Special Issue "Metal Foams"

Guest Editor
Dr. Afsaneh Rabiei
Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC 27695-7910, USA
Website: http://www.mae.ncsu.edu/rabiei/
E-Mail: arabiei@ncsu.edu
Interests: reliability and non-destructive evaluation (NDE) of materials and structures; processing, characterization, and failure analysis of advanced materials such as: metallic foams, coatings and thin films, composites, materials for MEMS structures, shape memory alloys, bio-materials/ materials for biomedical applications, surface modification

Guest Editor
Dr. Bazle Z. Haque
Center for Composite Materials (UD-CCM), University of Delaware, Newark, DE 19716, USA
Website: http://www.ccm.udel.edu/Tech/MAT162/Intro.htm
E-Mail: gama@udel.edu
Phone: +1 302 831 0248
Fax: +1 302 831 8525
Interests: composites – mechanics, design, processing, and repair; experimental and computational dynamics; dynamic behavior of materials – hopkinson bar techniques

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Type of Paper: Article
Title: Impact Response of Aluminium Foam Sandwiches for Light-Weight Ship Structures
Authors: V. Crupi, G. Epasto and E. Guglielmino
Affiliations: Department of Industrial Chemistry and Materials Engineering, University of Messina, Contrada di Dio, 98166 Messina, Italy; E-Mails: vcrupi@ingegneria.unime.it (V.C.); gepasto@ingegneria.unime.it (G.E.); eguglie@ingegneria.unime.it (E.G.)
Abstract: The structures realized using sandwich technologies combine low weight with high energy absorbing capacity, so they are suitable for applications in the transport industry (automotive, aerospace, shipbuilding industry), where the "lightweight design" philosophy and the safety of vehicles are very important aspects. While sandwich structures with polymeric foams have been applied for many years, currently there is a considerable and growing interest in the use of sandwiches with aluminium foam core. Aluminum foam sandwiches (AFS) [1, 2], obtained by combining metal face sheets with a lightweight metal foam core, are suitable for applications in automotive industry and ship construction [3], as they allow a speed increase with good passenger comfort, thanks to their specific weight and high damping capacity. In a previous research paper of the authors [4], the structural response of aluminum foam sandwiches under static loading was compared with that of the PVC foam sandwiches and different failure modes were observed. Aim of this paper was the analysis of low-velocity impact response of AFS panels and the investigation of their collapse modes. Low velocity impact tests were carried out by a drop test machine in order to investigate their structural response in terms of energy absorption capacity. The failure mode and the internal damage of the impacted AFS have been, also, investigated by a Computed Tomography (CT) system, that allows a three-dimensional reconstruction of the analyzed object. This non – invasive technique have been already used to characterize quantitatively the microstructure and the internal architecture of different typologies of closed cell aluminium alloy foam [5] and to obtain the data for Finite Element models of open-cell aluminium foam specimens [6].
Keywords: Aluminum foam sandwich; low velocity impact; Computed Tomography; shipbuilding

Title: The Manufacture and Characterisation of Aluminium Foams Made by Investment Casting using Dissolvable Preforms Made from Spherical NaCl Beads
Author: Andrew Kennedy et al.
Affiliation: Advanced Materials Research Group, School of Mechanical Materials and Manufacturing Engineering, University of Nottingham, University Park, Nottingham, NG7 2RD, UK; E-Mail: Andrew.Kennedy@nottingham.ac.uk
Abstract: Open cell Al foams have been made by infiltrating molten Al into the spaces in porous preforms, made from porous salt spheres, made by a novel method. Infiltration has been affected using simple pressure-assisted vacuum investment casting, avoiding the use of bespoke equipment. The foam structures and densities have been varied by changing the preform compaction conditions and infiltration pressures. A simple model, using Hg porosimetry data, has been used to predict the infiltration behaviour with confidence. The use of porous spheres greatly accelerates the rate of salt removal from the infiltrated preform, but higher infiltration pressures cause significant penetration of molten metal within these beads, decreasing the rate of NaCl dissolution and increasing the foam density without benefit to the foam strength.