Academic literature on the topic 'ECCENTRICITY SIMULATION'

Le but principal de ce travail était d'optimiser le processus standard d'étirage des tubes de manière à contrôler l'excentricité, qui peut être la réduction ou l'augmentation de l'excentricité. Pour cette raison, l'inclinaison et / ou le déplacement ont été introduits respectivement dans le matrice et / ou le tube. Plusieurs tubes de matériaux différents - tels que le cuivre, l'aluminium, le laiton et l'acier - de différentes dimensions ont été étudiés. L’effet sur l'excentricité a été analysé en utilisant divers angles d'inclinaison, valeurs de déplacement ou combinaison d'inclinaison et de décalage. Tout en influençant et en contrôlant l'excentricité, l'évolution des contraintes résiduelles et de la texture due à l'inclinaison et / ou au décalage introduits ont été étudiées. L'autre objectif de ce travail était de développer un modèle FEM universel, afin d'obtenir les paramètres d'entrée requis, liés au matériau ou au processus ou aux deux. Ce modèle FEM a été utilisé pour accomplir la simulation du processus de formage du métal défini par l'utilisateur et pour analyser des situations plus complexes. À cet égard, un modèle de simulation multi-échelle a été développé à l'aide d'une méthode de simulation multi-échelle avec l'approche Integrated Computational Material Engineering<br>The main and foremost aim of this work was to optimize the standard tube drawing process in a way that the eccentricity can be controlled, which can be the reduction or increase of eccentricity. For this reason, tilting and/or shifting was introduced to the die and/or tube, respectively. Different tubes of varied materials, such as copper, aluminum, brass, and steel with different dimensions were investigated by various tilting angles, shifting values, or combination of tilting and shifting and their effect on the eccentricity was analyzed. Along influencing and controlling the eccentricity, the evolution of the residual stresses and texture due to the introduced tilting and /or shifting were investigated. The other aim of this work was to develop a universal FEM model, which can get the required or desired input parameters, which can be material-related or process related or both, and perform the simulation of the user-defined metal forming process and therewith analyze more complex situations. In this regard, a simulation model was developed using a multiscale simulation method with Integrated Computational Material Engineering approach

Tesis de maestría<br>Using non-linear analyses and Monte Carlo simulations, a simplified accidental-torsion design procedure is evaluated. The design procedure does not use an accidental eccentricity like the building codes do. For the evaluation, four reinforced concrete frame building models of four and seven stories are dynamically studied in the nonlinear range. The models are subjected to a set of five firm-soil, bidirectional seismic records. The design procedure is evaluated by comparing the ductility demands of both beams and columns for three conditions of each building model: a) the torsionally balanced model without accidental torsion (model TB), which establishes the reference values of ductility demands; b) the same nominal model but incorporating accidental torsion via the Monte Carlo method; and c) a model with amplified strength (model AS) according to the accidental-torsion design procedure to be evaluated. Results indicate that there is a probability smaller than 2.5% that accidental torsion can cause ductility demands approximately 20% to 25% larger than those of similar building models without accidental torsion. A comparison of ductility demands for the reference models without accidental torsion and those of models with accidental torsion and designed with the procedure that is evaluated, reveals that the design procedure is effective to control the effects of accidental torsion.

Tesis de maestría. Artículo técnico.<br>A comparative analysis between the responses obtained with two procedures that consider the accidental torsion on the dynamic nonlinear analysis of buildings is presented. The first one involves the use of typical values of accidental eccentricities used in design process. The second procedure involve the variation of parameters that incise in the accidental torsion by means Monte Carlo simulations. The comparison is performed from the responses obtained, measured in terms of concentrated inelastic deformations and lateral distortions. In the study two models of multi-level symmetrical buildings are considered. The CANNY-E program is used for the nonlinear dynamic analysis of the proposed structural models. The results suggest move the position of the center of mass a distance equal to 0.05b to consider the effect of accidental torsion on the dynamic nonlinear analysis of buildings<br>Consejo Nacional de Ciencia y Tecnología

[cat] Aquesta tesi és un recull del treball realitzat en els darrers quatre anys d’investigació enfocats a la producció de simulacions de relativitat numèrica de forats negres binaris en configuracions genèriques, així com a l’anàlisi de les ones gravitacionals extretes de dites simulacions, les seves conseqüències pel models de formes d’ones gravitacionals existents i les seves implicacions per a la cerca i l’estimació dels paràmetres d’aquests sistemes en la natura. Per començar, he estudiat la prescripció de paràmetres inicials en les simulacions de relativitat numèrica. Un problema ben conegut a relativitat numèrica és la dificultat d’obtenir simulacions de forats negres en òrbites quasi-circulars, degut a imprecisions en la generació de les dades inicials que provoquen òrbites quasi-el líptiques amb una excentricitat residual. El primer projecte d’aquesta tesi ha estat el desenvolupament d’un procediment iteratiu, senzill i computacionalment eficaç per a la reducció de l’excentricitat a simulacions de relativitat numèrica de forats negres binaris, veure Cap. 4. Amb aquest mètode s’han generat formes d’ona gravitacionals quasi-circulars amb una excentricitat negligible, e O 􀀀��� 10􀀀���4 , que han estat utilitzades pel nostre grup per generar models quasi-circulars de formes d’ona gravitacionals. La flexibilitat del mètode anterior permet no tan sols reduir l’excentricitat de les simulacions numèriques, sinó també augmentar-la. Aquest fet ha permès la generació d’un banc de més de 60 simulacions de relativitat numèrica amb excentricitat moderada e 0:5. Aquest ha estat el segon projecte d’investigació de la tesi, veure Cap. 5. Amb aquest grup de simulacions s’han generat formes d’ona híbrides pel mode dominant (2; 2) entre les ones obtingudes per la teoria post-Newtoniana i les de relativitat numèrica. A més, s’ha estimat les limitacions dels models quasi-circulars actuals per estimar paràmetres d’aquestes fonts. Els resultats obtinguts demostren que els models quasi-circulars de formes d’ona que inclouen modes subdominants redueixen el biaix en alguns paràmetres com la distància i el ràtio de massa, respecte a models sense modes subdominants. Per altra banda, durant el doctorat també s’han estudiat les limitacions de dues aproximacions utilitzades habitualment per models d’ona quasi-circulars amb espins precessants, veure Cap. 6. Aquestes dues aproximacions s’han analitzat emprant únicament simulacions de relativitat numèrica incloent modes subdominants. Els resultats obtinguts confirmen el bon funcionament de les aproximacions pels modes dominants (2; 2), mentre que pel modes subdominants s’observa una degradació important degut a diferent causes depenent del mode estudiat, per exemple, els modes (2; 1) són molt sensibles a les asimetries entre modes que les aproximacions negligeixen, mentre que els modes (4; 3) i (3; 2) pateixen mescla de modes en la part del decaïment de l’ona que les aproximacions no tenen en compte. Finalment, s’ha analitzat la sensibilitat de dos algorismes de cerca emprats per les col laboracions LIGO i Virgo durant el segon període d’observació O2 per detectar senyals completes d’ones gravitacionals procedents de binàries de forats negres eccèntriques, veure Cap. 7. En aquest treball preliminar s’ha quantificat l’impacte de l’excentricitat sobre dos algorismes de cerca: un codi de filtrat adaptat basat en el coneixement de la morfologia de la senyal, i un codi de cerca sense modelat. En aquest estudi s’estima per primera vegada la sensibilitat d’ambdós algorismes injectant senyals excèntriques calculades a partir de simulacions de relativitat numèrica incloent espins alineats amb el moment angular orbital del sistema. Els resultats obtinguts mostren una major degradació de la sensibilitat de l’algorisme de filtrat adaptat a mesura que l’excentricitat augmenta, mentre que la sensibilitat de l’algorisme sense modelat no es veu quasi afectada per l’increment de l’excentricitat, i per tant, es pot identificar aquest darrer com una eina robusta per a la detecció de senyals excèntriques.<br>[spa] Esta tesis recoge el trabajo realizado en los últimos cuatro años de investigación enfocados en la producción de simulaciones de relatividad numérica de agujeros negros binarios en configuraciones genéricas, así como en el análisis de las ondas gravitacionales extraídas de dichas simulaciones, sus consecuencias para los modelos de formas de ondas existentes y sus implicaciones para la búsqueda y la estimación de los parámetros de dichos sistemas en la naturaleza. Para empezar, he estudiado la prescripción de parámetros iniciales en las simulaciones de relatividad numérica. Un problema bien conocido en relatividad numérica es la dificultad de obtener simulaciones de agujeros negros en órbitas casi-circulares, debido a imprecisiones en la generación de los datos iniciales que provocan órbitas casi-elípticas con una excentricidad residual. El primer proyecto de esta tesis ha sido el desarrollo de un procedimiento iterativo, sencillo y computacionalmente eficaz para la reducción de la excentricidad en simulaciones de relatividad numérica de agujeros negros binarios, ver Cap. 4. Con este método se han generado formas de onda gravitacionales casi-circulares con una excentricidad negligible, e O 􀀀�� 10􀀀��4 , que han sido usadas por nuestro grupo para generar modelos de formas de onda casi-circulares. La flexibilidad del método anterior permite no solo reducir la excentricidad de las simulaciones numéricas, sino también aumentarla. Este hecho ha permitido la generación de un banco de más de 60 simulaciones de relatividad numérica con excentricidad moderada e 0:5. Este ha sido el segundo proyecto de investigación de la tesis, ver Cap. 5. Con este grupo de simulaciones he generado formas de onda híbridas para el modo dominante (2; 2) entre las ondas obtenidas a partir de la teoría post- Newtoniana y las de relatividad numérica. Además, con colaboradores he estimado las limitaciones de los modelos casi-circulares actuales para estimar los parámetros de estas fuentes. Los resultados obtenidos demuestran que los modelos casi-circulares de formas de onda que incluyen modos subdominantes reducen el sesgo en algunos parámetros como la distancia y el ratio de masa, respecto a los modelos sin modos subdominantes. Por otro lado, durante el doctorado también se han estudiado las limitaciones de dos aproximaciones utilizadas comúnmente para modelos de onda casi-circulares con espines precesantes, ver Cap. 6. Estas dos aproximaciones se han analizado usando únicamente simulaciones de relatividad numérica incluyendo modos subdominantes. Los resultados obtenidos confirman el buen funcionamiento de las aproximaciones para los modos dominantes (2; 2), mientras que para los modos subdominantes se observa una degradación importante debido a diferentes causas dependiendo del modo estudiado, por ejemplo, los modos (2; 1) son muy sensibles a las asimetrías entre modos que las aproximaciones negligen, mientras que los modos (4; 3) y (3; 2) padecen mezcla de modos en la parte del decaimiento de la onda que las aproximaciones no tienen en cuenta. Finalmente, con colaboradores he analizado la sensibilidad de dos algoritmos de búsqueda, utilizados por las colaboraciones LIGO y Virgo durante el segundo período de observación O2, para detectar señales completas de ondas gravitacionales procedentes de binarias de agujeros negros excéntricos, ver Cap. 7. En este trabajo preliminar se ha cuantificado el impacto de la excentricidad sobre dos algoritmos de búsqueda: un código de filtrado adaptado y un código de búsqueda sin modelado. En este estudio se estima por primera vez la sensibilidad de ambos algoritmos inyectando señales excéntricas calculadas a partir de simulaciones de relatividad numérica. Los resultados muestran una mayor degradación de la sensibilidad del algoritmo de filtrado adaptado a medida que aumenta la excentricidad, mientras que el algoritmo sin modelado no se ve casi afectado por el aumento de la excentricidad, y por tanto, se puede identificar este último como una herramienta robusta para la detección robusta de señales excéntricas.<br>[eng] This thesis gathers all the work done in my last four years of research focused on the production of numerical relativity simulations of generic binary black holes, as well as the analysis of the gravitational waveforms from these simulations and their implications for searches and parameter estimation on those systems. I have started studying the prescription of initial parameters in numerical relativity simulations. A well known problem in numerical relativity is the difficulty to obtain simulations of black holes orbiting in quasi-circular orbits due to inaccuracies of the initial data, which cause elliptical orbits with residual eccentricity. The first project of the thesis has been the development of a simple, iterative and computationally efficient procedure to reduce the eccentricity in binary black hole numerical relativity simulations, see Chap. 4. With this method we have produced quasi-circular waveforms with negligible eccentricity, e O 􀀀� 10􀀀�4 , which have been used in our group to generate quasi-circular waveform models. The flexibility of the previous method permits not only the reduction of the eccentricity, but also increasing it. Using this fact I have produced a data set of more than 60 numerical relativity simulations with moderate eccentricity e 0:5. This has been the second project of the thesis, see Chap. 5. Taking this set of simulations, with collaborators I have generated hybrid waveforms for the dominant (2; 2) mode between post-Newtonian and numerical relativity waveforms. Moreover, we have estimated the limitations of the current quasi-circular waveform models to estimate the parameters from those sources. We have found that the quasi-circular models which include higher order modes reduce the bias in some parameters like the mass ratio and luminosity distance, with respect to those models not including higher order modes. Furthermore, during the Ph.D. I have also studied the limitations of two approximations commonly used by precessing quasi-circular waveform models, see Chap. 6. These two approximations have been analysed using exclusively numerical relativity simulations including higher order modes. The results confirm the good performance of the approximations for the (2; 2) modes, while one observes a clear degradation for higher order modes due to different reasons depending on the considered mode. For instance, the (2; 1) modes are found to be very sensitive to asymmetries which the approximations neglect, while the (4; 3) and (3; 2) modes, have mode-mixing in the ringdown part which is not properly taken into account by the simple approximations. Finally, with collaborators I have analysed the sensitivity of two search pipelines, used by the LIGO and Virgo collaborations during the O2 Science Run, to the full gravitational wave signal of eccentric binary black holes, see Chap. 7. In this preliminary work we have quantified the impact of eccentricity on two search pipelines: a matched-filter and an unmodeled search algorithm. We have for the first time estimated the sensitivity of both algorithms injecting eccentric signals computed from numerical relativity simulations. The results show a larger degradation of the sensitivity of the matched-filter algorithm with increasing eccentricity, while the sensitivity of the unmodeled search algorithm remains barely unaffected to the increase of eccentricity, thus, we consider the latter one a robust tool to detect such eccentric signals.

碩士<br>國立成功大學<br>系統及船舶機電工程學系碩博士班<br>98<br>Owing to the gradual depletion of oil and a concern for environmental protection, motors have become the drive system of the future instead of the combustion engine. Among various types of motors, induction motors are often used due to their simple structure, fast reaction, and powerful propulsion force. Thus, the safe operation of motor vehicles is a major concern with the trends in the online fault monitor. However, the accuracy of online monitoring is the most difficult task. Based on statistics, the motor failures caused by electric and mechanical parts may occur mainly in stator, bearing and rotor. Among mechanical faults, 80% of relevant troubles may cause the phenomenon of air-gap eccentricity, leading to the power factor decreasing, motor vibrations, power losses and enlargement of the fault area. Particularly, it may result in the rotor and stator sides to chaft each other in a serious situation. If one can detect motor faults in advance, maintenance schedule or parts replacement can be properly arranged to reduce the risk of suddenly shut down in motor operation. This thesis simulates the differences of the characteristics of electric current signals for a three-phase induction motor under normal condition, uneven dispose fault and air-gap eccentric fault using Matlab/Simulink. To verify the feasibility of the models developed in the MATLAB/Simulink environment, the simulated fault signals are compared with the results obtained by other research. Finally, this thesis shows that the air-gap eccentricity degree can rapidly and reliably be diagnosed without using the traditional method to transform the fault signals into the frequency domain by analyzing them with a neural algorithm.

The computational analysis of an eccentric rotor is based on the bondgraph approach where the eccentricity of the rotor is analysed using bondgraph. This approach is used in this experiment to justify the displacements in shaft rotation which is occurring due to eccentricity introduced in the shaft. The computational analysis is necessary because by getting these results, a graph can be plotted which will give an accurate result of the bondgraph approach and it can be seen that by how much the displacement is occurring when the eccentricity is increased. The modelling technique used in this approach introduces two shafts connected through a hub and is provided rotor excitation by connecting it through an external source that rotates it at different angular velocities. The shafts are connected in such a manner that it has displacements in radial axis and the displacement is noted. The bond graph modelling of shaft and spinning hub is done using symbol sonata software bond pad. Simulation of this model has been carried out on Symbols sonata software which uses the fourth order Runge-Kutta method. The variation in the position of centre mass of rotor with change in various parameters such as speed, clearance is observed. The data obtained is used to get plots.