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Design Formulas (design + formula)
Selected AbstractsQuerkrafttragfähigkeit von Fahrbahnplatten ohne QuerkraftbewehrungBETON- UND STAHLBETONBAU, Issue 10 2009Günter Rombach Prof. Dr.-Ing. Versuche; Berechnungs- und Bemessungsverfahren Abstract Es wird über Versuche zur Querkrafttragfähigkeit von Brückenfahrbahnplatten aus Stahlbeton berichtet. Diese zeigen, dass die bekannten Rechenansätze für Bauteile ohne Querkraftbewehrung nach DIN 1045-1 bzw. DIN-FB 102 für Fahrbahnplatten auf der sicheren Seite liegen, die tatsächliche Tragfähigkeit aber weit unterschätzt wird. Weitere Ansätze zur Berechnung der Querkrafttragfähigkeit von Stahlbetonbauteilen ohne Querkraftbewehrung werden erörtert. Während die Modelle bei der Auswertung einer Datenbank von Balkenversuchen eine gute Übereinstimmung aufweisen, zeigt der Vergleich mit den Modellversuchen, dass die meisten Rechenverfahren die Tragfähigkeit der Platten unterschätzen. Zur Berechnung der Querkrafttragfähigkeit von Platten ohne Querkraftbewehrung unter Punktlasten wird ein Modell vorgeschlagen, welches die Querkrafttragfähigkeit mit der Zugbeanspruchung der Biegezugzone im kritischen Bereich verknüpft. Shear Resistance of Bridge Decks without Transverse Reinforcement The design of concrete bridge deck slabs is of major concern since the introduction of the Eurocodes as the calculated shear capacity of slabs without stirrups and staggered reinforcement according to the new design standards is often considerably smaller compared to the former regulations i.e. DIN 1045:88. This raises the question whether the existing structures are still save. A series of 12 tests on 4 different specimens representing a bridge deck was performed to examine the real load bearing behaviour of a slab with and without shear reinforcement under a wheel (point) load. The evaluation of the test results revealed, that the current design formula with an assumed elastic shear force distribution leads to rather conservative values of shear capacity for bridge deck slabs. Various approaches for shear design are discussed and the accuracy is checked by means of a shear database and the test results. A new model to calculate the shear capacity is proposed which shows a better agreement with test data than the known approaches. [source] Kirschning and Jansen computer-aided design formulae for the analysis of parallel coupled linesMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 10 2009J. A. Brandão Faria Abstract Among the many computer-aided design (CAD) formulae used for the calculation of the wave parameters of coupled microstrip lines where fringing field effects occur, the Kirschning and Jansen equations are the most utilized ones, not only because of their high accuracy, but also because of their wide range of application. Here, we show that, despite the aforementioned advantages, such equations may lack physical meaning. We prove, for the first time, that the utilization of these widespread CAD equations can lead to positive valued mutual capacitances, an unacceptable result from the viewpoint of electromagnetic theory. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2466,2470, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24659 [source] Explicit design formulas for current-mode leap-frog OTA-C filters and 300,MHz CMOS seventh-order linear phase filterINTERNATIONAL JOURNAL OF CIRCUIT THEORY AND APPLICATIONS, Issue 4 2010Yichuang Sun Abstract The leap-frog (LF) configuration is an important structure in analogue filter design. Voltage-mode LF OTA-C filters have recently been studied in the literature; however, general explicit formulas do not exist for current-mode LF OTA-C filters and there is also need for current-mode LF-based OTA-C structures for realization of arbitrary transmission zeros. Three current-mode OTA-C structures are presented, including the basic LF structure and LF filters with an input distributor or an output summer. They can realize all-pole characteristics and functions with arbitrary transmission zeros. Explicit design formulas are derived directly from these structures for the synthesis of, respectively, all-pole and arbitrary zero filter characteristics of up to the sixth order. The filter structures are regular and the design formulas are straightforward to use. As an illustrative example, a 300,MHz seventh-order linear phase low-pass filter with zeros is presented. The filter is implemented using a fully differential linear operational transconductance amplifier (OTA) based on a source degeneration topology. Simulations in a standard TSMC 0.18µm CMOS process with 2.5,V power supply have shown that the cutoff frequency of the filter ranges from 260 to 320,MHz, group delay ripple is about 4.5% over the whole tuning range, noise of the filter is 420nA/,Hz, dynamic range is 66,dB and power consumption is 200,mW. Copyright © 2008 John Wiley & Sons, Ltd. [source] An arbitrary dual-band microstrip hybrid-ringMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 5 2006Santanu Dwari Abstract This paper presents the realization of a dual-band hybrid-ring and gives the design formulas. The simulated and measured results of a microstrip dual-band hybrid-ring operating at 900/1900 MHz are shown to have good agreement and exhibit good performance at both frequency bands. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 840,842, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21492 [source] | ||||||||||