TY - CHAP A1 - Möllmann, Klaus-Peter A1 - Pinno, Frank A1 - Vollmer, Michael T1 - Influence of wind effects on thermal imaging results – Is the wind chill effect relevant ? T2 - In: InfraMation proceedings Vol. 8 (2007), 21-31 Y1 - 2007 SP - 21 EP - 31 ER - TY - JOUR A1 - Gedzelman, Stanley David A1 - Vollmer, Michael T1 - Atmospheric Optical Phenomena and Radiative Transfer JF - In: Bulletin of the American Meteorological Society. 89 (2008) 4, 471-485 N2 - We present simple radiative transfer models for the radiance and color of atmospheric optical phenomena. Skylight, halos, and rainbows are treated as singly scattered sunlight that is depleted by scattering as it passes through a plane-parallel atmosphere and a vertical rain shaft or a geometrically thin cloud layer. Skylight in a molecular atmosphere grades from deep blue at the zenith to pale blue near the horizon whenever the solar zenith angle sun ≤ 80°. Skylight near the horizon is orange resulting from wavelength-dependent scattering by air molecules and aerosol particles through a long oblique path through the atmosphere when the sun is low in the sky (sun ≥ 85°). Halos (and coronas) seen through clouds facing the sun are brightest for cloud optical depth τcld ≈ cos(sun), and fade to obscurity for τcld ≥ 5. Rainbows (and glories), seen by light that is backscattered from clouds, also appear most dramatic when 0.2 ≤ τcld ≤ 1, but remain visible even in the thickest clouds. Y1 - 2008 U6 - https://doi.org/10.1175/BAMS-89-4-471 SP - 471 EP - 485 ER - TY - JOUR A1 - Vollmer, Michael T1 - Effects of absorbing particles on coronas and glories JF - In: Applied optics 44 (2005) 27, 5658-5666 N2 - Light scattering from small particles changes if the particles are absorbing. Whereas the effect is small for coronas and Bishop's ring, glories show pronounced attenuation with increasing absorption. Results indicate suitable wavelength regions for studies of glory scattering from cloud tops. The behavior of core-shell particles could have applications for studying the atmosphere of Venus; in addition it provides more insight into the simple ray-path model of the glory. © 2005 Optical Society of America Y1 - 2005 U6 - https://doi.org/10.1364/AO.44.005658 SP - 5658 EP - 5666 ER - TY - CHAP A1 - Christmann, S. A1 - Vollmer, Michael T1 - Jahrgangsübergreifendes Projekt zum Wetter für die Grundschule T2 - In: Didaktik der Physik : Beiträge zur Frühjahrstagung Düsseldorf 2004 ; CD zur Frühjahrstagung des Fachverbandes Didaktik der Physik in der Deutschen Physikalischen Gesellschaft / V. Nordmeier ... (Hrsg.). - Berlin : Lehmanns Media, 2004. - 1 CD-ROM. - ISBN 3-86541-066-9 Y1 - 2004 ER - TY - JOUR A1 - Gedzelman, Stanley David A1 - Vollmer, Michael T1 - Crepuscular rays: laboratory experiments and simulations JF - In: Applied Optics Vol. 50 (2011) 28, pp. F142-F151 N2 - Model simulations of laboratory-generated and natural crepuscular rays are presented. Rays are created in the laboratory with parallel light beams that pass through artificial fogs and milk–water solutions. Light scattered by 90° in a dilute mixture of whole milk first increases in intensity with distance from the source to a maximum as a result of multiple scattering by mainly small angles before decreasing exponentially due to extinction as distance continues to increase. Crepuscular rays are simulated for three cloud configurations. In case 1, the Sun at the zenith is blocked by a cloud with an overhanging anvil. The rays appear white against blue sky and are brightest when atmospheric turbidity, β≈11 . Shading by the anvil separates maximum brightness from apparent cloud edge. In case 2, a ray passes through a rectangular gap in a cloud layer. The ray is faint blue in a molecular atmosphere but turns pale yellow as β and solar zenith angle, ϕsun , increase. At ϕsun=60° it appears most striking when the cloud is optically thick, β≈5 , and the beam width Δx≈1000 m . In these cases, increasing aerosol radius, raer , to about 1000 nm brightens, narrows, and shortens rays. In case 3, the twilight Sun is shaded by a towering cloud or mountain. The shaded rays are deeper blue than the sunlit sky because the light originates higher in the atmosphere, where short waves have suffered less depletion from scattering. The long optical path taken by sunlight at twilight makes color and lighting contrasts of the rays greatest when the air is quite clean, i.e., for β−1≪1 . In all cases, the brightest rays occur when sunlight passes through an optical thickness of atmosphere, τ≈O(1) . © 2011 Optical Society of America Y1 - 2011 U6 - https://doi.org/http://dx.doi.org/10.1364/AO.50.00F142 ER - TY - JOUR A1 - Vollmer, Michael A1 - Möllmann, Klaus-Peter T1 - Rainbows, water droplets, and seeing—slow motion analysis of experiments in atmospheric optics JF - In: Applied optics Vol. 50 (2011) 28, pp. F21–F28 N2 - Many physics processes underlying phenomena in atmospheric optics happen on a rather short time scale such that neither the human eye nor video cameras are able to analyze the details. We report applications of high-speed imaging of laboratory experiments in atmospheric optics with subsequent slow motion analysis. The potential to study respective transient effects is investigated in general and for a few phenomena in detail, in particular for rainbow scattering due to single oscillating droplets during free fall, and for light propagation effects through atmospheric paths with turbulences, leading, e.g., to scintillation of stars or shimmering of mirage images. © 2011 Optical Society of America Y1 - 2011 U6 - https://doi.org/http://dx.doi.org/10.1364/AO.50.000F21 SP - F21 EP - F28 ER - TY - CHAP A1 - Vollmer, Michael A1 - Pinno, Frank A1 - Möllmann, Klaus-Peter T1 - Measurements of sun and moon with IR cameras: effects of air mass T2 - In: InfraMation proceedings. - Vol. 11 ( 2010) , 57-74 Y1 - 2010 SP - 74 ER - TY - CHAP A1 - Möllmann, Klaus-Peter A1 - Pinno, Frank A1 - Vollmer, Michael T1 - Two-color or ratio thermal imaging - potentials and limits T2 - In: InfraMation proceedings. - Vol. 11 (2010), pp.41-56 Y1 - 2010 SP - 41 EP - 56 ER - TY - CHAP A1 - Pinno, Frank A1 - Vollmer, Michael A1 - Möllmann, Klaus-Peter T1 - Improved sensitivity for blower door thermography using image subtraction T2 - In: InfraMation proceedings. - Vol. 11 (2010), p. 29-40 Y1 - 2010 SP - 29 EP - 40 ER - TY - CHAP A1 - Vollmer, Michael A1 - Möllmann, Klaus-Peter T1 - New book on IR imaging: the ultimate resource for all users T2 - In: InfraMation proceedings. - Vol. 11 (2010), pp 75-80 Y1 - 2010 SP - 75 EP - 80 ER - TY - CHAP A1 - Vollmer, Michael A1 - Möllmann, Klaus-Peter T1 - IR imaging of gases: potential applications for CO2 cameras T2 - In: InfraMation proceedings. - Vol. 10 (2009), p.113-124 Y1 - 2009 SP - 113 EP - 124 ER - TY - CHAP A1 - Vollmer, Michael A1 - Möllmann, Klaus-Peter T1 - IR imaging of gases: quantitative analysis T2 - In: InfraMation proceedings. - Vol. 10 (2009), p. 99-112 Y1 - 2009 SP - 99 EP - 112 ER - TY - CHAP A1 - Vollmer, Michael A1 - Vujković, M. A1 - Trellu, Y. A1 - Möllmann, Klaus-Peter T1 - IR feedback loops to spotlights: thermography and contemporary dancing T2 - In: InfraMation proceedings.- Vol. 10 (2009), p. 89-97 Y1 - 2009 SP - 89 EP - 97 ER - TY - CHAP A1 - Pinno, Frank A1 - Möllmann, Klaus-Peter A1 - Vollmer, Michael T1 - Solar load and reflection effects and respective time constants in outdoor building inspections T2 - In: Inframation proceedings Vol. 10 (2009), 319-330 Y1 - 2009 SP - 319 EP - 330 ER - TY - JOUR A1 - Oertel, Christian A1 - Fandre, A. T1 - Tire Model RMOD-K 7 and Misuse Load Cases JF - In: SAE technical papers 2009-01-0582 N2 - Among load cases concerning vehicle suspension strength and durability, the misuse case is very special because of large obstacles. In this paper, an extension of the flexible belt model RMOD-K 7 concerning misuse situations is discussed. In normal rolling conditions, contact occurs between tire and road surface. To handle misuse deformations, the contact between the inner surface of the tire and the rim has to be dealt with. Results of the validation process are shown, leading to normal forces up to 70 [kN]. The model can be used together with mbs full vehicle models. One example is the determination of the critical test velocity, which generates the maximum of suspension stresses and can be found using RMOD-K 7. Y1 - 2009 ER - TY - JOUR A1 - Oertel, Christian A1 - Wei, Yintao T1 - Tyre rolling kinematics and prediction of tyre forces and moments: part I - theory and method JF - In: Vehicle system dynamics 50 (2012) 11, 1673-1687 N2 - A new method to describe tyre rolling kinematics and how to calculate tyre forces and moments is presented. The Lagrange–Euler method is used to calculate the velocity and contact deformation of a tyre structure under large deformation. The calculation of structure deformation is based on the Lagrange method, while the Euler method is used to analyse the deformation and forces in the contact area. The method to predict tyre forces and moments is built using kinematic theory and nonlinear finite element analysis. A detailed analysis of the tyre tangential contact velocity and the relationships between contact forces, contact areas, lateral forces, and yaw and camber angles has been performed for specific tyres. Research on the parametric sensitivity of tyre lateral forces and self-aligning torque on tread stiffness and friction coefficients is carried out in the second part of this paper. Y1 - 2012 U6 - https://doi.org/10.1080/00423114.2012.694452 SP - 1673 EP - 1687 ER - TY - JOUR A1 - Wei, Yintao A1 - Oertel, Christian A1 - Shena, Xiaoliang T1 - Tyre rolling kinematics and prediction of tyre forces and moments: part II - simulation and experiment JF - In: Vehicle system dynamics 50 (2012) 11, 1689-1706 N2 - There are two aims for the second part of this paper: verifying the theory presented in the first part through parameter variation and comparison between simulation and experiment, and to study the effect of the belt structure on the cornering properties of radial tyres. Research has been carried out with a passenger car radial tyre and two different kinds of truck or bus radial tyres using both simulation and experiment. This second part of the paper shows that belt structure plays an important role in the generation of tyre forces and moments in addition to the effects of the tread stiffness and friction coefficients. The theory and method presented in this paper opens a new robust way to predict the tyre forces and moments from the tyre design and provides a reliable model for a generation mechanism. Y1 - 2012 U6 - https://doi.org/10.1080/00423114.2012.694453 SP - 1689 EP - 1706 ER - TY - RPRT A1 - Oertel, Christian T1 - Tyre models in vehicle dynamics: theory and application, part 1: vehicle dynamics tyre model Y1 - 2008 ER - TY - RPRT A1 - Oertel, Christian T1 - Tyre models in vehicle dynamics: theory and application, part 2: tyre structure dynamics tyre model Y1 - 2008 ER - TY - RPRT A1 - Oertel, Christian T1 - Reifenmodelle als Komponenten in der Gesamtfahrzeugmodellierung Y1 - 2007 ER - TY - RPRT A1 - Oertel, Christian T1 - RMOD-K V 7.09 Y1 - 2007 ER - TY - RPRT A1 - Oertel, Christian A1 - Friedemann, D. A1 - Deter, T. A1 - Quaissa, A. T1 - Methodenentwicklung Hindernisüberfahrt Y1 - 2005 ER - TY - RPRT A1 - Oertel, Christian T1 - High frequency related tyre modelling Y1 - 2004 ER - TY - JOUR A1 - Oertel, Christian T1 - Eigensystem of tangential contact in tyre models JF - In : Vehicle System Dynamics 38 (2002) 4, 245-260 N2 - Summary In this paper, a simplified model of tangential contact between tyre and rigid surface is investigated. By linearization the eigensystem of the contact equations is obtained and parameter variations are carried out. It is shown, that some vehicle model parameters have great influence on the eigensystem of tangential contact and can determine the highest eigenfrequency of the system vehicle and tyre. Root loci are used to investigate the influence of parameters like vehicle velocity and gridwidth of the discretization. Based on the eigensystem, stability areas of numerical methods in solving the partial differential equations of tangential contact are calculated. Numerical solutions using stiff and nonstiff integrators are compared with respect to the stability areas, computational effort and accuracy. The results are discussed with a view to further development. Y1 - 2002 U6 - https://doi.org/10.1076/vesd.38.4.245.8284 SP - 245 EP - 260 ER - TY - CHAP A1 - Platt, Ulrich A1 - Vollmer, Michael A1 - Pfeilsticker, Klaus T1 - Optical Phenomena in the Atmosphere T2 - In: Springer handbook of lasers and optics : with 163 tables / Träger (ed.). - 2. ed. - Berlin : Springer, 2012. - ISBN 978-3-642-19408-5 Y1 - 2012 SP - 1493 EP - 1517 ER - TY - CHAP A1 - Platt, Ulrich A1 - Pfeilsticker, Klaus A1 - Vollmer, Michael T1 - Radiation and Optics in the Atmosphere T2 - In: Springer handbook of lasers and optics / Träger (ed.). - New York : Springer, 2007 ISBN 978-0-387-95579-7 Y1 - 2007 SP - 1165 EP - 1203 ER - TY - CHAP A1 - Vollmer, Michael T1 - Optical Spectroscopy of Metal Clusters T2 - In: Atomic physics methods in modern research : selection of papers dedicated to Gisbert zu Putlitz on the occasion of his 65th birthday / K. Jungmann ... (ed.). - Berlin [u.a.] : Springer, 1997. - (Lecture notes in physics ; 499) ISBN 3-540-63716-8 Y1 - 1997 SP - 311 EP - 334 ER - TY - JOUR A1 - Hoheisel, W. A1 - Vollmer, Michael A1 - Träger, F. T1 - Laserdesorption von Metallatomen JF - In: Physikalische Blätter 49 (1993) 9, 795 - 799 N2 - Beleuchtet man die Oberfläche eines Festkörpers mit Laserlicht, können darauf adsorbierte Atome oder Moleküle abgelöst werden. Solche Desorptionsprozesse sind in jüngster Zeit in zahlreichen Experimenten untersucht worden, wobei sich das Interesse sowohl auf die Erforschung der zugrundeliegenden Mechanismen als auch auf mögliche Anwendungen dieser Reaktionen, zum Beispiel zur gezielten Modifizierung von Oberflächen, konzentriert. Besonders interessant ist das laserinduzierte Aufbrechen von Bindungen zur Oberfläche dann, wenn es nicht einfach als thermischer Prozeß durch eine Temperaturerhöhung hervorgerufen wird, sondern direkt auf einer elektronischen Anregung beruht. Solche nichtthermischen Prozesse werden selbst für Metalle beobachtet, obwohl die Kopplung der elektronischen Anregung an das Substrat hier besonders schnell abläuft. Der zugrundeliegende Mechanismus beruht auf dem Zusammenspiel einer kollektiven Elektronenoszillation und einer lokalisierten Einzelelektronenanregung, wobei auch nichtlokale optische Effekte in der Metalloberfläche eine wichtige Rolle spielen. Y1 - 1993 U6 - https://doi.org/10.1002/phbl.19930490909 ER - TY - CHAP A1 - Pinno, Frank A1 - Möllmann, Klaus-Peter A1 - Vollmer, Michael T1 - Dark colors of building walls – thermal problems due to solar load T2 - In: InfraMation proceedings. - Vol. 13 (2012) Y1 - 2012 ER - TY - CHAP A1 - Möllmann, Klaus-Peter A1 - Vollmer, Michael T1 - Thermal effects due to focused light from glass fronts T2 - InfraMation proceedings. - Vol. 13 (2012) Y1 - 2012 ER - TY - CHAP A1 - Vollmer, Michael A1 - Möllmann, Klaus-Peter A1 - Wood, S. T1 - Surprising warm edges associated with moisture on surfaces T2 - In: InfraMation proceeding. - Vol. 13 (2012) Y1 - 2012 ER - TY - JOUR A1 - Vollmer, Michael A1 - Möllmann, Klaus-Peter T1 - CO2 Detektion mit IR Kameras: Grundlagen, Experimente und Anwendungen JF - Technisches Messen : tm 79 (2012) 1, 65-72 N2 - Gasdetektion mit Infrarotkameras ist eine relativ neue Anwendung. Aufgrund der industriellen Bedeutung einiger Gase wurden sensitive Kameras mit Schmalbandfiltern entwickelt. Heute gibt es kommerzielle Systeme für die Detektion flüchtiger Kohlenwasserstoffe, Schwefelhexafluorid und Kohlenmonoxid. In dieser Arbeit werden Laborergebnisse der Detektion von CO2 vorgestellt und potenzielle Anwendungen diskutiert. Y1 - 2012 U6 - https://doi.org/10.1524/teme.2012.0189 ER - TY - CHAP A1 - Möllmann, Klaus-Peter A1 - Vollmer, Michael A1 - Winburn, M. T1 - Optics of glass fronts of buildings: the science of skyscraper “death rays” T2 - InfraMation proceedings. - 12 (2011), S. 79-92 Y1 - 2011 SP - 79 EP - 92 ER - TY - CHAP A1 - Vollmer, Michael T1 - Über die Farben der Sonne und des Himmels: Rayleigh- und Miestreuung in Demonstrationsexperimenten T2 - In: CD zur Frühjahrstagung des Fachverbandes Didaktik der Physik in der Deutschen Physikalischen Gesellschaft : Leipzig, 2002 / Red.: V. Nordmeier. - Berlin : Lehmann, [2002]. - 1 CD-ROM. - ISBN 3-936427-11-9 Y1 - 2002 ER - TY - CHAP A1 - Vollmer, Michael T1 - Freihandspektroskopieexperimente im Unterricht und als Hausaufgabe T2 - In: CD zur Frühjahrstagung des Fachverbandes Didaktik der Physik in der Deutschen Physikalischen Gesellschaft : Leipzig, 2002 / Red.: V. Nordmeier. - Berlin : Lehmann, [2002]. - 1 CD-ROM. - ISBN 3-936427-11-9 Y1 - 2002 ER - TY - JOUR A1 - Vollmer, Michael T1 - Finsternisse, Transits, Kometen und Meteore: ein Blick in die Zukunft JF - In: CD zur Frühjahrstagung des Fachverbandes Didaktik der Physik in der Deutschen Physikalischen Gesellschaft, Dresden 2000 ; weiterhin enthalten: Beiträge zu den Lehrertagen und Exponate der Kunstausstellung Grenzflächen bei der Frühjahrstagung Regensburg 2000 / Red.: V. Nordmeier . - Berlin : Lehmann, 2000. - 1 CD-ROM. - ISBN 3-931253-71-6 Y1 - 2000 ER - TY - CHAP A1 - Möllmann, Klaus-Peter A1 - Vollmer, Michael A1 - Karstädt, Detlef T1 - Tieftemperaturexperimente in der Experimentalphysikausbildung an Hochschulen: Experimente mit flüssigem Stickstoff in der Hochschullehre T2 - In: Frühjahrstagung des Fachverbands Didaktik der Physik in der Deutschen Physikalischen Gesellschaft, Ludwigsburg 1999 ; zusätzlich mit den Beiträgen des Lehrertages und der Kunstausstellung bei der Frühjahrstagung 1999 des Arbeitskreises Festkörperphysik in Münster. - Berlin : Lehmann, 1999. - 1 CD-ROM. - ISBN 3-931253-41-4 Y1 - 1999 ER - TY - CHAP A1 - Vollmer, Michael A1 - Möllmann, Klaus-Peter A1 - Shaw, J. A. A1 - Nugent, P. W. T1 - Measurements of the surface temperature of the moon from earth with IR cameras T2 - In: Temperatur 2013 : Fachtagung ; PTB Institut Berlin, 5./6. Juni 2013 ; [Verfahren und Geräte in der Temperatur- und Feuchtemesstechnik ; Tagungsband] / [Hrsg.: Physikalisch-Technische Bundesanstalt, Braunschweig und Berlin]. Fachl. Mitträger: VDI/VDE-Gesellschaft Mess- und Automatisierungstechnik (GMA), Fachgebiet 2.50: Temperatur und Feuchte. - Braunschweig [u.a.] : Physikalisch-Techn. Bundesanst., 2013. - ISBN 3-9810021-8-0 Y1 - 2013 SP - 149 EP - 154 ER - TY - CHAP A1 - Möllmann, Klaus-Peter A1 - Vollmer, Michael T1 - Einfache Charakterisierung der zeitlichen und räumlichen Auflösung von Wärmebildkameras T2 - In: Temperatur 2013 : Fachtagung ; PTB Institut Berlin, 5./6. Juni 2013 ; [Verfahren und Geräte in der Temperatur- und Feuchtemesstechnik ; Tagungsband] / [Hrsg.: Physikalisch-Technische Bundesanstalt, Braunschweig und Berlin]. Fachl. Mitträger: VDI/VDE-Gesellschaft Mess- und Automatisierungstechnik (GMA), Fachgebiet 2.50: Temperatur und Feuchte. - Braunschweig [u.a.] : Physikalisch-Techn. Bundesanst., 2013. - ISBN 3-9810021-8-0 Y1 - 2013 SP - 137 EP - 142 ER - TY - CHAP A1 - Vollmer, Michael A1 - Möllmann, Klaus-Peter T1 - Perspectives of IR imaging for industrial detection and monitoring of CO2 T2 - In: Temperatur 2009 : Fachtagung PTB Institut Berlin, 24./25. Juni 2009 ; [Verfahren und Geräte in der Temperatur- und Feuchtemesstechnik ; Tagungsband] / [Hrsg.: Physikalisch-Technische Bundesanstalt, Braunschweig und Berlin]. Fachl. Mitträger: VDI/VDE-Gesellschaft Mess- und Automatisierungstechnik (GMA), Fachgebiet 2.50: Temperatur und Feuchte. - Braunschweig [u.a.] : Physikalisch-Techn. Bundesanst., 2009. - ISBN 3-9810021-9-9 Y1 - 2009 SP - 27 EP - 36 ER - TY - RPRT A1 - Oertel, Christian A1 - Hempel, J. T1 - Finite Elemente für die Reifenmodellierung Y1 - 2010 ER - TY - JOUR A1 - Oertel, Christian T1 - Misuse load cases and MBS simulation JF - In: Tire technology international 2009, 62-64 Y1 - 2009 SP - 62 EP - 64 ER - TY - CHAP A1 - Wilden, J. A1 - Bergmann, J. P. A1 - Dolles, M. A1 - Reich, S. A1 - Fernandet, S. A1 - Goecke, Sven-Frithjof T1 - Low temperature brazing of zinc coated steel and steel/aluminium joints by setting ZnAl-alloys as brazing material T2 - In: Brazing and soldering : proceedings of the 3rd International Brazing and Soldering Conference, April 24 - 26, 2006, Crowne Plaza Riverwalk Hotel, San Antonio, Texas, USA / sponsored by ASM International, the Materials Information Society; AWS, [American Welding Society]. Ed. by John J. Stephens ... - Materials Park, Ohio: ASM Internat., 2006. - ISBN 0-87170-838-8 Y1 - 2006 SP - 32 EP - 39 ER - TY - CHAP A1 - Goecke, Sven-Frithjof A1 - Dorn, L. T1 - MAG-ChopArc-Schweißen für Feinblech größer gleich 0,2 mm T2 - In: Schweißen und Schneiden 2000 : Vorträge der gleichnamigen Großen Schweißtechnischen Tagung in Nürnberg vom 27. bis 29. September 2000 / Veranst.: DVS, Deutscher Verband für Schweißen und Verwandte Verfahren e.V.. - Als Ms. gedr. - Düsseldorf : Verl. für Schweißen und Verwandte Verfahren, DVS-Verl., 2000. - (DVS-Berichte ; 209). - ISBN 3-87155-667-X Y1 - 2000 SP - 163 EP - 168 ER - TY - CHAP A1 - Dorn, L. A1 - Goecke, Sven-Frithjof T1 - Influence of least active gas additions on pulsed current MIG-welding of aluminium T2 - In: Proceedings of the International Conference on the Joining of Materials JOM-8 : May 12 - 14, 1997, Helsingør, Denmark ; [optimization of joining technology for the industrial application, case study and repair welding, advanced welding technologies and developments] / ed. by the European Institute for the Joining of Materials. - Helsingør : JOM-Inst., 1997. - ISBN 87-89582-04-7 Y1 - 1997 SP - 100 EP - 105 ER - TY - JOUR A1 - Rose, Sascha A1 - Zähr, Julia A1 - Schnick, Michael A1 - Füssel, Uwe A1 - Goecke, Sven-Frithjof A1 - Hübner, Mark T1 - Arc attachments on aluminium during tungsten electrode positive polarity in TIG welding of aluminium JF - In: Welding in the World 55 (2011) 9-10, pp 91-99 N2 - In modem AC power sources, both balance and current of EP (tungsten electrode positive) and EN (tungsten electrode negative) can be readily adjusted. According to conventional assumptions the surface of aluminium workpieces is cleaned during EP but the tungsten electrode is more heated due to electron work function. During EN the tungsten electrode cools down and the workpiece is melted. Therefore, optimal settings of the power source mostly aim for maximal penetration and minimal electrode wear. This paper presents a study of arc attachments in TIG welding on aluminium. Two different arc attachments to the cathodic workpiece could be attested with only one of them actually cleaning the surface. The first one is a spot mode (highly dynamic) that attaches to the edges of oxide layers and cracks them. The second one is also a spot mode, but it attaches to weld pools. It does not clean the surface but heats the base material intensively. Both arc attachment modes compete against each other. As a result, the cleaning area narrows with wider weld pools due to an increasing attachment to the weld pool during EP. The influences on the arc attachment to the aluminium cathode as well as the contradictions in present literature are discussed. Possible adjustments of the AC balance for optimized processes are proposed. Y1 - 2011 U6 - https://doi.org/10.1007/bf03321325 SN - 1878-6669 VL - 55 IS - 9-10 SP - 91 EP - 99 ER - TY - JOUR A1 - Wilden, J. A1 - Jahn, S. A1 - Melahin, N. A1 - Rehfeldt, L. A1 - Luhn, T. A1 - Goecke, Sven-Frithjof A1 - Schmid, E. A1 - Berger, U. T1 - Brazing as the key to resource-efficient and energy-efficient joining in the product life cycle JF - In: Welding and cutting (2010) 5, 301-312 Y1 - 2010 SN - 1612-3433 SP - 301 EP - 312 ER - TY - JOUR A1 - Wilden, J. A1 - Jahn, S. A1 - Milahin, N. A1 - Luhn, T. A1 - Rehfeldt, L. A1 - Goecke, Sven-Frithjof A1 - Schmid, E. A1 - Berger, U. T1 - Perspektiven und Visionen zum Schweissen moderner Stahlwerkstoffe JF - In: Stahl und Eisen 130 (2010) 10, S. 71-75 Y1 - 2010 SN - 0340-4803 SP - 71 EP - 75 ER - TY - JOUR A1 - Ghosh, P. K. A1 - Dorn, L. A1 - Goecke, Sven-Frithjof T1 - Universality of correlationships among pulse parameters for different MIG Welding Power Sources JF - In: The international journal for the joining of materials : JOM 13 (2001), 40-47 Y1 - 2001 SN - 0905-6866 SP - 40 EP - 47 ER - TY - JOUR A1 - Bergmann, J. P. A1 - Wilden, J. A1 - Reich, S. A1 - Goecke, Sven-Frithjof T1 - Methods and solutions for joining plates made from different metals using voltaic arc welding JF - In: Welding International 23 (2009) 12, pp 895-903 N2 - For some years now, the light engineering sector has been in search of welding and/or joining technologies allowing high-speed processing at low temperatures. This way, damage to galvanized coating, for example in the case of steels, could be avoided or significantly reduced. Damage to the galvanized coating represents an outwardly visible phenomenon that can have a negative impact on the component's corrosion resistance. On the other hand, from the metallurgical viewpoint, controlling heat input represents an important way to solve the problems associated with heat joining of metals with incomplete solid-state solubility. The formation of fragile intermetallic phases during cooling, for example, occurs with aluminium/steel or aluminium/titanium. The process and the correct choice of filler materials are key points for the success of the joining method. In the case of the combination of aluminium and steel, zinc represents a suitable filler material, for example for brazing. The melting temperature is around 420°C and the wettability, with regard to galvanized steel, is favoured by the zinc layer, while on the aluminium part, it is possible to avoid the use of flux, thanks to the activating action of the voltaic arc. However, the low melting and vaporization temperatures of zinc make even ‘short arc’ processing rather difficult. Only new developments in electrical sources for welding, and in particular new processes, offer the possibility of reducing the heat input by modifying the ‘short arc’ process. The difficulties described are also valid for the combination of titanium and aluminium, and are associated with the formation of phases such as Ti x A1 y . Again in this case, this paper will present a strategy for joining sheets less than 2 mm thick. In the past years, an increasing number of strategies to join zinc-coated steels can be observed. Brazing represents a profitable way to join zinc-coated steels at low temperatures, reducing or avoiding zinc evaporation. In order to completely avoid damaging zinc coating, the set of ZnAl-fìllers was already investigated for laser brazing of zinc-coated steels as well as for joining steel with aluminium. Furthermore, thanks to new developments in arc wire technology, ZnAl-electrodes can be used for MIG-brazing as well. In this case, the conventional short arc, which normally does not allow brazing with zinc wires as eruption-like evaporation occurs, is modified and controlled. The drop formation on the wire tip, the metal transfer, and the heat input can be controlled and modified very precisely, so that processing of filler material can be performed easily for thin sheets (till 0.8–1.5 mm) and at low-processing speed, below 0.3–0.4 m/min. The control of the heat input occurs due to abruptly reducing the current after short arc. The disadvantages connected with a lower heat input in the base material are a restricted wetting behaviour of the zinc pool on the base material and the low-brazing speed due to a very high cooling rate. The focus of the presented investigation is the development of strategies, in order to enhance process conditions for brazing sheets of zinc-coated steels and aluminium. Y1 - 2009 U6 - https://doi.org/10.1080/09507110902843289 SN - 0950-7116 SP - 895 EP - 903 ER -