TY - JOUR A1 - Bettge, Dirk A1 - Starcevic, Jasminka T1 - Topographic properties of the contact zones of wear surfaces in disc brakes N2 - Disc brakes are widely used in cars, trains, and other vehicles. For understanding the basic processes occurring during the friction process, information on the surface topography of brake pads and discs is needed, in addition to information about chemistry and thermodynamics. In this paper, samples of pads and discs were analysed using white light interferometry. The topography of the surfaces was measured quantitatively. Using software tools described in a previous paper [Wear 248 (2001) 121], the distributions of area, height, and slope of the contact patches were computed. Characteristic properties of the contact patches were found to describe the influence of the test parameters such as friction power and testing time. KW - Disc brakes KW - Topographic analysis KW - Size distribution KW - Orientation distribution PY - 2002 U6 - https://doi.org/10.1016/S0043-1648(03)00012-7 SN - 0043-1648 VL - 254 IS - 3-4 SP - 195 EP - 202 PB - Elsevier AN - OPUS4-38224 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Nolze, Gert ED - Sen Gupta, S. P. ED - Chatterjee, P. T1 - PowderCell : a mixture between crystal structure visualizer, simulation and refinement tool N2 - The program PowderCell is a crystallographic tool for visualization of Crystal structures. However, it offers also non-conventional features like the fulautomatical generation of subgroups or the consideration of non-standard settings of space-group types. On the one Hand the program is very useful for non-crystallographers who like to get an impression of the atomic arrangement within the unit cell. But also for crystallographers it is recommendable because it contains a lot of additional information which can be extracted and used like data given in the International Tables for Crystallography, Vol. A. However, the most important advantage of the program is the simultaneous calculation of the X-ray or neutron diffraction powder patterns for a mixture of up to 10 crystalline phases. Between more than 7 different characteristic radiations can be chosen and their influence on the resulting powder pattern can be studied. Furthermore, experimental diffractograms can be analysed using a refinement procedure. The implemented LeBail-algorithm allows the investigation of unknown phases. In combination with the refinement algorithm an interface to Shelx offers the possibility for a step by step ab initio structure analysis. Certainly, the user-friendly shell is one reason that especially users who are not so familar with space-group symmetry, crystal structure data or diffractometry use this powerful tool for the solution of scientific or analytical problems as well as in teaching. KW - XRD KW - Simulation KW - Crystal structure KW - Neutron diffraction PY - 2002 SN - 8177642626 SN - 9788177642629 SP - 146 EP - 155 PB - Allied Publishers CY - Kolkata, India AN - OPUS4-38035 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Nolze, Gert ED - Sen Gupta, S. P. ED - Chatterjee, P. T1 - The determination of residual stress N2 - X-ray stress analysis on crystalline materials is based on the determination of elastic lattice strains. The strains described by the shift of peak positions are converted to stresses by the means of theory of elasticity. The development of the sin2ψ-method of X-ray stress analysis introduced an enormous progress in X-ray stress analysis during the last decades. This report outlines some important elements of X-ray physics and fundamentals of theory of elasticity. The Standard measuring procedure are described and special experimental differences to the common powder diffractometry are outlined. KW - XRD KW - Residual stress PY - 2002 SN - 81-7764-262-6 SN - 9788177642629 SP - 77 EP - 83 PB - Allied Publishers CY - Kolkata, India AN - OPUS4-38036 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -