PSI - Issue 79

Available online at www.sciencedirect.com

ScienceDirect

Procedia Structural Integrity 79 (2026) 97–104

© 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 IGF28 - MedFract3 organizers Keywords: Sandwich structures; Composite material; PMI foam; Cohesive zone models; four-point bending. Abstract Sandwich structures are widely applied in aerospace, marine, transportation, and renewable energy industries, where enhanced strength-to-weight ratios and impact resistance are essential. However, accurate predictive models that capture their complex failure mechanisms are required. This study investigates the mechanical behavior of sandwich panels subjected to four-point bending (4PB) through both experimental testing and finite element modelling. The structures were composed of composite skins bonded to a polymethacrylimide (PMI) foam core (ROHACELL ® ) using the adhesive SikaForce ® 7710 L100. Two composite skin configurations were considered. The numerical analysis was conducted using Cohesive Zone Models (CZM) to simulate adhesive behavior, a fractured foam model for the core, and the Tsai-Wu criterion for skin failure. The experimental-numerical comparison demonstrated a good correspondence between both outcomes, with deviations below 20% in critical parameters. 1. Introduction A typical sandwich structure resides on the outer face sheets and the core embedded between them. Combining the bending resistance of the skin and the shear resistance of the core provides low density, high specific strength 28th International Conference on Fracture and Structural Integrity - 3rd Mediterranean Conference on Fracture and Structural Integrity Experimental and numerical investigation of sandwich structures under 4-point bending using progressive damage models H.G.E. da Silva a , R.J.B. Rocha b , R.D.S.G. Campilho a,b, *, P.J.R.O. Nóvoa a,b , K. Madani 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.

* Corresponding author. Tel.: +351939526892; fax: +351228321159. E-mail address: raulcampilho@gmail.com

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 IGF28 - MedFract3 organizers 10.1016/j.prostr.2025.12.312