EUROSTEEL 2017, September 13–15, 2017, Copenhagen, Denmark Exploring the potentials of metal foams in structural elements for civil/building applications Diana Faiella* ,a , Simona Viscovo a , Elena Mele a a Department of Structures for Engineering and Architecture (DiSt) diana.faiella@unina.it, s.viscovo@studenti.unina.it, elenmele@unina.it ABSTRACT Sandwich foam beams and panels, made of solid skins and aluminium foam core, are widely applied in high-tech engineering fields; on the contrary structural use in the civil engineering field is not so common. An initial, explorative study on the structural application of metal foams in the civil and building engineering field is presented in this paper. The potentials of sandwich foam beams, made of solid skins (aluminium or steel) and aluminium foam core, are studied through analytical models and parametric analyses. The sandwich flexural response is investigated under four point bending test. For this purpose, an analytical tool able to provide design indications for sandwich foam beams is presented and applied in a parametric analysis, adopting some commercial aluminium foams and skins both in steel and aluminium alloys. The cross section failure modes under bending action (namely: skin fracture, core fracture, face wrinkling,) are studied, and failure mode maps are proposed for different combinations of solid- skins–foam-core in order to identify the dominant failure mode varying the skin thickness to beam depth ratio for practical design purposes. An experimental campaign is being planned to validate the presented results. Keywords: aluminium foams, mechanical properties, civil engineering, lightweight structures 1 INTRODUCTION Metal foams are a relatively new class of materials with cellular structure, namely a solid metal, frequently aluminium, depleted by a large volume fraction of pores. Since the density of both the solid and depleted materials ( and   , respectively) affect the overall mechanical properties, the relative density, i.e. /  , is adopted as the main variable for defining the generic foam property, , through scaling laws, which have the following form [1, 2]:    ={    }  (1) where the subscript  indicates the property of the solid metal from which the foam is made;  is a constant and  a fixed exponent. While aluminium foams are widely applied in high-tech engineering fields (aeronautics, mechanical, automotive, etc.) they are not yet adopted in civil structures, despite of their potential for lightweight and efficient solutions [3, 4]. In fact, sandwich configurations for structural elements, made of solid skins and aluminium foam core, can exhibit excellent stiffness-to-weight and strength-to-weight ratios thanks to so-called sandwich concept. The separation of the skins by means of the core increases the moment of inertia and the section strength modulus, with only a slight increase in weight, producing an efficient structure for bending resistance. Possible failure modes for sandwich beams include tensile or compressive failure of the skins, debonding at the core/skin interface, indentation failure under concentrated loads, core failure, wrinkling of the compression face and global buckling. In the present paper, considering the cross- section behaviour of the composite beam under four point bending, the failure modes investigated are: the attainment of the ultimate strain in the skins (skin fracture), the attainment of the tensile ductility in the core (core fracture), the wrinkling of the compressive face (face wrinkling) [5]. https://doi.org/10.1002/cepa.501 wileyonlinelibrary.com/journal/cepa © Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG, Berlin · ce/papers 1 (2017), No. 2 & 3 4417