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Aurel M Alessandrescu - One of the best experts on this subject based on the ideXlab platform.
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twenty years after the production of the first heavy water drop in romania july 17th 1988 july 17th 2008 Piping Systems
ASME 2008 9th Biennial Conference on Engineering Systems Design and Analysis, 2008Co-Authors: Aurel M AlessandrescuAbstract:1. Heavy Water application. 2. Heavy Water technology. 3. Isotope exchange installation- Piping Systems characterstics. 3.1. Piping Systems characteristics: (a) crack-inducing corrosion in wet and gaseous hydrogen sulphide medium. (b) selection of a higher nominal pressure than the normal pressure for pipe classes. (c) minimization of flanged pipe joints. (d) provision of Piping Systems selfcompensation in case that lenticular pipe expansion loops can not be used. (e) use of spiral-wound gaskets for all the Piping Systems flanged connections. 3.2. Piping-equipment system interaction. 3.2.1. Severe limitation of the loads in the Piping Systems-equipments joints. 3.2.2. Use of constant elastic supports to protect the Piping Systems associated equipment nozzles. 3.3. Bearing range. 4. Today objectives: to extend the predicted service-life of the Piping Systems. 5. Nomenclature. 6. References.Copyright © 2008 by ASME
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Twenty Years After the Production of the First Heavy Water Drop in Romania: July 17th, 1988 – July 17th, 2008—Piping Systems
Volume 3: Design; Tribology; Education, 2008Co-Authors: Aurel M AlessandrescuAbstract:1. Heavy Water application. 2. Heavy Water technology. 3. Isotope exchange installation- Piping Systems characterstics. 3.1. Piping Systems characteristics: (a) crack-inducing corrosion in wet and gaseous hydrogen sulphide medium. (b) selection of a higher nominal pressure than the normal pressure for pipe classes. (c) minimization of flanged pipe joints. (d) provision of Piping Systems selfcompensation in case that lenticular pipe expansion loops can not be used. (e) use of spiral-wound gaskets for all the Piping Systems flanged connections. 3.2. Piping-equipment system interaction. 3.2.1. Severe limitation of the loads in the Piping Systems-equipments joints. 3.2.2. Use of constant elastic supports to protect the Piping Systems associated equipment nozzles. 3.3. Bearing range. 4. Today objectives: to extend the predicted service-life of the Piping Systems. 5. Nomenclature. 6. References.Copyright © 2008 by ASME
G. R. Reddy - One of the best experts on this subject based on the ideXlab platform.
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Risk-Based Seismic Performance Assessment of Pressurized Piping Systems Considering Ratcheting
Journal of Pressure Vessel Technology-transactions of The Asme, 2019Co-Authors: A. Ravi Kiran, G. R. Reddy, M. K. AgrawalAbstract:Abstract A procedure is described for risk-based seismic performance assessment of pressurized Piping Systems considering ratcheting. The procedure is demonstrated on a carbon steel Piping system considered for OECD-NEA benchmark exercise on quantification of seismic margins. Initially, fragility analysis of the Piping system is carried out by considering variability in damping and frequency. Variation in damping is obtained from the statistical analysis of the damping values observed in earlier experiments on Piping Systems and components. The variation in ground motion is considered by using 20 strong motion records of the intraplate region. Floor motion of a typical reactor building of a nuclear power plant under these actual earthquake records is evaluated and applied to the Piping system. The performance evaluation of the Piping system in terms of ratcheting is carried out using a numerical approach, which was earlier validated with shake table ratcheting tests on Piping components and Systems. Three limit states representing performance levels of the Piping system under seismic load are considered for fragility evaluation. For each limit state, probability of exceedance at different levels of floor motion is evaluated to generate a fragility curve. Subsequently, the fragility curves of the Piping Systems are convoluted with hazardous curves for a typical site to obtain the risk in terms of annual probability of occurrence of the performance limits.
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Optimum X-plate dampers for seismic response control of Piping Systems
International Journal of Pressure Vessels and Piping, 2006Co-Authors: S.v. Bakre, R.s. Jangid, G. R. ReddyAbstract:In a vibrating system, the most effective mechanism to dissipate energy is the inelastic strain of supplemental metallic elements with plastic deforming characteristics. An X-plate damper (XPD) is one device that is capable of sustaining many cycles of stable yielding deformation resulting in a high level of energy dissipation or damping. The present paper focuses on a numerical study to investigate the seismic effectiveness of an XPD for Piping Systems in industrial units (e.g. chemical and petrochemical industries) and utilities such as thermal and nuclear power plants. The seismic performance of Piping Systems is investigated under important parametric variations of the damper properties (i.e. height, width and thickness of the XPD) under arbitrary ground motions. Investigations are reported for an industrial Piping system equipped with an XPD and the response quantities of interest are the relative displacements, absolute accelerations and support reactions of the Piping system. The response quantities of the controlled (with XPD) Piping system are compared with the corresponding uncontrolled (without XPD) Piping Systems, to establish the seismic effectiveness of the XPD. Seismic energy dissipation in the Piping system, which is represented by the hysteretic energy of the XPD, is also evaluated and compared. It is observed that the XPDs are very effective in reducing the seismic response of Piping Systems. Moreover, for a given Piping system and ground motion, it is difficult to arrive at the optimum properties of an XPD from the parametric variation of the properties of the XPD and by monitoring the responses of the Piping system. Therefore, use of hysteretic energy dissipation by an XPD is proposed to obtain the optimum properties of the XPD. Furthermore, the effects of the properties of an XPD on the free vibration characteristics of the Piping system are also presented, which is crucial for the design of Piping Systems with XPDs.
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Passive Control of Seismic Response of Piping Systems
Journal of Pressure Vessel Technology-transactions of The Asme, 2005Co-Authors: Y. M. Parulekar, G. R. Reddy, K. K. Vaze, K. MuthumaniAbstract:Passive energy dissipating devices, such as elastoplastic dampers (EPDs) can be used for eliminating snubbers and reducing the response of Piping Systems subjected to seismic loads. Cantilever and three-dimensional Piping Systems were tested with and without EPD on shaker table. Using a finite element model of the Piping Systems, linear and nonlinear time-history analysis is carried out using Newmark’s time integration technique. Equivalent linearization technique, such as Caughey method, is used to evaluate the equivalent damping of the Piping Systems supported on elastoplastic damper. An iterative response spectrum method is used for evaluating response of the Piping system using this equivalent damping. The analytical maximum response displacement obtained at the elastoplastic damper support for the two Piping Systems is compared with experimental values and time history analysis values. It has been concluded that the iterative response spectrum technique using Caughey equivalent damping is simple and results in reasonably acceptable response of the Piping Systems supported on EPD.
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Passive Control of Seismic Response of Piping Systems
Seismic Engineering Volume 2, 2004Co-Authors: Y. M. Parulekar, G. R. Reddy, K. K. Vaze, K. MuthumaniAbstract:Passive energy dissipating devices like Elasto-plastic dampers (EPDs) can be used for eliminating snubbers and reducing the response of Piping Systems subjected to seismic loads. Cantilever and 3-dimensional Piping Systems were tested with and without EPD on shake table. Using a finite element model of the Piping Systems, linear and nonlinear time history analysis is carried out using Newmark’s time integration technique. Equivalent linearization technique such as Caughey method is used to evaluate the equivalent damping of the Piping Systems supported on Elasto-Plastic damper. An iterative response spectrum method is used for evaluating response of the Piping system using this equivalent damping. The analytical maximum response displacement obtained at the Elasto-Plastic damper support for the two Piping Systems is compared with experimental values and time history analysis values. It has been concluded that, iterative response spectrum technique using Caughey equivalent damping is simple and results in reasonably acceptable response of the Piping Systems supported on EPD.Copyright © 2004 by ASME
Soichi Mabuchi - One of the best experts on this subject based on the ideXlab platform.
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Seismic Evaluation Method of Piping Systems by Inelastic Response Spectrum Analysis: Part 1 — Response Analysis
Volume 8: Seismic Engineering, 2019Co-Authors: Ichiro Tamura, Michiya Sakai, Ryuya Shimazu, Hiroaki Tamashiro, Shinichi Matsuura, Soichi MabuchiAbstract:Abstract An inelastic response-spectrum-analysis method for multi-degree-of-freedom Systems was proposed. The method has lower analysis loads and good outlook given by the inelastic response spectrum like the elastic response-spectrum-analysis method, and is not an equivalent-linearization method. We propose a seismic evaluation method of Piping Systems to conduct seismic design using the inelastic response-spectrum-analysis. In this paper, the inelastic analysis method of Piping Systems for the seismic evaluation method is proposed and applied to a benchmark analysis problem of a Piping system vibration test. The analysis result is compared with the vibration test result of the Piping system. They are consistent and applicability of the analysis to the Piping system was confirmed.
E M Wahba - One of the best experts on this subject based on the ideXlab platform.
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modelling the attenuation of laminar fluid transients in Piping Systems
Applied Mathematical Modelling, 2008Co-Authors: E M WahbaAbstract:Abstract The damping of laminar fluid transients in Piping Systems is studied numerically using a two-dimensional water hammer model. The numerical scheme is based on the classical fourth order Runge–Kutta method for time integration and central difference expressions for the spatial terms. The results of the present method show that the damping of transients in Piping Systems is governed by a non-dimensional parameter representing the ratio of the Joukowsky pressure force to the viscous force. In terms of time scales, this non-dimensional parameter represents the ratio of the viscous diffusion time scale to the pipe period. For small values of this parameter, the damping of the fluid transient becomes more pronounced while for large values, the fluid transient is subjected to insignificant damping. Moreover, the non-dimensional parameter is shown to influence other important transient phenomena such as line packing, instantaneous wall shear stress values and the Richardson annular effect.
Fabrizio Paolacci - One of the best experts on this subject based on the ideXlab platform.
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Seismic Assessment of Petrochemical Piping Systems Using a Performance-Based Approach
Journal of Pressure Vessel Technology-transactions of The Asme, 2016Co-Authors: Oreste S Bursi, S. Reza, Silvia Alessandri, Fabrizio Paolacci, Nicola TondiniAbstract:The need of enhanced seismic analysis and design rules for petrochemical Piping Systems is widely recognized, where the allowable stress design method is still the customary practice. This paper presents an up-to-date performance-based seismic analysis (PBSA) of Piping Systems. The concept of performance-based analysis is introduced and a link between limit states and earthquake levels is proposed, exemplifying international code prescriptions. A brief review on seismic design criteria of Piping Systems is then provided by identifying the main critical issues. Finally, the actual application of the performance-based approach is illustrated through nonlinear seismic analyses of two realistic petrochemical Piping Systems.
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MAIN ISSUES ON THE SEISMIC DESIGN OF INDUSTRIAL Piping Systems AND COMPONENTS
Volume 8: Seismic Engineering, 2013Co-Authors: Fabrizio Paolacci, S. Reza, Oreste S Bursi, A. M. Gresnigt, Anil KumarAbstract:A significant number of damages in Piping Systems and components during recent seismic events have been reported in literature which calls for a proper seismic design of these structures. Nevertheless, there exists an inadequacy of proper seismic analysis and design rules for a Piping system and its components. Current seismic design Codes are found to be over conservative and some components, e.g., bolted flange joints, do not have guidelines for their seismic design. Along this line, this paper discusses about the main issues on the seismic analysis and design of industrial Piping Systems and components. Initially, seismic analysis and component design of refinery Piping Systems are described. A review of current design approaches suggested by European (EN13480:3) and American (ASME B31.3) Codes is performed through a Case Study on a Piping system. Some limits of available Codes are identified and a number of critical aspects of the problem e. g., dynamic interaction between pipes and rack, correct definition of the response factor and strain versus stress approach, are illustrated. Finally, seismic performance of bolted flange joints based on the results of experimental investigations carried out by the University of Trento, Italy, will be discussed.
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seismic performance of bolted flange joints in Piping Systems for oil and gas industries
15th World Conf. on Earth. Eng. 15WCEE, 2012Co-Authors: S Reza, Anil Kumar, Fabrizio PaolacciAbstract:Recent seismic events showed a quite high vulnerability of industrial Piping Systems and components, where damage ranges from simple failure of joints to failure of supporting structures. The performance of the whole Piping system strictly depends on the functionality of its individual components. Moreover, the behaviour of bolted joints is complex and critical under seismic actions. Therefore, they need special attention and deep investigation. In addition even for refinery industries, it is also important to know the leakage behaviour of typical flanged joints. Currently, both American and European codes are available to design flanged joints under static loading. Nonetheless, there is no code available to take into account seismic loading effects on these joints. Along these lines, we intend to present in this paper the results of a test campaign on two different types of flanged joints carried out at the University of Trento(Italy), by means of bending and axial loading, respectively. Test results were favourable and were analysed and compared with: 1) the demand provided by Piping Systems connected to a typical support structure, 2) allowable, yielding and ultimate design values provided by available codes.
