Tesis sobre el tema "Linear FEM analyse"
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VIALE, NICOLA. "A new flat jack test for evaluating shear properties on unreinforced masonry". Doctoral thesis, Politecnico di Torino, 2020. http://hdl.handle.net/11583/2846617.
Texto completoLofink, Paul [Verfasser], Wolfgang H. [Akademischer Betreuer] Müller, Wolfgang H. [Gutachter] Müller y Nikolai D. [Gutachter] Tutyshkin. "FEM-gestützte Analyse der linear-elastischen und hyperelastischen eigengravitierenden Erde unter dem Aspekt geometrischer und physikalischer Nichtlinearitäten / Paul Lofink ; Gutachter: Wolfgang H. Müller, Nikolai D. Tutyshkin ; Betreuer: Wolfgang H. Müller". Berlin : Technische Universität Berlin, 2018. http://d-nb.info/1156276659/34.
Texto completoJakel, Roland. "Lineare und nichtlineare Analyse hochdynamischer Einschlagvorgänge mit Creo Simulate und Abaqus/Explicit". Universitätsbibliothek Chemnitz, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-171812.
Texto completoThe presentation describes how to analyze the impact of an idealized fragment into a stell protective panel with different dynamic analysis methods. Two different commercial Finite Element codes are used for this: a.) Creo Simulate: This code uses the method of modal superposition for analyzing the dynamic response of linear dynamic systems. Therefore, only modal damping and no contact can be used. The unknown force-vs.-time curve of the impact event cannot be computed, but must be assumed and applied as external force to the steel protective panel. As more dynamic the impact, as sooner the range of validity of the underlying linear model is left. b.) Abaqus/Explicit: This code uses a direct integration method for an incremental (step by step) solution of the underlying differential equation, which does not need a tangential stiffness matrix. In this way, matieral nonlinearities as well as contact can be obtained as one result of the FEM analysis. Even for extremely high-dynamic impacts, good results can be obtained. But, the nonlinear elasto-plastic material behavior with damage initiation and damage evolution must be characterized with a lot of effort. The principal difficulties of the material characterization are described
Teklemariam, Daniel Mekonnen y Bennie Hamunzala. "Design of Thick Concrete Beams : Using Non-Linear FEM". Thesis, KTH, Bro- och stålbyggnad, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-189141.
Texto completoDe experimentella studier som utförts på tjocka betongbalkar som utsätts för statisk last har visat att skjuvning spelar en viktig roll i brottmekanismen. Syftet med detta examensarbete är att rekommendera lämpliga dimensioneringsmetoder för tjock betongbalkar utsatt for statisk koncentrerad last enligt Eurokod 2 med hjälp av ickelinjära finita element metod. Abaqus/Explicit användes genom att utnyttja konstitutiva materialmodeller för att fånga materialens icke-linjäritet och minskad styvhet. Tre dilatationsvinklar (30°, 38° och 45°) och två brottenergi från FIB 1990 (76 N/m) och FIB 2010 (142 N/m) tillämpas för att kontrollera deras inverkan på FE-modellerna. Dilatationsvinkel med 38° och FIB 2010 med högre brottenergi valdes i de icke-linjära finita elementanalyserna. Kontroll av FE-modellerna är baserad på ”American Concret Institutes” experimentella resultat på de tjocka betongbalkarna. Handberäkningar av tjocka betongbalkar har utförts i brott- och bruksgränstillstånd med tre dimensioneringsmetoder i Eurokod 2 nämligen balk metoden, fackverksmetoden och linjära-FE skalelementmetoden. Jämförelse har gjorts för de olika dimensioneringsmetoderna, genom att använda de armeringsdetaljer av handberäkningar i de verifierade och kalibrerade icke linjära FE-modellerna i Abaqus/Explicit. Resultaten i fråga är last för 0.3 mm handberäknad sprikvidd, FE-last för 0.3 mm sprikvidd, armeringsmängd och FE-brottlast. Jämförelse av resultaten mellan de tre dimensioneringsmetoder (balkmetod, fackverksmetod och skalelementmetod) visar att fackverksmetod är bättre design metod, eftersom det är relativt ekonomiskt med avseende på armeringsmängd, har högre lastkapacitet och last på 0.3 mm sprickvidd.
Dettmann, Aaron. "Loosely coupled, modular framework for linear static aeroelastic analyses". Thesis, KTH, Lättkonstruktioner, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-262047.
Texto completoRapporten beskriver en beräkningsmodell för linjära, statisk aeroelastiska analyser. Modellen kan användas för konceptuella designstudier av flygplan. En partitionerad metod används, d v s separata lösare för aerodynamik- och strukturanalyser kopplas på ett lämpligt sätt, och bildar tillsammans en modell för aeroelastiska simulationer. Aerodynamik modelleras med hjälp av en så kallad vortex-lattice method (VLM), en enkel modell för beräkningsströmningsdynamik (CFD) som är baserad på friktionsfri strömning. Strukturen representeras av en tredimensionell (3D) Euler-Bernoulli-balkmodell implementerad med hjälp av en finita elementmetod (FEM). Ovannämnda modeller har utvecklats med fokus på modularitet och lös koppling. Kärnan i den aeroelastiska modellen har abstraherats så att den inte beror på specifika detaljer i de underliggande aerodynamik- och strukturmodulerna. Aeroelasticitetsmodellen i sin helhet består av separata mjukvaruprogram för VLM och balk-FEM, såväl som ett ramverk som möjliggör den aeroelastiska kopplingen. Dessa olika program har utvecklats som en del av examensarbetet. Ett vindtunnelförsök med en enkel vingmodell presenteras som ett valideringstest. Dessutom beskrivs en analys av ett elastiskt obemannad flygplan (OptiMale) och resultaten jämförs med en befintlig studie som har genomförts med modeller av högre trovärdighet.
Denimal, Enora. "Prédiction des instabilités de frottement par méta-modélisation et approches fréquentielles : Application au crissement de frein automobile". Thesis, Lyon, 2018. http://www.theses.fr/2018LYSEC039/document.
Texto completoBrake squeal is a noise nuisance that represents significant costs for the automotive industry. It originates from complex phenomena at the frictional interface between the brake pads and the disc. The stability analysis remains the preferred method in the industry today to predict the stability of a brake system despite its over- and under-predictive aspects.In order to build a robust brake system, it is necessary to find the technology that limits instabilities despite some uncertain parameters present in the system. Thus, one of the main objectives of the PhD thesis is to develop a method to treat and propagate the uncertainty and variability of some parameters in the finite element brake model with reasonable numerical costs.First, the influence of a first group of parameters corresponding to contacts within the system was studied in order to better understand the physical phenomena involved and their impacts on the squealing phenomenon. An approach based on the use of a genetic algorithm has also been implemented to identify the most unfavourable set of parameters in terms of squeal propensity on the brake system.In a second step, different meta-modelling methods were proposed to predict the stability of the brake system with respect to different parameters that may be design parameters or uncertain parameters related to the environment of the brake system.In a third step, a non-linear analysis method complementary to the stability analysis was proposed and developed. It is based on the tracking of the stability of an approximate vibrational solution and allows the identification of unstable modes present in the dynamic response of the system. This method was applied to a simple academic model before demonstrating its feasibility on the complete industrial brake finite element model under study
Makhlouf, Heba. "Essais virtuels pour l'industrie du meuble". Thesis, Paris Est, 2015. http://www.theses.fr/2015PESC1164.
Texto completoThe work joins within the framework of a collaboration between the Pole Furnishing FCBA and the Laboratory MSME of the UPEM. The objective was to finalize(to work out) a tool of simulation allowing FCBA to lead a study of validation (held the normalized(standardized) tests) before the manufacturing of the piece of furniture
Pablos, Rabano Alejandro. "Modeling of a PMSynRel stator with concentrated windings using FEM and non-linear reluctance networks". Thesis, KTH, Elektrisk energiomvandling, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-124543.
Texto completoAlagbada, Adefemi Samuel. "Thermo-Mechanical Fatigue Assessment of Marine Boiler : Using linear Finite Element Analyses". Thesis, Linnéuniversitetet, Institutionen för maskinteknik (MT), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-95439.
Texto completoSelli, Nicola. "Static and seismic analysis of a historic masonry building in San Pio delle Camere". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2022.
Buscar texto completoPolidori, Andrea. "Analisi numerica non lineare di un nodo trave colonna in conglomerato cementizio". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2011. http://amslaurea.unibo.it/2623/.
Texto completoAmin, Handren. "A comparative study of 2 CAD-integrated FE-programs using the linear static analysis". Thesis, Halmstad University, School of Business and Engineering (SET), 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-2355.
Texto completoThis Master’s thesis is summery of a comparative study of 2 commercial CAD-integrated
FE-programs. These FE-programs were CATIA v5 and ABAQUS 6.3-7. The primary
objective of this study is to investigate the basic FEA capabilities of CATIA and
ABAQUS 6.7-3 in performing the linear static analysis and to identify whether there are
any differences and similarities between results the both Finite Element FE codes give.
The overall research question in the present thesis is: Do different FE programs, here
CATIA and ABAQUS, give the same results for FE analysis giving the same models if
subjected to the same boundary conditions? This research seeks to achieve its aims
through making a comparative qualitative study. Certain pre-selections were performed in
advance of conducting Finite element analysis and the comparison process to ensure that
results would reflect only the most relevant and meaningful differences and similarities
between the both FE-codes. Five different 3D solid models have been selected to perform
linear static Finite element analysis on. All these models (case studies) are created in
CATIA V5 and the linear static analysis conducted on using FE-codes CATIA v5 and
ABAQUS 6.7-3. Three static responses (results) of the linear static analysis have been
adopted as criteria for comparisons purposes. These criteria were: (1) displacements, (2)
Von Mises stress, and (3) principal stress. The results of comparisons showed that there is
a very good agreement in most cases and small gap between in a few cases. Results of
this study demonstrate that the both FE-programs CATIA v5 and ABAQUS 6.7-3 have
good capabilities to perform FE-analysis and they give very near results. Reason behind
differences is that each of them uses a different algorithm for solving problems. The final
answer for the research question is given with valuable recommendations for future work
in the scope of this research.
Desai, D. A. "Comparative non-linear simulation of temperature profiles induced in an exhaust manifold during cold-starting". Journal for New Generation Sciences, Vol 8, Issue 1: Central University of Technology, Free State, Bloemfontein, 2010. http://hdl.handle.net/11462/549.
Texto completoThe simulation of an exhaust manifold's thermal behaviour is an important concern for various reasons. Amongst them is the need to minimise catalyst light-offtime as significant exhaust emissions are generated within this period. Modelling such behaviour is not simplistic as it is governed by complex interactions between exhaust gas flow and the manifold itself. Computational fluid dynamics (CFD) is a powerful tool for such simulations. However its applicability for transient simulations is limited by high central processing unit (CPU) demands. The present study proposes an alternative computational method to assess and rank the relative impact of the manifold's thermal properties on its exterior temperature. The results show that stainless steel manifolds potentially minimise heat loss from the exhaust gas when compared with their cast iron counterparts. This may result in an increase in thermal energy being available to heat the catalyst.
Yan, Charlotte. "Vaildation of nonlinear FE-simulation for design improvement". Universitätsbibliothek Chemnitz, 2013. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-114592.
Texto completoZiel der Studie ist es ein adäquates Simulationsmodell zu entwickeln, welches zur Gewichtsreduzierung einer Standardprofil Aluminium Sitzschiene im Flugzeug verwendet werden kann. In einer nichtlinearen Analyse unter Berücksichtigung der Plastizität des Materials und von Materialfehlern wird die Auswirkung der Geometrieänderungen auf die maximale Traglast analysiert (ABAQUS 6.11). Zunächst wird das nicht-lineare Modell mit experimentell ermittelten Daten überprüft: Randbedingungen und Materialeigenschaften werden basierend auf Lastverschiebungskurven, Informationen von Dehnungsmessstreifen und Versagensmustern angepasst. Dabei wurden weniger als 1% Abweichung zwischen Simulation und Test erzielt. Die Berücksichtigung von Materialfehlern führte zu einer 5%-igen Verbesserung der Ergebnisse. Mit dem validierten Modell wird abschließend eine Gewichtsreduzierung mittels Geometrievariation durchgeführt
Jonsson, Karl. "Two Problems in non-linear PDE’s with Phase Transitions". Licentiate thesis, KTH, Matematik (Avd.), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-223562.
Texto completoQC 20180222
Di, Fabrizio Vincenzo. "Modellazione e analisi non lineare del degrado artificiale di un prototipo di edificio in muratura in scala reale". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021.
Buscar texto completoSingh, Subrat y Shreedhara Sreehari Veditherakal. "CAE modelling of cast aluminium in automotive structures". Thesis, Linköpings universitet, Mekanik och hållfasthetslära, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-162190.
Texto completoFerrari, Rosalba (ORCID:0000-0002-3989-713X). "An elastoplastic finite element formulation for the structural analysis of Truss frames with application to ha historical iron arch bridge". Doctoral thesis, Università degli studi di Bergamo, 2013. http://hdl.handle.net/10446/28959.
Texto completoVirgulto, Giorgio. "Valutazione delle potenzialità del BIM per analisi di loss assessment sismico". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020.
Buscar texto completoPtáček, Petr. "Termálně-strukturální analýza válce čtyřdobého spalovacího motoru". Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2016. http://www.nusl.cz/ntk/nusl-254374.
Texto completoLonzi, Giuditta. "La cupola del Duomo di Siena: ricerca storica, analisi costruttiva e modellazione strutturale tramite FEA finalizzate alla comprensione del comportamento statico". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018. http://amslaurea.unibo.it/16541/.
Texto completoPham, Anh Tu. "Détermination numérique des propriétés de résistance de roches argileuses". Thesis, Paris Est, 2017. http://www.theses.fr/2017PESC1237/document.
Texto completoThe strength capacities of Callovo-Oxfordian (COx) argillite which is a potential host rock for the deep underground repository of high-level radioactive waste in France are investigated. At a micro-scale, micro-pores can be observed in the matrix. A first strength homogenization step has been performed in order to evaluate the matrix strength criteria. The microstructure analysis of this material at some hundreds of micromet scale, referred at meso-scale, shows a clay matrix and a random distribution of mineral inclusions (quartz and calcite).Aiming to the determination of COx argillite strength domain, an FEM numerical tool has been developed in the context of the elastoplastic behavior of the matrix. Several morphological patterns of the representative elementary volume have been considered and subjected to an incremental loading in periodic conditions until collapse occurs. As a result of such elastoplastic calculation, one point of the boundary of the strength domain is obtained. The latter then could be reached by successive elastoplastic calculations.As an alternative to direct elastoplastic simulations, kinematic and static approaches of limit analysis are performed. The stress-based (static approach) and the velocity-based (kinematic approach) finite element method are used to develop a numerical tool able to derive a lower bound and upper bound of strength domain, respectively
Jindra, Daniel. "Stanovení požární odolnosti konstrukcí". Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2019. http://www.nusl.cz/ntk/nusl-392030.
Texto completoMarchionni, Elianires. "Valutazione del rischio sismico di un edificio strategico destinato a sede della di.coma.c di Parma". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021.
Buscar texto completoPavelka, Roman. "Hydraulické posunovače". Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2011. http://www.nusl.cz/ntk/nusl-229740.
Texto completoMoro, Lorenzo. "Structure borne noise due to marine diesel engines: experimental study and numerical simulation for the prediction of the dynamic behaviour of resilient mounts". Doctoral thesis, Università degli studi di Trieste, 2015. http://hdl.handle.net/10077/11114.
Texto completoGli alti livelli di comfort che sono richiesti oggigiorno a bordo di navi da crociera e mega-yachts, portano i progettisti a concentrare la loro attenzione sul problema del rumore strutturale. I motori diesel quattro tempi che sono installati a bordo nave come motori principali o diesel generatori, sono tra le principali sorgenti di rumore strutturale. Per questa ragione, al fine di ridurre l’energia vibrazionale generata da queste sorgenti e trasmessa, tramite le strutture nave, ai locali alloggio, i motori diesel sono sospesi mediante elementi resilienti. Tali elementi resilienti disaccoppiano la sorgente di rumore e vibrazioni (motore diesel) dal mezzo di propagazione (le strutture nave) e isolano dunque la sorgente dalle strutture riceventi. I livelli di rumore strutturale misurati alle fondazioni del motore diesel dipendono dai livelli di velocità misurati sulla sorgente (cioè ai piedi del motore diesel), dai livelli di impedenza meccanica degli elementi resilienti e dai livelli di mobilità meccanica delle fondazioni del motore diesel. Il single-point approach è un approccio semplificato per la previsione dei livelli di rumore strutturale che trascura l’interazione tra elementi resilienti. Secondo tale teoria, al fine di ridurre il rumore strutturale trasmesso attraverso gli elementi resilienti alle strutture nave, si deve ridurre l’impedenza meccanica degli elementi resilienti così come la mobilità meccanica delle fondazioni del motore diesel. In altre parole, si devono aumentare la rigidezza dinamica degli elementi resilienti così come l’impedenza meccanica delle fondazioni del motore diesel. Ad oggi, l’impedenza meccanica degli elementi resilienti può essere ricavata solo mediante prove sperimentali in laboratorio, mentre la mobilità meccanica del motore diesel è solitamente misurata quando la nave è in costruzione. Dunque non vi è la possibilità di predire, in fase progettuale, il rumore strutturale dovuto ai motori diesel. In questa tesi, viene presentata una procedura per la simulazione del rumore strutturale dovuto a motori diesel marini. La procedura si basa su test sperimentali e simulazioni numeriche. Nella prima parte della tesi sono richiamate le basi teoriche necessarie per l’esecuzione delle procedure numeriche e delle prove sperimentali. Sono dunque presentati i risultati delle analisi numeriche per simulare la mobilità delle fondazioni dei motori diesel marini. I risultati delle analisi FEM sono stati validati mediante confronto dei risultati delle analisi numeriche con i dati ottenuti da una campagna di misure eseguite a bordo nave. Successivamente sono presentati i risultati di una serie di prove eseguite per collaudare una nuova macchina sperimentale per misurare l’impedenza meccanica degli elementi resilienti. Lo scopo del collaudo era definire una procedura per l’utilizzo della macchina e per l’esecuzione di prove sperimentali in accordo alla ISO 10846, che è considerata normativa di riferimento per questo tipo di prove. Si è dunque proceduto con l’esecuzione di prove sperimentali eseguite su un elemento resiliente per motori diesel marini. Le prove sono state eseguite a differenti carichi statici. I risultati di queste prove sperimentali sono stati utilizzati per settare un modello numerico che simuli il comportamento non-lineare del componente in gomma del resiliente. I risultati ottenuti sia dalle prove sperimentali sia dalle simulazioni numeriche sono stati utilizzati per predire il rumore strutturale generato dai motori diesel, in accordo al single-point approach. I risultati ottenuti dall’applicazione del metodo sono stati confrontati con misure eseguite a bordo e sono stati discussi per evidenziare vantaggi e svantaggi dell’applicazione del metodo. Le procedure numeriche per la simulazione del comportamento dinamico del resiliente e della fondazione costituiscono un primo passo per l’ottimizzazione del sistema di isolazione del motore diesel marino.
The high level of comfort that is required today on board cruise vessels and mega-yachts, leads the designers to focus their attention on structure-borne noise issues. Four-stroke diesel engines that are installed on board as main diesel engines for the propulsion system and as gen-sets, are usually the main sources of structure-borne noise. For this reason, the diesel engines are usually resiliently mounted in order to reduce the vibration energy generated by these sources and transmitted through the ship structures to the accommodation areas. These mounts decouple the noise and vibration source (diesel engine) from the means of wave propagation (ship structures) and so, they isolate the source from the receiving structures. The structure-borne noise levels measured at the diesel engine foundation depend on the velocity levels measured at the source (diesel engine feet), on the mechanical impedance levels of the resilient mounts and on the mechanical mobility levels of the diesel engine foundation. The simplified theory of the single-point approach neglects the interaction among the resilient mounts. According to this theory, to decrease the structure-borne noise transmitted through the resilient mounts towards the ship structures, the mechanical impedance of the resilient mounts as well as the mechanical mobility of the diesel engine foundation are to be lowered. In other words the dynamic stiffness of the resilient mounts has to be decreased and the mechanical impedance of the diesel engine foundation has to be increased. To date, the mechanical impedance of real resilient mounts can only be obtained by laboratory tests and the mechanical mobility of the diesel engine foundation is usually measured when the ship is under construction, so it is not available for predictive analyses. In the thesis, a procedure for simulating the structure-borne noise generated by marine diesel engine is discussed. The procedure is based on both experimental tests and numerical simulations. In the first part of the thesis, some notes on the theoretical background are presented. Then, the results of FE analyses for simulating the mechanical mobility of a diesel engine foundation are shown. The FE models have been validated by the results of a measurement campaign carried out on board a ship. Then, the results of a series of tests performed to tune a new test rig, designed and built up at the University of Trieste for measuring the mechanical impedance of resilient mounts, are discussed. The campaign for tuning the test rig has been carried out in order to set an experimental procedure that allows achieving results in compliance with the ISO 10846 Standard, which is a sound reference for this kind of tests. As a case study, a large resilient mount for marine diesel engines has been tested to achieve its mechanical impedance curve at different static pre-loads. The outcomes of the experimental tests have been used for tuning the best numerical model of the resilient mount that properly takes into account the nonlinear behaviour of the rubber core. The data of the experimental tests carried out on board ships as well as in laboratory and the outcomes of numerical simulations have been used to predict the structure-borne noise according to the single-point approach. The outcomes achieved by the application of the method have been compared with on board measurements and pros and cons of the method are widely discussed. Moreover, the numerical procedures for the simulation of the dynamic behaviour of the resilient mount and the diesel engine foundation, pave the way for the optimization of the decoupling system of marine diesel engines.
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Baldazzi, Michele. "Modello dinamico di un motore tubolare sincrono a magneti permanenti". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018.
Buscar texto completoPecorella, Daniele. "Methodology for the design and optimization of a morphing wing droop-nose structure for greener aircraft". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2022.
Buscar texto completoBaldanza, Chiara. "Modellazione di dettaglio di un sistema innovativo di rinforzo esterno per il miglioramento sismico degli edifici senza interruzione d’uso". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/20722/.
Texto completoMussoni, Giacomo. "Progettazione di un sistema innovativo di rinforzo esterno per il miglioramento sismico degli edifici senza interruzione d’uso". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/20757/.
Texto completoSuárez, Sergio Andrés Pardo. "Análise numérica de barras gerais 3D sob efeitos mecânicos de explosões e ondas de choque". Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/18/18134/tde-07032017-103309/.
Texto completoThis work consists in the use of the Finite Element Method (FEM) for numerical analysis of fluid-bar structures, focusing on transient problems involving explosions or other actions with shock waves propagation. For this purpose, one needs to study three different aspects: the computational structural dynamics, the computational fluid dynamics and the coupling problem. Regarding computational structural dynamics, one need firstly to identify the requirements for an element to be adequate to analyze such problems, taking into account the fact that such element should admit large displacements. In order to avoid problems related to finite rotation approximations and to give a realist representation of a 3D bar structure, we chose a formulation defined in terms of positions and that considers the cross-section warping effects. Regarding computational fluid dynamics, we seek for a stable formulation for compressible flows, and at same time, sensitive to the movement of the structure, leading to an explicit time integration algorithm based on characteristics with governing equations described in the Arbitrary Lagrangian-Eulerian (ALE) form. Regarding to coupling, we chose to use a weak (explicit) partitioning coupling model in order to ensure modularity and versatility. The developed coupling scheme is bases on boundary conditions transfer techniques (Dirichlet-Neummann), and we study the effects of using bidirectional or unidirectional boundary conditions transfers.
Bringmann, Philipp. "Adaptive least-squares finite element method with optimal convergence rates". Doctoral thesis, Humboldt-Universität zu Berlin, 2021. http://dx.doi.org/10.18452/22350.
Texto completoThe least-squares finite element methods (LSFEMs) base on the minimisation of the least-squares functional consisting of the squared norms of the residuals of first-order systems of partial differential equations. This functional provides a reliable and efficient built-in a posteriori error estimator and allows for adaptive mesh-refinement. The established convergence analysis with rates for adaptive algorithms, as summarised in the axiomatic framework by Carstensen, Feischl, Page, and Praetorius (Comp. Math. Appl., 67(6), 2014), fails for two reasons. First, the least-squares estimator lacks prefactors in terms of the mesh-size, what seemingly prevents a reduction under mesh-refinement. Second, the first-order divergence LSFEMs measure the flux or stress errors in the H(div) norm and, thus, involve a data resolution error of the right-hand side f. These difficulties led to a twofold paradigm shift in the convergence analysis with rates for adaptive LSFEMs in Carstensen and Park (SIAM J. Numer. Anal., 53(1), 2015) for the lowest-order discretisation of the 2D Poisson model problem with homogeneous Dirichlet boundary conditions. Accordingly, some novel explicit residual-based a posteriori error estimator accomplishes the reduction property. Furthermore, a separate marking strategy in the adaptive algorithm ensures the sufficient data resolution. This thesis presents the generalisation of these techniques to three linear model problems, namely, the Poisson problem, the Stokes equations, and the linear elasticity problem. It verifies the axioms of adaptivity with separate marking by Carstensen and Rabus (SIAM J. Numer. Anal., 55(6), 2017) in three spatial dimensions. The analysis covers discretisations with arbitrary polynomial degree and inhomogeneous Dirichlet and Neumann boundary conditions. Numerical experiments confirm the theoretically proven optimal convergence rates of the h-adaptive algorithm.
Larisch, Lukas. "Three-dimensional Modeling and Simulation of a Tuning Fork". Thesis, 2018. http://hdl.handle.net/10754/628716.
Texto completoDediyagala, Nithila. "Optical Fibre Bragg Grating Analysis Through FEA and its Application to Pressure Sensing". Thesis, 2019. https://vuir.vu.edu.au/39484/.
Texto completoUplekar, Amruta Shrikant. "Structural characterization and analysis of the Castle of Arbeteta, Spain". Master's thesis, 2019. http://hdl.handle.net/1822/62322.
Texto completoThe Castle of Arbeteta, Guadalajara (Spain) is strategically located on top of the cliff rocks with a drawbridge as its only entrance. The castle has undergone various changes in over the time of centuries. It was once a two storey structure, of which only the ruins of the external walls exist. The castle is in a continuous state of degradation due to abandonment. Currently, there is an ongoing intervention project where a new use is going to be given to the castle. This will inevitably alter the current state of the existing structure. Preliminary inspection works and a detailed archaeological survey was carried out which specified the phases of construction of different sections of the castle. However, there is still need of a better characterization of the stone masonry walls and their structural behaviour. The main research question of the present thesis deals with the possible influence of the construction evolution of the castle on its structural behaviour. The thesis thus try to link two commonly separated and hermetic fields from the conservation projects: archaeological survey and structural analysis. For that matter, a non-destructive campaign consisting of indirect sonic tests and dynamic identification, which aimed at a thorough characterization of all the structural elements was planned. The campaign was carefully planned according to an archaeological research previously carried out. Secondly, a numerical model was made to analyse the structural behaviour of the castle, based upon photogrammetry model and the same archaeological survey. The experimental data collected through indirect sonic tests and dynamic identification was used to calibrate the model.. The results of the thesis show that indeed taking into account the archaeological findings improved our knowledge on the structural behaviour of the castle and has to be taken into account before carrying out a rigorous structural analysis.
O castelo de Arbeteta, em Guadalajara (Espanha) está estratégicamente situado no topo de um penhasco rocoso que tem uma ponte levadiça como unico acesso. O castelo tem sido submetido a muitos cambios e alterações estruturais durante estes séculos. Num momento da sua história, o castelo era uma estrutura de dois andares, dos que agora só as ruinas das paredes de alvenaria de pedra exteriores ainda existem. O castelo está agora num processo de degradação continuo devido ao seu abandono. No momento, existe um projeto de intervenção no castelo e um novo uso vai ser proposto no castelo. Esto vai alterar inevitavelmente o estado atual da estrutura existente. Inspeções preliminares do castelo e um levantamento arqueologico detalhado foram realizados e ajudaram a identificar as diferentes fases de construção nas diferentes partes do castelo. Contudo, uma melhor caracterização das paredes de alvenaria de pedras é necessária, para ajudar a compreender melhor o seu comportamento estrutural. Esta investigação estuda principalmente a possível influência da evolução estrutural do castelo no seu comportamento estrutural. A tese portanto trata de ligar dois campos necessários nos projetos de conservação que estão normalmente separados e muito compartimentados: o levantamento arqueologico e a análise estrutural. Com este objetivo, uma campaha de ensaios experimentais não destrutivos que incluiu ensaios sónicos indireitos e ensaios de identificação dinâmica foi planejada e destinada a caracterizar em detalhe todos os elementos estruturais do castelo. A campanha foi planejada cuidadosamente de acordo à investigação arqueologica previamente realizada. Numa segunda parte do trabalho, um modelo numerico foi preparado para analisar o comportamento estrutural do castelo, baseado no modelo fotogrametrico e no levantamento arqueologico. Os resultados experimentais recoletados dos ensaios sonicos e dinamicos foram usados para calibrar o modelo numérico. A tese mostra que, de fato, a consideração das descobertas arqueologicas melhoraram o entendimento do comportamento estrutural do castelo e tem de ser tidos em conta antes de realizar um análise estrutural rigoroso.
Allahvirdizadeh, Reza. "Modelling of the seismic behaviour of TRM-strengthened rammed earth walls". Master's thesis, 2017. http://hdl.handle.net/1822/54582.
Texto completoEarthen constructions constitute a considerable part of the existing heritage and a large percentage of the World population is still living or working in buildings built with this structural system. Like other types of masonry structures, rammed earth constructions are acceptably stable under gravity loads, although they are significantly vulnerable to earthquakes. Therefore, a precise understanding of their behavior in case of being subjected to ground motions and the proposing of effective strengthening techniques achieved a great interest both in research and practice. Strengthening methods should be not only to enhance capacity and ductility of the building, but also to satisfy a variety of criteria such as being compatible with the substrate, economical and reversible. Considering all, the low-cost textile reinforced mortar (LC-TRM) strengthening is introduced, and its efficiency on rammed earth walls is studied numerically in the present thesis. In the current study, the seismic performance of both unstrengthened and strengthened rammed earth structural components is investigated. In this regard, in-plane and out-of-plane behaviors are studied by means of different constructed nonlinear finite element models. At first, pushover analysis by massbased lateral load pattern is conducted on unstrengthened walls to evaluate their capacity and understand possible failure mechanisms. Furthermore, the outcomes of these analyses are employed to select the most proper modeling approach from shell or solid elements and the walls with appropriate geometrical dimensions. In the following, pushover analyses are conducted on strengthened walls to choose between different strengthening materials and assess the effectiveness of the adopted strengthening technique. Furthermore, the frequency change of the walls with the damage states (lateral displacement levels) is studied to represent the initiation and propagation of damage in unstrengthened walls and to evaluate the effectiveness of TRM strengthening method. Finally, an artificially generated ground motion record was applied to both unstrengthened and strengthened walls to perform nonlinear time-history analyses. The outcomes were used to compare the dynamic behavior of the walls against the results of the pushover analyses.
As construções de terra constituem uma parte considerável do património construído e uma grande parte da população mundial ainda vive ou trabalha em edifícios construídos com este sistema estrutural. Como outros tipos de estruturas de alvenaria, as construções de terra são estáveis face a cargas gravíticas, embora sejam significativamente vulneráveis a sismos. Portanto, a compreensão do seu comportamento perante a ocorrência de movimentos do solo e a proposta de técnicas efetivas de reforço despertam um grande interesse, tanto a nível da investigação como na prática. Os métodos de reforço devem ser adequados não só para aumentar a capacidade e a ductilidade da construção, mas também para satisfazer uma variedade de critérios, como a compatibilidade com o substrato, custo económico e reversibilidade. Considerando todos estes aspetos, apresenta-se uma técnica baseada em argamassa reforçada com malhas têxteis de baixo custo (LC-TRM), cuja eficiência em paredes de terra é estudada na presente tese do ponto de vista numérico. No presente trabalho, investiga-se o desempenho sísmico de componentes estruturais de taipa não reforçados e reforçados. A este respeito, estudam-se os comportamentos no plano e fora do plano, por meio de diferentes modelos de elementos finitos não lineares. Em primeiro lugar, realiza-se a análise pushover proporcional à massa em paredes não reforçadas para avaliar sua capacidade e compreender possíveis mecanismos de colapso. Adicionalmente, estes resultados são utilizados para selecionar a técnica de modelação mais apropriada (elementos de casca ou sólidos) e as dimensões geométricas mais apropriadas. De seguida, realiza-se a análise pushover em paredes reforçadas para escolher de entre diferentes materiais de reforço e avaliar a eficácia da técnica de reforço adotada. Além disso, a variação das frequências das paredes com os estados de dano (níveis de deslocamento lateral) é estudada para identificar o início e a propagação de dano em paredes não reforçadas e avaliar a estabilidade do método de reforço baseado na técnica TRM. Finalmente, selecionou-se um registro sísmico artificial para realizar análises temporais não lineares de paredes simples e reforçadas. Os resultados são utilizados para comparar o comportamento dinâmico das paredes com os resultados da análise pushover.
This present work was developed within the framework of SAHC Erasmus Mundus Master Course (www.msc-sahc.org) and the project of POCI-01-0145-FEDER-016737 (PTDC/ECM-EST/2777/2014), financed by FEDER funds through the Competitivity Factors Operational Programme - COMPETE and by national funds through FCT – Foundation for Science and Technology. They are both kindly acknowledged.
Azil, chima. "Essai d’élaboration d’une démarche méthodologique de diagnostic sur les coupoles du Souf en Algérie". Doctoral thesis, 2022. http://hdl.handle.net/2158/1256035.
Texto completo(7847843), Rahul Deshmukh. "Influence of geometry and placement configuration on side forces in compression springs". Thesis, 2019.
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