Development and characterization of sandwich panels with aluminium foam core

• Autor(a) principal: Silva, Ana Sofia Caldeira da
• Data de Publicação: 2022
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10773/35950
• topic: Aluminium alloy foam; In-situ foam filled tubes; In-situ foam sandwich panels; Three-point bending; Uniaxial and cyclic uniaxial compression; Deformation modes; Energy absorption

Structures made of aluminium alloy foams have been demonstrated, over the years due to their properties that they can be used as passive safety systems in transport. They have great potential in terms of economic, environmental and road safety. While they reduce deaths and injuries, they are able to make vehicles lighter, reducing the number of gases released and optimizing the engine's energy efficiency. Aluminium alloy foams are being used in structures in which the core is bonded to the facesheets by using glues, making these panels non-recyclable and flammable. The main objective of this dissertation was to develop experimental methodologies to manufacture aluminium alloy structures filled with aluminium alloy foam through the powder metallurgy process, promoting the metallic bond between the foam core and the aluminium sheets or the inner walls of the tube, during the formation of the foam itself. Foam filled tubes made of aluminium alloys (designated in-situ FFT), sandwich panels with aluminium alloy core (designated in-situ AFS) were developed and tested using materials characterization methods such as X-ray microcomputed tomography, monotonic and cyclic uniaxial compression tests and three-point bending tests. Two experimental methodologies are proposed to develop these in-situ structures through the use of precursor material which is obtained by the combination of hot isostatic pressing and hot extrusion of a powder mixture of aluminium, silicon and titanium hydride. The first methodology is the heating precursor material into the thin-walled tubes to temperatures close to the melting temperature of the precursor material. The second methodology is the heating of a steel mould containing a piece of precursor material in the middle of the aluminium sheets of the mould to temperatures close to the melting temperature of the precursor material. The results show that both methodologies promote the metallic bonding between the foam (filler or core) and the inner walls of the tubes or sheets, obtaining lightweight, recyclable and non-flammable structures with good energy absorption capacity with the potential to be incorporated into automobile vehicles.