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UPCommons, el portal d'accés obert al coneixement de la UPC, està format pel conjunt de dipòsits institucionals oberts de la UPC i té com a missió garantir la preservació de la producció docent i de recerca cientificotècnica de la Universitat, maximitzant-ne la visibilitat i, conseqüentment, incrementant-ne l’impacte en la docència i la recerca de tot el món.
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Anàlisis de les fases de projectes d'enginyeria i validació de les dades en Minitab

dt., 02/13/2018 - 11:26
Anàlisis de les fases de projectes d'enginyeria i validació de les dades en Minitab López Romeu, Jordi La finalitat del projecte recau en la recol·lecció de grans quantitats d’informació (que son generades setmanalment en Excels) per tal d’analitzar-la i avaluar extreure conclusions del passat present i futur dels Projectes de l’empresa. El Projecte es centra el tractament de una sèrie de dades que son generades setmanalment en una fulla d’Excel, aquestes dades contenen el “timing” amb la duració de les fases i el recursos assignats a aquestes, aquests excels abracen un històric que arriba fins al 2011. Mitjançant el desenvolupament de un codi amb VBA , podrem agafar les dades de cada Excel amb el màxim d’informació possible per projecte, ordenar-la, referenciar-la i envia-la a una base de dades SQL Aquesta informació bolcada a SQL es tractada amb PHP per tal de ordenar i filtrar tota la informació per al de reconstruir la informació i envia-la de nou a SQL Mitjançant una consulta al servidor aquest es comunica amb la BD i aquesta genera un CSV amb la informació que li hem demanat. L’últim Pas es la generació de gràfics amb Minitab per tal de poder visualitzar les dades, com que tenim un volum de projectes molt gran hi haurà una gran quantitat de gràfiques per projecte, hem automatitzat la generació d’aquestes amb la implementació de macros que generessin automàticament les gràfiques desitjades. Aquestes dades son útils per veure com va avançant un projecte i com s’han modificat els temps Aquest Projecte nomes es la primera fase d’un projecte molt mes gran on l’objectiu final es adquirir dades de mes fonts d’informació com ara SAP i poder correlar totes aquestes dades i tenir una visió i un control molt mes acurat del temps i els recursos que es gestionen per cada projecte.
Categories: Novetats

Remodelació d'una cadena de pintura per cataforesi: introducció del decapat químic

dt., 02/13/2018 - 11:23
Remodelació d'una cadena de pintura per cataforesi: introducció del decapat químic Lineros Herrerias, Núria La corrosió és un dels principals problemes de la indústria metal·lúrgica i el tema d’estudi d’aquest treball. Gestamp Metalbages disposa d’una cadena de pintura per cataforesi per pintar les peces que es produeixen i protegir-les de la corrosió. La cataforesi és una tècnica de pintat hidrosoluble per electrodeposició catòdica. El procés està basat en el desplaçament de partícules carregades (pintura) dins d'un camp elèctric, on el càtode és la peça a pintar i l’ànode és un elèctrode auxiliar (Cataforesi ≈ Desplaçament cap al càtode). En el nostre cas, l’efecte més perjudicial de la corrosió és que afecta sobretot als cordons de la soldadura. En els cordons s’adhereixen les restes de silicats procedents del revestiment de l’elèctrode del procés de soldadura, també anomenats calamines, i que no s’aconsegueix eliminar amb el pretractament anterior a la pintura per cataforesis. En aquest pretractament es duran a terme tres etapes essencials: l’etapa de rentat, l’etapa d’afinació i l’etapa de fosfatació. Generalment les calamines protegeixen de la corrosió atmosfèrica sempre i quan no es produeixi una ruptura en aquesta capa, és per això que es vol aplicar el decapat químic per eliminar-les i oferir una qualitat total als clients. La solució proposta és aplicar un procés de decapat químic aprofitant el projecte que s’està estudiant per instal·lar una nova cadena de pintura. El decapat químic remou els òxids superficials i neteja les superfícies per deixar el metall nu d'imperfeccions. Aquest procés químic és un dels més costosos i contaminants en la indústria de l'acer a causa de la presència d'àcids altament corrosius i substàncies com el crom i òxids de nitrogen (NOx). Per estudiar l’eficàcia del tractament del decapat químic s’han realitzat els assajos amb els dos tipus de materials que s’utilitzen a Metalbages: el ferro i el galvanitzat. A més, s’han valorat amb dos tipus de decapat químic diferents, el decapat àcid i el decapat neutre, per tal de decidir quin dels dos ens interessa més utilitzar tenint en compte els resultats obtinguts i les seves característiques. Quant a les anàlisis dels resultats obtinguts, s’ha realitzat l’anàlisi fotogràfic i l’assaig de corrosió. Els resultats obtinguts determinen que el decapat més eficaç ha sigut el decapat àcid ja que ha aconseguit eliminar gairebé més del 70% de les calamines inicials. A part de la quantitat de calamines eliminades, el decapat també ha netejat perfectament el cordó de soldadura i la brutícia i òxids generats en el procés de soldadura, per tant, aquest procés és molt eficaç ja que la peça queda completament neta i amb la superfície preparada per ser pintada i evitar en un futur que la pintura salti degut a la brutícia.
Categories: Novetats

Verb similarity: Comparing corpus and psycholinguistic data

dt., 02/13/2018 - 11:05
Verb similarity: Comparing corpus and psycholinguistic data Gil-Vallejo, Lara; Coll-Florit, Marta; Castellón Masalles, Irene; Turmo Borras, Jorge Similarity, which plays a key role in fields like cognitive science, psycho- linguistics and natural language processing, is a broad and multifaceted concept. In this work we analyse how two approaches that belong to different perspectives, the corpus view and the psycholinguistic view, articulate similarity between verb senses in Spanish. Specifically, we compare the similarity between verb senses based on their argument structure, which is captured through semantic roles, with their similarity defined by word associations. We address the question of whether verb argument structure, which reflects the expression of the events, and word associations, which are related to the speakers’ organization of the mental lexicon, shape similarity between verbs in a congruent manner, a topic which has not been explored previously. While we find significant correlations between verb sense similarities obtained from these two approaches, our findings also highlight some discrepancies between them and the importance of the degree of abstraction of the corpus annotation and psycholinguistic representations.
Categories: Novetats

Solutions to reduce CO2 emissions for autonomous robotics

dt., 02/13/2018 - 10:32
Solutions to reduce CO2 emissions for autonomous robotics Grau Saldes, Antoni; Bolea Monte, Yolanda; Sanfeliu Cortés, Alberto Mobile robots can be used in many different applications, including mapping, search, rescue, reconnaissance, hazard detection, and carpet cleaning, exploration, etc. However, they are limited due to their reliance on traditional energy sources such as electricity and oil which cannot always provide a convenient energy source in all situations. In an ever more eco-conscious world, solar energy offers the most environmentally clean option of all energy sources. Electricity presents threats of pollution resulting from its production process, and oil poses a huge threat to the environment. Not only does it pose harm by the toxic emissions (for instance CO2 emissions), it produces the combustion process necessary to produce energy, but there is the ever present risk of oil spillages and damages to ecosystems. Solar energy can help to mitigate carbon emissions by replacing more carbon intensive sources of heat and power. The challenge of this work is to propose the design and the implementation of electric battery recharge stations. Those recharge docks are based on the use of renewable energy such as solar energy (with photovoltaic panels) with the object to reduce the CO2 emissions. In this paper, a comparative study of the CO2 emission productions (from the use of different energy sources: natural gas, gas oil, fuel and solar panels) in the charging process of the Segway PT batteries is carried out. To make the study with solar energy, a photovoltaic panel, and a Buck-Boost DC/DC block has been used. Specifically, the STP005S-12/Db solar panel has been used to carry out our experiments. This module is a 5Wp-photovoltaic (PV) module, configured with 36 monocrystalline cells serially connected. With those elements, a battery recharge station is made to recharge the robot batteries. For the energy storage DC/DC block, a series of ultracapacitors have been used. Due to the variation of the PV panel with the temperature and irradiation, and the non-integer behavior of the ultracapacitors as well as the non-linearities of the whole system, authors have been used a fractional control method to achieve that solar panels supply the maximum allowed power to recharge the robots in the lesser time. Greenhouse gas emissions for production of electricity vary due to regional differences in source fuel. The impact of an energy technology on the climate can be characterised by its carbon emission intensity, a measure of the amount of CO2, or CO2 equivalent emitted by unit of energy generated. In our work, the coal is the fossil energy more hazardous, providing a 53% more of gas emissions than natural gas and a 30% more than fuel. Moreover, it is remarkable that existing fossil fuel technologies produce high carbon emission intensity through the combustion of carbon-rich fuels, whilst renewable technologies such as solar produce little or no emissions during operation, but may incur emissions during manufacture. The solar energy thus can help to mitigate carbon emissions.
Categories: Novetats

Forjados de bajo costo: análisis de la situación del área metropolitana de Bucaramanga

dt., 02/13/2018 - 09:57
Forjados de bajo costo: análisis de la situación del área metropolitana de Bucaramanga Caballero Moreno, William Gustavo
Categories: Novetats

Gel reaction flow patterns in a non-element reactor with two branch flows

dv., 02/09/2018 - 21:15
Gel reaction flow patterns in a non-element reactor with two branch flows Rodríguez Vallinas, Diego In the framework of chemical and energy engineering fluids have been the subject of many studies for a lot years. In some cases, these fluids upon contact form gels. These gels have many applications like medical, food, cleaning... The peculiarity of these materials that share both properties of solids and liquids are yet to be described. In this study, a qualitative and quantitative analysis of the mass transfer is carried out when in a reactor without internal element 10 mass% PVA (polyvinyl alcohol) and 3 mass% Borax are introduced. The PVA solution was supplied to the main flow pipe at a constant inlet pressure of 20 kPa. The Borax solution was red dyed to visualize in a better way the flow pattern and it is introduced at a constant velocity of 30 mm/s during 16 seconds in a perpendicular direction to the nonelement mixer. It has been previously studied that these compounds upon interaction form a gel. This gel, for its future industrialized production must be divided into independent capsules and for this PVA is introduced again by a new branch to the reactor in order to divide into two parts the formed gel pill. The second injection of PVA was dyed blue and parameters of velocity and chemical composition were varied in order to know which are the boundary conditions for the splitting phenomena. The analysis of the transfer of matter is carried out by a code (also developed in the present work) of Matlab of recognition of intensity of colors in images. The experiments have been recorded. For the quantitative analysis, a pressure sensor has been placed along the reactor which provides data along the reactor.
Categories: Novetats

Marketing innovation: past, present and future

dv., 02/09/2018 - 20:37
Marketing innovation: past, present and future López Granadal, Sheila The aim of this project is to analyze the future of the most relevant emerging technologies until today, relating them to the world of marketing and studying their possible success in the coming years. For this, it has been considered convenient to associate the concepts explained to a time scale where past, present and future are analyzed as follows: Firstly, it starts with the “past”. The most important aspects of marketing and innovation are mentioned separately, for example, by going deeper into what both mean and observing their evolution to this day. Secondly, it continues with the “present”. It is intended to reflect the union of both concepts explaining the most promising technological innovations in the world of marketing, accompanied by creative and poignant examples. Finally, it finishes with the “future”. This third block resembles the creation of a start-up of a product related to the concepts learned through the previous two blocks. In order to do this, an initial idea of the feasibility of the project is drawn up and also a first outline of the “next steps” that should be carried out to launch this innovative product related to marketing innovation
Categories: Novetats

Cost-benefit analysis of a hydrogen supply chain deployment case for fuel cell vehicles use in Midi-Pyrénées region

dv., 02/09/2018 - 20:31
Cost-benefit analysis of a hydrogen supply chain deployment case for fuel cell vehicles use in Midi-Pyrénées region Martínez García, Guillem Nowadays, hydrogen is increasingly being promoted as an alternative energy carrier for mobility and stationary fuel cell system applications. Yet, the challenge of developing a future commercial hydrogen economy still remains through the deployment of a viable hydrogen supply chain (HSC) and an increasing fuel cell vehicle market share, which allow to narrow the existing cost difference regarding the conventional fossil fuel vehicle market. In this work, the hydrogen fuel cell vehicle (FCV) market penetration from 2020 to 2050, as a substitute for internal combustion engine vehicles (ICEVs) in the French region of Midi-Pyrénées, is evaluated from a social and governmental perspective. To do so, two cost-benefit analyses (CBAs), each one regarding each point of view, have been conducted to determine whether the hydrogen mobility deployment increases enough the social welfare to compensate its costs and, therefore, should be implemented. The results found are sustained by a HSC deployment, performed previously through an optimization process, that adapts to the region and to the hydrogen needs estimated. These results show that in 2050 the costs are not fully compensated. Nevertheless, the fact of incorporating the externalities helps to finance an important proportion of these costs from 2020 to 2050, even being able to fully compensate them before 2070.
Categories: Novetats

Integrating logistics and production

dv., 02/09/2018 - 20:09
Integrating logistics and production Rabasa Martínez, Víctor The purpose of this research project is to help a supply chain manager to decision making easier in order to deliver final product on time to final customer. Coordination between all members of a supply chain are essential to achieve this objective and reduce bullwhip effect. The members considered on this thesis are going to be a manufacture, its supplier and supplier of that supplier (sub-supplier). A common purchase forecast is done thanks to Collaborative Planning Forecasting and Replenishment (CPFR) using an order point policy. A dashboard is elaborated with Key Performance Indicators (KPI) and graphics that shows the status of the supply chain. Then a simulation of a real case test how robust is the supply chain using normal random variables and evaluate how good and reliable are each of the members of the supply chain. At the end of the project there is a little experiment where a supply chain is checked with two different scenarios in which stability of demand are different. The results of that projects show an easy to use dashboard which evaluate a supply chain and its members and gives numerical and graphic information to the manager.
Categories: Novetats

Influencia térmica y lumínica del uso de barandillas de vidrio en las terrazas de edificios residenciales: caso de un edificio en San Cugat del Valles

dv., 02/09/2018 - 19:15
Influencia térmica y lumínica del uso de barandillas de vidrio en las terrazas de edificios residenciales: caso de un edificio en San Cugat del Valles Sorto Díaz, Estela Lourdes Màster universitari en Estudis Avançats en Arquitectura: Innovació tecnològica a l’arquitectura
Categories: Novetats

Prospectiva de materiales amorfos para la ejecución de pavimentos continuos: posibilidades de la robótica aplicada

dv., 02/09/2018 - 18:52
Prospectiva de materiales amorfos para la ejecución de pavimentos continuos: posibilidades de la robótica aplicada Marrero Aquino, Margarita Màster universitari en Estudis Avançats en Arquitectura: Innovació tecnològica a l’arquitectura
Categories: Novetats

A European Garden City on the Mediterranean Sand: Tel Aviv & Haifa preliminary urban expansions as two case studies of costal Mediterranean metropolitan developments in Israel

dv., 02/09/2018 - 17:15
A European Garden City on the Mediterranean Sand: Tel Aviv & Haifa preliminary urban expansions as two case studies of costal Mediterranean metropolitan developments in Israel Arbel Chemla, Dori Màster universitari en Estudis Avançats en Arquitectura: Urbanisme
Categories: Novetats

Sistemas de ayuda a la decisión en Ingeniería Civil: posibilidades y perspectivas

dv., 02/09/2018 - 17:11
Sistemas de ayuda a la decisión en Ingeniería Civil: posibilidades y perspectivas Oñate Ibáñez de Navarra, Eugenio; Marcipar, Javier; Piazzese, Javier Ignacio La eclosión de las Tecnologías de la Información y las Comunicaciones (TIC), y en particular de Internet, ha facilitado el desarrollo de sistemas que, apoyados por bases de datos y potentes programas de simulación, transforman la información que existe en relación con un problema concreto, en conocimiento que permite tomar decisiones para su solución. Los denominados Sistemas de Ayuda a la Decisión (SAD) son ya una realidad en múltiples áreas de la ingeniería. En este trabajo se analizan las posibilidades y perspectivas de los SAD en ingeniería civil y se presentan tres ejemplos concretos de su aplicación a la prevención del riesgo de inundaciones y a la gestión de las emergencias correspondientes, al diseño de instalaciones en proyectos urbanísticos y a la gestión energética en municipios.
Categories: Novetats

Fault diagnosis

dv., 02/09/2018 - 15:59
Fault diagnosis Escobet Canal, Teresa; Sarrate Estruch, Ramon; Comasòlivas Font, Ramon This book presents a set of approaches for the real-time monitoring and control of drinking-water networks based on advanced information and communication technologies. It shows the reader how to achieve significant improvements in efficiency in terms of water use, energy consumption, water loss minimization, and water quality guarantees. The methods and approaches presented are illustrated and have been applied using real-life pilot demonstrations based on the drinking-water network in Barcelona, Spain. The proposed approaches and tools cover: - decision-making support for real-time optimal control of water transport networks, explaining how stochastic model predictive control algorithms that take explicit account of uncertainties associated with energy prices and real demand allow the main flow andpressure actuators—pumping stations and pressure regulation valves—and intermediate storage tanks to be operated to meet demand using the most sustainable types of source and with minimum electricity costs; - decision-making support for monitoring water balance and distribution network quality in real time, implementing fault detection anddiagnosis techniques and using information from hundreds of flow,pressure, and water-quality sensors together with hydraulic and quality-parameter-evolution models to detect and locate leaks in the network, possible breaches in water quality, and failures in sensors and/or actuators; - consumer-demand prediction, based on smart metering techniques, producing detailed analyses and forecasts of consumption patterns,providing a customer communications service, and suggesting economic measures intended to promote more efficient use of water at the household level. Researchers and engineers working with drinking-water networks will find this a vital support in overcoming the problems associated with increased population, environmental sensitivities and regulation, aging infrastructures, energy requirements, and limited water sources.
Categories: Novetats

Wissen fabrik. Una carta per a Zürich

dv., 02/09/2018 - 15:46
Wissen fabrik. Una carta per a Zürich Badia Rafart, Roger Al 1998 Marcel Meili escrivia “Perifèria. Una carta para Zurich”. Una crida a arquitectes i dissenyadors per donar significat als talls i ruptures que la infraestructura dels setanta i els llargs murs de les àrees industrials havien deixat a la ciutat. Recordant els pensaments de Robert Walser, en aquest context de vies ràpides però fragments separats, la intersecció entre un tall d'escala infraestructural i la possibilitat d'una linealitat d'escala humana evidenciaria la necessitat de intervenció. Sent conscients que les infraestructures van sempre lligades a la condició de marginalitat, la única manera d'evitar la barrera psicològica seria ocupant-ne els intersticis: domesticar la superestructura i donar-li un ús específic. En un terrain vague entre viaductes, es planteja un edifici per donar visibilitat als projectes de gran escala proposats per universitats, grups d'investigació o individuals. El nivell superior de la fàbrica, pensat per al públic general, permetria la observació i debat al voltant dels treballs exposats i en desenvolupament com si d'un museu es tractés. D'aquesta manera es genera una economia que es basa en el procés i no en el producte i el fet de que la transformació en coneixement, a través del museu, representi el motor per seguir produint. Una economia immaterial basada en la producció de coneixement; un escenari “Yes to All” on l'inesperat hi pot tenir cabuda. Qualificació obtinguda: 9 M.H.
Categories: Novetats

Marangoni stress induced by free-surface for pressure reduction in reverse osmosis

dv., 02/09/2018 - 14:42
Marangoni stress induced by free-surface for pressure reduction in reverse osmosis Arias Montenegro, Francisco Javier Marangoni hydrodynamic motion and its potential technological application in reverse osmosis (RO) process for seawater desalination is discussed. The fundamental core idea in this note is the possibility to take advantage of the inherent concentration gradient in a RO process. It is well known that to run a RO process, it is necessary to apply a hydrodynamic pressure to overcome the osmotic pressure, however, by inducing a free-surface, e.g., a Leidenfrost surface, on the membrane wall, an additional hydrodynamic Marangoni stress could be generated, which, likewise than the osmotic pressure is driven by the concentration gradient but acting in the opposite direction, i.e., reducing the external hydraulic pressure to be applied. Utilizing a simplified geometrical and physical model, an analytical expression for the pressure reduction was derived. One important preliminary result in this work, is that the Marangoni stress can provide pressure against the osmotic pressure for membrane porous that are less than micrometric size. © 2018. This version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/
Categories: Novetats

Discussion about the use of Bayesian networks models for making predictive maintenance decisions

dv., 02/09/2018 - 14:22
Discussion about the use of Bayesian networks models for making predictive maintenance decisions Bortolini, Rafaela; Forcada Matheu, Núria The performance of a building decreases with time and this process is accelerated if proper maintenance is not carried out. This paper presents a discussion about the importance of predictive maintenance actions to enhance the condition of existing buildings. An approach based on Bayesian networks (BN) is proposed to predict the condition of a building. The proposed approach consists of a conceptual and generic model, including the factors with more influence in the condition of a building, which were identified by a literature review. The relationships between these factors and a discussion about the application of this model in maintenance decision-making are provided.
Categories: Novetats

Performance characterization of mid-infrared difference-frequency-generation in orientation-patterned gallium phosphide

dv., 02/09/2018 - 12:14
Performance characterization of mid-infrared difference-frequency-generation in orientation-patterned gallium phosphide WEI, JUNXIONG; kumar, S. Chaitanya; Ye, Hanyu; Schunemann, P. G.; Ebrahim-Zadeh, M. We present a detailed characterization of the optical properties of the recently developed nonlinear material, orientation-patterned gallium phosphide (OP-GaP), by performing difference-frequency-generation experiments in the 2548-2782 nm wavelength range in the mid-infrared (mid-IR). Temperature and spectral acceptance bandwidth measurements have been performed to study the phase-matching characteristics of OP-GaP, and the dependence of nonlinear gain on the polarization of input incident fields has been investigated. The transmission of the OP-GaP crystal at the pump and signal wavelengths has been studied and found to be dependent on polarization as well as temperature. Further, we have observed a polarization-dependent spatial shift in the transmitted pump beam through the OP-GaP sample. We have also measured the damage threshold of the OP-GaP crystal to be 0.84 J/cm2 at 1064 nm.
Categories: Novetats

Disseny geomètric de dovel·les de formigó per a TBM i la seva possible influència als acabats del túnel

dv., 02/09/2018 - 11:44
Disseny geomètric de dovel·les de formigó per a TBM i la seva possible influència als acabats del túnel Casanova Bertomeu, Marc Elements clau dins la infraestructura de qualsevol país, els túnels juguen un paper fonamental per al desenvolupament i creixement de la societat. Aquests, la major part situats fora de la vista, són els encarregats d’impulsar i permetre el funcionament d’un gran nombre de sectors claus en la economia d’un territori. Persones, materials, béns i altres serveis de transport han estat els factors causants d’un augment important al llarg dels darrers anys de la construcció de túnels. Diferents han estat els mètodes constructius utilitzats al llarg de tota la història, tot i així, avui en dia el mètode més utilitzat es la construcció mitjançant una màquina tuneladora. TBM (de l’anglès Tunnel Boring Machine) és el nom que reben aquest tipus de màquines, les quals són les encarregades de realitzar la perforació del terreny a secció completa i al mateix temps permeten la instal·lació del revestiment estructural final a mesura que es va avançant. Aquest està format per dovelles, segments de formigó armat que units formen anells que seqüencialment van modelant el túnel. Tot i la utilització actual d’aquest mètode constructiu, gran part dels projectes es basen en l’anàlisi dels resultats obtinguts de construccions prèvies d’aquest tipus. Per tant, la utilització de dovelles a l’hora de construir un túnel està fortament influenciada per experiències anteriors. D’altra banda, la gran varietat d’ambients constructius que es troben en cadascun dels projectes com també la necessitat de disminuir els costos de fabricació de les dovelles, fa que aquest element estructural prengui protagonisme. Com a conseqüència, és imprescindible conèixer i entendre aquest component tecnològic clau en el procés de fabricació. Tenint en compte la demanda en entendre en major mesura els paràmetres que influeixen en la utilització d’aquest mètode, el present treball pretén aportar nova recerca sobre el tema. La fonamentació d’aquest ha estat la recopilació, extracció, anàlisis i gestió d’un elevat volum d’informació obtinguda a partir de 15 projectes constructius diferents, ja realitzats, amb l’objectiu d’obtenir patrons o correlacions. S’ha analitzat la possible influència que pot tenir el disseny geomètric d’aquestes dovelles amb l’acabat final del túnel. Amb aquesta idea en ment, també s’ha intentat extreure paràmetres provinents dels materials i quantitats dels mateixos per tal de trobar possibles relacions. El punt de partida ha estat caracteritzar cada projecte individualment i posteriorment comparar-ho i/o correlacionar-lo amb els altres amb la finalitat d’obtenir indicis o camins a seguir en el disseny d’aquest element estructural. A la part final del treball s’han redactat una sèrie de conclusions relatives als resultats obtinguts com també unes futures línies d’investigació.; Tunnels are key elements in the infrastructure of any country, playing a fundamental role in terms of development and growth of its society. These, mostly located out of sight, are responsible for promoting and allowing the operations of a huge number of sectors with a direct impact on the country’s economy. People, materials, goods and transport services were responsible for the significant increase in tunnel construction in recent years. Different construction methods have been used throughout tunnel history; however, today’s most widely used method is a TBM or Tunnel Boring Machine. Such machines are responsible to perform the drilling ground whole section and at the same time to allow the installation of the final structural lining. The tunnel is build by precast concrete segments that together form a ring, sequentially shaping the tunnel. Despite the current use of this construction method, projects are largely based on the analysis of the results of previous tunnel constructions. Therefore, the segments used when constructing a tunnel are strongly influenced by past experiences. Moreover, the variety of building environments that are in each of the projects as well as the need to reduce manufacturing costs of the segments makes this structural component a key element. As a result, to master this technology is a must in the manufacturing process. Taking into account the increasing demand in understanding the parameters that influence the use of this method, this paper aims to provide new research on the subject. The foundation for this has been the collection, extractions, analysis and management of a high volume of information gathered from 15 different construction projects. The projects already undertaken have been used with the aim of obtaining patterns or correlations. It has been analysed the possible influence the geometric design of these segments may have with the finishing stage of the tunnel. Whit that in mind, the study has also tried to extract parameters from the materials and quantities used to find potential relationships. The starting point has been to characterize each project individually and then compare and/or correlate it with others in order to obtain evidence or paths to follow when it comes to the design of this structural element. At the end of the research a number of conclusions have been highlighted and future research possibilities have been suggested.
Categories: Novetats

Numerical simulation strategies for superadobe walls and arches

dv., 02/09/2018 - 11:37
Numerical simulation strategies for superadobe walls and arches Rodríguez Jimeno, Sara The superadobe is a construction technique that consists on building using bags filled with soil and adding barbwire between the courses. It is a simple, durable, sustainable, and affordable technique that has increased in popularity over the last years. Moreover, a remarkable effort was performed in the past years in order to analyse the structural behaviour and characterize the mechanical properties of these constructions. However, since it is a relatively recent technique, no previous studies of complete structures have been performed using numerical strategies and there is still a lack of knowledge regarding its structural response. Consequently, the present thesis attempts to analyse these type of structures using the finite element method, assessing its suitability and applicability to the superadobe. For this purpose, several models of both walls and arches are studied, subjected to different load dispositions and considering three construction types, plain, adding barbwire and stabilizing the infill. Initially two possible constitutive models are considered, Mohr Coulomb and Total strain crack based, and they are evaluated and compared in order to select the most suitable for all the cases studied. Afterwards, all the analyses are performed and calibrated to match the results obtained from the experimental campaigns developed in the University of Bath by Pelly (2009), Vagdama (2010) and Croft (2011). Finally, a sensitivity analysis is also carried out to examine the influence of certain parameters, which had to be adjusted during the analyses, into the structural response of the models.; El superadobe es una solución constructiva que consiste en la utilización de bolsas rellenas de tierra apisonadas a las que se les añade alambre de espino entre ellas para aportar cohesión y Resistencia a tracción al conjunto. Es una técnica simple, duradera, sostenible y asequible cuya popularidad ha ido creciendo durante los últimos años. Además, recientemente se ha realizado un notable esfuerzo con el fin de analizar el comportamiento estructural y determinar las propiedades mecánicas del superadobe. No obstante, al tratarse de una técnica relativamente nueva, no se han desarrollado aún estudios de estructuras completas utilizando estrategias numéricas, y existe todavía una carencia de información en lo que respecta a la respuesta estructural de estas construcciones. Por consiguiente, la presente tesis tiene como objetivo el análisis de estas estructuras utilizando el método de los elementos finitos, evaluando su compatibilidad y aplicabilidad al superadobe. Con este fin, se estudian varios modelos, tanto de muros como de arcos, sujetos a diferentes disposiciones de carga y considerando tres tipos de construcción, simple, añadiendo alambre de espino y estabilizando el relleno de las bolsas. Inicialmente se consideran dos posibles modelos constitutivos, Mohr Coulomb y Total strain crack based, se evalúan y comparan a fin de seleccionar el que más se adecúa a todos los casos estudiados. Posteriormente, se llevarán a cabo y calibrarán todos los análisis para hacer coincidir los resultados con los obtenidos en las campañas experimentales desarrolladas en la Universidad de Bath por Pelly (2009), Vagdama (2010) y Croft (2011). Finalmente, también se realizará un estudio de sensibilidad para examinar la influencia de ciertos parámetros, que han debido ser ajustados durante los análisis, en la respuesta estructural de los modelos.
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