Production technology for hybrid-lightweight-structures with aluminum foam core-sub-project within the cluster of excellence MERGE

Production technology for hybrid-lightweight-structures with aluminum foam core - Sub-project within the Cluster of Excellence MERGE MERGE is the one and only Federal Cluster of Excellence in the field of research and development of innovative key-technologies for lightweight structures in Germany. The main objective of the Cluster “Merge Technologies for Multifunctional Lightweight Structures” is to create lightweight and material-efficient components by merging currently separated production processes of different material groups. One focused topic is the development of lightweight-sandwich-composites made of metal foam and fiber-reinforced plastics (FRP). Because of their low density, high energy absorption capability, stiffness and strength and very good damping behavior metal foams are excellently suitable for lightweight structures. The combination of metal foam with sheet metal covers as sandwich structure is already used in manifold applications. In order to enhance the level of lightweight construction in metal sandwich structures, the substitution of metal cover sheets with fiber-plastic composites provides an effective approach. By adapting the thickness of core and FRP layers in combination with high performance fibers and load specific design customized structural properties are possible to be to be realized. One key aspect is the bonding of both components. To find an optimal combination many experiments have been carried out to investigate the influence of various parameters, e.g. the modification of the metal foam surface and thermoplastics or the use of adhesive-agents. The permanent bonding of the sandwich components is realized in a pressing process. Therefore, the sandwich components need to be preheated. To increase the energy efficiency, a technology will be developed using the process heat of the foaming instead of additional preheating. For achieving a high functional density, the injection molding processes can be used to implement thermoplastic elements, e.g. stiffening rips or mounting interfaces, into these sandwich structures based upon metal foam cores

Smart rollerski - radius pultrusion in application: Poster presentedt at 5th International Composites Conference, ICC 2019, 10. - 12. September 2019, Stuttgart, im Rahmen der Fachmesse COMPOSITES EUROPE

Lightweight applications made of fiber-reinforced plastics have been used in top-class sports for many years. With an innovative rollerski – developed in the joint project "SmartFrame +" funded by the BMBF – different target groups are addressed. On the one hand, users who are looking for fun and physical exercise. On the other hand, there are winter sports enthusiasts who want to improve their skiing skills during the summer break. Especially in this case, the challenge is to achieve a congruence in motion compared to the classic winter ski and thus to train the motor skills and muscle groups targeted. This will be supported by integrated sensors

Technologie zur Herstellung hybrider Leichtbaustrukturen mit Aluminiumschaumkern: Vortag gehalten auf dem 7. Landshut - Ingolstädter Leichtbausymposium, "Fügen und Verbinden - Schlüsseltechnologien der Fertigung hybrider Leichtbaustrukturen", 24. Juni 2014, Ingolstadt

Aufgrund der immer höher werdenden Forderungen nach Leichtbau in vielen Bereichen, unter anderem im Maschinenbau, werden immer häufiger Leichtbaumaterialien wie Faserkunststoffverbunde und Metallschaum eingesetzt. Um Bauteile und Baugruppen mit Hilfe dieser Werkstoffe umzusetzen werden spezielle Fügetechniken benötigt. Eine Auswahl wird im Vortrag vorgestellt

Querlenker aus Hybrid-Aluminiumschaum-Sandwich

Das Fraunhofer IWU hat gemeinsam mit der TU Chemnitz einen Querlenker aus hochbelastbaren Kernverbunden mit Metallschaumkern und Deckschichten aus Hybridlaminaten entwickelt. Im Vergleich zu konventionellen Querträgern ist der entwickelte Technologiedemonstrator leichter und führt durch die Reduzierung der ungefederten Massen zu verbesserten Fahreigenschaften

Smartes Leichtgewicht auf Rollen: Sensorierter Skiroller in Leichtbauweise aus Glas- und Kohlenstofffaserhalbzeugen

Leichte Anwendungen aus Faser-Kunststoff-Verbunden werden bereits seit Jahrzehnten im Spitzensport eingesetzt. Ein innovativer Skiroller – entwickelt in dem vom BMBF geförderten Verbundvorhaben „SmartFrame

Composite sandwich with aluminum foam core and adhesive bonded Carbon Fiber Reinforced Thermoplastic cover layer

The combination of metals and fiber reinforced plastics is also known as hybrid metal composites. They offer the fusion of the good static mechanical properties of the fiber reinforced plastics and the good dynamic mechanical properties of the metal. For that reason, parts made of hybrid metal composites are predestined for the use as load relevant parts. The purpose of this study was to develop new technologies for semi finished hybrid metal composite materials. Thermoplastic Fiber-Reinforced Composites (TP-FRC) were arranged with new, isotropic, closed pore Aluminum Foam (AF) structures to an Extrinsically Combined Composite Sandwich (ECCS) by adhesive bonding. They form the basis for novel weight-optimized as well as cost-effective applications. The entire manufacturing process for the continuous semi-finished product was examined and verified according DIN EN 2563. This was done with regard to subsequent characterization by the specific bending modulus and specific bending stiffness. The examinations show a high bending stiffness and high strength structures combined with excellent damping properties at high damage tolerances. These are the most requested in automotive applications

Wishbone made of hybrid aluminum foam sandwich

Fraunhofer IWU and the TU Chemnitz have developed a wishbone made of a high-strength sandwich with a metal foam core and hybrid laminate cover layer. The potential is shown in the form of a lightweight wishbone as technology demonstrator, in which the weight reduction leads to a reduction of unsprung masses and thus to a direct improvement of the driving properties

Sandwich structures consisting of aluminum foam core and fiber reinforced plastic top layers

Thinking of new approaches for light weight design with sandwiches, the combination of aluminum foam as core and fiber reinforced plastics as top layers can be a good way to increase the light weight aspect and combine advantages of both materials. For structural applications, often a high bending stiffness and a good damping capability in the combination with the lightweight aspect are needed. For these new sandwiches, especially, the bonding properties are crucial for later applications. Therefore, investigations regarding the bonding properties of the combination of the two components are carried out. The objective is to find a way of combining these materials without adhesives. Different ways of composite manufacturing are tested and compared according to DIN 53292: "testing of sandwiches; tensile test perpendicular to the faces". Furthermore, different pretreatments of the foam core are compared. These include sandblasting with a chemically modified blasting materi al, a structure included by a modification of the foaming tool, and untreated foam for comparison reasons to the state of the art. It is found that the structure induced during the foaming step is suitable for adhesive bonding, but not for the other processes. Better results can be expected by further adaption of the implemented structure. The best results in the compression molding process are obtained with the sandblasted foam cores

Sandwich structures consisting of aluminum foam core and fiber reinforced plastic top layers: Presentation held at 4th International Conference on Cellular Materials, December 7 to 9, 2016, Dresden

Thinking of new approaches for light weight design with sandwiches the combination of aluminum foam as core and fiber reinforced plastics as top layers can be a good way to increase the light weight aspect and combine advantages of both materials. For structural applications often a high bending stiffness and a good damping capability in the combination with the lightweight aspect are needed. For these new sandwiches especially the bonding properties are crucial for later applications. Therefore investigations regarding the bonding properties of the combination of the two components are carried out. The objective is to find a way of combining these materials without adhesives. Different ways of composite manufacturing are tested and compared according to DIN 53292: “testing of sandwiches; tensile test perpendicular to the faces”. Furthermore different pretreatments of the foam core are compared. These include sandblasting with a chemically modified blasting material, a structure included by a modification of the foaming tool and untreated foam for comparison reasons to the state of the art. It is found that the structure induced during the foaming step is suitable for adhesive bonding, but not for the other processes. Better results can be expected by further adaption of the implemented structure. The best results in the compression molding process are obtained with the sandblasted foam cores

Sandwichbauteile aus Aluminiumschaumkern mit faserverstärkten Kunststoffdecklagen mit komplexer Geometrie - Querlenkerdemonstrator

Im Rahmen des, von der DFG geförderten, Exzellenzclusters „MERGE – Technologiefusion für multifunktionale Leichtbaustrukturen“ wird die Verschmelzung verschiedener großserientauglicher Technologien aus unterschiedlichsten Bereichen erforscht. Ziel ist die Gewichtsoptimierung unter dem Fokus Ressourcen- und Energieeffizienz. Im Rahmen eines Teilprojektes ist das Ziel, eine komplexe geometrische Struktur als Sandwichbauteil aus einem Aluminiumschaumkern und faserverstärkten thermoplastischen Decklagen umzusetzen. Hierfür wurde zunächst ein Demonstratorbauteil im Rahmen des Projektes ausgewählt. Zu berücksichtigende Randbedingungen für die Auswahl eines geeigneten Bauteils waren:• Eingeschränkte Größe, um den Demonstrator real fertigen zu können • Eine komplexe Geometrie, um Grenzen hinsichtlich der Designfreiheit zu bestimmen bzw. aufzuzeigen• Hauptbelastung: Biegung / Torsion Aus diesen Gründen wurde als Demonstrator ein Querlenker ausgewählt. Dieser wurde hinsichtlich des Bauraumes und der einzusetzenden Materialien umkonstruiert. Die Konstruktion wurde mittels überschlägiger FEM-Berechnungen angepasst. Als nächster Schritt wurden zwei Werkzeuge für die Umsetzung des Demonstrators konstruiert und gefertigt. Es handelt sich hierbei um ein Schäumwerkzeug und ein Presswerkzeug zum Aufbringen der Decklagen. Insbesondere die Integration von Lasteinleitungselementen, welche bereits beim Schäumen mit integriert wurden, stellte einen Schwerpunkt dar. Diese Elemente bestehen aus Stahl und dienen als Aufnahmepunkte für die Lager und die Befestigung am Rad. Aluminiumschaumkerne für den Querlenker wurden bereits geschäumt. Im weiteren Projektverlauf werden die Decklagen aufgepresst und anschließend die Lager in die Inserts eingebracht. Nach der erfolgreichen Fertigung der Demonstratorbauteile ist ein weiteres Ziel des Projektes die fertigungstechnische Umsetzung der Teile in einem kombinierten Prozess durchzuführen, so dass die Restwärme des Schäumvorganges für das Aufschmelzen und Aufpressen der Decklagen genutzt werden kann