Hybrid composites of plastic and aluminum foam. - In: 2. Internationale Konferenz Euro Hybrid Materials and Structures, (2016), S. 170-177
https://edocs.tib.eu/files/e01fn16/859763315.pdf
The influence of fiber undulation on the mechanical properties of flat and single curved FRP-laminates. - In: Junior Euromat 2016, ISBN 978-2-8399-1926-5, (2016), Abstract number: 2847, Seite 88
http://nbn-resolving.de/urn/resolver.pl?urn=urn:nbn:ch:bel-573360
Process design for void-minimized liquid composite molding. - In: Junior Euromat 2016, ISBN 978-2-8399-1926-5, (2016), Abstract number: 2639, Seite 55-56
The production of fiber reinforced lightweight components for automotive and aerospace industry in resin transfer molding (RTM) has achieved considerable progress during the last decade. Cycle times were reduced from hours to minutes and processes are being automated continuously. A major obstacle for industrial serial manufacturing is the formation of voids during the process as injection times tend to be reduced. These defects are usually air entrapments in a microscopic scale. Voids can be formed due to inaccurate molds and material handling as well as process inherent circumstances. Two different categories can be classified. Air entrapments can be measured in the fiber bundles and in the flow channels between the bundles. The parameters effecting these voids in resin transfer molding were examined using a glass wall mold and an inline measurement. It could be shown that void formation is frequently a product of unbalanced flow fronts. The conditions for the two classes can be expressed in the dimensionless modified capillary number. Based on the design of experiments method this number was tested on the predictability of void formation during injection in RTM processes. In the experiments a major effect of the fiber reinforcement setup could be detected. By means of additional wetting analyses in a microscopic scale, characteristic flow front shapes were measured. The bundle geometry and the weave pattern were identified as influencing factors on the flow front. These are not included in the modified capillary number leading to a lower quality level. New key numbers were derived implementing these parameters to improve the accuracy of a prediction of void formation. The key numbers were used to create a process simulation based on analytical approaches. An algorithm was implemented that calculates feasible process parameters referring to process boundary conditions and used materials. The viscosity development of the resin is included using a new Weibull approach characterizing the processing ability of the resin. The outputs of the simulation are all necessary parameters for a production of parts with minimum cycle time at a user specified maximum void level. Means to apply these parameters to industrial processes include the volume flow rate control during injection. The selection of fiber reinforcements and resins based on process design aims is assisted. The results are transferable to other processes and enable a faster start-up of production processes for newly designed lightweight components.
http://nbn-resolving.de/urn/resolver.pl?urn=urn:nbn:ch:bel-573360
Application of desert sands for polymer concrete. - In: Junior Euromat 2016, ISBN 978-2-8399-1926-5, (2016), Abstract number: 2853, Seite 43
The refugee crisis has shown that the fast construction of medium-term homes in crisis regions is a major challenge. Particularly in the middle east the lacks of suitable construction sands, energy, water and infrastructure leads to the requirement of novel production methods for building blocks. In the present work, methods for the application of local sands in polymer concrete bricks were developed. The basic conditions and requirements for a concept of a mobile production plant for bricks were analyzed. A layout consisting of standard shipping containers was chosen. A production chain with defined mixtures of cleaned quartz sands, rock flour and polyester resin could be configured to manifacture bricks containing 87 % filling material in an inline-process with a cycle time of less than one hour. The adaption for natural desert sands started with an analysis of variying temperatures and humidity. Sands from multiple countries around the earth were analyzed in rheometer experiments. It could be shown that the curing times depend on the filling sand, preventing a simplified implementation into the established processes. The desert sands were characterized for differences in particle size, particle shape, specific heat capacity and chemical composition. Particle analysis showed that a larger angle of repose leads to fewer void content in the brick. The minor differences of specific heat were not sufficient to inhibit the self-acceleration of the exothermic resin reaction. The divergences of the chemical composition were identified as the most important obstacle. The premise is that available sands should be used. Thus the only possibility was to adapt the mixture of the polyester resin to the filling material. The resin is inhibited to ensure adequate time for wetting the sand. MEKP hardeners were combined with cobalt and cobalt-amine accelerators. The analysis showed that especially cobalt-amine accelerators lead to the pursued cycle time of under 60 minutes. On the other hand a correlation between the metallic elements in the sand and the viscosity increase of the polymer concrete could be obtained. These elements impede the effect of the cobalt complex in the accelerator. Particular ratios of hardener and accelerator for every sand must be applied. A user-friendly fast test was developed that can be performed on site. So the suitability of the resin and the filling material is ensured. The mechanical properties of desert sand and quartz sand polymer concrete were measured in standard devices. The results show that the strength of common polymer concrete can almost be achieved. Desert sand bricks could be used even to build two-storey houses. Based on the examinations a mold concept for the establishment of a series process was derived. The comparatively high shrinkage of the polyester resin and the friction of the sand were taken into account to design a manufacturing mold with a reusable core. It could be shown that the application of desert sands for the production of building blocks is possible. The impacting factors were examined and a concept for a process adapted to the natural resources was established. A mobile production plant can now be built to help diminish the harm of refugees in crisis regions.
http://nbn-resolving.de/urn/resolver.pl?urn=urn:nbn:ch:bel-573360
Schlussbericht zum Wachstumskern LEANTEC-Antrieb : Verbundprojekt 3: Demonstratoren : Teilprojekt 3.3: Extruder mit elektrischem Hauptantrieb. - Ilmenau : Technische Universität Ilmenau, Fachgebiet Kunststofftechnik. - 1 Online-Ressource (36 Seiten, 868,45 KB)Förderkennzeichen BMBF 03WKBY03C. - Verbund-Nummer 01083285
https://edocs.tib.eu/files/e01fb16/860138003.pdf
Das Fachgebiet Kunststofftechnik. - In: Jenaer Jahrbuch zur Technik- und Industriegeschichte, ISSN 2198-6746, Bd. 18 (2015), S. 261-269
Herstellung von 3D-Hochleistungs-Holzspan-Kunststoff-Verbunden (HHKV) in geschlossenen Formwerkzeugen. - In: Technomer 2015, 2015, V 4.3, insges. 3 S.
Kurzfassung S. 51
Korrelation von Eigenschaften und Parametern beim Folienhinterspritzen. - In: Technomer 2015, 2015, V 1.3, insges. 1 S.
Kurzfassung S. 9
The relationship between fibre orientation and electrical conductivity of molded plastic parts. - In: Abstracts of papers, (2015), S. 10-11
Functionalization by adding conductive fibers into thermoplastic matrices offers a transfer of electrical charge through a plastic component. A percolation network can be generated using contacting particles that create conductive paths through insulating thermoplastic. Injection molding parameters influences the generation of this network, thus electrical conductivity. Especially, the particle orientation and distribution result in obtaining a percolation path. To identify the main influences, a processing parameter study was carried out and verified by FEM flow simulation. A comparison of calculated and measured results shows differences resulting from interactions between individual fibers and variant cooling as a result of altered thermal conductivity. The predictability of flow orientation leads to suitable processing conditions to effect electrical conductivity patterns.
Wpływ modifikacji powierzchni na mieszanki pianek metalicznych z materiałami termoplastycznym :
Influences of surface-modifications on metalfoam-thermoplastic compounds. - In: Abstracts of papers, (2015), S. 7