Issue 30

D. Tumino et alii, Frattura ed Integrità Strutturale, 30 (2014) 317-326; DOI: 10.3221/IGF-ESIS.30.39 317 Focussed on: Fracture and Structural Integrity related Issues Mechanical behavior of a sandwich with corrugated GRP core: numerical modeling and experimental validation D. Tumino Facoltà di Ingegneria e Architettura, Università degli Studi di Enna Kore, Cittadella Universitaria, 94100 Enna (Italy) davide.tumino@unikore.it T. Ingrassia, V. Nigrelli, G. Pitarresi, V. Urso Miano Dipartimento di Ingegneria Chimica, Gestionale, Informatica, Meccanica, Università degli Studi di Palermo, Viale delle Scienze, 90128 Palermo (Italy) A BSTRACT . In this work the mechanical behaviour of a core reinforced composite sandwich structure is studied. The sandwich employs a Glass Reinforced Polymer (GRP) orthotropic material for both the two external skins and the inner core web. In particular, the core is designed in order to cooperate with the GRP skins in membrane and flexural properties by means of the addition of a corrugated laminate into the foam core. An analytical model has been developed to replace a unit cell of this structure with an orthotropic equivalent thick plate that reproduces the in plane and out of plane behaviour of the original geometry. Different validation procedures have been implemented to verify the quality of the proposed method. At first a comparison has been performed between the analytical model and the original unit cell modelled with a Finite Element mesh. Elementary loading conditions are reproduced and results are compared. Once the reliability of the analytical model was assessed, this homogenised model was implemented within the formulation of a shell finite element. The goal of this step is to simplify the FE analysis of complex structures made of corrugated core sandwiches; in fact, by using the homogenised element, the global response of a real structure can be investigated only with the discretization of its mid-surface. Advantages are mainly in terms of time to solution saving and CAD modelling simplification. Last step is then the comparison between this FE model and experiments made on sandwich beams and panels whose skins and corrugated cores are made of orthotropic cross-ply GRP laminates. Good agreement between experimental and numerical results confirms the validity of the proposed model. K EYWORDS . Sandwich Structures; Corrugated Core; Homogenisation; Finite Element. I NTRODUCTION omposite sandwiches are a structural solution trying to integrate the advantages of the sandwich concept, high specific flexural rigidity, with those of Fibre Reinforced Polymer (FRP) composites, such as lightweight, complex shaping and flexible material assembling [1]. An optimised composite sandwich solution is a potential replacement of thick and heavy monolithic bidimensional structures, and hence an effective lightweight design strategy [2]. Therefore C