143,955 research outputs found
Modelo continuo para el análisis dinámico de vigas sometidas a interacción con fluido
No full textFil: Pérez Segura, M. E. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Estructuras Argentina.Fil: Inaudi, J. A. Instituto Universitario Aeronáutico. Facultad de Ingeniería; Argentina.La motivación de este trabajo surge en la necesidad de analizar de manera simplificada el comportamiento de sistemas mecánicos en problemas de interacción fluido-estructura (IFE), dentro del campo de la aeroelasticidad.Fil: Pérez Segura, M. E. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Estructuras Argentina.Fil: Inaudi, J. A. Instituto Universitario Aeronáutico. Facultad de Ingeniería; Argentina.Mecánica Aplicad
Su un modello costitutivo Isteretico-Evolutivo per Dispositivi a Smorzamento Viscoelastico
No full textNella nota viene proposto un modello isteretico evolutivo per modellare il comportamento degli smorzatori viscoelastici in condizioni di temperatura non costante. L'influenza delle frequenze di eccitazione sulle proprietà di smorzamento e rigidezza viene modellata in modo efficace mediante l'utilizzo di di un legame costitutivo alle derivate frazionarie; l'equazione che descrive tale legame viene integrata iterativamente nel dominio della frequenza. L'incremento di temperatura nello smorzatore, dovuto alla dissipazione di energia, è calcolato in osservanza dei principi della termomeccanica; si assume l'ipotesi di materiale termoreologicamente semplice per il quale vige il principio di equivalenza temperatura-frequenza. A partire da alcune prove sperimentali cicliche già disponibili in letteratura, nella nota si mostra il buon accordo tra esperienza e simulazione numerica nel caso di eccitazione sinusoidale. Seguono alcune considerazioni di carattere progettuale
Formulación de ecuaciones de movimiento vía proyección sobre vectores naturales de coordenadas generalizadas
No full textFil: Inaudi, J. A. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Física; Argentina.En este trabajo se plantea una formulación alternativa al principio de D’Alembert para obtener las ecuaciones de
movimiento de modelos cuya descripción cinemática se realiza mediante coordenadas generalizadas con y sin
ligaduras. Las ecuaciones de movimiento se obtienen mediante la proyección de las ecuaciones de equilibrio
dinámico Newtoniano de cada partícula sobre los vectores naturales de cada partícula del sistema asociados a las
coordenadas generalizadas del modelo, sin la necesidad de definir los conceptos de desplazamiento virtual y
trabajo virtual. La formulación puede ser utilizada de manera análoga en sistemas discretos de partículas o
modelos continuos deformables mediante técnicas de interpolación de los campos de desplazamiento con un
numero finito de coordenadas generalizadas. A partir de las ecuaciones de movimiento en coordenadas
generalizadas derivadas mediante proyección sobre vectores de sistema, se derivan las ecuaciones de Lagrange
para modelos sin y con fuerzas de ligadura. Se desarrollan ejemplos de aplicación de la metodología propuesta
en modelos discretos, modelos continuos simples y reducción de orden de ecuaciones diferenciales de modelos
discretos. El concepto de vectores naturales asociados a coordenadas generalizadas se considera un concepto
importante formación en mecánica de estudiantes de ingeniería y de gran utilidad en la mecánica computacional.Fil: Inaudi, J. A. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Física; Argentina.Mecánica Aplicad
Heat Generation Effects on Viscoelastic Dampers in Structures
No full textThe first part of this paper is concerned with the response of viscoelastic dampers subjected to transient temperature conditions caused by heat generation during cyclic deformation. Simple tools for modeling viscoelastic materials are discussed and verified using experimental data obtained in a test program on shear dampers using polymer Scotchdamp 109 of The 3M Company conducted at the Laboratory of the Civil Engineering Department of the University of California at Berkely. The second part of this study is a numerical investigation of the effects of heat generation on the response of structures with supplemental viscoelastic dampers with the aim of defining design guidelines for structures incorporating this type of dissipator
Evolutionary Model of Viscoelastic Dampers for Structural Applications
No full textThe effects of temperature on the energy dissipation of viscoelastic dampers (VED) for seismic mitigation of structures are investigated. In order to simulate the damper behaviour, an evolutionary model is proposed to describe the dependence of the mechanical properties of the damper on the deformation frequency and the temperature increase due to dissipation. The heat losses of the material due to radiation and conduction are neglected in the evaluation of the increase of temperature of the damper during operation.
Thermorheologically simple materials are considered and the influence of the deformation frequency on the storage and loss moduli is modelled using fractional derivatives operators. The effect of material temperature on the force-deformation relation is modelled using the concept of evolutionary transfer function and the proposed model is implemented using a step-by-step technique in the frequency domain. The predictions of the proposed model in the case of sinusoidal and seismic deformations show good agreement with experimental results.
Finally, the response spectra of single-degree-of-freedom structures with added VED and subjected to seismic excitation are computed using the proposed evolutionary model; the results obtained show that the thermal effect due to energy dissipation is not always negligible
I. A. Binet: Mémoire visuelle géometrique, II. A. Binet: Notes complémmentaires sur M. Jaques Inaudi, III. J. M. Charcot et A. Binet: Un calculateur du type visuel. Rev. philos. Bd. 35, S. 104–106, Jan. 1893, Ebda., S. 106–112, Ebda., S. 590–594, Juni 1893
No full textI. A. BINET: MÉMOIRE VISUELLE GÉOMETRIQUE, II. A. BINET: NOTES COMPLÉMMENTAIRES SUR M. JAQUES INAUDI, III. J. M. CHARCOT ET A. BINET: UN CALCULATEUR DU TYPE VISUEL. REV. PHILOS. BD. 35, S. 104–106, JAN. 1893, EBDA., S. 106–112, EBDA., S. 590–594, JUNI 1893
Zeitschrift für Psychologie und Physiologie der Sinnesorgane (-)
Zeitschrift für Psychologie und Physiologie der Sinnesorgane (7) (a0001)
I. A. Binet: Mémoire visuelle géometrique, II. A. Binet: Notes complémmentaires sur M. Jaques Inaudi, III. J. M. Charcot et A. Binet: Un calculateur du type visuel. Rev. philos. Bd. 35, S. 104–106, Jan. 1893, Ebda., S. 106–112, Ebda., S. 590–594, Juni 1893 (7) (p0222
[Report to Chief J. E. Curry, by an unknown author #1]
No full textReport to Chief J. E. Curry, by an unknown author. The report contains a list of officers who gave depositions to the United States Attorney
[Report to Chief J. E. Curry, by an unknown author #2]
No full textReport to Chief J. E. Curry, by an unknown author. The report contains a list of officers who gave depositions to the United States Attorney
Evidence for the decay B0→J/ψω and measurement of the relative branching fractions of meson decays to J/ψη and J/ψη′
No full textFirst evidence of the B 0 → J / ψ ω decay is found and the B s 0 → J / ψ η and B s 0 → J / ψ η ′ decays are studied using a dataset corresponding to an integrated luminosity of 1.0 fb -1 collected by the LHCb experiment in proton-proton collisions at a centre-of-mass energy of sqrt(s) = 7 TeV. The branching fractions of these decays are measured relative to that of the B 0 → J / ψ ρ 0 decay:frac(B (B 0 → J / ψ ω), B (B 0 → J / ψ ρ 0)) = 0.89 ± 0.19 (stat) - 0.13 + 0.07 (syst),frac(B (B s 0 → J / ψ η), B (B 0 → J / ψ ρ 0)) = 14.0 ± 1.2 (stat) - 1.5 + 1.1 (syst) - 1.0 + 1.1 (frac(f d, f s)),frac(B (B s 0 → J / ψ η ′), B (B 0 → J / ψ ρ 0)) = 12.7 ± 1.1 (stat) - 1.3 + 0.5 (syst) - 0.9 + 1.0 (frac(f d, f s)), where the last uncertainty is due to the knowledge of f d / f s, the ratio of b-quark hadronization factors that accounts for the different production rate of B 0 and B s 0 mesons. The ratio of the branching fractions of B s 0 → J / ψ η ′ and B s 0 → J / ψ η decays is measured to befrac(B (B s 0 → J / ψ η ′), B (B s 0 → J / ψ η)) = 0.90 ± 0.09 (stat) - 0.02 + 0.06 (syst)
Measurement of the time-dependent CP asymmetry in B0 -> J/ψ KS0 decays
No full textThis Letter reports a measurement of the CP violation observables SJ/ψK0S and CJ/ψK0S in the decay channel B0→J/ψK0S performed with 1.0 fb−1 of pp collisions at s√=7 TeV collected by the LHCb experiment. The fit to the data yields SJ/ψK0S=0.73±0.07(stat)±0.04(syst) and CJ/ψK0S=0.03±0.09(stat)±0.01(syst). Both values are consistent with the current world averages and within
expectations from the Standard Model
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