TY - JOUR A1 - Staat, Manfred T1 - Plastic collapse analysis of longitudinally flawed pipes and vessels N2 - Improved collapse loads of thick-walled, crack containing pipes and vessels are suggested. Very deep cracks have a residual strength which is better modelled by a global limit load. In all burst tests, the ductility of pressure vessel steels was sufficiently high whereby the burst pressure could be predicted by limit analysis with no need to apply fracture mechanics. The relative prognosis error increases however, for long and deep defects due to uncertainties of geometry and strength data. KW - Druckbehälter KW - Stahl KW - Druckbelastung KW - Druckbeanspruchung KW - Rohr KW - Rohrbruch KW - Druckbehälter KW - Stahl KW - Druckbelastung KW - Druckbeanspruchung KW - Rohrbruch KW - Fehlerstellen KW - pipes KW - vessels KW - load limit KW - burst tests KW - burst pressure KW - flaw Y1 - 2004 ER - TY - CHAP A1 - Surtees, A. J. A1 - Gillespie, A. A1 - Kern, Alexander A1 - Rousseau, A. T1 - DEVELOPMENT OF A RISK ASSESSMENT CALCULATOR BASED ON A SIMPLIFIED FORM OF THE IEC 62305-2 STANDARD ON LIGHTNING PROTECTION N2 - Neue Blitzschutznorm IEC 62305. Entwicklung einer einfachen Software zur Risikoabwägung N2 - IEC Technical Committee 81 is currently creating the new IEC 62305 series of standards on Lightning Protection. Working Group 9 is responsible for Part 2 of this series, which deals with the assessment and management of risk its CDV (Committee Draft for Voting) stage and has been circulated to National Committees for comment. The paper details the development of the Simplified IEC Risk Assessment Calculator software tool as described in Informative Annex J of IEC62305-2 Ed.1/CDV 2. This tool is intended as a simplified implementation of the more rigorous treatment of risk management found in the written document. It is designed to be relatively intuitive for users who wish to obtain an initial assessment of risk sensitivity, but should not be considered a substitute to a full understanding of the methods provided in the standard when dealing with more complicated structures or those where greater risks to personal or system operation are involved. KW - Risiko KW - Risikoabwägung KW - Blitzrisiko KW - Blitzschutz KW - Risk KW - Risk Management KW - Risk Assessment KW - Lightning Risk KW - Lightning Protection Y1 - 2004 ER - TY - CHAP A1 - Kern, Alexander A1 - Heidler, Fridolin A1 - Seevers, M. A1 - Zischank, Wolfgang J. T1 - Magnetic Fields and Induced Voltages in case of a Direct Strike - Comparison of Results obtained from Measurements at a Scaled Building to those of IEC 62305-4 N2 - In the paper the results obtained from experiments at a modelled reinforced building in case of a direct lightning strike are compared with calculations. The comparison includes peak values of the magnetic field Hmax, its derivative (dH/dt)max and of induced voltages umax in typical cable routings. The experiments are performed at a 1:6 scaled building and the results are extrapolated using the similarity relations theory. The calculations are based on the approximate formulae given in IEC 62305-4 and have to be supplemented by a rough estimation of the additional shielding effect of a second reinforcement layer. The comparison shows, that the measured peak values of the magnetic field and its derivative are mostly lower than the calculated. The induced voltages are in good agreement. Hence, calculations of the induced voltages based on IEC 62305-4 are a good method for lightning protection studies of buildings, where the reinforcement is used as a grid-like electromagnetic shield. N2 - Auswirkungen eines direkten Blitzeinschlages auf ein Gebäude, Vergleich von experimentellen Ergebnissen und Berechnungen basierend auf einer Formel aus der IEC 62305-4 KW - Blitz KW - Direkter Blitzschlag KW - Elektromagnetischer Schutzschild KW - Magnetische Felder KW - Induzierte Spannungen KW - Kalkulation KW - Direct lightning strike KW - electromagnetic shield KW - magnetic fields KW - induced voltages KW - calculations Y1 - 2004 SN - 0304-3886 N1 - Journal of electrostatics: Beitr. auf S. 379 - 385. doi:10.1016/j.elstat.2006.09.004 ER - TY - CHAP A1 - Zischank, Wolfgang J. A1 - Heidler, Fridolin A1 - Wiesinger, J. A1 - Stimper, K. A1 - Kern, Alexander A1 - Seevers, M. T1 - Magnetic Fields and Induced Voltages inside LPZ 1 Measured at a 1:6 Scale Model Building N2 - Laborexperimente zu Blitzschutzzonen in Stahlbetongebäuden anhand eines Modells im Maßstab 1:6 N2 - For the application of the concept of Lightning Protection Zones (LPZ), the knowledge of the magnetic fields and induced voltages inside a structure is necessary. Laboratory experiments have been conducted at a downscaled model of a building (scale factor 1:6) to determine these electromagnetic quantities in case of a direct strike to the structure. The model (3 m x 2 m x 2 m) represented a small industrial building using the reinforcement of the concrete as electromagnetic shield. The magnetic fields and magnetic field derivatives were measured at several location inside the scaled model. Further, the voltages induced on three typical cable routes inside the model was determined. The influence of the lightning current waveshape, point-of-strike, bonding of the cable routes, and bridging of an expansion joint in the middle of the building on these quantities was studied. KW - Blitzschlag KW - Elektromagnetischer Schutzschild KW - Stahlbeton KW - Maßstabsgetreues Modell KW - Lightning KW - electromagnetic shielding KW - reinforced concrete KW - scaled model Y1 - 2004 ER - TY - JOUR A1 - Vu, Duc-Khoi A1 - Staat, Manfred T1 - An algorithm for shakedown analysis of structure with temperature dependent yield stress N2 - This work is an attempt to answer the question: How to use convex programming in shakedown analysis of structures made of materials with temperature-dependent properties. Based on recently established shakedown theorems and formulations, a dual relationship between upper and lower bounds of the shakedown limit load is found, an algorithmfor shakedown analysis is proposed. While the original problem is neither convex nor concave, the algorithm presented here has the advantage of employing convex programming tools. KW - Einspielen KW - Temperaturabhängigkeit KW - Fließgrenze KW - Shakedown KW - shakedown analysis KW - yield stress Y1 - 2004 ER - TY - JOUR A1 - Kühn, Raoul-Roman A1 - Haugner, Werner A1 - Staat, Manfred A1 - Sponagel, Stefan T1 - A Two Phase Mixture Model based on Bone Observation N2 - An optimization method is developed to describe the mechanical behaviour of the human cancellous bone. The method is based on a mixture theory. A careful observation of the behaviour of the bone material leads to the hypothesis that the bone density is controlled by the principal stress trajectories (Wolff’s law). The basic idea of the developed method is the coupling of a scalar value via an eigenvalue problem to the principal stress trajectories. On the one hand this theory will permit a prediction of the reaction of the biological bone structure after the implantation of a prosthesis, on the other hand it may be useful in engineering optimization problems. An analytical example shows its efficiency. KW - Knochen KW - Knochenbildung KW - Knochenchirugie KW - Strukturanalyse KW - Schwammknochen KW - Knochendichte KW - Wolffsches Gesetz KW - bone structure KW - bone density KW - Wolff's Law KW - cancellous bone Y1 - 2004 ER -