Papers by Keyword: Foil

Abstract: This work presents a photolithographic rapid prototyping process for producing thin films ("Rapid Phototyping"). This process allows a quick and cost-effective generation of scalable thermopile microstructures using commercial equipment and materials. Structural widths of 100x250μm can be produced reproducible in a lift-off process with an accuracy of 5 microns vertically and 30 microns horizontally.

Abstract: The degradation of laminated glass as a result of increased temperature has become one of the important problem of reconstructions and designs of new glass structures, for instance high-rise buildings that are exposed to the impacts of an intensive heating caused e. g. by sunshine. The temperatures during heating can reach very high values, commonly from 60 to 70 °C. The effect of heating was simulated using the thermal chamber where the glass panes with the size of 120 x 1100 mm were heated. The deformation course under the increase of temperature was continually monitored by a measuring unit. In total six types of foils joining particular layers of glass were examined. In this paper the experimentally gained results are compared with a numeric computer analysis and the particular kinds of interlayers are evaluated using the loss of shear interaction.

Abstract: The shear interaction of laminated glass belongs to the essential characteristics of this material. The impact of the increased temperature on deformation properties was tested within investigation of basic mechanical properties of laminated glass panes. The specimens of laminated glass with the size of 120 x 1100 mm loaded by four-point bending load were exposed to the effect of the gradually increasing temperature up to approximately 65 °C in a thermal chamber. The progress of the deformation was continuously monitored by a measuring device during both temperature rise and subsequent cooling. Four kinds of interlayers were tested in total. In this paper the obtained experimental results are compared to numerical FE analysis and also the degree of an interaction of particular interlayer is evaluated.

Abstract: Elastic-plastic deformation properties of austenitic stainless steel foils were evaluated by using polychromatic laboratory X-rays. The transmitted optical system was used for stress measurement. The diffraction elastic constants for several diffraction planes were measured under monotonic loading by the cos2χ method. The diffraction energy decreased almost linearly with increasing cos2χ, and the slope of the cos2χ diagram decreased with increasing applied stress. Measured diffraction elastic constants were compared with the theoretical values calculated by the Kröner model. The experimental value agreed well with the theoretical value. The lattice strain measured during plastic deformation depended on the diffraction plane. The full width at half maximum increased with applied plastic strain. From the the diffraction-plane dependence of the lattice strain, the full width at half maximum and the diffraction intensity can be evaluated using polychromatic laboratory X-rays.

Abstract: The basic principles of the cold and foil aluminium rolling technology used in most rolling plants today have been around for many years with the major flatness control developments taking place 30 years ago. A crucial component of this technology is the coolant and lubricant fluid used for this process. In cold and foil rolling, kerosene is used as a coolant for the work rolls and as a lubricant for the rolling process, with the aid of specific additives. A lot of alternatives have been tested in the past but the kerosene medium has remained as the industry standard. An overview of the alternative technologies is discussed.

Abstract: A novel clinching process design to join thin metal sheets and foils is proposed. In this process a small cup is first stretched out of the sheet plane. A shape interlock between the two sheets is then created by a movement of the die and blank holder in the sheet plane lateral to the cup wall. Such an approach makes the undesired upsetting of the cup bottom redundant, which promises less energy consumption and a longer tool life when compared to conventional clinching processes. The process principle and its finite element analysis for austenitic steel sheets as well as deep-drawing steel sheets (both 0.3 mm thick) are presented. The numerical results suggest feasibility of the proposed design to produce a good shape interlock between two thin sheets.

Abstract: The design, fabrication and testing of piezoelectric energy harvesting modules for floors is described. These modules are used beneath a parquet floor to harvest the energy of people walking over it. The harvesting modules consist of monoaxial stretched PVDF-foils. Multilayer modules are built up as roller-type capacitors. The fabrication process of the harvesting modules is simple and very suitable for mass production. Due to the use of organic polymers, the modules are characterized by a great flexibility and the possibility to create them in almost any geometrical size. The energy yield was determined depending on the dynamic loading force, the thickness of piezoelectric active material, the size of the piezoelectric modules, their alignment in the walking direction and their position on the floor. It was possible to generate up to 2.1mWs per pulse with loads of about 70 kg using a specific module design. An increase of the energy yield at higher loading forces and higher thicknesses of the modules is possible in general. Furthermore a test floor was assembled to determine the influence of the size, alignment and position of the modules on the energy yield.

Abstract: The AlMn and AlMnSi foils were fabricated by rapid solidification technology. The phase transformation temperatures, microstructures and distribution of elements were characterized by Differential Scanning Calorimetry (DSC), Transmission Electron Microscope (TEM), X-ray Diffraction (XRD) and Energy Disperse Spectroscopy (EDS) respectively. The result shows that the phases of AlMn7 nanofoil conclude Al, Al6Mn and quasicrystal phase, the crystal size is about 120nm; the phases of AlMn5Si5 nanofoil conclude Al, Al4.01MnSi0.74 and Al9Mn3Si, the crystal size is about 60nm. The phase transformation temperatures of AlMn7 and AlMn5Si5 nanofoils are 543K and over 873K, respectively. The microstructure morphology of AlMn7 nanofoil are rod, block and petal-like, but the microstructure morphology of AlMn5Si5 nanofoil is homogeneous globular.

Abstract: Fins in automotive heat exchangers are manufactured from Al-Mn-Fe-Si foils. Since continuous twin-roll casting (TRC) reduces energy and work consumption, it is the preferred manufacturing technology. The precipitation processes resulting from annealing of TRC Al-Mn-Fe- Si based alloys were studied by resistometric measurements during linear heating from room temperature up to 620 °C, hardness measurements and transmission electron microscopy examinations. Primary particles and precipitates of the cubic α-Al15(Mn,Fe)3Si2, hexagonal Al8Fe2Si and orthorhombic Al6(Fe,Mn) phases were identified. Phases of different types prevail in different alloys depending on composition. The increase of cold rolling prestrain prior to annealing induces a significant shift to lower temperatures of the start of precipitation. Prestrain accelerates precipitation kinetics by redistributing solute atoms and favoring their segregation on nucleation sites such as dislocations, subgrain and grain boundaries.

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