Claudiu Iavornic - Academia.edu (original) (raw)
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Papers by Claudiu Iavornic
OSTI OAI (U.S. Department of Energy Office of Scientific and Technical Information), Apr 12, 2022
The paper presents a method to detect, locate and evaluate damage severity of Euler-Bernoulli bea... more The paper presents a method to detect, locate and evaluate damage severity of Euler-Bernoulli beams, based on how natural frequencies change due to damages. Previous researches that dealt with this issue focused only on
DOAJ (DOAJ: Directory of Open Access Journals), 2012
The paper presents a research regarding the use of a "virtual" material in order to compensate th... more The paper presents a research regarding the use of a "virtual" material in order to compensate the loss of mass in the case of the damaged beam. Because of the loss of mass, the frequency of the beam suffer an increase over the natural frequency of the undamaged beam and so we have proposed the use of this material, having the same density with the density of the beam, in the gap left by damage.
DOAJ (DOAJ: Directory of Open Access Journals), 2012
Transient dynamic characteristics of a friction pendulum can be determined using experimental way... more Transient dynamic characteristics of a friction pendulum can be determined using experimental ways. Nowadays, numerical simulation techniques allow obtaining these characteristics using mathematical models. The express advantage is represented by almost unlimited possibilities to extract and quantified in the regime of "post processing" regarding the results. In terms of efficiency this means increased performance regarding the research and product development.
Applied Mechanics and Materials, Sep 1, 2013
For the study and design of the elastomeric seismic devices is essential to know the mathematical... more For the study and design of the elastomeric seismic devices is essential to know the mathematical relation between the horizontal displacement and the force leading it. In this paper we present mathematical models for three types of devices: (i) natural rubber bearings, (ii) lead rubber bearings and (iii) hybrid device combining the two first mentioned bearings. For all devices the specific domains of operation are determined and for each domain the relations connecting horizontal displacement and stiffness is contrived, highlighting the hysteretic behaviour in respect to ground excitation. Finally we present numerical results and a comparison between the three devices, defining the opportunity to involve them in specific applications, in function of the type and nature of the isolated structure.
DOAJ (DOAJ: Directory of Open Access Journals), Sep 1, 2012
A modern tool to study the behavior of elastomeric elements for earthquake isolation is the Finit... more A modern tool to study the behavior of elastomeric elements for earthquake isolation is the Finite Element Method. The results of the simulations obtained in this way provide a large series of data about the behavior of the elastomeric elements under different types of loads and help in taking right decisions regarding geometrical optimizations needed for improve such kind of devices.
Patent Publication US2016045440, 2017
Conferinta hidroenergeticienilor 2006, Politehnica, Bucharest, 2006
Present paper refers to assessing behavior of a butterfly valve from hydrodynamic and vibration p... more Present paper refers to assessing behavior of a butterfly valve from hydrodynamic and vibration point of view in two disadvantageous exploitation regimes in order to confirm correctness of entrance geometry. Respective device operates as entrance valve in a HEPP equipped with Pelton turbines. The first part shortly refers to some theoretical aspects concerning used simulation methods. After presenting the used software and data preparation, later on the computed parameters are referred to: hydrodynamic parameters, loads and stresses and determination of own frequencies. The obtained results, also compared to results from specialty literature, lead to the conclusion that entrance area geometry is suitable for analyzed exploitation regimes.
OSTI OAI (U.S. Department of Energy Office of Scientific and Technical Information), Apr 12, 2022
L'invention concerne des machines hydro-motrices, par exemple des hydroturbines et des hydrop... more L'invention concerne des machines hydro-motrices, par exemple des hydroturbines et des hydropompes comprenant des vannes d'arret integrees a faible perte de charge. Des reseaux d'hydroturbines de ce type facilitent la production d'electricite au sein de l'espace limite disponible dans des structures de gestion de l'eau a vannes preexistantes. Une roue mobile d'hydroturbine a pas reglable particulierement apropriee pour une utilisation avec ladite vanne d'arret integree a faible perte de charge presente une puissance delivree et une vitesse specifique superieures a celles des hydroturbines de l'etat anterieur de la technique dans des installations hydroelectriques de basse chute. Les reseaux de pompes selon a presente invention assurent une haute capacite de debit dans un espace limite, chaque pompe individuelle au sein du reseau comprenant une vanne integree a faible perte de charge pour la prevention du debit nul et du retour d'eau.
ABSTRACT The earthquakes have been, and are a great danger against humanity. The study presented ... more ABSTRACT The earthquakes have been, and are a great danger against humanity. The study presented in this paper aims to determine the response of an insulated structure due to earthquakes vibration loads, which are randomly, non-periodic and contain various frequencies. The study, made on a two-story structure involved finite element analysis, to determine the displacements, velocities and accelerations in various locations on the structure. The actual results were obtained using statistical methods, in order to determine the dynamic behavior of a vibrating structure.
Analele Universitatii "Eftimie Murgu" Resita - Fascicula de Inginerie, 2011
In Modern tools as Finite Element Method can be used to study the behavior of elastomeric isolati... more In Modern tools as Finite Element Method can be used to study the behavior of elastomeric isolation systems. The simulation results obtained in this way provide a large series of data about the behavior of elastomeric isolation bearings under different types of loads and help in taking right decisions regarding geometrical optimizations needed for improve such kind of devices.
Analele Universităţii Eftimie Murgu Reşiţa. Fascicula de Inginerie, 2012
Transient dynamic characteristics of a friction pendulum can be determined using experimental way... more Transient dynamic characteristics of a friction pendulum can be determined using experimental ways. Nowadays, numerical simulation techniques allow obtaining these characteristics using mathematical models. The express advantage is represented by almost unlimited possibilities to extract and quantified in the regime of "post processing" regarding the results. In terms of efficiency this means increased performance regarding the research and product development.
Modern tools as Finite Element Method can be used to study the behavior of elastomeric isolation ... more Modern tools as Finite Element Method can be used to study the behavior of elastomeric isolation systems. The simulation results obtained in this way provide a large series of data about the behavior of elastomeric isolation bearings under different types of loads and help in taking right decisions regarding geometrical optimizations needed for improve such kind of devices.
Analele Universităţii Eftimie Murgu Reşiţa. Fascicula de Inginerie, 2012
Applied Mechanics and Materials, 2013
For the study and design of the elastomeric seismic devices is essential to know the mathematical... more For the study and design of the elastomeric seismic devices is essential to know the mathematical relation between the horizontal displacement and the force leading it. In this paper we present mathematical models for three types of devices: (i) natural rubber bearings, (ii) lead rubber bearings and (iii) hybrid device combining the two first mentioned bearings. For all devices the specific domains of operation are determined and for each domain the relations connecting horizontal displacement and stiffness is contrived, highlighting the hysteretic behaviour in respect to ground excitation. Finally we present numerical results and a comparison between the three devices, defining the opportunity to involve them in specific applications, in function of the type and nature of the isolated structure.
In Modern tools as Finite Element Method can be used to study the behavior of elastomeric isolati... more In Modern tools as Finite Element Method can be used to study the behavior of elastomeric isolation systems. The simulation results obtained in this way provide a large series of data about the behavior of elastomeric isolation bearings under different types of loads and help in taking right decisions regarding geometrical optimizations needed for improve such kind of devices.
OSTI OAI (U.S. Department of Energy Office of Scientific and Technical Information), Apr 12, 2022
The paper presents a method to detect, locate and evaluate damage severity of Euler-Bernoulli bea... more The paper presents a method to detect, locate and evaluate damage severity of Euler-Bernoulli beams, based on how natural frequencies change due to damages. Previous researches that dealt with this issue focused only on
DOAJ (DOAJ: Directory of Open Access Journals), 2012
The paper presents a research regarding the use of a "virtual" material in order to compensate th... more The paper presents a research regarding the use of a "virtual" material in order to compensate the loss of mass in the case of the damaged beam. Because of the loss of mass, the frequency of the beam suffer an increase over the natural frequency of the undamaged beam and so we have proposed the use of this material, having the same density with the density of the beam, in the gap left by damage.
DOAJ (DOAJ: Directory of Open Access Journals), 2012
Transient dynamic characteristics of a friction pendulum can be determined using experimental way... more Transient dynamic characteristics of a friction pendulum can be determined using experimental ways. Nowadays, numerical simulation techniques allow obtaining these characteristics using mathematical models. The express advantage is represented by almost unlimited possibilities to extract and quantified in the regime of "post processing" regarding the results. In terms of efficiency this means increased performance regarding the research and product development.
Applied Mechanics and Materials, Sep 1, 2013
For the study and design of the elastomeric seismic devices is essential to know the mathematical... more For the study and design of the elastomeric seismic devices is essential to know the mathematical relation between the horizontal displacement and the force leading it. In this paper we present mathematical models for three types of devices: (i) natural rubber bearings, (ii) lead rubber bearings and (iii) hybrid device combining the two first mentioned bearings. For all devices the specific domains of operation are determined and for each domain the relations connecting horizontal displacement and stiffness is contrived, highlighting the hysteretic behaviour in respect to ground excitation. Finally we present numerical results and a comparison between the three devices, defining the opportunity to involve them in specific applications, in function of the type and nature of the isolated structure.
DOAJ (DOAJ: Directory of Open Access Journals), Sep 1, 2012
A modern tool to study the behavior of elastomeric elements for earthquake isolation is the Finit... more A modern tool to study the behavior of elastomeric elements for earthquake isolation is the Finite Element Method. The results of the simulations obtained in this way provide a large series of data about the behavior of the elastomeric elements under different types of loads and help in taking right decisions regarding geometrical optimizations needed for improve such kind of devices.
Patent Publication US2016045440, 2017
Conferinta hidroenergeticienilor 2006, Politehnica, Bucharest, 2006
Present paper refers to assessing behavior of a butterfly valve from hydrodynamic and vibration p... more Present paper refers to assessing behavior of a butterfly valve from hydrodynamic and vibration point of view in two disadvantageous exploitation regimes in order to confirm correctness of entrance geometry. Respective device operates as entrance valve in a HEPP equipped with Pelton turbines. The first part shortly refers to some theoretical aspects concerning used simulation methods. After presenting the used software and data preparation, later on the computed parameters are referred to: hydrodynamic parameters, loads and stresses and determination of own frequencies. The obtained results, also compared to results from specialty literature, lead to the conclusion that entrance area geometry is suitable for analyzed exploitation regimes.
OSTI OAI (U.S. Department of Energy Office of Scientific and Technical Information), Apr 12, 2022
L'invention concerne des machines hydro-motrices, par exemple des hydroturbines et des hydrop... more L'invention concerne des machines hydro-motrices, par exemple des hydroturbines et des hydropompes comprenant des vannes d'arret integrees a faible perte de charge. Des reseaux d'hydroturbines de ce type facilitent la production d'electricite au sein de l'espace limite disponible dans des structures de gestion de l'eau a vannes preexistantes. Une roue mobile d'hydroturbine a pas reglable particulierement apropriee pour une utilisation avec ladite vanne d'arret integree a faible perte de charge presente une puissance delivree et une vitesse specifique superieures a celles des hydroturbines de l'etat anterieur de la technique dans des installations hydroelectriques de basse chute. Les reseaux de pompes selon a presente invention assurent une haute capacite de debit dans un espace limite, chaque pompe individuelle au sein du reseau comprenant une vanne integree a faible perte de charge pour la prevention du debit nul et du retour d'eau.
ABSTRACT The earthquakes have been, and are a great danger against humanity. The study presented ... more ABSTRACT The earthquakes have been, and are a great danger against humanity. The study presented in this paper aims to determine the response of an insulated structure due to earthquakes vibration loads, which are randomly, non-periodic and contain various frequencies. The study, made on a two-story structure involved finite element analysis, to determine the displacements, velocities and accelerations in various locations on the structure. The actual results were obtained using statistical methods, in order to determine the dynamic behavior of a vibrating structure.
Analele Universitatii "Eftimie Murgu" Resita - Fascicula de Inginerie, 2011
In Modern tools as Finite Element Method can be used to study the behavior of elastomeric isolati... more In Modern tools as Finite Element Method can be used to study the behavior of elastomeric isolation systems. The simulation results obtained in this way provide a large series of data about the behavior of elastomeric isolation bearings under different types of loads and help in taking right decisions regarding geometrical optimizations needed for improve such kind of devices.
Analele Universităţii Eftimie Murgu Reşiţa. Fascicula de Inginerie, 2012
Transient dynamic characteristics of a friction pendulum can be determined using experimental way... more Transient dynamic characteristics of a friction pendulum can be determined using experimental ways. Nowadays, numerical simulation techniques allow obtaining these characteristics using mathematical models. The express advantage is represented by almost unlimited possibilities to extract and quantified in the regime of "post processing" regarding the results. In terms of efficiency this means increased performance regarding the research and product development.
Modern tools as Finite Element Method can be used to study the behavior of elastomeric isolation ... more Modern tools as Finite Element Method can be used to study the behavior of elastomeric isolation systems. The simulation results obtained in this way provide a large series of data about the behavior of elastomeric isolation bearings under different types of loads and help in taking right decisions regarding geometrical optimizations needed for improve such kind of devices.
Analele Universităţii Eftimie Murgu Reşiţa. Fascicula de Inginerie, 2012
Applied Mechanics and Materials, 2013
For the study and design of the elastomeric seismic devices is essential to know the mathematical... more For the study and design of the elastomeric seismic devices is essential to know the mathematical relation between the horizontal displacement and the force leading it. In this paper we present mathematical models for three types of devices: (i) natural rubber bearings, (ii) lead rubber bearings and (iii) hybrid device combining the two first mentioned bearings. For all devices the specific domains of operation are determined and for each domain the relations connecting horizontal displacement and stiffness is contrived, highlighting the hysteretic behaviour in respect to ground excitation. Finally we present numerical results and a comparison between the three devices, defining the opportunity to involve them in specific applications, in function of the type and nature of the isolated structure.
In Modern tools as Finite Element Method can be used to study the behavior of elastomeric isolati... more In Modern tools as Finite Element Method can be used to study the behavior of elastomeric isolation systems. The simulation results obtained in this way provide a large series of data about the behavior of elastomeric isolation bearings under different types of loads and help in taking right decisions regarding geometrical optimizations needed for improve such kind of devices.
NREL/CP-5000-74121, 2019
An innovative reversible pump-turbine runner with a 180-degree flow direction reversal has been d... more An innovative reversible pump-turbine runner with a 180-degree flow direction reversal has been designed and optimized using computational fluid dynamics (CFD) modeling. The reversible pump-turbine configuration provides a cost-effective means of achieving adequate submergence below tailwater, thereby permitting higher-speed turbine and generator operation and reduced equipment size. Results from CFD modeling and analysis of the hydraulics and runner design are presented. The benchmarks for these parameters are the performance parameters of conventional pump turbines with scroll-case turbine inlets. The model efficiencies were independently verified, and a sensitivity analysis of the results is presented. The results do not reveal a region of pump instability that is characteristic of pumps and pump turbines with scroll cases.