Les Inscriptions à la Bibliothèque sont ouvertes en
ligne via le site: https://biblio.enp.edu.dz
Les Réinscriptions se font à :
• La Bibliothèque Annexe pour les étudiants en
2ème Année CPST
• La Bibliothèque Centrale pour les étudiants en Spécialités
A partir de cette page vous pouvez :
| Retourner au premier écran avec les recherches... |
Journal of Engineering Mechanics (ASCE) |
Dépouillements
Ajouter le résultat dans votre panierVibration of tensioned beams with intermediate damper. I / Joseph A. Main in Journal of engineering mechanics, Vol. 133 N°4 (Avril 2007)
in Journal of engineering mechanics > Vol. 133 N°4 (Avril 2007) . - pp.369–378.
Titre : Vibration of tensioned beams with intermediate damper. I : formulation, influence of damper location Type de document : texte imprimé Auteurs : Joseph A. Main, Auteur ; Nicholas P. Jones, Auteur Année de publication : 2007 Article en page(s) : pp.369–378. Note générale : Applied mechanics Langues : Anglais (eng) Mots-clés : Vibration Damping Modal analysis Eigenvalues Beams Résumé : Exact analytical solutions are formulated for free vibrations of tensioned beams with an intermediate viscous damper. The dynamic stiffness method is used in the problem formulation, and characteristic equations are obtained for both clamped and pinned supports. The complex eigenfrequencies form loci in the complex plane that originate at the undamped eigenfrequencies and terminate at the eigenfrequencies of the fully locked system, in which the damper acts as an intermediate pin support. The fully locked eigenfrequencies exhibit “curve veering,” in which adjacent eigenfrequencies approach and then veer apart as the damper passes a node of an undamped mode shape. Consideration of the evolution of the eigenfrequency loci with varying damper location reveals three distinct regimes of behavior, which prevail from the taut-string limit to the case of a beam without tension. The second regime corresponds to damper locations near the first antinode of a given undamped mode shape; in this regime, the loci bend backwards to intersect the imaginary axis, and two distinct nonoscillatory decaying solutions emerge when the damper coefficient exceeds a critical value. ISSN : 0733-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%290733-9399%282007%29133%3A4%2836 [...] [article] Vibration of tensioned beams with intermediate damper. I : formulation, influence of damper location [texte imprimé] / Joseph A. Main, Auteur ; Nicholas P. Jones, Auteur . - 2007 . - pp.369–378.
Applied mechanics
Langues : Anglais (eng)
in Journal of engineering mechanics > Vol. 133 N°4 (Avril 2007) . - pp.369–378.
Mots-clés : Vibration Damping Modal analysis Eigenvalues Beams Résumé : Exact analytical solutions are formulated for free vibrations of tensioned beams with an intermediate viscous damper. The dynamic stiffness method is used in the problem formulation, and characteristic equations are obtained for both clamped and pinned supports. The complex eigenfrequencies form loci in the complex plane that originate at the undamped eigenfrequencies and terminate at the eigenfrequencies of the fully locked system, in which the damper acts as an intermediate pin support. The fully locked eigenfrequencies exhibit “curve veering,” in which adjacent eigenfrequencies approach and then veer apart as the damper passes a node of an undamped mode shape. Consideration of the evolution of the eigenfrequency loci with varying damper location reveals three distinct regimes of behavior, which prevail from the taut-string limit to the case of a beam without tension. The second regime corresponds to damper locations near the first antinode of a given undamped mode shape; in this regime, the loci bend backwards to intersect the imaginary axis, and two distinct nonoscillatory decaying solutions emerge when the damper coefficient exceeds a critical value. ISSN : 0733-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%290733-9399%282007%29133%3A4%2836 [...]
in Journal of engineering mechanics > Vol. 133 N°4 (Avril 2007) . - pp.379–388.
Titre : Vibration of tensioned beams with intermediate damper. II : damper near a support Type de document : texte imprimé Auteurs : Joseph A. Main, Auteur ; Nicholas P. Jones, Auteur Année de publication : 2007 Article en page(s) : pp.379–388. Note générale : Applied mechanics Langues : Anglais (eng) Mots-clés : Vibration Damping Beams Cables Bridges cable-stayed Optimization Résumé : Analytical solutions are used to investigate the free vibrations of tensioned beams with a viscous damper attached transversely near a support. This problem is of particular relevance for stay-cable vibration suppression, but no restrictions on the level of axial load are introduced, and the results are quite broadly applicable. Characteristic equations for both clamped and pinned supports are rearranged into forms suitable for numerical solution by fixed-point iteration, whereby the complex eigenfrequencies and corresponding damping ratios can be accurately computed within a few iterations. Explicit asymptotic approximations for the complex eigenfrequencies are also obtained, subject to restrictions on the closeness of the eigenfrequencies to their undamped values. These asymptotic approximations are expressed in the same “universal” form identified in previous studies. It is observed that the maximum attainable modal damping ratios and the corresponding optimal values of the damper coefficient can be significantly affected by bending stiffness and by the nature of the support conditions, and a nondimensional parameter grouping is identified that enables an assessment of when bending stiffness should be considered. ISSN : 0733-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%290733-9399%282007%29133%3A4%2837 [...] [article] Vibration of tensioned beams with intermediate damper. II : damper near a support [texte imprimé] / Joseph A. Main, Auteur ; Nicholas P. Jones, Auteur . - 2007 . - pp.379–388.
Applied mechanics
Langues : Anglais (eng)
in Journal of engineering mechanics > Vol. 133 N°4 (Avril 2007) . - pp.379–388.
Mots-clés : Vibration Damping Beams Cables Bridges cable-stayed Optimization Résumé : Analytical solutions are used to investigate the free vibrations of tensioned beams with a viscous damper attached transversely near a support. This problem is of particular relevance for stay-cable vibration suppression, but no restrictions on the level of axial load are introduced, and the results are quite broadly applicable. Characteristic equations for both clamped and pinned supports are rearranged into forms suitable for numerical solution by fixed-point iteration, whereby the complex eigenfrequencies and corresponding damping ratios can be accurately computed within a few iterations. Explicit asymptotic approximations for the complex eigenfrequencies are also obtained, subject to restrictions on the closeness of the eigenfrequencies to their undamped values. These asymptotic approximations are expressed in the same “universal” form identified in previous studies. It is observed that the maximum attainable modal damping ratios and the corresponding optimal values of the damper coefficient can be significantly affected by bending stiffness and by the nature of the support conditions, and a nondimensional parameter grouping is identified that enables an assessment of when bending stiffness should be considered. ISSN : 0733-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%290733-9399%282007%29133%3A4%2837 [...]
in Journal of engineering mechanics > Vol. 133 N°4 (Avril 2007) . - pp.389–399.
Titre : Closed-form sensitivity of earthquake input energy to soil-structure interaction system Type de document : texte imprimé Auteurs : Izuru Takewaki, Auteur Année de publication : 2007 Article en page(s) : pp.389–399. Note générale : Applied mechanics Langues : Anglais (eng) Mots-clés : Closed-form solutions Earthquake resistant structures Frequency analysis Sensitivity analysis Soil-structure interaction Structural design Energy methods. Résumé : The input energy to a soil-structure interaction (SSI) system during earthquake shaking is taken as a structural performance measure and is formulated in the frequency domain. The purpose of this paper is to derive the closed-form expression of the sensitivity of the input energy to the SSI system with respect to uncertain parameters representing soil stiffness and damping. It is demonstrated first that the input energy expression can be of a compact form consisting of the product between the input motion component (Fourier amplitude spectrum of acceleration) and the structural model component (so-called energy transfer function). With the help of this compact form, it is shown that the formulation of earthquake input energy in the frequency domain is essential for deriving the closed-form expressions of the sensitivity of the input energy to the SSI system with respect to uncertain parameters in contrast to the time-domain formulation including inevitable numerical error and instability. This formulation is then extended to a multidegree-of-freedom superstructure model. Numerical examples support the fact that the closed-form expressions enable one to find in a reliable and efficient way the most critical combination of the uncertain parameters that leads to the maximum energy input. ISSN : 0733-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%290733-9399%282007%29133%3A4%2838 [...] [article] Closed-form sensitivity of earthquake input energy to soil-structure interaction system [texte imprimé] / Izuru Takewaki, Auteur . - 2007 . - pp.389–399.
Applied mechanics
Langues : Anglais (eng)
in Journal of engineering mechanics > Vol. 133 N°4 (Avril 2007) . - pp.389–399.
Mots-clés : Closed-form solutions Earthquake resistant structures Frequency analysis Sensitivity analysis Soil-structure interaction Structural design Energy methods. Résumé : The input energy to a soil-structure interaction (SSI) system during earthquake shaking is taken as a structural performance measure and is formulated in the frequency domain. The purpose of this paper is to derive the closed-form expression of the sensitivity of the input energy to the SSI system with respect to uncertain parameters representing soil stiffness and damping. It is demonstrated first that the input energy expression can be of a compact form consisting of the product between the input motion component (Fourier amplitude spectrum of acceleration) and the structural model component (so-called energy transfer function). With the help of this compact form, it is shown that the formulation of earthquake input energy in the frequency domain is essential for deriving the closed-form expressions of the sensitivity of the input energy to the SSI system with respect to uncertain parameters in contrast to the time-domain formulation including inevitable numerical error and instability. This formulation is then extended to a multidegree-of-freedom superstructure model. Numerical examples support the fact that the closed-form expressions enable one to find in a reliable and efficient way the most critical combination of the uncertain parameters that leads to the maximum energy input. ISSN : 0733-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%290733-9399%282007%29133%3A4%2838 [...]
in Journal of engineering mechanics > Vol. 133 N°4 (Avril 2007) . - pp.400–413.
Titre : Influence of sediment layers on dynamic behavior of aged concrete dams Type de document : texte imprimé Auteurs : Indrani Gogoi, Auteur ; Damodar Maity, Auteur Année de publication : 2007 Article en page(s) : pp.400–413. Note générale : Applied mechanics Langues : Anglais (eng) Mots-clés : Dams concrete Finite element method Reservoirs Degradation Absorption Sediment Résumé : The assessment of response of an aged concrete dam is important for the prediction of its behavior during earthquakes, so that remedial measures can be taken at the right time to withstand future earthquakes. The assessment is necessary, since the analyses procedures may become obsolete and the state of the art may change as the time of construction and the structural material may deteriorate due to harsh environmental conditions. At the same time, the sediment will be accumulated at the reservoir bottom on the upstream side of the dam. The process of siltation depends on the reservoir topography and climatic variability, i.e., increased flood frequency and river inflow. The decision of retrofitting or strengthening the aged dam necessitates accurate analysis of the same in the presence of accumulated sediment. In this paper, an approach to include the time-dependent degradation of concrete owing to environmental factors and mechanical loading in terms of isotropic degradation index is presented. The absorption of pressure waves at the bottom of the reservoir due to the presence of sediments has been incorporated in the hydrodynamic pressure equation. The response of an aged concrete dam in the presence of sediment layers under seismic excitation is studied. The outcomes show the efficiency of the proposed algorithm. ISSN : 0733-9399 En ligne : http://ascelibrary.org/action/showAbstract?page=400&volume=133&issue=4&journalCo [...] [article] Influence of sediment layers on dynamic behavior of aged concrete dams [texte imprimé] / Indrani Gogoi, Auteur ; Damodar Maity, Auteur . - 2007 . - pp.400–413.
Applied mechanics
Langues : Anglais (eng)
in Journal of engineering mechanics > Vol. 133 N°4 (Avril 2007) . - pp.400–413.
Mots-clés : Dams concrete Finite element method Reservoirs Degradation Absorption Sediment Résumé : The assessment of response of an aged concrete dam is important for the prediction of its behavior during earthquakes, so that remedial measures can be taken at the right time to withstand future earthquakes. The assessment is necessary, since the analyses procedures may become obsolete and the state of the art may change as the time of construction and the structural material may deteriorate due to harsh environmental conditions. At the same time, the sediment will be accumulated at the reservoir bottom on the upstream side of the dam. The process of siltation depends on the reservoir topography and climatic variability, i.e., increased flood frequency and river inflow. The decision of retrofitting or strengthening the aged dam necessitates accurate analysis of the same in the presence of accumulated sediment. In this paper, an approach to include the time-dependent degradation of concrete owing to environmental factors and mechanical loading in terms of isotropic degradation index is presented. The absorption of pressure waves at the bottom of the reservoir due to the presence of sediments has been incorporated in the hydrodynamic pressure equation. The response of an aged concrete dam in the presence of sediment layers under seismic excitation is studied. The outcomes show the efficiency of the proposed algorithm. ISSN : 0733-9399 En ligne : http://ascelibrary.org/action/showAbstract?page=400&volume=133&issue=4&journalCo [...]
in Journal of engineering mechanics > Vol. 133 N°4 (Avril 2007) . - pp.414–421.
Titre : Stochastic dynamic analysis of inelastic structures using force analogy method Type de document : texte imprimé Auteurs : Zhe Wang, Auteur ; Kevin K. Wong, Auteur Année de publication : 2007 Article en page(s) : pp.414–421. Note générale : Applied mechanics Langues : Anglais (eng) Mots-clés : Inelastic action Dynamic analysis Structural analysis Rotation Monte Carlo method Résumé : The force analogy method which has been proven to be very efficient in dynamic analysis of inelastic structures is here introduced for the first time into the field of stochastic dynamic analysis for inelastic structures. This stochastic force analogy method (SFAM) maintains the advantage of the high efficiency in the numerical computation of the force analogy method in dynamic analysis. According to the SFAM, the variance covariance functions of inelastic dynamic responses, such as displacement, velocity, inelastic displacement of the entire moment-resisting framed structures, and plastic rotation at individual plastic hinge location, can be produced for structures subject to random excitation. Detailed theoretical development of the SFAM is derived, and a simple numerical example using a single degree of freedom system is presented. The reasonability of the proposed method is validated by the good agreement between the results from the proposed SFAM and those obtained from Monte Carlo simulation. ISSN : 0733-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%290733-9399%282007%29133%3A4%2841 [...] [article] Stochastic dynamic analysis of inelastic structures using force analogy method [texte imprimé] / Zhe Wang, Auteur ; Kevin K. Wong, Auteur . - 2007 . - pp.414–421.
Applied mechanics
Langues : Anglais (eng)
in Journal of engineering mechanics > Vol. 133 N°4 (Avril 2007) . - pp.414–421.
Mots-clés : Inelastic action Dynamic analysis Structural analysis Rotation Monte Carlo method Résumé : The force analogy method which has been proven to be very efficient in dynamic analysis of inelastic structures is here introduced for the first time into the field of stochastic dynamic analysis for inelastic structures. This stochastic force analogy method (SFAM) maintains the advantage of the high efficiency in the numerical computation of the force analogy method in dynamic analysis. According to the SFAM, the variance covariance functions of inelastic dynamic responses, such as displacement, velocity, inelastic displacement of the entire moment-resisting framed structures, and plastic rotation at individual plastic hinge location, can be produced for structures subject to random excitation. Detailed theoretical development of the SFAM is derived, and a simple numerical example using a single degree of freedom system is presented. The reasonability of the proposed method is validated by the good agreement between the results from the proposed SFAM and those obtained from Monte Carlo simulation. ISSN : 0733-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%290733-9399%282007%29133%3A4%2841 [...]
in Journal of engineering mechanics > Vol. 133 N°4 (Avril 2007) . - pp.422–430.
Titre : Stochastic partial differential equation-based model for suspended sediment transport in surface water flows Type de document : texte imprimé Auteurs : Chuanjian Man, Auteur ; Tsai, Christina W., Auteur Année de publication : 2007 Article en page(s) : pp.422–430. Note générale : Applied mechanics Langues : Anglais (eng) Mots-clés : Suspended sediment Surface waters Water flow Markov process Stochastic models White noise Résumé : A stochastic partial differential equation-based model has been derived based on the law of mass conservation and the Langevin equation of particle displacement to simulate suspended sediment transport in open-channel flows. In this model, the movement of any suspended sediment particle in turbulent flows is modeled as a stochastic diffusion process, which is composed of a drift term and a random term. The stochastic formula of fluid velocity is then substituted into the advection-diffusion (AD) equation to obtain the stochastic partial differential equation (SPDE) for suspended sediment transport. The lattice approximation is applied to solve the SPDE of suspended sediment transport in open channel flow. The proposed model, explicitly expressing the randomness of sediment concentration, has the advantage of capturing any randomly selected scenarios of particle movement and thus a more comprehensive quantitative description of sediment concentrations compared with the deterministic AD equation. As a result, the probability distribution of the sediment transport rate can be characterized based on a number of realizations obtained in the numerical experiments. It is found from the numerical experiments of particle trajectory that the transport of sediment particles is in the form of fully suspended load when the Rouse number is less than one. The ensemble mean sediment concentration of the proposed SPDE, obtained by the Monte Carlo simulation, agrees well with that of the deterministic AD equation. ISSN : 0733-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%290733-9399%282007%29133%3A4%2842 [...] [article] Stochastic partial differential equation-based model for suspended sediment transport in surface water flows [texte imprimé] / Chuanjian Man, Auteur ; Tsai, Christina W., Auteur . - 2007 . - pp.422–430.
Applied mechanics
Langues : Anglais (eng)
in Journal of engineering mechanics > Vol. 133 N°4 (Avril 2007) . - pp.422–430.
Mots-clés : Suspended sediment Surface waters Water flow Markov process Stochastic models White noise Résumé : A stochastic partial differential equation-based model has been derived based on the law of mass conservation and the Langevin equation of particle displacement to simulate suspended sediment transport in open-channel flows. In this model, the movement of any suspended sediment particle in turbulent flows is modeled as a stochastic diffusion process, which is composed of a drift term and a random term. The stochastic formula of fluid velocity is then substituted into the advection-diffusion (AD) equation to obtain the stochastic partial differential equation (SPDE) for suspended sediment transport. The lattice approximation is applied to solve the SPDE of suspended sediment transport in open channel flow. The proposed model, explicitly expressing the randomness of sediment concentration, has the advantage of capturing any randomly selected scenarios of particle movement and thus a more comprehensive quantitative description of sediment concentrations compared with the deterministic AD equation. As a result, the probability distribution of the sediment transport rate can be characterized based on a number of realizations obtained in the numerical experiments. It is found from the numerical experiments of particle trajectory that the transport of sediment particles is in the form of fully suspended load when the Rouse number is less than one. The ensemble mean sediment concentration of the proposed SPDE, obtained by the Monte Carlo simulation, agrees well with that of the deterministic AD equation. ISSN : 0733-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%290733-9399%282007%29133%3A4%2842 [...]
in Journal of engineering mechanics > Vol. 133 N°4 (Avril 2007) . - pp.431–441.
Titre : Linear predictor-based lossless compression of vibration sensor data : systems approach Type de document : texte imprimé Auteurs : Yunfeng Zhang, Auteur ; Jian Li, Auteur Année de publication : 2007 Article en page(s) : pp.431–441. Note générale : Applied mechanics Langues : Anglais (eng) Mots-clés : Data processing Information management Monitoring Sensors Signal processing Vibration Résumé : This paper presents a novel systems approach to compressing sensor network data. Unlike previous data compression methods, the proposed lossless linear predictor-based sensor data compression method utilizes structural system information to minimize the signal correlation in sensor network data. In the proposed method, linear predictor is derived in a system identification framework in which auto-regressive (AR) model is used as its model structure and the instrumental variables (IV) method is used to calculate the predictor parameters. A parametric study was carried out to study the effects of changes in system property, number of sensors, and sensor noise level on the compression performance of the proposed method. Both numerical simulation and experimental results show that the proposed sensor data compression method has a better compression performance than conventional linear predictor-based data compression method for single sensor. ISSN : 0733-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%290733-9399%282007%29133%3A4%2843 [...] [article] Linear predictor-based lossless compression of vibration sensor data : systems approach [texte imprimé] / Yunfeng Zhang, Auteur ; Jian Li, Auteur . - 2007 . - pp.431–441.
Applied mechanics
Langues : Anglais (eng)
in Journal of engineering mechanics > Vol. 133 N°4 (Avril 2007) . - pp.431–441.
Mots-clés : Data processing Information management Monitoring Sensors Signal processing Vibration Résumé : This paper presents a novel systems approach to compressing sensor network data. Unlike previous data compression methods, the proposed lossless linear predictor-based sensor data compression method utilizes structural system information to minimize the signal correlation in sensor network data. In the proposed method, linear predictor is derived in a system identification framework in which auto-regressive (AR) model is used as its model structure and the instrumental variables (IV) method is used to calculate the predictor parameters. A parametric study was carried out to study the effects of changes in system property, number of sensors, and sensor noise level on the compression performance of the proposed method. Both numerical simulation and experimental results show that the proposed sensor data compression method has a better compression performance than conventional linear predictor-based data compression method for single sensor. ISSN : 0733-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%290733-9399%282007%29133%3A4%2843 [...]
in Journal of engineering mechanics > Vol. 133 N°4 (Avril 2007) . - pp.442–451.
Titre : Flotation to trigger lateral buckles in pipelines on a flat seabed Type de document : texte imprimé Auteurs : Ralf Peek, Auteur ; Heedo Yun, Auteur Année de publication : 2007 Article en page(s) : pp.442–451. Note générale : Applied mechanics Langues : Anglais (eng) Mots-clés : Buckling Sea floor Underwater pipelines Deflection Résumé : Triggering lateral buckles in subsea pipelines can be an effective way to ensure that the thermal expansion is spread over several buckles at a controlled spacing, rather than concentrating in a single buckle that may become overstressed, or causing excessive displacements at the ends of a pipeline where spool-piece connections or jumpers may become overstressed. For a given location where a buckle is to be triggered one calculates that axial load that would develop if the buckle fails to form, and ensures the buckle would be triggered at or below this axial load. This paper gives simple analytical expressions for triggering of such lateral buckles by applying buoyancy to the pipeline, e.g., by inflatable parachute-like bags, which can later be removed. The expressions apply for a single buoyancy load, two equal buoyancy loads, or distributed buoyancy over a specified length. They explicitly solve the design problem of establishing the required amount of buoyancy for a given axial load at which the buckle must be triggered. It is shown quite generally that bifurcation buckling into a lateral buckling mode occurs before vertical instability, and at moderate uplift displacements. The analytical results are based on a flat seabed, the theory of moderately large deflections, and elastic pipe behavior. An example involving a single point buoyancy load is also solved by finite-element analysis based on large deflection theory to verify the accuracy of the approach. ISSN : 0733-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%290733-9399%282007%29133%3A4%2844 [...] [article] Flotation to trigger lateral buckles in pipelines on a flat seabed [texte imprimé] / Ralf Peek, Auteur ; Heedo Yun, Auteur . - 2007 . - pp.442–451.
Applied mechanics
Langues : Anglais (eng)
in Journal of engineering mechanics > Vol. 133 N°4 (Avril 2007) . - pp.442–451.
Mots-clés : Buckling Sea floor Underwater pipelines Deflection Résumé : Triggering lateral buckles in subsea pipelines can be an effective way to ensure that the thermal expansion is spread over several buckles at a controlled spacing, rather than concentrating in a single buckle that may become overstressed, or causing excessive displacements at the ends of a pipeline where spool-piece connections or jumpers may become overstressed. For a given location where a buckle is to be triggered one calculates that axial load that would develop if the buckle fails to form, and ensures the buckle would be triggered at or below this axial load. This paper gives simple analytical expressions for triggering of such lateral buckles by applying buoyancy to the pipeline, e.g., by inflatable parachute-like bags, which can later be removed. The expressions apply for a single buoyancy load, two equal buoyancy loads, or distributed buoyancy over a specified length. They explicitly solve the design problem of establishing the required amount of buoyancy for a given axial load at which the buckle must be triggered. It is shown quite generally that bifurcation buckling into a lateral buckling mode occurs before vertical instability, and at moderate uplift displacements. The analytical results are based on a flat seabed, the theory of moderately large deflections, and elastic pipe behavior. An example involving a single point buoyancy load is also solved by finite-element analysis based on large deflection theory to verify the accuracy of the approach. ISSN : 0733-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%290733-9399%282007%29133%3A4%2844 [...]
in Journal of engineering mechanics > Vol. 133 N°4 (Avril 2007) . - pp.452–463.
Titre : Effect of longitudinal stress gradients on elastic buckling of thin plates Type de document : texte imprimé Auteurs : Yu Cheng, Auteur ; Benjamin W. Schafer, Auteur Année de publication : 2007 Article en page(s) : pp.452–463. Note générale : Applied mechanics Langues : Anglais (eng) Mots-clés : Buckling Stability Thin wall structures Elasticity Cold-formed steel Plates Résumé : This paper analyzes the effect of longitudinal stress gradients on the elastic buckling of thin isotropic plates. Two types of thin plates are considered: (1) a plate simply supported on all four edges and rotationally restrained on two longitudinal edges; and (2) a plate simply supported on three edges with one longitudinal edge free and the opposite longitudinal edge rotationally restrained. These two cases illustrate the influence of longitudinal stress gradient on stiffened and unstiffened elements, respectively. A semianalytical method is derived and presented herein to calculate the elastic-buckling stress of both types of rectangular thin plates subjected to nonuniform applied longitudinal stresses. Finite-element analysis using ABAQUS is employed to validate the semianalytical model for plates with fixed and/or simple supports. Empirical formulas are produced to calculate the buckling coefficients of plates with fixed and/or simple supports under longitudinal stress gradients. The results help establish a better understanding of the effect of longitudinal stress gradients on the elastic buckling of thin plates and are intended to aid in the development of design provisions to include these effects in the strength prediction of thin-walled beams under moment gradients. ISSN : 0733-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%290733-9399%282007%29133%3A4%2845 [...] [article] Effect of longitudinal stress gradients on elastic buckling of thin plates [texte imprimé] / Yu Cheng, Auteur ; Benjamin W. Schafer, Auteur . - 2007 . - pp.452–463.
Applied mechanics
Langues : Anglais (eng)
in Journal of engineering mechanics > Vol. 133 N°4 (Avril 2007) . - pp.452–463.
Mots-clés : Buckling Stability Thin wall structures Elasticity Cold-formed steel Plates Résumé : This paper analyzes the effect of longitudinal stress gradients on the elastic buckling of thin isotropic plates. Two types of thin plates are considered: (1) a plate simply supported on all four edges and rotationally restrained on two longitudinal edges; and (2) a plate simply supported on three edges with one longitudinal edge free and the opposite longitudinal edge rotationally restrained. These two cases illustrate the influence of longitudinal stress gradient on stiffened and unstiffened elements, respectively. A semianalytical method is derived and presented herein to calculate the elastic-buckling stress of both types of rectangular thin plates subjected to nonuniform applied longitudinal stresses. Finite-element analysis using ABAQUS is employed to validate the semianalytical model for plates with fixed and/or simple supports. Empirical formulas are produced to calculate the buckling coefficients of plates with fixed and/or simple supports under longitudinal stress gradients. The results help establish a better understanding of the effect of longitudinal stress gradients on the elastic buckling of thin plates and are intended to aid in the development of design provisions to include these effects in the strength prediction of thin-walled beams under moment gradients. ISSN : 0733-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%290733-9399%282007%29133%3A4%2845 [...]
in Journal of engineering mechanics > Vol. 133 N°4 (Avril 2007) . - pp.464–472.
Titre : Elastoplastic damage behavior of a mortar subjected to compression and desiccation Type de document : texte imprimé Auteurs : Chen, D., Auteur ; I. Yurtdas, Auteur ; N. Burlion, Auteur Année de publication : 2007 Article en page(s) : pp.464–472. Note générale : Applied mechanics Langues : Anglais (eng) Mots-clés : Elastoplasticity Damage Compression Dewatering Mortars Résumé : This paper deals with experimental investigation and numerical modeling of drying effects on the mechanical behavior of cement-based materials. First, the main results from an experimental study on the mechanical behavior (failure strength, induced damage, and plastic deformation) of a mortar subjected to the desiccation process are presented. Then, a coupled elastoplastic damage model is proposed to describe the mechanical behavior of cement-based materials subjected to tensile and compressive stresses. A particular emphasis is put on the pressure sensitivity of plastic flow and damage evolution. Capillary effects on mechanical behavior due to desiccation have been taken into account in the framework of partially saturated porous media. Finally, numerical simulations and experimental data are compared in order to verify the capacity of the model to reproduce the basic characteristics of the mortar in saturated and unsaturated conditions. ISSN : 0733-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%290733-9399%282007%29133%3A4%2846 [...] [article] Elastoplastic damage behavior of a mortar subjected to compression and desiccation [texte imprimé] / Chen, D., Auteur ; I. Yurtdas, Auteur ; N. Burlion, Auteur . - 2007 . - pp.464–472.
Applied mechanics
Langues : Anglais (eng)
in Journal of engineering mechanics > Vol. 133 N°4 (Avril 2007) . - pp.464–472.
Mots-clés : Elastoplasticity Damage Compression Dewatering Mortars Résumé : This paper deals with experimental investigation and numerical modeling of drying effects on the mechanical behavior of cement-based materials. First, the main results from an experimental study on the mechanical behavior (failure strength, induced damage, and plastic deformation) of a mortar subjected to the desiccation process are presented. Then, a coupled elastoplastic damage model is proposed to describe the mechanical behavior of cement-based materials subjected to tensile and compressive stresses. A particular emphasis is put on the pressure sensitivity of plastic flow and damage evolution. Capillary effects on mechanical behavior due to desiccation have been taken into account in the framework of partially saturated porous media. Finally, numerical simulations and experimental data are compared in order to verify the capacity of the model to reproduce the basic characteristics of the mortar in saturated and unsaturated conditions. ISSN : 0733-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%290733-9399%282007%29133%3A4%2846 [...]
in Journal of engineering mechanics > Vol. 133 N°4 (Avril 2007) . - pp.473–480.
Titre : Computational analysis of masonry structures with a funicular odel Type de document : texte imprimé Auteurs : A. Andreu, Auteur ; L. Gil, Auteur ; P. Roca, Auteur Année de publication : 2007 Article en page(s) : pp.473–480. Note générale : Applied mechanics Langues : Anglais (eng) Mots-clés : Masonry Optimization Equilibrium Computation Cables Tension Résumé : This paper presents a computational approach for the assessment of masonry structures based on the well known analogy between the equilibrium of arches and that of hanging strings or cables working in tension. According to the analogy, the hanging strings model the inverted shape of the equilibrium lines (or thrust lines) describing the locus of the equilibrium forces acting across the sections of the arch. The approach proposed combines two developments. First, a new cable element is proposed to numerically model the strings used to describe the equilibrium lines. The formulation proposed, obtained as a modification of the conventional equations for inextensible cables, is based on an exact analytical derivation. Compared to other available numerical approaches, it has the advantage of ensuring the exact equilibrium of the cable net after deformation. Second, complementary algorithms are proposed for the assessment of the strength of masonry structures by the application of the limit theorems of plasticity (static approach). These algorithms are intended to find optimized solutions complying with the so-called safe (or lower-bound) and uniqueness theorems. Two examples of application are described to illustrate the accuracy of the method and its ability to handle masonry structural systems. ISSN : 0733-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%290733-9399%282007%29133%3A4%2847 [...] [article] Computational analysis of masonry structures with a funicular odel [texte imprimé] / A. Andreu, Auteur ; L. Gil, Auteur ; P. Roca, Auteur . - 2007 . - pp.473–480.
Applied mechanics
Langues : Anglais (eng)
in Journal of engineering mechanics > Vol. 133 N°4 (Avril 2007) . - pp.473–480.
Mots-clés : Masonry Optimization Equilibrium Computation Cables Tension Résumé : This paper presents a computational approach for the assessment of masonry structures based on the well known analogy between the equilibrium of arches and that of hanging strings or cables working in tension. According to the analogy, the hanging strings model the inverted shape of the equilibrium lines (or thrust lines) describing the locus of the equilibrium forces acting across the sections of the arch. The approach proposed combines two developments. First, a new cable element is proposed to numerically model the strings used to describe the equilibrium lines. The formulation proposed, obtained as a modification of the conventional equations for inextensible cables, is based on an exact analytical derivation. Compared to other available numerical approaches, it has the advantage of ensuring the exact equilibrium of the cable net after deformation. Second, complementary algorithms are proposed for the assessment of the strength of masonry structures by the application of the limit theorems of plasticity (static approach). These algorithms are intended to find optimized solutions complying with the so-called safe (or lower-bound) and uniqueness theorems. Two examples of application are described to illustrate the accuracy of the method and its ability to handle masonry structural systems. ISSN : 0733-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%290733-9399%282007%29133%3A4%2847 [...]
in Journal of engineering mechanics > Vol. 133 N°4 (Avril 2007) . - pp.481–493.
Titre : Approximate reliability-based optimization using a three-step approach based on subset simulation Type de document : texte imprimé Auteurs : Jianye Ching, Auteur ; Yi-Hung Hsieh, Auteur Année de publication : 2007 Article en page(s) : pp.481–493. Note générale : Applied mechanics Langues : Anglais (eng) Mots-clés : Optimization Simulation Stochastic processes Reliability Résumé : A novel three-step approach is proposed to solve reliability-based optimization (RBO) problems. The new approach is based on a novel approach previously developed by the authors for estimating failure probability functions. The major advantage of the new approach is that it is applicable to RBO problems with high-dimensional uncertainties and with arbitrary system complexities. The basic idea is to transform the reliability constraint in the target RBO problem into nonprobabilistic one by first estimating the failure probability function and the confidence intervals using minimal amount of computation, in fact, using just a single subset simulation (SubSim) run for each reliability constraint. Samples of the failure probability function are then drawn from the confidence intervals. In the second step, candidate solutions of the RBO problems are found based on the samples, and in the third step, the final design solution is screened out of the candidates to ensure that the failure probability of the final design meets the target, which also only costs a single SubSim run. Four numerical examples are investigated to verify the proposed novel approach. The results show that the approach is capable of finding approximate solutions that are usually close to the actual solution of the target RBO problem. ISSN : 0733-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%290733-9399%282007%29133%3A4%2848 [...] [article] Approximate reliability-based optimization using a three-step approach based on subset simulation [texte imprimé] / Jianye Ching, Auteur ; Yi-Hung Hsieh, Auteur . - 2007 . - pp.481–493.
Applied mechanics
Langues : Anglais (eng)
in Journal of engineering mechanics > Vol. 133 N°4 (Avril 2007) . - pp.481–493.
Mots-clés : Optimization Simulation Stochastic processes Reliability Résumé : A novel three-step approach is proposed to solve reliability-based optimization (RBO) problems. The new approach is based on a novel approach previously developed by the authors for estimating failure probability functions. The major advantage of the new approach is that it is applicable to RBO problems with high-dimensional uncertainties and with arbitrary system complexities. The basic idea is to transform the reliability constraint in the target RBO problem into nonprobabilistic one by first estimating the failure probability function and the confidence intervals using minimal amount of computation, in fact, using just a single subset simulation (SubSim) run for each reliability constraint. Samples of the failure probability function are then drawn from the confidence intervals. In the second step, candidate solutions of the RBO problems are found based on the samples, and in the third step, the final design solution is screened out of the candidates to ensure that the failure probability of the final design meets the target, which also only costs a single SubSim run. Four numerical examples are investigated to verify the proposed novel approach. The results show that the approach is capable of finding approximate solutions that are usually close to the actual solution of the target RBO problem. ISSN : 0733-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%290733-9399%282007%29133%3A4%2848 [...]
Exemplaires
| Code-barres | Cote | Support | Localisation | Section | Disponibilité |
|---|---|---|---|---|---|
| aucun exemplaire | |||||
