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Fakultätsübergreifendes Institut für Werkstofftechnik


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im Institut für Werkstofftechnik

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Albrecht, Robert; Lange, Günther
Pulvermetallurgisch hergestellte Aluminiumschäume. - In: Lightweight design : die Fachzeitschrift für den Leichtbau bewegter Massen. - Wiesbaden : Vieweg und Teubner/Springer Fachmedien, ISSN 21928738, Bd. 7 (2014), 6, S. 26-31

Eine Erhöhung der Festigkeiten metallischer Werkstoffe ist ein andauerndes Entwicklungsziel. Für Monomaterialien oder auch Verbundwerkstoffe sind hier in letzten Jahren viele Ansätze entwickelt worden. Bei den Metallschäumen hingegen wurde eine Verbesserung der mechanischen Eigenschaften bisher hauptsächlich durch die Anwendung als Kernmaterial in einem Sandwichverbund erreicht. Faserverstärkte Aluminiumschäume wurden bisher weder in der Literatur erwähntnoch imBereich der Forschung und Entwicklung näher untersucht. Infolge dessen sind auch die durch dieGlasfasern veränderten Eigenschaften, derdadurch noch komplexerwerdende Herstellungsprozess und auch entsprechendeSimulations- und Berechnungsansätze nicht untersucht worden. Mit Hilfe der pulvermetallurgischen Herstellungsroute konnten glasfaserverstärkte geschlossenporige Aluminiumschäume erfolgreich hergestellt werden. Der Glasfaseranteil betrug dabei bis zu 2 Gewichtsprozent. Für diese neuen Faserschaumverbunde wurde ein zweistufiges Kompaktierungsverfahren entwickelt. Mit einer definierten Temperaturführung konnten anschließend die Pulverpresslinge zuglasfaserverstärkten geschlossenporigen Aluminiumschäumen mit einer Aufschäumrate von 500% - 600% hergestellt werden. Dabei lag eine gleichmäßige Verteilung der Glasfasern in den Aluminiumschaumproben vor. Eine Agglomeration oder eine durch die Kompaktierung hervorgerufene Ausrichtung der Glasfasern konnte nicht beobachtet werden.


http://dx.doi.org/10.1365/s35725-014-0436-4
Laufer, Nico; Hansmann, Harald; Koch, Michael
High pressure capillary rheometry on wood plastic composites with variation of wood content and matrix polymer. - In: Shaping the future by engineering : 58th IWK, Ilmenau Scientific Colloquium, Technische Universität Ilmenau, 8 - 12 September 2014 ; proceedings. - Ilmenau : Univ.-Bibliothek, ilmedia / Ilmenau Scientific Colloquium. Technische Universität Ilmenau ; 58 (Ilmenau) : 2014.09.08-12., (2014), insges. 9 S.
http://nbn-resolving.de/urn:nbn:de:gbv:ilm1-2014iwk-170:9
Hartmann, Robert; Koch, Michael
CFRP and aluminum foam hybrid composites. - In: Shaping the future by engineering : 58th IWK, Ilmenau Scientific Colloquium, Technische Universität Ilmenau, 8 - 12 September 2014 ; proceedings. - Ilmenau : Univ.-Bibliothek, ilmedia / Ilmenau Scientific Colloquium. Technische Universität Ilmenau ; 58 (Ilmenau) : 2014.09.08-12., (2014), insges. 9 S.

One way to minimize the energy consumption of production processes is to reduce moving masses in machinery. This reduction of mass can be carried out through the exchange of solid material, like steel or aluminum, with hybrid materials. These hybrid materials combine application-oriented different type of materials and their properties. This paper deals with the RTM manufacturing process and FEM simulation of such a hybrid material. By using the sandwich design method two tensile-stiff carbon fiber reinforced plastic (CFRP) layers are connected to a low-density aluminum foam (AF) core in order to produce hereafter parts with high weight-specific bending stiffness. At the beginning of this paper an analytical calculation method on the basis of the beam theory is developed, which allows an estimation of the achievable mechanical properties of the composite. The bending stiffness of such a composite is mainly determined by the outer layer modulus and the gravity axis distance of the outer layers. These findings are incorporated into the development of a FEM model, which allows the simulation of various load cases with selectable composite structure. The challenge in developing this model is the implementation of the material-specific peculiarities. These include the anisotropy of the CFRP layers and the core structure of the AF. An experimental plan is developed by using the DoE method. It allows the determination of the RTM process parameters, which will lead to components with the highest weight-specific bending stiffness. On this account preliminary tests are carried out to identify the usable range of injection pressure, mold temperature and compression pressure of the press. This paper can demonstrate, that the production of CFRP/ AF hybrid material by means of the RTM process is feasible. The first manufactured specimens exhibit no displacement of the fibers and almost no air inclusions. The simulation of CFRP/ AF hybrid material could be implemented. The anisotropy of the CFRP layers can be simulated with the ANSYS fiber fracture software ACP. The structure of the AS core can be mapped with great computational effort. The next step is the execution of the developed experimental plan with an especially designed RTM mold for sandwich composites.


http://nbn-resolving.de/urn:nbn:de:gbv:ilm1-2014iwk-100:6
Fiebig, Christian; Koch, Michael
The influence of fiber undulation on the mechanical properties of FRP-laminates. - In: Shaping the future by engineering : 58th IWK, Ilmenau Scientific Colloquium, Technische Universität Ilmenau, 8 - 12 September 2014 ; proceedings. - Ilmenau : Univ.-Bibliothek, ilmedia / Ilmenau Scientific Colloquium. Technische Universität Ilmenau ; 58 (Ilmenau) : 2014.09.08-12., (2014), insges. 8 S.
http://nbn-resolving.de/urn:nbn:de:gbv:ilm1-2014iwk-099:3
Woyan, Felix; Koch, Michael; Schneidmadel, Stefan
Process parameters affecting the quality of functionalized in-mold decoration injection molded composites. - In: Shaping the future by engineering : 58th IWK, Ilmenau Scientific Colloquium, Technische Universität Ilmenau, 8 - 12 September 2014 ; proceedings. - Ilmenau : Univ.-Bibliothek, ilmedia / Ilmenau Scientific Colloquium. Technische Universität Ilmenau ; 58 (Ilmenau) : 2014.09.08-12., (2014), insges. 9 S.

This report studies the fundamental parameters affecting the wash-off and the warpage of parts manufactured in in-mold decoration process (IMD). The purpose is to derive a process model for describing the wash-off and the warpage of the parts as a function of the main influencing parameters based on a dimensional analysis. In order to investigate the influence of the materials and various processing conditions, a test mold was created for experiments and simulations were carried out. First of all the main influencing factors have been identified. To quantify the influence of each factor, a full factorial design was used. A DOE of process parameters including injection speed, injection pressure, melt temperature, mold temperature, post-injection pressure and the material were designed and executed. Based on the DOE specimens with a 250 [my]m and 375 [my]m thick PC film and a part thickness of 2 mm and 3 mm made from different thermoplastics were produced. In addition, the results of the experiment were compared with the simulation.


http://nbn-resolving.de/urn:nbn:de:gbv:ilm1-2014iwk-095:0
Röder, Martin; Koch, Michael
Integration of connecting elements in hybrid-composite components. - In: Shaping the future by engineering : 58th IWK, Ilmenau Scientific Colloquium, Technische Universität Ilmenau, 8 - 12 September 2014 ; proceedings. - Ilmenau : Univ.-Bibliothek, ilmedia / Ilmenau Scientific Colloquium. Technische Universität Ilmenau ; 58 (Ilmenau) : 2014.09.08-12., (2014), insges. 7 S.
http://nbn-resolving.de/urn:nbn:de:gbv:ilm1-2014iwk-089:1
Bruchmüller, Matthias; Koch, Michael
Improvement of tribological properties of plastic compounds. - In: Shaping the future by engineering : 58th IWK, Ilmenau Scientific Colloquium, Technische Universität Ilmenau, 8 - 12 September 2014 ; proceedings. - Ilmenau : Univ.-Bibliothek, ilmedia / Ilmenau Scientific Colloquium. Technische Universität Ilmenau ; 58 (Ilmenau) : 2014.09.08-12., (2014), insges. 7 S.
http://nbn-resolving.de/urn:nbn:de:gbv:ilm1-2014iwk-084:0
Simon, Christian; Türk, Marko; Koch, Michael
Oxygen and water vapor permeability and required layer thickness for barrier packaging. - In: Shaping the future by engineering : 58th IWK, Ilmenau Scientific Colloquium, Technische Universität Ilmenau, 8 - 12 September 2014 ; proceedings. - Ilmenau : Univ.-Bibliothek, ilmedia / Ilmenau Scientific Colloquium. Technische Universität Ilmenau ; 58 (Ilmenau) : 2014.09.08-12., (2014), insges. 11 S.
http://nbn-resolving.de/urn:nbn:de:gbv:ilm1-2014iwk-076:8
Steffen, Maik Eno; Koch, Michael
Manufacturing hybrid lightweight compounds of closed-cell aluminium foam and thermosoftening plastics in injection moulding processes. - In: Shaping the future by engineering : 58th IWK, Ilmenau Scientific Colloquium, Technische Universität Ilmenau, 8 - 12 September 2014 ; proceedings. - Ilmenau : Univ.-Bibliothek, ilmedia / Ilmenau Scientific Colloquium. Technische Universität Ilmenau ; 58 (Ilmenau) : 2014.09.08-12., (2014), insges. 8 S.
http://nbn-resolving.de/urn:nbn:de:gbv:ilm1-2014iwk-053:0
Caba, Stefan; Koch, Michael
Simulation of the resin transfer molding process (RTM) by analysis of the process fundamentals. - In: Shaping the future by engineering : 58th IWK, Ilmenau Scientific Colloquium, Technische Universität Ilmenau, 8 - 12 September 2014 ; proceedings. - Ilmenau : Univ.-Bibliothek, ilmedia / Ilmenau Scientific Colloquium. Technische Universität Ilmenau ; 58 (Ilmenau) : 2014.09.08-12., (2014), insges. 8 S.

Fiber reinforces plastics (FRP) technologies enable the production of lightweight components. The RTM technique is attractive to obtain vehicle parts with little post-processing in industrial scales. The closed mold process provides a desired freedom in part-design combined with high and reproducible production rates compared to other FRP processes. However, the shorter the mold-closed time the higher the risk to run into quality consistency issues resulting from air entrapments. The acceleration of the process can only be achieved by the knowledge of the fundamental process parameters. The effects of void formation and process speed can be managed to reach progresses in both cycle time and void content. The major mechanism of void formation is the entrapment of air due to flow front inconsistencies. These are generated by the differences of the flow front as a result of advancing forces, viscosity and flow resistances. A faster flow front advancement in the fiber tows results in spherical voids, because air in the flow channel between the tows can be entrapped. On the other hand a faster advance in the flow channels results in cylindrical voids in the tows. Only a balanced flow front could enable a process with low void rates. The resin flow in the channels is primarily driven by the inlet pressure. The flow resistance is low in comparison to the fiber tows where the channel radius has a smaller order of magnitude. In the tows the resin flow is additively caused by the capillary pressure that occurs in the small channels between the fibers in the tow. So the flow behavior of the flow front depends on different factors. The established factors for influencing the RTM cycle are mold temperature, inlet pressure, application of vacuum, resin and fiber volume content. However, the impact of the capillary effect has not been examined sufficiently. Possible factors influencing the wicking are finish of the fiber, weave of the reinforcements and the radius of the tows. In addition all factors may have interdependencies on each other. Process trials were conducted using a DOE-approach under consideration of material and process parameters for simple 2D parts. The analysis shows the impact of principle process parameters on the achievable part quality.


http://nbn-resolving.de/urn:nbn:de:gbv:ilm1-2014iwk-035:0