PSI - Issue 72

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ScienceDirect

Procedia Structural Integrity 72 (2025) 26–33

12th Annual Conference of Society for Structural Integrity and Life (DIVK12) Experimental and numerical evaluation of composite sandwich H.G.E. da Silva a , R.D.S.G. Campilho a,b, *, P.J.R.O. Nóvoa a,b , R.J.B. Rocha b , K. Madani c , M. Benyettou c a CIDEM, ISEP – School of Engineering, Polytechnic Institute of Porto, R. Dr. António Bernardino de Almeida, 431, 4200-072 Porto, Portugal. b Institute of Science and Innovation in Mechanical and Industrial Engineering, Rua Dr. Roberto Frias, 400, 4200-465 Porto, Portugal. c Department of Mechanical Engineering, University of Sidi Bel Abbes, BP 89, Cité Ben M’hidi, 22000, Sidi Bel Abbes, Algeria. Abstract The development of predictive methods to assess the mechanical behavior of sandwich structures in service is imperative, assisting the design process and minimizing the necessity for costly experimental testing. This study addresses the behavior of sandwich structures under three-point bending (3PB) tests. Experimental tests were conducted to obtain the load-displacement ( P -  ) curves. Two material configurations were evaluated for the composite skins, while polymethacrylimide (PMI) foam was considered for the core, and SikaForce ® -7710 L100 adhesive to bond the skins with the core. The numerical models involved cohesive zone models (CZM) for the adhesive, the crushable foam model for the core, and the Tsai-Wu criterion for the skins. The experimental results indicated minimal variation between the two skins. Numerically, precise replication of the experimental tests was achieved. © 2026 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 Aleksandar Sedmak, Branislav Djordjevic, Simon Sedmak Dr. Simon Sedmak, ssedmak@mas.bg.ac.rs, Innovation Center of Faculty of Mechanical Engineering, Belgrade, Serbia

Keywords: Sandwich structures; Composite material; PMI foam; Cohesive zone models; three-point bending

1. Introduction The concept of a sandwich structure dates back a few centuries due to the advantages of using faces operating together, separated by a distance. This concept was discussed by Duleau in 1820 and later by Fairbairn (Olsson 1987). It was only in the last century, at World Wars, that these structures began to be used on aircraft (Allen 1969, Zenkert 1997, Vinson 1999). Sandwich structures have thin layers (skins), which are stiff and capable of withstanding high

* Corresponding author. Tel.: +351-939526892; fax: +351-228321159. E-mail address: raulcampilho@gmail.com

2452-3216 © 2026 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 Aleksandar Sedmak, Branislav Djordjevic, Simon Sedmak Dr. Simon Sedmak, ssedmak@mas.bg.ac.rs, Innovation Center of Faculty of Mechanical Engineering, Belgrade, Serbia 10.1016/j.prostr.2025.08.070