corresponding author. Tel.: +49 421 2246 7371. E-mail address: vinicius.carrillo.beber@ifam.fraunhofer.de * Corresponding author. Tel.: +49 421 2246 7371. E-mail address: vinicius.carrillo.beber@ifam.fraunhofer.de

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.2020.11.018