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CHUN - Chinesischunterricht, Bd. 20 (2005): CHUN - Chinesischunterricht

Robots play an important role in today's manufacturing. However, the interaction between workers and industrial robots is often dangerous and therefore undesirable. Soft robotics provide a solution to this problem, but mass production of these soft components is costly and difficult. Novel polymer product engineering methods make it possible to manufacture soft robots and soft actuators easily and quickly using 3D printing. The deformation behaviour of the materials used is strongly influenced by the ambient temperature. Furthermore, the strain rate affects the viscoelastic response of these materials. In order to realise a successful and long lasting design of such components, the time-temperature dependency have to be mathematically modelled. Thus, proper material parameters for numerical analysis and modelling of the constitutive behaviour must be determined based on experimental testing. In this study, 3D printed materials and components of a fully 3D printed robot with pneumatic actuators were investigated. The soft components such as a pressure bellow were printed using the PolyJet method, which is based on photopolymerization. In this case the soft material Agilus (Stratasys Corp., MN, US) was selected. Rigid components were manufactured by the PolyJet method using the Verv White Plus material (Stratasys Corp., MN, US) as well as selective laser sintering, in which polyamide 12 powder (PA\,2200, EOS GmbH., Germany) is fused using a laser system. The short-term behaviour of the 3D-printed materials at different temperatures and loading rates, as well as long-term loading scenarios, were investigated to assess the suitability of the materials for the desired applications. The short-term behaviour was investigated by monotonic component and material tests as well as dynamic mechanical characterisation, which allowed the determination of the viscoelastic properties. The long term creep behaviour of the rigid materials was characterised both on the specimen and the component level. The long term cyclic behaviour was investigated for 3D printed bellow actuators that were produced by multi-material printing using the PolyJet process. It was shown, that although the rigid photopolymer material reveals a lower long term stability and a high temperature dependency of the mechanical properties, the advantage of using it in a multi-material printing process outweighs its disadvantages. For components that operate under elevated temperatures and don’t require multi-materials, selective laser sintered polyamide proves to be advantageous. Author Michael Lackner Masterarbeit Universität Linz 2022

Mit dieser Arbeit wollen wir zeigen, dass wir die Nichtgleichgewichtsdynamik in einem Adsorbatsystem mit Hilfe eines neuartigen spektroskopischen Aufbaus verfolgen können. Die Idee ist, dass ein schmalbandiger IR-Puls spezifische Schwingungen in der Adsorbatschicht anregt. Nach einer bestimmten Zeitverzögerung sondiert ein breitbandiger IR-Puls die Adsorbatschicht, um festzustellen welche Schwingungsmoden gerade angeregt sind. Die Neuheit dieses Experiments liegt darin begründet, dass die Frequenz des Pumppulses unabhängig von der des Probepulses ist. Folglich muss der untersuchte Spektralbereich nicht unbedingt mit dem gepumpten Spektralbereich übereinstimmen. Als untersuchtes Adsorbatsystem diente eine Calciumarachidat Monoschicht auf Glas. Aus den spektroskopischen Daten konnten wir Informationen über die Lebensdauern der beteiligten Schwingungsmoden, die Energieumverteilung zwischen diesen Schwingungsmoden und mögliche Energierelaxationspfade erhalten. Dissertation, Universität Duisburg-Essen, 2021