Dissertations / Theses on the topic 'Non-Intrusive methods'
To see the other types of publications on this topic, follow the link: Non-Intrusive methods.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 32 dissertations / theses for your research on the topic 'Non-Intrusive methods.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Remscrim, Zachary (Zachary N. ). "Mathematical methods for non-intrusive load monitoring." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/61617.
Full textAbstract:
Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2010.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 195-197).
The calculation of the Discrete Fourier Transform (DFT) of a discrete time signal is a fundamental problem in discrete-time signal processing. This thesis presents algorithms that use methods from number theory and algebra to exploit additional constraints about a signal to aid in the calculation of its DFT. First, an algorithm is presented that estimates the DFT of an unquantized signal given only a quantized version of that signal. Second, an algorithm to estimate the value of one subset of DFT coefficients from knowledge of another subset of DFT coefficients, for an appropriately constrained class of waveforms, is presented and analyzed. Thirdly, an algorithm to classify electrical loads on the basis of a subset of the DFT coefficients of load current is demonstrated. Finally, an embedded system that calculates DFT coefficients of measured current and makes this information available in convenient forms is considered.
by Zachary Remscrim.
M.Eng.
2
Schantz, Christopher James. "Methods for non-intrusive sensing and system monitoring." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/92173.
Full textAbstract:
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2014.Cataloged from PDF version of thesis.
Includes bibliographical references.
Improving the efficiency of collection, transmission, and consumption of resources is the focus of a wide swath of engineering research. Current technological solutions for capturing or mitigating energy and resource waste are asymmetrical. A dilemma is becoming increasingly apparent in monitoring and control systems. Networking tools provide potentially inexpensive remote access to information, but gathering useful information, however, may require the installation of an array of costly and intrusive sensors. The promise of highly effective and useful networked solutions is hemmed in by a sensing frontier consisting of significant challenges. At any time in the service life of a machine or system it may perform below its design efficiency. Valves may leak, belts might slip, and equipment may be left on when not needed. Systems under feedback control like HVAC plants will mask the effect of incipient faults from the user by increasing their duty cycle and wasting energy. Water distribution networks will supply healthy and leaky loads alike without obvious change save in perhaps a monthly bill delivered in the mail. To meet these challenges, this thesis uses easily installed non-intrusive sensors coupled with advanced signal processing algorithms to provide a collated corrected picture of consumption and to provide opportunities for fault detection. Specific contributions are made in three areas: Electric motor driven machine fault detection; a motor like an induction machine can serve as its own fine resolution speed and torque sensor with performance to rival optical shaft encoders and exceeding most torque sensors, all from simple voltage and current signals. Full time fluid flow and hydraulic load tracking from clamp on vibration and magnetic field sensing. Non intrusive techniques for capturing vibration data for rotating machine fault detection, and methods to combine electrical and vibration information to create virtual inputs for performing output only or single sensor system identification.
by Christopher James Schantz.
Ph. D.
3
Peric, Vedran. "Non-intrusive Methods for Mode Estimation in Power Systems using Synchrophasors." Doctoral thesis, KTH, Elkraftteknik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-182134.
Full textAbstract:
Real-time monitoring of electromechanical oscillations is of great significance for power system operators; to this aim, software solutions (algorithms) that use synchrophasor measurements have been developed for this purpose. This thesis investigates different approaches for improving mode estimation process by offering new methods and deepening the understanding of different stages in the mode estimation process. One of the problems tackled in this thesis is the selection of synchrophasor signals used as the input for mode estimation. The proposed selection is performed using a quantitative criterion that is based on the variance of the critical mode estimate. The proposed criterion and associated selection method, offer a systematic and quantitative approach for PMU signal selection. The thesis also analyzes methods for model order selection used in mode estimation. Further, negative effects of forced oscillations and non-white noise load random changes on mode estimation results have been addressed by exploiting the intrinsic power system property that the characteristics of electromechanical modes are predominately determined by the power generation and transmission network. An improved accuracy of the mode estimation process can be obtained by intentionally injecting a probing disturbance. The thesis presents an optimization method that finds the optimal spectrum of the probing signals. In addition, the probing signal with the optimal spectrum is generated considering arbitrary time domain signal constraints that can be imposed by various probing signal generating devices. Finally, the thesis provides a comprehensive description of a practical implementation of a real-time mode estimation tool. This includes description of the hardware, software architecture, graphical user interface, as well as details of the most important components such as the Statnett’s SDK that allows easy access to synchrophasor data streams.The Doctoral Degrees issued upon completion of the programme are issued by Comillas Pontifical University, Delft University of Technology and KTH Royal Institute of Technology. The invested degrees are official in Spain, the Netherlands and Sweden, respectively.
QC 20160218
FP7 iTesla
4
Biezemans, Rutger. "Multiscale methods : non-intrusive implementation, advection-dominated problems and related topics." Electronic Thesis or Diss., Marne-la-vallée, ENPC, 2023. http://www.theses.fr/2023ENPC0029.
Full textAbstract:
Cette thèse porte sur les méthodes numériques pour les équations aux dérivées partielles (EDP) multi-échelles, et en particulier sur la méthode dite des éléments finis multi-échelles (MsFEM). Celle-ci est une méthode de type éléments finis qui consiste en une approximation de Galerkin de l'EDP sur une base problème-dépendante. Trois difficultés particulières liées à cette méthode sont abordées dans cette thèse. Premièrement, puisque la MsFEM utilise une base problème-dépendante, la méthode ne peut être facilement implémentée dans des codes industriels génériques. Cela freine la diffusion de la MsFEM au-delà des environnements académiques. Une méthodologie générique est proposée pour convertir la MsFEM en un problème effectif qui peut être résolu par des codes génériques. Il est démontré par des résultats théoriques ainsi que des expériences numériques que la nouvelle méthodologie est aussi précise que la MsFEM originale. Deuxièmement, les MsFEM adaptées aux problèmes advection-dominés sont étudiées. Ce régime spécifique rend instables les discrétisations naïves. Une explication est trouvée pour l'instabilité de certaines méthodes proposées précédemment. Des expériences numériques montrent la stabilité d'une MsFEM avec des conditions aux limites de type Crouzeix-Raviart enrichie par des fonctions bulles. Troisièmement, une nouvelle analyse de convergence pour la MsFEM est présentée, permettant pour la première fois d'établir la convergence sous des hypothèses de régularité minimales. Cette démarche est importante pour réduire l'écart entre la théorie pour la MsFEM et son application en pratique, où les hypothèses de régularité habituelles sont rarement satisfaitesThis thesis is concerned with computational methods for multiscale partial differential equations (PDEs), and in particular the multiscale finite element method (MsFEM). This is a finite element type method that performs a Galerkin approximation of the PDE on a problem-dependent basis. Three particular difficulties related to the method are addressed in this thesis. First, the intrusiveness of the MsFEM is considered. Since the MsFEM uses a problem-dependent basis, it cannot easily be implemented in generic industrial codes and this hinders its adoption beyond academic environments. A generic methodology is proposed that translates the MsFEM into an effective problem that can be solved by generic codes. It is shown by theoretical convergence estimates and numerical experiments that the new methodology is as accurate as the original MsFEM. Second, MsFEMs for advection-dominated problems are studied. These problems cause additional instabilities for naive discretizations. An explanation is found for the instability of previously proposed methods. Numerical experiments show the stability of an MsFEM with Crouzeix-Raviart type boundary conditions enriched with bubble functions. Third, a new convergence analysis for the MsFEM is presented that, for the first time, establishes convergence under minimal regularity hypotheses. This bridges an important gap between the theoretical understanding of the method and its field of application, where the usual regularity hypotheses are rarely satisfied
5
Cannermo, Trine P. W. "Non-Intrusive Methods for Documentating Upholstery : five ways to approach an intriguing conundrum." Thesis, Linköpings universitet, Carl Malmsten - furniture studies, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-113566.
Full textAbstract:
During my internship at the Upholstery conservation department at the Metropolitan Museum of art in New York, I came across a chair that caught my interest and therefore I chose to dedicate the last two months of my internship, investigating this chair. It was said about the chair that it had the original upholstery and cover, but some questions appeared. These questions I have tried to solve, as I will reveal in the following, by using mostly non-intrusive methods, in attempt to see how much useful information this approach can provide, concerning frame structure, inner-upholstery, showcover and possible campaigns (interventions). I found out, that it was possible to gather a great amount of useful information. In fact I will go so far as to claim that I found out even more than I would have found out, by isassembling the object manually.
6
Parson, Oliver. "Unsupervised training methods for non-intrusive appliance load monitoring from smart meter data." Thesis, University of Southampton, 2014. https://eprints.soton.ac.uk/364263/.
Full textAbstract:
Non-intrusive appliance load monitoring (NIALM) is the process of disaggregating a household’s total electricity consumption into its contributing appliances. Smart meters are currently being deployed on national scales, providing a platform to collect aggregate household electricity consumption data. Existing approaches to NIALM require a manual training phase in which either sub-metered appliance data is collected or appliance usage is manually labelled. This training data is used to build models of the house- hold appliances, which are subsequently used to disaggregate the household’s electricity data. Due to the requirement of such a training phase, existing approaches do not scale automatically to the national scales of smart meter data currently being collected. In this thesis we propose an unsupervised training method which, unlike existing approaches, does not require a manual training phase. Instead, our approach combines general appliance knowledge with just aggregate smart meter data from the household to perform disaggregation. To do so, we address the following three problems: (i) how to generalise the behaviour of multiple appliances of the same type, (ii) how to tune general knowledge of appliances to the specific appliances within a single household using only smart meter data, and (iii) how to provide actionable energy saving advice based on the tuned appliance knowledge. First, we propose an approach to the appliance generalisation problem, which uses the Tracebase data set to build probabilistic models of household appliances. We take a Bayesian approach to modelling appliances using hidden Markov models, and empirically evaluate the extent to which they generalise to previously unseen appliances through cross validation. We show that learning using multiple appliances vastly outperforms learning from a single appliance by 61–99% when attempting to generalise to a previously unseen appliance, and furthermore that such general models can be learned from only 2–6 appliances. Second, we propose an unsupervised solution to the model tuning problem, which uses only smart meter data to learn the behaviour of the specific appliances in a given house-hold. Our approach uses general appliance models to extract appliance signatures from a household’s smart meter data, which are then used to refine the general appliance models. We evaluate the benefit of this process using the Reference Energy Disaggregation Data set, and show that the tuned appliance models more accurately represent the energy consumption behaviour of a given household’s appliances compared to when general appliance models are used, and furthermore that such general models can per- form comparably to when sub-metered data is used for model training. We also show that our tuning approach outperforms the current state of the art, which uses a factorial hidden Markov model to tune the general appliance models. Third, we apply both of these approaches to infer the energy efficiency of refrigerators and freezers in a data set of 117 households. We evaluate the accuracy of our approach, and show that it is able to successfully infer the energy efficiency of combined fridge freezers. We then propose an extension to our model tuning process using factorial hidden semi-Markov models to model households with a separate fridge and freezer. Finally, we show that through this extension our approach is able to simultaneously tune the appliance models of both appliances. The above contributions provide a solution which satisfies the requirements of a NIALM training method which is both unsupervised (no manual interaction required during training) and uses only smart meter data (no installation of additional hardware is required). When combined, the contributions presented in this thesis represent an advancement in the state of the art in the field of non-intrusive appliance load monitoring, and a step towards increasing the efficiency of energy consumption within households.
7
Pickering, Todd Michael. "Methods for Validation of a Turbomachinery Rotor Blade Tip Timing System." Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/47496.
Full textAbstract:
This research developed two innovative test methods that were used to experimentally evaluate the performance of a novel blade tip timing (BTT) system from Prime Photonics, LC. The research focused on creating known blade tip offsets and tip vibrations so that the results from a BTT system can be validated. The topic of validation is important to the BTT field as the results between many commercial systems still are not consistent. While the system that was tested is still in development and final validation is not complete, the blade tip offset and vibration frequency validation results show that this BTT system will be a valuable addition to turbomachinery research and development programs once completed.
For the first test method custom rotors were created with specified blade tip offsets. For the blade tip offset alternate measurement, the rotors were optically scanned and analyzed in CAD software with a tip location uncertainty of 0.1 mm. The BTT system agreed with the scanned results to within 0.13 mm. Tests were also conducted to ensure that the BTT system identified and indexed the blades properly.
The second developed test method used an instrumented piezoelectric blade to create known dynamic deflections. The active vibration rotor was able to create measureable deflection over a range of frequencies centered on the first bending mode of the blade. The results for the 110 Hz, 150 Hz, 180 Hz first bending resonance, 200 Hz, and 1036 Hz second bending resonance cases are presented. A strain gage and piezoelectric sensor were attached to the active blade during the dynamic deflection tests to provide an alternate method for determining blade vibration frequency. The BTT system correctly identified the active blade excitation frequencies as well as a 120 Hz frequency from the drive motor.
This thesis also explored applying BTT methods and testing to more realistic blade geometry and vibration. Blade vibrations are usually classified by their frequency relative to the rotation speed. Synchronous vibrations are integer multiples of the rotational speed and are often excited by struts or vanes fixed to the engine case. For this reason, special probe placement algorithms were explored that use sine curve fitting to optimize the probe placement. Knowing how the blade will vibrate at operation before testing is critical as well. In preparation for future research, ANSYS Mechanical was used to predict the first three modes of a PT6A-28 first stage rotor blade at 1,966, 5,539, and 7,144 Hz. These frequencies were validated to within 4% using scanning laser vibrometry. The simulation was repeated at speed to produce a Campbell Diagram to highlight synchronous excitation crossings.Master of Science
8
Papaioannou, Iason [Verfasser], Ernst Akademischer Betreuer] Rank, Daniel [Akademischer Betreuer] Straub, and Manolis [Akademischer Betreuer] [Papadrakakis. "Non-intrusive finite element reliability analysis methods / Iason Papaioannou. Gutachter: Daniel Straub ; Ernst Rank ; Manolis Papadrakakis. Betreuer: Ernst Rank." München : Universitätsbibliothek der TU München, 2012. http://d-nb.info/1024161439/34.
Full text
9
Stewart, Ian. "Experimental verification and comparison of non-intrusive methods for detecting laminar-turbulent transition on a natural laminar flow axisymmetric body." Thesis, University of Southampton, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.245394.
Full text
10
Nunez, Ramirez Jorge. "A multi time-step partitioned approach for the coupling of SPH and FE methods for nonlinear FSI problems." Thesis, Lyon, 2017. http://www.theses.fr/2017LYSEI040/document.
Full textAbstract:
Dans le cadre de ce travail, une technique non-intrusive est proposée pour coupler la méthode Smoothed Particle Hydrodynamics (SPH) à la méthode des Eléments Finis afin de résoudre numériquement des problèmes dynamiques et non-linéaires d’interaction fluide-structure en permettant l’utilisation des pas de temps différents dans les deux domaines de calcul (fluide et solide). Ces développements sont motivés par le besoin de simuler numériquement des phénomènes rapides et très non-linéaires qui prennent en compte des impacts en se servant des intégrateurs temporels explicites dans chaque sous-domaine de calcul (Newmark explicite pour le solide et Runge-Kutta 2 pour le fluide). De ce fait, le pas de temps de stabilité est limité par des caractéristiques intrinsèques au modèle numérique du phénomène étudié et en conséquence, il devient important de pouvoir intégrer chaque sous-domaine numérique avec un pas de temps proche de son pas de temps de stabilité. Pour permettre d’utiliser un pas de temps proche du pas de temps de stabilité pour chaque sous-domaine, des méthodes de décomposition de domaines dual-Schur sont implémentées et validées pour des cas en 1-D, 2-D, et 3-D. Des simulations numériques d’impacts de cailloux sur des aubes des turbines hydrauliques sont aussi effectue´es afin de prédire le dommage que cet évènement peut engendrerA method to couple smoothed particle hydrodynamics and finite elements methods for nonlinear transient fluid–structure interaction simulations by adopting different time-steps depending on the fluid or solid sub-domains is proposed. These developments were motivated by the need to simulate highly non-linear and sudden phenomena that take into acount solid impacts and hence require the use of explicit time integrators on both sub-domains (explicit Newmark for the solid and Runge–Kutta 2 for the fluid). However, due to critical time-step required for the stability of the explicit time integrators in, it becomes important to be able to integrate each sub-domain with a different time-step while respecting the features that a previously developed mono time-step coupling algorithm offered. For this matter, a dual-Schur decomposition method originally proposed for structural dynamics was considered, allowing to couple time integrators of the Newmark family with different time-steps with the use of Lagrange multipliers
11
Chitt, Mira. "Simultaneous measurements of velocity and temperature by non-intrusive optical methods in a complex geometry : Application to the upper plenum of the sodium cooled reactor ASTRID." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS598.
Full textAbstract:
Des problématiques thermo-hydrauliques du plénum supérieur d'ASTRID ne peuvent être étudiés à partir du retour d’expérience des réacteurs et des simulations numériques puisque les codes de calcul ne permettent pas de modéliser ces problèmes avec une confiance suffisante. Pour valider les approches numériques et la conception d'ASTRID, il a été identifié des besoins en maquettes expérimentales. La maquette MICAS représentative du plenum supérieur a été conçue à cette fin. Pour valider les codes numériques, les champs de vitesse et de température sont très importants. Si la mesure de champ de vitesse par PIV est fréquemment utilisée au LTHC, la méthode LASER Induced Fluorescence (LIF) a nécessité de développement et mise en œuvre. La fluorescence induite par laser consiste en l'émission spontanée de photons par les molécules d'un traceur, à la suite de l'absorption d'un rayonnement laser. Des expériences d'étalonnage de LIF à un colorant ont été réalisées pour étudier leur réponse en fluorescence. La LIF à deux colorants est très intéressante aussi. PIV et LIF à deux colorants sont appliquées sur une nouvelle installation expérimentale (géométrie complexe à deux jets) conçue pendant cette thèse afin de permettre une représentative de la maquette MICASThermal hydraulic problems of the upper plenum of ASTRID cannot be studied from the feedback of the reactors and the numerical simulations since the codes do not make it possible to model these problems with a sufficient confidence. To validate the numerical approaches and the design of ASTRID, needs have been identified for experimental models. The representative MICAS model of the upper plenum has been designed for this purpose. To validate the numeric codes, the velocity and temperature fields are mustbe measured. While PIV technique is frequently used at the LTHC, the LASER Induced Fluorescence (LIF) method required development and implementation. The principle of LIF is based on the spontaneous emission of photons by the molecules of a tracer, as a result of the absorption of laser radiation. LIF calibration experiments with a dye were performed to study their fluorescence response. The LIF with two dyes is very interesting too. PIV and LIF with two dyes are applied on a new experimental installation (complex geometry with two jets) conceived during this thesis in order to allow a representative of the model MICAS
12
Karamooz, Mahdiabadi Morteza [Verfasser], Daniel J. [Akademischer Betreuer] Rixen, Daniel J. [Gutachter] Rixen, and Matthew S. [Gutachter] Allen. "Nonlinear Model Order Reduction and Substructuring for Structural Dynamics Analysis : Non-intrusive methods / Morteza Karamooz Mahdiabadi ; Gutachter: Daniel J. Rixen, Matthew S. Allen ; Betreuer: Daniel J. Rixen." München : Universitätsbibliothek der TU München, 2019. http://d-nb.info/1220320552/34.
Full text
13
Krištof, Ondřej. "Vytváření kapalinové clony pro absorpci plynných exhalací." Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2020. http://www.nusl.cz/ntk/nusl-409524.
Full textAbstract:
The dissertation thesis deals with the application of absorption methods for the separation of gaseous pollutants from polluted gaseous mixtures using a pilot plant scrubber. The efficiency of the gaseous pollutant removal was determined based on the hydrodynamic distribution of fluids inside the spray chamber. A TF-28 150 spiral nozzle, which was used to spray the absorption liquid, was experimentally characterized. Specifically, the pressure impact pattern of the liquid produced by the nozzle was investigated using intrusive methods and the effective spray angles, the modes of primary and secondary atomization, the droplet size and liquid velocity distributions were determined using non-intrusive optical methods. Numerical simulations of flow of model gas phase inside the sprinkler head and spraying of the liquid through the spiral nozzle were also carried out. The obtained data can be applied to estimate the interface area and together with the determination of the coefficient of total mass transfer thus define the kinetics of chemisorption for a given absorbent/absorbate combination.
14
Blanchard, Maxime. "Méthode global/local non-intrusive pour les simulations cycliques non-linéaires." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLN003/document.
Full textAbstract:
Cette thèse vise à proposer des outils innovants pour le calcul de structures aéronautiques évoluant à haute température. En effet, les régimes de fonctionnement des moteurs actuels conduisent à des évolutions élasto-viscoplastiques généralisées dans les pièces métalliques et l’utilisation de modèles simplifiés (élastiques) n’est plus totalement satisfaisante en terme de précision, même en phase de préconception. De même, la géométrie complexe permettant le refroidissement continu des pièces (micro-perforations) doit être prise en compte de manière exacte. Les techniques de calcul standard pour ce genre de problème conduiraient à des simulations lentes et peu flexibles (la moindre modification entraînant une remise en œuvre complète de la chaîne de calcul). Plus précisément, cette thèse étend les méthodes de type global/local non-intrusives au cas de la viscoplasticité généralisée en utilisant deux échelles de temps et d'espace, chacune adaptée aux phénomènes locaux et globaux à capturer. La méthode est ensuite étendue au calcul de nombreux cycles complexes de chargement, par des techniques de saut de cycles. Le schéma de couplage en temps permet alors une adaptation locale du pas de temps par sous-domaine. Des techniques d’accélération de convergence sont proposées, à l’échelle d’un incrément puis à celle de la succession de cycles (sauts de cycles). Ces développements permettent d’obtenir rapidement et précisément une estimation du cycle limite qui alimente un modèle de durée de vie. Le couplage non-intrusif est réalisé dans un script de programmation pilotant un code commercial (dans notre cas le langage Python et Abaqus/Standard). La méthode a été appliquée sur des plateformes de calculs industrielles, en réutilisant directement des maillages et les mises en données issues de modèles intervenant plus tôt dans la chaîne de calcul. Un cas métier, issu d’un bureau d’études de Safran Aircraft Engines, a pu être traitéThis thesis consists in developing innovating tools destined to the simulation of aeronautical structures evolving at high temperature. Indeed, working rates of current engines lead to an elasto-viscoplastic evolution generalized in metallic parts and the use of simplified models (linear elastic) are no longer totally satisfying in term of accuracy, even in initial design process. Likewise, the complex geometry allowing the continuous cool down process of parts (micro-perforations) has to be exactly taken into account. The standard computation techniques dedicated to this kind of models would lead to slow simulations with a lack of flexibility (the slightest modifications leading to restart the whole design process of the computation chain).More precisely, this thesis extends the noninvasive global/local methods to the framework of viscoplasticity generalized to the whole structure, using two scales in time and space, each one adapted to global and local phenomena to capture. The method is then extended to the computation of high number of complex load cycles, by skipped cycles techniques. The time coupling scheme lets then a local adaptation of time steps per subdomain. Convergence acceleration techniques are also set up, first for one time step and then through several load cycles (skipped cycles). These developments conduct to obtain quickly an evaluation of the limit cycle providing data to a lifetime expectancy model.The noninvasive coupling is realized in a programming language script managing the commercial software (respectively in our case Python and Abaqus/Standard). The method has been applied on industrial computational platforms, by reusing directly meshes and data from previous engineering tasks appearing earlier in the computational chain. A genuine test case from a Safran Aircraft Engines design office, was performed successfully
15
Kieviet, Johan. "A non-intrusive video tracking method to measure movement of a moored vessel." Thesis, Stellenbosch : Stellenbosch University, 2015. http://hdl.handle.net/10019.1/97074.
Full textAbstract:
Thesis (MSc)--Stellenbosch University, 2015.ENGLISH ABSTRACT: There are several ports around the world currently experiencing problems with moored vessel motions. Extreme vessel motions are mainly caused by long waves, which can become trapped inside a harbour basin. The extreme motions can cause downtime in port operations and in some instances cause mooring lines to break. Methods and procedures currently available to measure motions of moored vessels require vessel specific information as input. The implementation of these methods is seen as impractical to implement on every vessel visiting the port and require the physical measurement of some points on the vessel and/or the placement of some kind of measurement device on the vessel. A new Six Degree of Freedom (6DOF) motion measurement system for a moored vessel is presented in this document. The system analyses a video image sequence from one camera. The method estimates the 3D rigid motion for an object of known size by using a Pose from Orthography and Scaling with ITerations (POSIT) algorithm. The object for which the motion is estimated is located on the deck of the vessel and within the camera field of view. Geometric rigid body calculations allow for the calculation of camera perspective rotations and translation of an object on the vessel. Further geometric calculations allow for converting camera perspective motions to the 6DOF object motions. The primary objective of this study was to validate and verify the motions obtained from two proof-of-concept tracking systems. For evaluation purposes, the validation was done by using a small scale physical model set-up in a hydraulics laboratory and using a known method as reference. The Keoship system from the Council for Scientific and Industrial Research (CSIR) is currently one of the most accurate small scale vessel motion measurement systems and was used as reference. The first method tested was the tracking of a 2D LED rectangle mounted on the vessel. This method tracked a 2D object and was primarily used as a stepping stone to measure movement of a 3D object. The second method tracked a 3D object on the vessel. Each tracking method was tested for four different wave conditions with each condition additionally repeated twice as repeatability tests, resulting in a total of 12 tests for each tracking method. When comparing the 2D LED tracking and 3D Object tracking data to data measured with the Keoship system, results show that in general, the 3D Object tracking data compared better to the Keoship data. Tests under controlled conditions enabled a direct estimation of the absolute accuracy of the two developed methods. The verification and accuracy test results, indicated that the 2D LED tracking system should not be pursued further. The results also indicated that for prototype motions exceeding 0.6 m (i.e. storm events) the 3D Object tracking system would have an accuracy close to the maximum allowable accuracy criterion of 0.1 m. This makes the system viable at its current proof-of-concept stage for further development which would enable rapid deployment during a storm event in a prototype situation.
AFRIKAANSE OPSOMMING: Daar is verskeie hawens regoor die wêreld wat tans bewegings probleme op gemeerde skepe ervaar. Hierdie buitensporige bewegings word veroorsaak deur lang periode golwe wat binne die hawe bekkens vasgekeer word. Dit kan daartoe lei dat hawe bedrywighede tot stilstand kom en in ernstige gevalle ook veroorsaak dat meringslyne breek. Huidige metodes vir die meet van skeepsbewegings op vasgemeerde skepe, vereis skeep spesifieke inligting as inset. Die toepassing van hierdie metodes op elke skip wat die hawe besoek, word as onprakties beskou, aangesien dit die fisiese meting van sekere punte op die skip behels. In sekere gevalle is dit selfs nodig om meet toestelle op die skip te plaas. In hierdie dokument word ‘n nuwe metode aangebied om die ses grade van vryheid bewegings vir ‘n vasgemeerde skip te meet. Hierdie stelsel analiseer ‘n video beeld reeks van een kamera. Die metode bereken die 3D rigiede beweging van ‘n voorwerp, waarvan die grootte bekend is. ’n ‘Pose from Orthography and scaling with Iterations’ (POSIT) algoritme word hiervoor gebruik. Die voorwerp waarvoor beweging gemeet word is op die dek van die skip en in kamera sig. Rigiede geometriese voorwerp berekeninge word gebruik om die rotasie en translasie vanuit ‘n kamera perspektief te bereken. Verdere geometriese berekeninge maak dit moontlik om die bewegings vanuit die kamera perspektief te omskep in die ses grade van vryheid bewegings van die voorwerp. Die hoof doelwit van hierdie ondersoek was om die gemete bewegings van twee beweging stelsels te valideer en te verifieer. Die validasie en verifiëring was in ‘n hidrolise laboratorium met ‘n klein skaal model opstelling getoets. ‘n Meet metode van skeepsbeweging op klein skaal wat reeds bekend is, is gebruik as ‘n verwysingsraamwerk waarteen die metings vergelyk kan word. Die Keoship stelsel van die Wetenskaplike Nywerheids Navorsings Raad (WNNR) is tans een van die mees akkurate klein skaal skeepsbeweging meet stelsels, en was as verwysing gebruik. Die eerste bewegings metode is getoets op ‘n 2D reghoek vervaaridig uit ligstralede diodes. Hierdie metode het die 2D voorwerp gevolg en is hoofsaaklik gebruik as ‘n boublok om die beweging van ‘n 3D voorwerp te volg. Die tweede metode het die beweging van ‘n 3D voorwerp op ‘n skip gevolg. Vir elke meet metode was daar vier verskillende golf toestande. Elke golf toestand was ook ‘n verdere twee keer herhaal vir herhaalbaarheids doeleindes. Saam met die herhaalbaarheids toetse was daar in totaal, 12 toetse vir elkeen van die twee metodes gedoen. Met die Keoship metode as verwysing, bewys hierdie toetse dat die 3D metode beter resultate lewer as die 2D metode. Toetse onder beheerde toestande, het dit moontlik gemaak om die absolute akkuraatheid van albei sisteme wat ontwikkel was, te evalueer. Verifikasie en akuraatheids toetse het aangedui dat verdere ontwikkeling van die 2D metode gestuit moet word. Die resultate het ook aangedui dat die 3D metode ‘n akuraatheid baie na aan die maatstaf van 0.1 m sal hê wanneer prototipe bewegings 0.6 m oorskrei (b.v. gedurende ‘n storm). Dit sal die oplossing lewensvatbaar maak by die huidige bewys van konsep fase vir die verdere ontwikkeling wat vinnige ontplooiing gedurende ‘n storm sal moontlik maak.
16
Congedo, Pietro Marco. "Contributions to the reliability of numerical simulations in fluid mechanics. Application to the flow simulation of thermodynamically complex gases." Habilitation à diriger des recherches, Université Sciences et Technologies - Bordeaux I, 2013. http://tel.archives-ouvertes.fr/tel-00940088.
Full textAbstract:
At the interface of physics, mathematics, and computer science, Uncertainty Quanti cation (UQ) aims at developing a more rigorous framework and more reliable methods to characterize the impact of uncertainties on the prediction of Quantities Of Interest (QOI). Despite signi cant improvements done in the last years in UQ methods for Fluid Mechanics, there is nonetheless a long way to go before there can be talk of an accurate prediction when considering all the numerous sources of uncertainties of the physical problem (boundary conditions, physical models, geometric tolerances, etc), in particular for shock-dominated problems. This manuscript illustrates my main contributions for improving the reliability of the numerical simulation in Fluid Mechanics: i) the development of e cient and exible schemes for solving at low-cost stochastic partial di erential equations for compressible ows, ii) various works concerning variancebased and high-order analysis, iii) the design of some low-cost techniques for the optimization under uncertainty. The application of interest is the robust design of turbines for Organic Rankine Cycles (ORC). Some contributions to the numerical ow prediction of the thermodynamically complex gases involved in ORC will be presented. This manuscript is divided in two parts. In the rst part, some intrusive algorithms are introduced that feature an innovative formulation allowing the treatment of discontinuities propagating in the coupled physical/stochastic space for shock-dominated compressible ows. Then, variance and higher-order based decompositions are described, that could alleviate problems with large number of uncertainties by performing a dimension reduction with an improved control. Some ANOVAbased analyses are also applied to several ows displaying various types of modeling uncertainties, be it cavitation, thermodynamic or turbulence modeling. Two algorithms for handling stochastic inverse problems are then introduced for improving input uncertainty characterization by directly using experimental data. Finally, robust-optimization algorithms are introduced, that are e cient when dealing with a large number of uncertainties, relying on di erent formulations, i.e. with decoupled/ coupled approaches between the stochastic and the optimization solvers. The second part is devoted to the study of dense gas ow in ORC-cycles, which represent a highly demanding eld of application as far as ow simulation reliability is concerned. The numerical ingredients necessary for this kind of simulation are described. Then, some recent results are illustrated : i) high- delity turbine computations; ii) a feasibility study concerning the appearance and the occurrence of a Rarefaction Shock Wave, using experimental data and di erent operating conditions (in monophasic and two-phase ows); iii) a stochastic study concerning the thermodynamic model uncertainties. This set of research works has produced several papers in international journals and peer-reviewed conferences.
17
Radhakrishnan, Kapilan. "A non-intrusive method to evaluate perceived voice quality of VoIP networks using random neural networks." Thesis, Glasgow Caledonian University, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.547414.
Full text
18
Oumaziz, Paul. "Une méthode de décomposition de domaine mixte non-intrusive pour le calcul parallèle d’assemblages." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLN030/document.
Full textAbstract:
Les assemblages sont des éléments critiques pour les structures industrielles. De fortes non-linéarités de type contact frottant, ainsi que des précharges mal maîtrisées rendent complexe tout dimensionnement précis. Présents en très grand nombre sur les structures industrielles (quelques millions pour un A380), cela implique de rafiner les modèles localement et donc de gérer des problèmes numé-riques de très grandes tailles. Les nombreuses interfaces de contact frottant sont des sources de difficultés de convergence pour les simulations numériques. Il est donc nécessaire de faire appel à des méthodes robustes. Il s’agit d’utiliser des méthodes itératives de décomposition de domaine, permettant de gérer des modèles numériques extrêmement grands, couplées à des techniques adaptées afin de prendre en compte les non-linéarités de contact aux interfaces entre sous-domaines. Ces méthodes de décomposition de domaine restent encore très peu utilisées dans un cadre industriel. Des développements internes aux codes éléments finis sont souvent nécessaires et freinent ce transfert du monde académique au monde industriel.Nous proposons, dans ces travaux de thèse, une mise-en-oeuvre non intrusive de ces méthodes de décomposition de domaine : c’est-à-dire sans développement au sein du code source. En particulier, nous nous intéressons à la méthode Latin dont la philosophie est particulièrement adaptée aux problèmes non linéaires. La structure est décomposée en sous-domaines reliés entre eux au travers d’interfaces. Avec la méthode Latin, les non-linéarités sont résolues séparément des aspects linéaires. La résolution est basée sur un schéma itératif à deux directions de recherche qui font dialoguer les problèmes linéaires globaux etles problèmes locaux non linéaires.Au cours de ces années de thèse, nous avons développé un outil totalement non intrusif sous Code_Aster permettant de résoudre par une technique de décomposition de domaine mixte des problèmes d’assemblage. Les difficultés posées par le caractère mixte de la méthode Latin sont résolues par l’introduction d’une direction de recherche non locale. Des conditions de Robin sur les interfaces des sous-domaines sont alors prises en compte simplement sans modifier les sources de Code_Aster. Nous avons proposé une réécriture algébrique de l’approche multi-échelle assurant l’extensibilité de la méthode. Nous nous sommes aussi intéressés à coupler la méthode Latin en décomposition de domaine à un algorithme de Krylov. Appliqué uniquement à un problème sous-structuré avec interfaces parfaites, ce couplage permet d’accélérer la convergence. Des structures préchargées avec de nombreuses interfaces de contact frottant ont été traitées. Des simulations qui n’auraient pu être menées par un calcul direct sous Code_Aster ont été réalisées via cette stratégie de décomposition de domaine non intrusiveAbstract : Assemblies are critical elements for industrial structures. Strong non-linearities such as frictional contact, as well as poorly controlled preloads make complex all accurate sizing. Present in large numbers on industrial structures (a few million for an A380), this involves managing numerical problems of very large size. The numerous interfaces of frictional contact are sources of difficulties of convergence for the numerical simulations. It is therefore necessary to use robust but also reliable methods. The use of iterative methods based on domain decomposition allows to manage extremely large numerical models. This needs to be coupled with adaptedtechniques in order to take into account the nonlinearities of contact at the interfaces between subdomains. These methods of domain decomposition are still scarcely used in industries. Internal developments in finite element codes are often necessary, and thus restrain this transfer from the academic world to the industrial world.In this thesis, we propose a non-intrusive implementation of these methods of domain decomposition : that is, without development within the source code. In particular, we are interested in the Latin method whose philosophy is particularly adapted to nonlinear problems. It consists in decomposing the structure into sub-domains that are connected through interfaces. With the Latin method the non-linearities are solved separately from the linear differential aspects. Then the resolution is based on an iterative scheme with two search directions that make the global linear problems and the nonlinear local problems dialogue.During this thesis, a totally non-intrusive tool was developed in Code_Aster to solve assembly problems by a mixed domain decomposition technique. The difficulties posed by the mixed aspect of the Latin method are solved by the introduction of a non-local search direction. Robin conditions on the subdomain interfaces are taken into account simply without modifying the sources of Code_Aster. We proposed an algebraic rewriting of the multi-scale approach ensuring the extensibility of the method. We were also interested in coupling the Latin method in domain decomposition to a Krylov algorithm. Applied only to a substructured problem with perfect interfaces, this coupling accelerates the convergence. Preloaded structures with numerous contact interfaces have been processed. Simulations that could not be carried out by a direct computationwith Code_Aster were performed via this non-intrusive domain decomposition strategy
19
Li, Fei. "A non-intrusive method for the determination of overhead line configuration and the derivation of system voltage waveforms." Thesis, University of Strathclyde, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.435127.
Full text
20
Kim, Chuyoung. "Algorithms for Tomographic Reconstruction of Rectangular Temperature Distributions using Orthogonal Acoustic Rays." Thesis, Virginia Tech, 2016. http://hdl.handle.net/10919/73754.
Full textAbstract:
Non-intrusive acoustic thermometry using an acoustic impulse generator and two microphones is developed and integrated with tomographic techniques to reconstruct temperature contours. A low velocity plume at around 450 °F exiting through a rectangular duct (3.25 by 10 inches) was used for validation and reconstruction. 0.3 % static temperature relative error compared with thermocouple-measured data was achieved using a cross-correlation algorithm to calculate speed of sound. Tomographic reconstruction algorithms, the simplified multiplicative algebraic reconstruction technique (SMART) and least squares method (LSQR), are investigated for visualizing temperature contours of the heated plume. A rectangular arrangement of transmitter and microphones with a traversing mechanism collected two orthogonal sets of acoustic projection data. Both reconstruction techniques have successfully recreated the overall characteristic of the contour; however, for the future work, the integration of the refraction effect and implementation of additional angled projections are required to improve local temperature estimation accuracy. The root-mean-square percentage errors of reconstructing non-uniform, asymmetric temperature contours using the SMART and LSQR method are calculated as 20% and 19%, respectively.Master of Science
21
Wagner, Philipp [Verfasser], Andreas [Akademischer Betreuer] Herkersdorf, Martin [Gutachter] Leucker, and Andreas [Gutachter] Herkersdorf. "DiaSys: A Method and Tool for Non-Intrusive Runtime Diagnosis of Embedded Software / Philipp Wagner ; Gutachter: Martin Leucker, Andreas Herkersdorf ; Betreuer: Andreas Herkersdorf." München : Universitätsbibliothek der TU München, 2019. http://d-nb.info/1195140819/34.
Full text
22
Navello, Lorris. "Développement d’un pyromètre bichromatique impulsionnel pour mesures de températures de surfaces solides et liquides en milieux perturbés." Thesis, Paris 10, 2015. http://www.theses.fr/2015PA100143/document.
Full textAbstract:
Les méthodes optiques passives de mesures de température comme la thermographie ou la pyrométrie optique sont intéressantes car elles permettent une mesure non intrusive de l’objet cible à condition de connaître le facteur d’émission. La connaissance de ce facteur est critique pour déterminer la température de surface par le rayonnement thermique émis dans un domaine spectral. Le pyromètre bichromatique impulsionnel permet de surmonter la connaissance de ce paramètre à condition que le choix des valeurs de longueurs d’onde soit fait avec précautions. Lorsque l’objet à mesurer est situé dans un environnement industriel, de telles méthodes optiques sont fortement perturbées par la présence d’un milieu optiquement absorbant. C’est également le cas pour des objets situés dans des environnements très chauds qui émettent d’intenses radiations interférentes. Dans cette thèse, nous présentons une méthode radiométrique active bichromatique pour mesurer la température d’une surface en milieu industriel. Cette méthode est basée sur une excitation locale par une source laser modulée dans l’infrarouge. La détection de la température qui est corrélé avec l’excitation permet d’extraire par détection synchrone le signal modulé noyé dans un bruit jusqu’à un million de fois supérieur. Travailler à courtes longueurs d’onde (domaine visible et proche infrarouge) offre une grande dynamique et minimise l’erreur induite par les variations d’émissivité avec la longueur d’onde. Ce système collecte le rayonnement émis par l’objet à distance, de quelques mètres à plusieurs dizaines de mètres selon la configuration du système optique. Le principe de la méthode de mesure, le système optique et l’appareillage sont présentés dans ce rapport ainsi que les études théoriques et expérimentales sur la sensibilité, sa calibration et les résultats obtenus sur différents sites industrielsOptical passive methods of temperature measurements such as thermography or optical pyrometry are very interesting because they allow a non-intrusive measurement with the target object provided to know the emission factor. The knowledge of this factor is critical for determining the actual temperature of a surface from the thermal radiation emitted in a wavelength band. The bichromatic pulsed pyrometer allows to overcome the knowledge of this parameter provided that precautions are taken in the choice of the values of wavelengths. When the object to be measured is placed in industrial environments, such passive optical methods are greatly disturbed by the presence of an optically absorbing medium. It is also distorted for objects located in very hot environments emitting intense interfering radiation. In this thesis, we present an active bichromatic radiometric method for measuring the temperature of a surface in harsh environments. The method is based on a localized excitation by a modulated laser source in the infrared range. Detecting the temperature range which is correlated with the excitation allows a synchronous detection to extract the signal embedded in a noise up to 106 times superior. Working at short wavelengths (visible range and near infrared range) offers a large dynamic range and minimizes the error due to variations in emissivity with the wavelength. This system collects the radiation emitted by the object at a distance from a few meters up to dozens of meters depending on the configuration of the optical system. The principle of the measurement method, the optical wavelength separation system and the telemetry apparatus are presented in this report as well as the theoretical and experimental study of the sensitivity of the device, its calibration and the results obtained in different industrial sites
23
Karim, Yassine. "Caractérisation robuste de liaisons amortissantes avec dispositifs piezo-électriques pour la réduction de vibrations de structures." Phd thesis, Conservatoire national des arts et metiers - CNAM, 2013. http://tel.archives-ouvertes.fr/tel-00953330.
Full textAbstract:
L'étude présentée dans ce document a pour objet l'étude de différents modes de réduction de vibrations dans les structures avec liaisons. Le premier mode étudié se base sur la dissipation d'énergie apportée par la déformation d' éléments piézoélectriques connectés à un circuit électrique adapté. Le second mode proposé se base sur la propriété de la liaison boulonnée à changer les fréquences propres d'une structure en fonction du serrage appliqué. Cette propriété est utilisée avec plusieurs lois de contrôle du serrage afin d'éviter les plages de fréquences critiques. Ensuite une étude probabiliste est effectuée pour déterminer la robustesse de la réduction de vibrations par rapport à la variation de certains paramètres du modèle. Cette étude de robustesse est effectuée à travers des méthodes stochastiques non-intrusives, parmi lesquelles une méthode originale proposée. Elle permet une réduction de la taille du modèle stochastique à résoudre, ce qui réduit très considérablement le temps de calcul sans perte de qualité significative.
24
Duval, Mickaël. "Apports du couplage non-intrusif en mécanique non-linéaire des structures." Thesis, Toulouse 3, 2016. http://www.theses.fr/2016TOU30088/document.
Full textAbstract:
Le projet ANR ICARE, dans lequel s'inscrit cette thèse, vise au développement de méthodes pour l'analyse de structures complexes et de grande taille. Le défi scientifique consiste à investiguer des zones très localisées, mais potentiellement critiques vis-à-vis de la tenue mécanique d'ensemble. Classiquement, sont mis en œuvre aux échelles globale et locale des représentations, discrétisations, modèles de comportement et outils numériques adaptés à des besoins de simulation gradués en complexité. Le problème global est traité avec un code généraliste dans le cadre d'idéalisations topologiques (formulation plaque, simplification géométrique) et comportementale (homogénéisation) ; l'analyse locale quant à elle demande la mise en œuvre d'outils spécialisés (routines, codes dédiés) pour une représentation fidèle de la géométrie et du comportement.L'objectif de cette thèse consiste à développer un outil efficace de couplage non-intrusif pour la simulation multi-échelles / multi-modèles en calcul de structures. Les contraintes de non-intrusivité se traduisent par la non modification de l'opérateur de rigidité, de la connectivité et du solveur du modèle global, ce qui permet de travailler dans un environnement logiciel fermé. Dans un premier temps, on propose une étude détaillée de l'algorithme de couplage global/local non-intrusif. Sur la base d'exemples et de cas-test représentatifs en calcul de structures (fissuration, plasticité, contact...), on démontre l'efficacité et la flexibilité d'un tel couplage. Aussi, une analyse comparative de plusieurs outils d'optimisation de l'algorithme est menée, et le cas de patchs multiples en interaction est traité. Ensuite le concept de couplage non-intrusif est étendu au cas de non-linéarités globales, et une méthode de calcul parallèle par décomposition de domaine avec relocalisation non-linéaire est développée. Cette méthode nous a permis de paralléliser un code industriel séquentiel sur un mésocentre de calcul intensif. Enfin, on applique la méthode de couplage au raffinement de maillage par patchs d'éléments finis. On propose un estimateur d'erreur en résidu explicite adapté au calcul de solutions multi-échelles via l'algorithme de couplage. Puis, sur la base de cet estimateur, on met en œuvre une procédure non-intrusive de raffinement local de maillage. Au travers de ces travaux, un outil logiciel de couplage non-intrusif a été mis au point, basé sur l'échange de données entre différents codes de calcul (protocole Message Passing Interface). Les développements effectués sont intégrés dans une surcouche Python, dont le rôle est de coupler plusieurs instances de Code_Aster, le code d'analyse de structures développé par EDF R&D, lequel sera utilisé dans l'ensemble des travaux présentésThis PhD thesis, part of the ANR ICARE project, aims at developing methods for complex analysis of large scale structures. The scientific challenge is to investigate very localised areas, but potentially critical as of mechanical systems resilience. Classically, representation models, discretizations, mechanical behaviour models and numerical tools are used at both global and local scales for simulation needs of graduated complexity. Global problem is handled by a generic code with topology (plate formulation, geometric approximation...) and behaviour (homogenization) simplifications while local analysis needs implementation of specialized tools (routines, dedicated codes) for an accurate representation of the geometry and behaviour. The main goal of this thesis is to develop an efficient non-intrusive coupling tool for multi-scale and multi-model structural analysis. Constraints of non-intrusiveness result in the non-modification of the stiffness operator, connectivity and the global model solver, allowing to work in a closed source software environment. First, we provide a detailed study of global/local non-intrusive coupling algorithm. Making use of several relevant examples (cracking, elastic-plastic behaviour, contact...), we show the efficiency and the flexibility of such coupling method. A comparative analysis of several optimisation tools is also carried on, and the interacting multiple patchs situation is handled. Then, non-intrusive coupling is extended to globally non-linear cases, and a domain decomposition method with non-linear relocalization is proposed. Such methods allowed us to run a parallel computation using only sequential software, on a high performance computing cluster. Finally, we apply the coupling algorithm to mesh refinement with patches of finite elements. We develop an explicit residual based error estimator suitable for multi-scale solutions arising from the non-intrusive coupling, and apply it inside an error driven local mesh refinement procedure. Through this work, a software tool for non-intrusive coupling was developed, based on data exchange between codes (Message Passing Interface protocol). Developments are integrated into a Python wrapper, whose role is to connect several instances of Code_Aster, the structural analysis code developed by EDF R&D, which will be used in the following work
25
Nouisri, Amine. "Identification paramétrique en dynamique transitoire : traitement d’un problème couplé aux deux bouts." Thesis, Université Paris-Saclay (ComUE), 2015. http://www.theses.fr/2015SACLN005/document.
Full textAbstract:
Les travaux de thèse portent sur l'identification paramétrique en dynamique transitoire à partir des mesures fortement bruitées, l'un des objectifs à long terme étant de proposer une méthode d’identification peu intrusive afin de pouvoir être implémentée dans des codes de calcul éléments finis commerciaux. Dans ce travail, le concept de l'erreur en relation de comportement modifiée a été retenu pour traiter le problème d’identification des paramètres matériau. La minimisation de la fonctionnelle coût sous contraintes débouche, dans le cas de la dynamique transitoire, sur un problème dit « aux deux bouts » dans lequel il s’agit de résoudre un problème différentiel spatio-temporel avec des conditions à la fois initiales et finales en temps. Il en résulte un problème couplé entre les champs direct et adjoint dont le traitement est délicat. Dans un premier temps, des méthodes précédemment développées telles que la « méthode de Riccati » et la « méthode de tirs » ont été étudiées. Il est montré que l’identification par ces méthodes est robuste même pour des mesures fortement corrompues, mais qu’elles sont limitées par la complexité d’implémentation dans un code industriel, des problèmes de conditionnement ou de coût de calcul. Dans un second temps, une approche itérative basée sur une méthode de sur-relaxation a été développée et comparée à celles précédemment mentionnées sur des exemples académiques, validant l’intérêt de cette nouvelle approche. Enfin, des comparaisons ont été menées entre cette technique et une variante « discrétisée » de la formulation introduite par Bonnet et Aquino [Inverse Problems, vol. 31, 2015]This thesis deals with parameters identification in transient dynamic in case of highly noisy experimental data. One long-term goal is the derivation of a non-intrusive method dedicated to the implementation in a commercial finite element code.In this work, the modified error in the constitutive relation framework is used to treat the identification of material parameters. The minimization of the cost function under constraints leads, in the case of transient dynamics, to a « two points boundary value problem » in which the differential space-time problem involves both initial and final time conditions. This results in a problem coupling the direct and adjoint fields, whose treatment is difficult.In the first part, methods such as those based on the « Riccati equations » and the « shooting methods » have been studied. It is shown that the identification is robust even in the case of highly corrupted measures, but these methods are limited either by the implementation intrusiveness, conditioning problems or the numerical cost.In the second part, an iterative over-relaxation approach is developed and compared to the aforementioned approaches on academic problems in order to validate the interest of the method. Finally, comparisons are carried out between this approach and a « discretized » variation of the formulation introduced by Bonnet and Aquino [Inverse Problems, vol. 31, 2015]
26
Bertrand, Clment. "Mesure et modlisation dynamique de la couche de gele dans un racteur mtallurgique." Thèse, Universit de Sherbrooke, 2014. http://savoirs.usherbrooke.ca/handle/11143/5343.
Full textAbstract:
Rsum : La mesure des profils transitoires et de la vitesse de solidification sont deux donnes importantes pour le contrle de procds industriels impliquant un changement de phase. Dans le cas de llectrolyse de laluminium, ce processus de solidification assure la protection du systme et influe sur la performance nergtique du procd de fabrication. Malheureusement, ces donnes se rvlent, dans la plupart des cas, difficilement accessibles. Ce travail de thse porte sur le dveloppement de nouveaux outils permettant ltude et la caractrisation de la solidification de matriaux changement de phase et haute temprature. Lobjectif est de dvelopper un systme de mesure du front de solidification de matriaux changement de phase non destructif et ne perturbant pas le milieu de mesure, tout en assurant une prcision et une rponse suffisamment rapide pour exploiter de nouvelles stratgies de contrle dans les cuves dlectrolyse. Ce travail couple une tude exprimentale fondamentale de la solidification de la cryolithe avec une modlisation numrique de phnomne de changement de phase solide-liquide dans des conditions proches du fonctionnement de cuves dlectrolyse. // Abstract : Measurement of transient solidification fronts and of solidification rate are two important
data for controlling industrial processes involving a solid-liquid phase change. In the case
of aluminium electrolysis, this solidification process protects the system and affects the
energy performance of the manufacturing process. Unfortunately, these data are not easy
to obtain in most cases. This thesis focuses on the development of new tools for the study
and on the solidification characterization of phase change materials at high temperature.
The goal is to develop a nondestructive solidification front measurement system for phase
change materials without disturbing the measurement medium, while ensuring accuracy
and a fast enough response time to exploit new control strategies in electrolysis cells.
This work couples a fundamental experimental study of the cryolite solidification with
numerical modeling of solid-liquid phase change phenomenon under conditions close to
those during normal operation of electrolytic cells.
27
Bertrand, Clément. "Mesure et modélisation dynamique de la couche de gelée dans un réacteur métallurgique." Thèse, Université de Sherbrooke, 2014. http://savoirs.usherbrooke.ca/handle/11143/5343.
Full textAbstract:
Résumé : La mesure des profils transitoires et de la vitesse de solidification sont deux données importantes pour le contrôle de procédés industriels impliquant un changement de phase. Dans le cas de l’électrolyse de l’aluminium, ce processus de solidification assure la protection du système et influe sur la performance énergétique du procédé de fabrication. Malheureusement, ces données se révèlent, dans la plupart des cas, difficilement accessibles. Ce travail de thèse porte sur le développement de nouveaux outils permettant l’étude et la caractérisation de la solidification de matériaux à changement de phase et à haute température. L’objectif est de développer un système de mesure du front de solidification de matériaux à changement de phase non destructif et ne perturbant pas le milieu de mesure, tout en assurant une précision et une réponse suffisamment rapide pour exploiter de nouvelles stratégies de contrôle dans les cuves d’électrolyse. Ce travail couple une étude expérimentale fondamentale de la solidification de la cryolithe avec une modélisation numérique de phénomène de changement de phase solide-liquide dans des conditions proches du fonctionnement de cuves d’électrolyse. // Abstract : Measurement of transient solidification fronts and of solidification rate are two important
data for controlling industrial processes involving a solid-liquid phase change. In the case
of aluminium electrolysis, this solidification process protects the system and affects the
energy performance of the manufacturing process. Unfortunately, these data are not easy
to obtain in most cases. This thesis focuses on the development of new tools for the study
and on the solidification characterization of phase change materials at high temperature.
The goal is to develop a nondestructive solidification front measurement system for phase
change materials without disturbing the measurement medium, while ensuring accuracy
and a fast enough response time to exploit new control strategies in electrolysis cells.
This work couples a fundamental experimental study of the cryolite solidification with
numerical modeling of solid-liquid phase change phenomenon under conditions close to
those during normal operation of electrolytic cells.
28
Gstalter, Étienne. "Réduction d’ordre de modèle de crash automobile pour l’optimisation masse / prestations." Thesis, Compiègne, 2020. http://www.theses.fr/2020COMP2576.
Full textAbstract:
Cette thèse est une contribution à un thème de recherche sur les applications de la réduction de modèle à l’ingénierie RENAULT. Elle fait suite aux travaux du projet IRT SystemX ROM (Réduction de modèles et Optimisation Multidisciplinaire) et aux thèses CIFRE RENAULT [Vuong], [Charrier]. L’application industrielle principale du thème est la mise au point de la structure d’un véhicule sollicité en crash; des travaux sont également en cours sur la combustion, l’acoustique et l’aérodynamique. Les travaux de cette thèse sont à la fois un apport à la méthode générique ReCUR et son adaptation à l’optimisation de la caisse d’un véhicule pour le crash. RENAULT utilise largement l’optimisation pour la mise au point de la caisse en crash, avec un outil d’optimisation numérique basé sur la méthode des plans d’expériences. Cette méthode nécessite beaucoup de calculs crash car cette simulation est considérée comme une boite noire, en utilisant uniquement les entrées et sorties. La méthode ReCUR prend le contre-pied en exploitant un maximum d’informations de chaque simulation crash, dans le but de réduire fortement leur nombre. Les travaux de cette thèse ont permis de remplir cet objectif pour les applications de mise au point au nominal et pour l’optimisation robuste dans des cas complexes comme le choc frontal et arrièreThis thesis is a part of a global research work dedicated to reduced-order modelling applications in the Renault engineering direction. It's research topic has been improved in the IRT System)('s project on Reduced Order Model and Multi-disciplinary Optimization. Some previous thesis can help understand the context. ([Vuong], [Charrier]). The main industrial application of the research theme is the focus on a body structure, in a crash loading. Some research works on acoustic, combustion and aerodynamic are currently ongoing. This thesis is both a contribution to the generic ReCUR method, and its application to a car body structure optimization for crash loadings. Engineering teams at Renault uses optimization to obtain the best crash simulation, with a numerical optimization software, based on designs of experiments. It requires a lot of crash simulation because each simulation is considered as unique, with only one response for each parameter. Only Inputs and Outputs are known. The ReCUR method consider that each simulation is a huge mine that needs our attention. We hope that we can decrease the number of crash simulation required to compute a model, by using much more data for each simulation
29
Pled, Florent. "Vers une stratégie robuste et efficace pour le contrôle des calculs par éléments finis en ingénierie mécanique." Phd thesis, École normale supérieure de Cachan - ENS Cachan, 2012. http://tel.archives-ouvertes.fr/tel-00776633.
Full textAbstract:
Ce travail de recherche vise à contribuer au développement de nouveaux outils d'estimation d'erreur globale et locale en ingénierie mécanique. Les estimateurs d'erreur globale étudiés reposent sur le concept d'erreur en relation de comportement à travers des techniques spécifiques de construction de champs admissibles, assurant l'aspect conservatif ou garanti de l'estimation. Une nouvelle méthode de construction de champs admissibles est mise en place et comparée à deux autres méthodes concurrentes, en matière de précision, coût de calcul et facilité d'implémentation dans les codes éléments finis. Une amélioration de cette nouvelle méthode hybride fondée sur une minimisation locale de l'énergie complémentaire est également proposée. Celle-ci conduit à l'introduction et à l'élaboration de critères géométriques et énergétiques judicieux, permettant un choix approprié des régions à sélectionner pour améliorer localement la qualité des champs admissibles. Dans le cadre des estimateurs d'erreur locale basés sur l'utilisation conjointe des outils d'extraction et des estimateurs d'erreur globale, deux nouvelles techniques d'encadrement de l'erreur en quantité d'intérêt sont proposées. Celles-ci sont basées sur le principe de Saint-Venant à travers l'emploi de propriétés spécifiques d'homothétie, afin d'améliorer la précision des bornes d'erreur locale obtenues à partir de la technique d'encadrement classique fondée sur l'inégalité de Cauchy-Schwarz. Les diverses études comparatives sont menées dans le cadre des problèmes d'élasticité linéaire en quasi-statique. Le comportement des différents estimateurs d'erreur est illustré et discuté sur des exemples numériques tirés d'applications industrielles. Les travaux réalisés constituent des éléments de réponse à la problématique de la vérification dans un contexte industriel.
30
Koraitem, Khalid. "Characterization of Conical and Elliptical Fuel Spray Nozzles using Non-Intrusive Laser Diagnostic Methods." Thesis, 2011. http://spectrum.library.concordia.ca/7733/1/Koraitem__MASc_F2011.pdf.
Full textAbstract:
Spray nozzles and atomizers have several applications in many forms of industry such as aerospace, automotive, combustion, pharmaceutical, and spray coating industries. These nozzles vary in design and performance depending on the application they are used in. Nevertheless, the primary objective for all atomizers is to disperse liquids in a controlled and uniformed manner while minimizing the amount of energy needed in the breakup process to achieve high quality atomization.
Air-assist and air-blast atomizers are fuel injector nozzles commonly used in gas turbine engines in the aerospace, and power generation industries. The flow in these atomizers is considered to be two-phase flow since a portion of air taken from the compressor is also used to assist in the breakup of the fuel inside the combustion chamber. These nozzles play a critical role in determining the efficiency of gas turbine engines as their ability to disperse liquid fuel into fine droplets allows for better mixture and evaporation rates; therefore, improving engine performance, reducing emissions, and maximizing fuel efficiency.
The objective of this study is to experimentally analyze two gas turbine fuel injector nozzles. The first nozzle is a standard hollow cone nozzle currently used in gas turbine engines, whereas the other is a hollow elliptical nozzle designed to offer greater control over fuel distribution as well as improve overall atomization. The nozzles are investigated under varying gas to liquid ratios (GLR) where key spray parameters such as droplet diameter, velocity, volume flux, as well as spray angle are measured to characterize the nozzles using methods such as Shadowgraph, Optical Patternation, Phase Doppler Particle Analyzer (PDPA), and Particle Image Velocimetry (PIV).
31
Martins, Alexandre dos Santos. "A new method for non-intrusive online wiring health monitoring." Master's thesis, 2015. http://hdl.handle.net/10400.26/11966.
Full textAbstract:
This work presents a method for preventing faults in cables prior to their happening, e.g.
due to wire ageing and mounting xtures. The proposed method focus in large diameter
cables delivering high currents in aircraft. However, this method could be useful in other
scenarios where wiring problems could cause critical problems such as in nuclear power
plants, automobiles or trains.
The method consists of a sensor embedded in the cable. The sensor is made of several
thin wires wrapped around the insulator of the monitoring cable in a mesh grid pattern.
The cable with the embedded sensor is then covered with a second layer of insulation.
Measuring the equivalent resistance of the sensor, allows to determine the health of the
cable, as a fault would also damage the sensor changing its equivalent resistance. Cha ng
faults, e.g. caused by wires rubbing against each other or bare wiring contact to ground
or with the chassis of the vehicle, are analysed. The sensor equivalent resistance for each
type of fault and its distance from the measurement system is characterized, enabling
localization and prevention of wiring malfunctions.
A complete prototype of the system is described, including the hardware and software
components of the sensor.
Additionally, the system is tested to verify operation in a environment similar to the
one experienced in an aircraft.
This work was developed as part of an internship in the company Active Space
Technologies.
32
Zhou, Jing-Han, and 周敬翰. "Artificial Intelligence-Based Non-intrusive Load Monitoring Method for Microgrid." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/09087358627942130144.
Full textAbstract:
碩士中原大學
電機工程研究所
99
Microgrids can increase usage of renewable energies and avoid power penetration caused by distributed generation in the power system. The interface (i.e., point of common coupling, PCC) between the microgrid and power utility should satisfy some standards, e.g., IEEE Sd. 1547. Monitoring the microgrid loads at the PCC by the power utility becomes crucial because the utility cannot install advanced meters at different locations in the microgrid. This paper presents a new nonintrusive load monitoring method using artificial neural network. The fundamental component, characteristic and characteristic harmonic currents /voltage measured at the PCC serve as the signatures for the artificial neural network inputs. The nonintrusive load monitoring at the PCC is addressed to identify different load levels for individual linear/nonlinear loads in the microgrid. With the help of load monitoring results, the power utility can make further load management policy. Simulation results obtained from a microgrid consisting of diesel generation, wind-turbine-generator, converter, and cycle-converter show the applicability of the proposed method.