TY - CONF A1 - Schulz, Eckhard A1 - Kalinka, Gerhard A1 - Sturm, Heinz A1 - Munz, Martin T1 - Investigation on mechanical behaviour of heterogeneous polymeric systems and fibre reinforced composites using micro indentation and scanning force microscopy T2 - 18th Disc. Conf. and 56th PMM CY - Prague, Czech Republic DA - 1998-07-20 PY - 1998 AN - OPUS4-6451 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hampe, Andreas A1 - Kalinka, Gerhard A1 - Marotzke, Christian T1 - Comparison of the Interfacial Toughness Measured by the Single Fibre Pull-Out, the Indentation and the Fragmentation Test T2 - NIST, Workshop on Micro-Mechanics Measurement Technologies for Fiber-Polymer Interfaces CY - Gaithersburg, MD, USA DA - 1997-05-28 PY - 1997 AN - OPUS4-5928 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kalinka, Gerhard A1 - Hana, K. A1 - Fujihara, I. A1 - Hayasaki, S. A1 - Hamada, H. T1 - Comparison of Interfacial Properties obtained by using Single Filament Embedded Tensile Test and Push-in Test T2 - Recent Advancement of Interfacial Materials Science on Composite Materials '97 CY - Kyoto, Japan DA - 1997-05-07 PY - 1997 AN - OPUS4-12213 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schulz, Eckhard A1 - Kalinka, Gerhard A1 - Leistner, André A1 - Sturm, Heinz A1 - Munz, Martin A1 - Hampe, Andreas T1 - Investigation of polymeric composites reinforced with high oriented short glass fibres using the single fibre push-out test T2 - Euro-Conf. Surfaces and Interfaces in Polymers and Composites CY - Lausanne, Switzerland DA - 1997-06-03 PY - 1997 AN - OPUS4-6439 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schulz, Eckhard A1 - Kalinka, Gerhard A1 - Sturm, Heinz A1 - Munz, Martin T1 - Investigations of the mechanical behaviour of heterogeneous polymeric systems and fibre reinforced composites using micro indentation and scanning force microscopy T2 - Special Lectures, 18. Disc. Conf. And 56the PMM.: Mech. Behaviour of polymeric materials CY - Prague, Czech Republic DA - 1998-07-20 PY - 1998 AN - OPUS4-12092 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Munz, Martin A1 - Sturm, Heinz A1 - Kalinka, Gerhard T1 - On the stiffness gradient at the interface between an amine-cured epoxy and a thermoplast T2 - 6. Workshop 'Rasterkraftmikroskopie in der Werkstoffwissenschaft' an der Uni Erlangen, Inst. für Werkstoffwissenschaften veranstaltet vom Arbeitskreis 'Rastersondenmikroskopie in der Werkstoffwissenschaft' im Fachausschuss Metallographie der Deutschen Gesellschaft für Materialkunde (DGM) CY - Erlangen, Germany DA - 2005-02-17 PY - 2005 AN - OPUS4-7137 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Elabshihy, Karim A1 - Kalinka, Gerhard T1 - Investigation of the time-dependent behavior of cnt-filled epoxy using nanoindentation N2 - Epoxy/Carbon nanotube (CNT) composites are interesting materials that could be used in a wide variety of applications. In this study, CNT contents of 0.25, 0.5, 1 and 2 wt% were used for reinforcing epoxy. A nanoindentation device and a temperature regulating system were developed in order to investigate the effect of CNTs on the time-dependent properties of epoxy using relaxations and creep tests on the nano scale. The relaxation tests showed a significant shift for the relaxation spectrum towards shorter times with introducing a low CNT content of 0.25 wt%. Additionally, creep tests showed that both the holding time at a constant load and the unloading velocity have a major effect on the contact stiffness. However, there was no effect for the CNTs on the creep behavior with contents lower than 1 wt%, which was related to the presence of a percolation threshold around this value. T2 - Nanobrücken 2013 CY - Dresden, Germany DA - 20.03.2013 KW - Epoxy KW - CNT KW - Time-dependent KW - Nanoindentation PY - 2013 AN - OPUS4-35533 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rabe, Torsten A1 - Schulz, Bärbel A1 - Paulick, C. A1 - Kalinka, Gerhard T1 - Helical zirconia (TZP) springs manufacturing and testing under mechanical and thermal load N2 - Helical springs with a rectangular cross-section have been machined from sintered and grinded hollow cylinders with high geometrical precision and good reproducibility. Such springs made from tetragonal zirconia polycrystal (TZP) ceramic show excellent edge quality because of high fracture toughness and bending strength of the starting material. Hence, springs with desired geometric dimension and tailored spring constant can be manufactured for highly demanding applications at high temperatures and in harsh environments. Prior to any practical use, application limits of springs under mechanical and thermal load have to be analyzed. Therefore, different displacement experiments were carried out on the helical TZP springs. - Dynamic displacement tests at various temperatures from -15°C to +60°C using a piezo actor to load/unload springs with frequencies between 1 and 40 Hz: Springs remained undamaged and the spring constants were not altered, even after more than one million cycles of compression loading. - Long-time displacement measurements under static tensile loading at room temperature with a high-precision interferometer test facility: Significant spring elongation under constant strain was surprisingly proved over a period of many hours already at room temperature. - Creeping experiments for 48 h under static compression load at different temperatures up to 1000 °C: After cooling down and load removing no permanent length reduction of springs was observed for test temperatures up to 700 °C. However, reshaping of TZP springs by plastic deformation is possible at higher temperatures and opens up additional possibilities for spring design and manufacturing. T2 - German Ceramic Society, Annual Meeting 2018 CY - München, Germany DA - 09.04.2018 KW - Ceramic springs KW - Manufacturing KW - Mechanical and thermal testing PY - 2018 AN - OPUS4-44728 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Elabshihy, Karim T1 - Nano-mechanical characterization of epoxy/Cu interphase N2 - Characterization of the mechanical properties of interphases is essential when designing multicomponent materials such as fiber-reinforced matrices, protective coatings or multi-layered structures for integrated circuits. It can provide vital information about the durability of the finished product as a composite because failure is often initiated in the interfacial region induced by internal or external stress during fabrication or service. Nanoindentation is a powerful tool for investigating mechanical properties on the micro/nano scale. However, there are some challenges associated with conducting nanoindentation near interface regions. One main challenge is that the small thickness of the interphase region (typically 1-2µm) makes it difficult to apply several adjacent indents without overlap. Another issue is that the indentations are usually restricted by local reinforcement, and it becomes difficult to isolate the change in mechanical properties due solely to interphase formation. In this study we try to gauge the feasibility of nanoindentation for characterizing epoxy/Cu interphases. We develop a sample preparation method and optimize nanoindentation parameters in an attempt to avoid the restrictions mentioned above. Atomic force microscopy (AFM) and finite element analysis are employed as reference techniques to evaluate the effectiveness of our technique. We show the influence of preparation method and nanoindentaion parameters on measurements of interphase properties and how they relate the mentioned challenges. T2 - Nanobrücken 2016 CY - Saarbrücken, Germany DA - 02.03.2016 KW - Composite KW - Epoxy KW - Interphase KW - Nanoindentation PY - 2016 AN - OPUS4-35496 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sturm, Heinz A1 - Silbernagl, Dorothee A1 - Ghasem Zadeh Khorasani, Media T1 - Improving polymer matrix additives for composite structures: a focus on boehmite N2 - The aims of the Research Unit „Acting Principles of Nano-Scaled Matrix Additives for Composite Structures“ (DFG FOR 2021) are based on different synergetic pathways. Challenges are to achieve an improved damage tolerance combined with unchanged processability and a proof of the nano-based effect from molecular scale up to structural level. First of all, a comprehensive understanding of the acting mechanisms of nano-scaled ceramic additives onto polymer matrices of continuous fibre reinforced polymer composites with respect to improved matrix dominated properties is in focus. To proof of the nanoscopic and microscopic effects up to structural level; experimental investigations start on the functional correlation between the particle properties and the resulting properties of the epoxy as suspension and in the solid state. This includes tests for the resulting composite structures as well. Along the entire process chain different multi-scale simulations are performed from molecular modelling up to the macroscopic, structural level. The combination of experimental investigations and simulation methods enables a holistic understanding of the acting principles and basic mechanisms. Specialized techniques based on Scanning Force Microscopy are the basis of our analysis of physicochemical properties of the boehmite nanoparticles and their polymer environment. A surface map of mechanical properties as an input for simulations facilitate a deeper understanding of such composites across all scales. This enables us to understand the macroscopic structure-property relationship and to predict failure mechanisms as well as routes for optimization. T2 - 92nd DKG annual meeting and symposium on high performance ceramics CY - Berlin, Germany DA - 19.03.2017 KW - Boehmite nanoparticle KW - Intermodulation AFM KW - Composite structures KW - Pull-out test KW - Thermoset KW - Crack propagation energy PY - 2017 AN - OPUS4-39519 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -