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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Design methodology for wing trailing edge device mechanisms

Martins Pires, Rui Miguel 04 1900 (has links)
Over the last few decades the design of high lift devices has become a very important part of the total aircraft design process. Reviews of the design process are performed on a regular basis, with the intent to improve and optimize the design process. This thesis describes a new and innovative methodology for the design and evaluation of mechanisms for Trailing Edge High-Lift devices. The initial research reviewed existing High-Lift device design methodologies and current flap systems used on existing commercial transport aircraft. This revealed the need for a design methodology that could improve the design process of High-Lift devices, moving away from the conventional "trial and error" design approach, and cover a wider range of design attributes. This new methodology includes the use of the innovative design tool called SYNAMEC. This is a state-of-the-art engineering design tool for the synthesis and optimizations of aeronautical mechanisms. The new multidisciplinary design methodology also looks into issues not usually associated with the initial stages of the design process, such as Maintainability, Reliability, Weight and Cost. The availability of the SYNAMEC design tool and its ability to perform Synthesis and Optimization of mechanisms led to it being used as an important module in the development of the new design methodology. The SYNAMEC tool allows designers to assess more mechanisms in a given time than the traditional design methodologies. A validation of the new methodology was performed and showed that creditable results were achieved. A case study was performed on the ATRA - Advance Transport Regional Aircraft, a Cranfield University design project, to apply the design methodology and select from within a group of viable solutions the most suitable type of mechanism for the Variable Camber Wing concept initially defined for the aircraft. The results show that the most appropriate mechanism type for the ATRA Variable Camber Wing is the Link /Track Mechanism. It also demonstrated how a wide range of design attributes can now be considered at a much earlier stage of the design.
22

Design methodology for wing trailing edge device mechanisms

Martins Pires, Rui Miguel January 2007 (has links)
Over the last few decades the design of high lift devices has become a very important part of the total aircraft design process. Reviews of the design process are performed on a regular basis, with the intent to improve and optimize the design process. This thesis describes a new and innovative methodology for the design and evaluation of mechanisms for Trailing Edge High-Lift devices. The initial research reviewed existing High-Lift device design methodologies and current flap systems used on existing commercial transport aircraft. This revealed the need for a design methodology that could improve the design process of High-Lift devices, moving away from the conventional "trial and error" design approach, and cover a wider range of design attributes. This new methodology includes the use of the innovative design tool called SYNAMEC. This is a state-of-the-art engineering design tool for the synthesis and optimizations of aeronautical mechanisms. The new multidisciplinary design methodology also looks into issues not usually associated with the initial stages of the design process, such as Maintainability, Reliability, Weight and Cost. The availability of the SYNAMEC design tool and its ability to perform Synthesis and Optimization of mechanisms led to it being used as an important module in the development of the new design methodology. The SYNAMEC tool allows designers to assess more mechanisms in a given time than the traditional design methodologies. A validation of the new methodology was performed and showed that creditable results were achieved. A case study was performed on the ATRA - Advance Transport Regional Aircraft, a Cranfield University design project, to apply the design methodology and select from within a group of viable solutions the most suitable type of mechanism for the Variable Camber Wing concept initially defined for the aircraft. The results show that the most appropriate mechanism type for the ATRA Variable Camber Wing is the Link /Track Mechanism. It also demonstrated how a wide range of design attributes can now be considered at a much earlier stage of the design.
23

Controle da variação do arqueamento de um aerofólio utilizando atuadores de memória de forma /

Faria, Cássio Thomé de. January 2010 (has links)
Resumo: O projeto de aeronaves convencionais, em geral, apresentam uma série de dificuldades de se realizar de maneira eficiente um amplo número de missões, uma vez que para atender esses requisitos estas aeronaves deveriam ser capazes de realizar grandes alterações em sua geometria. Surge então um novo conceito de projeto de aeronaves, as chamadas aeronaves adaptativas, as quais são capazes de alterar sua geometria, de modo a adaptar a aeronave a um dado tipo de missão. Este novo conceito se tornou ainda mais atrativo com os avanços tecnológicos promovidos pelo estudo de novos materiais, os chamados materiais inteligentes, que apresentam alta densidade de energia, vantagem que leva a uma redução de peso nos mecanismos atuados desta maneira. Este trabalho apresenta um novo modelo adaptativa, utilizando fios atuadores de ligas de memória de forma para realizar uma rotação relativa entre duas seções de um aerofólio, este mecanismo possibilitaria a variação da linha de arqueamento de uma seção aeronáutica. Neste trabalho uma modelagem matemática para se descrever o comportamento deste sistema é apresentada, bem como um modelo aerodinâmico para se verificar o comportamento do sistema em funcionamento. Um controlador do tipo nebuloso é ainda projetado para se controlar a forma do perfil, e ensaios experimentais são conduzidos para se verificar a modelagem termo-mecânica apresentada. / Abstract: Conventional airplane design, in general, has a large difficulty to attend in an efficient way several mission requirements, once that to attend these requirements the airplane has to perform great shape changes in its structure. Motivated by this problem a new concept in airplane design arise, one called morphing airplanes, which are air vehicles capable of changing its shape to adapt it self to a defined mission. This new concept became even more attractive with the development of active smart material, which can be a high power density actuator, reducing the weight of such morphing mechanism. This work proposes a novel model for morphing wings, using a pair of shape memory alloy wires to create a rotation between two wing sections, this mechanism allows the airfoil to change its camber line. A mathematical model is derived to describe the thermo-mechanical structure behavior, and also an aerodynamic model is investigated. A fuzzy controller is designed to control the system shape, and some experimental tests are used to verify the thermo-mechanical modeling proposed. / Orientador: Vicente Lopes Junior / Coorientador: Carlos de Marqui Junior / Banca: Gustavo Luiz Chagas Manhães de Abreu / Banca: Álvaro Martins Abdalla / Mestre
24

Konstrukční návrh zavěšení předních kol závodního automobilu / Design of Racing Car Front Suspension

Kroliczek, Václav January 2017 (has links)
This work deals with design of front trapezoidal suspension for racing car Škoda 130RS. The first part describes types of current suspensions and provides a review of important suspension parameters that have great influence to vehicle handling. The second part deals with kinematic analysis existing suspension, its modification and design of new type.
25

Aeroelasticidade transônica de aerofólio com arqueamento variável / Transonic aeroelasticity of variable camber airfoil

Silva, Ticiano Monte Lucio da 17 June 2010 (has links)
Os recentes desenvolvimentos na tecnologia de sistema aeronáutico de geometria variável têm sido motivados principalmente pela necessidade de melhorar o desempenho de aeronaves. O conceito de Morphing Aircraft, por meio da variação da linha de arqueamento, representa uma alternativa para sistemas aeronáuticos mais eficientes. No entanto, para aeronaves de alto desempenho, projetos com estes novos conceitos podem gerar reações aeroelásticas adversas, o que representa uma questão importante e pode vir a limitar esses novos projetos. A compreensão adequada do comportamento aeroelástico devido à variação da linha de arqueamento, particularmente em regimes transônico, compreende uma questão importante. Este trabalho consiste num estudo preliminar das consequências aeroelásticas de um sistema aeronáutico de geometria variável. O objetivo desse trabalho é explorar as repostas aeroelásticas transônicas de um aerofólio com arqueamento variável no tempo. A metodologia para análise aeroelástica é baseada num modelo de seção típica. A integração no tempo do sistema aeroelástico é obtida pelo método de Runge-Kutta de quarta ordem. A representação do escoamento transônico não estacionário foi computada por um código CFD em um contexto de malhas não estruturadas com uma formulação dada pelas equações de Euler-2D. Esses resultados preliminares podem fornecer aos projetistas informações importantes sobre as respostas aeroelásticas de um sistema aeronáutico com variação da linha de arqueamento, permitindo estabelecer um quadro adequado para futuras investigações de controle aeroelástico de sistema aeronáutico de geometria variável. / Recent developments on aircraft variable geometry technologies have been mainly motivated by the need for improving the flight performance. The morphing wing concept, by means of variable camber, represents an alternative towards more efficient lifting surfaces. However, for higher performance aircraft, this technology may lead to designs that create unsteady loads, which may result in adverse aeroelastic responses, which represents an important and limiting issue. Proper understanding of the aeroelastic behavior, particularly in transonic flight regimes, due to variations in camber comprises an important matter. This work is a primary study of aeroelastic consequences of an real-time adaptive aircraft. The objective of this work is to investigate prescribed variations to airfoil camberline and their influence to the aeroelastic response in transonic flight regime. The methodology is based on computational simulations of typical section with unsteady transonic aerodynamics solved with a Computational Fluid Dynamics (CFD) code. The time integration of the aeroelastic system is obtained by Runge-Kutta fourth order. The unsteady transonic flow was computed by a CFD code based on the 2D-Euler equations with unstructured mesh. Prescribed camber variation of a symmetrical airfoil is transferred to the CFD mesh, and aeroelastic responses and loading is assessed. These preliminary results may provide the designers valuable information on the interaction between changes in camber during airfoil aeroelastic reactions, allowing establishing an adequate framework for further aeroelastic control investigations of morphing wings.
26

Development of an aeroelastic methodology for surface morphing rotors

Cook, James Richard 22 May 2014 (has links)
A Computational Fluid Dynamics/Computational Fluid Dynamics (CFD/CSD) coupling interface was developed to obtain aeroelastic solutions of a morphing rotor. The methodology was implemented in Fully Unstructured Navier-Stokes (FUN3D) solver, which communicates aerodynamic forces on the blade surface to University of Michigan’s Nonlinear Active Beam Solver (UM/NLABS) and then imports structural deflections of the blade surface during each time step. Development of this methodology adds the capability to model elastic rotors with flexible airfoils. The method was validated through an aerodynamic work analysis, comparison of sectional blade loads and deflections with experimental data, and two-dimensional stability analyses for pitch/plunge flutter and camber flutter. Computational simulations were performed for a rotor in forward flight with the CFD/CSD solver and with a comprehensive CSD solver using finite-state (F-S) aerodynamics, and results were compared. Prescribed three-per-revolution camber deflections were then applied, and solutions of the CFD/CSD and comprehensive CSD computations indicated that three-per-revolution camber actuation has the potential to minimize hub forces and moments with deflections as small as 0.25%c. In anticipation of active rotor experiments inside enclosed facilities, the capability of CFD for accurately simulating flow inside enclosed volumes was examined. It was determined that URANS models are not suitable for rotor simulations in an enclosed facility, and components that are a distance of two to three rotor radii from the hub were also observed to have a large influence on recirculation and performance.
27

Processens påverkan på rakhet hos bandstål : Från inkommande råmaterial till färdigt halvfabrikat

Hämquist, Susanna January 2018 (has links)
Examensarbetet har utförts under våren 2017 vid Bergsskolan i Filipstad, i samarbete med voestalpine Precision Strip i Munkfors. Att producera så kostnadseffektivt som möjligt likväl att minimera material som kasseras är något företag idag ser som självklart. På samma gång som detta efterlevs bör även kundnöjdheten maximeras. Utrymmet att göra fel har minskat vilket leder till en ständig strävan att undvika att produkter med oönskade defekter går ut till kund. För att nå detta måste företaget ha en förståelse för vilka mekanismer som påverkar vilka defekter. Syftet med det här arbetet är att dokumentera bandstålets processteg, från råmaterial till halvfabrikat. På så vis kan arbetets mål uppnås, det vill säga att hitta vilka möjliga orsaker som kan påverka bandstålets rakhet, specifikt den så kallade kortkrokigheten. Det finns två typer av rakhet, långkrok och kortkrok. Den som ställer till med problem vid beläggning och slipning av bandstål är den så kallade kortkroken. Därmed är det detta som voestalpine Precision Strip önskat hjälp med att kartlägga. Materialet som studerats var tre olika band av samma stålsort (UHB 20C), dessa var alla tänkta att gå vidare till beläggningen. För att bandet ska kunna beläggas måste materialet vara helt rakt, toleransen är +/- 33 µm, vilket många gånger innebär att bandet ser rakt ut trots en rakhetsavvikelse. Finns en avvikelse går det inte att färdigställa produkten utifrån kundspecifikation och materialet används då till annan slutprodukt, eller i värsta fall skrotas. För att kartlägga vilka mekanismer som bandstålet utsattes för användes den teoretiska ansatsen ”de sju förbättringsverktygen”, en teori utvecklad i Japan som är användbar då kvalitetsförbättringar efterfrågas. Arbetet börjades med litteraturstudier, det var svårt att hitta studier och annan litteratur som behandlar ämnet kortkrok i allmänhet och kortkrok i kallvalsat bandstål i synnerhet. Förutom litteratur erhölls en del information av personal på voestalpine Precision Strip i Munkfors. Det gjordes inga intervjuer utan enbart samtal med personal på plats i Munkfors. Dessa samtal ledde till ökad förståelse för vad problemet innebär och ett orsak-verkan-diagram gjordes. Fem möjliga orsaker till kortkrok vid kallvalsning av stål identifierades. Utifrån detta ritades ett flödesschema över hela processen upp. De fem möjliga orsakerna som studerades närmre var ·        tvärprofil ·        reduktionen i tre olika valsverk ·        kontaktlängd och valsmaterial i valsverken ·        rullsaxen som kantskär och slittar materialet ·        den mänskliga faktorn. Utifrån detta arbete kunde flera alternativa svar på problemet till varför kortkrok uppstår identifieras. Det kan vara stickserien i valsverk 311, bomberingen som var sliten/icke-sliten i valsverk 322, kontaktlängden i valsverk 345, materialet i arbetsvalsen i valsverk 311 eller rullsaxen. Ett antal orsaker som kan påverka att kortkrok uppkommer är överhuvudtaget inte är studerade. Till exempel värmebehandling, friktion och smörjmedel. I arbetet framkom en orsak som mest trolig till varför kortkroken uppstår, rullsaxen. Att rullsaxen påverkat kortkrokens uppkomst kan bero på den mänskliga faktorn likväl som att det kan bero på att den är felkonstruerad för just detta ändamål. I dagsläget saknas exakta rutiner för hur arbetsprocessen vid rullsaxen utförs, vilket inneburit att de som arbetar vid maskinen gör samma sak men på olika vis. Slutresultatet kan ha påverkats av vilken person som arbetat vid valsen. Det finns en möjlighet att voestalpine Precision Strip kan vinna på att ha detaljerade inställningsscheman så det är möjligt att utesluta att slutresultatet påverkas av vem som arbetar vid maskinen. / This thesis has been carried out during the spring of 2017 at Bergsskolan in Filipstad, in cooperation with voestalpine Precision Strip in Munkfors. The demands to produce as cost-effectively as possible is increasing as well as demands to minimize the amount of discarded materials and at the same time maximize customer satisfaction. To achieve this, the company must have an understanding for the mechanisms that influence the defects. The purpose of the thesis is to document the production steps of the strip steel process, from raw materials to processed steel. Doing that the goal can be achieved, i.e. to find the parameters that influence the strip steel's straightness, specifically the so-called camber. There are two types of straightness which causes problems and the important one in this thesis is the so-called camber. The material studied was three different strips of the same steel (UHB20C) which were all supposed to move on to the department CCB (Coated Coater Blades). But to proceed, the material must be perfectly straight. The tolerance is as small as +/-33 microns, which often means that the strip looks straight even when there is a straightness deviation. If so, the material may be used in a different application and occasionally it will be scrapped. To identify the mechanisms the strip steel was exposed to, the theoretical approach “the seven QC-tools", was used. This is a theory usable when quality improvements are demanded. The work begun with literature studies, however, it was very difficult to find studies and other literature that discussed camber in cold-rolled strip steel. In addition to literature some information was obtained through conversations with the staff in Munkfors. This led to better understanding about the problem. Afterwards it was time to draw a chart over the causes effecting the camber. Five parameters were identified as important and was chosen for closer looking. The parameters studied more closely were: ·        transverse profile ·        reductions done in the three different rolling mills ·        contact length and materials in the work roll ·        slitter scorer (the machine that slits the material) ·        human influence Then a flow chart of the entire process was drawn up. There are several alternative answers to the problem this paper is trying to solve. The answer could be among the parameters studied but it may as well be found among causes not studied. For example friction, lubricants or the heat treatment the material is exposed to. Due to all measurements done in this study there is one parameter most likely to be the cause of camber, the slitter scorer seems to influence the material straightness most of all. Though it is not cleared why the slitter scorer affects the camber more than the other production steps. It could be caused by human influence, it is a machine where very small mistakes, probably unconscious, can lead to big consequences. It may also be due to malfunction of the machine. Rolling is a craft which means that the person working at the rolling mill, and the other machines in the production process, has a big influence on final outcome. Voestalpine Precision Strip could probably gain a lot by having detailed setting schedules and measuring instruments that would help the staff doing the exact same thing every time. Hopefully the outcome would not fluctuate as much as it does in the current situation. / <p>Presentationen har redan ägt rum, i juni 2017 på Bergsskolan i Filipstad</p>
28

Controle da variação do arqueamento de um aerofólio utilizando atuadores de memória de forma

Faria, Cássio Thomé de [UNESP] 27 July 2010 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:27:13Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-07-27Bitstream added on 2014-06-13T19:55:32Z : No. of bitstreams: 1 faria_ct_me_ilha.pdf: 2001879 bytes, checksum: 8c06397bc7d8057b53383eaa08ea1d01 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O projeto de aeronaves convencionais, em geral, apresentam uma série de dificuldades de se realizar de maneira eficiente um amplo número de missões, uma vez que para atender esses requisitos estas aeronaves deveriam ser capazes de realizar grandes alterações em sua geometria. Surge então um novo conceito de projeto de aeronaves, as chamadas aeronaves adaptativas, as quais são capazes de alterar sua geometria, de modo a adaptar a aeronave a um dado tipo de missão. Este novo conceito se tornou ainda mais atrativo com os avanços tecnológicos promovidos pelo estudo de novos materiais, os chamados materiais inteligentes, que apresentam alta densidade de energia, vantagem que leva a uma redução de peso nos mecanismos atuados desta maneira. Este trabalho apresenta um novo modelo adaptativa, utilizando fios atuadores de ligas de memória de forma para realizar uma rotação relativa entre duas seções de um aerofólio, este mecanismo possibilitaria a variação da linha de arqueamento de uma seção aeronáutica. Neste trabalho uma modelagem matemática para se descrever o comportamento deste sistema é apresentada, bem como um modelo aerodinâmico para se verificar o comportamento do sistema em funcionamento. Um controlador do tipo nebuloso é ainda projetado para se controlar a forma do perfil, e ensaios experimentais são conduzidos para se verificar a modelagem termo-mecânica apresentada. / Conventional airplane design, in general, has a large difficulty to attend in an efficient way several mission requirements, once that to attend these requirements the airplane has to perform great shape changes in its structure. Motivated by this problem a new concept in airplane design arise, one called morphing airplanes, which are air vehicles capable of changing its shape to adapt it self to a defined mission. This new concept became even more attractive with the development of active smart material, which can be a high power density actuator, reducing the weight of such morphing mechanism. This work proposes a novel model for morphing wings, using a pair of shape memory alloy wires to create a rotation between two wing sections, this mechanism allows the airfoil to change its camber line. A mathematical model is derived to describe the thermo-mechanical structure behavior, and also an aerodynamic model is investigated. A fuzzy controller is designed to control the system shape, and some experimental tests are used to verify the thermo-mechanical modeling proposed.
29

Aeroelasticidade transônica de aerofólio com arqueamento variável / Transonic aeroelasticity of variable camber airfoil

Ticiano Monte Lucio da Silva 17 June 2010 (has links)
Os recentes desenvolvimentos na tecnologia de sistema aeronáutico de geometria variável têm sido motivados principalmente pela necessidade de melhorar o desempenho de aeronaves. O conceito de Morphing Aircraft, por meio da variação da linha de arqueamento, representa uma alternativa para sistemas aeronáuticos mais eficientes. No entanto, para aeronaves de alto desempenho, projetos com estes novos conceitos podem gerar reações aeroelásticas adversas, o que representa uma questão importante e pode vir a limitar esses novos projetos. A compreensão adequada do comportamento aeroelástico devido à variação da linha de arqueamento, particularmente em regimes transônico, compreende uma questão importante. Este trabalho consiste num estudo preliminar das consequências aeroelásticas de um sistema aeronáutico de geometria variável. O objetivo desse trabalho é explorar as repostas aeroelásticas transônicas de um aerofólio com arqueamento variável no tempo. A metodologia para análise aeroelástica é baseada num modelo de seção típica. A integração no tempo do sistema aeroelástico é obtida pelo método de Runge-Kutta de quarta ordem. A representação do escoamento transônico não estacionário foi computada por um código CFD em um contexto de malhas não estruturadas com uma formulação dada pelas equações de Euler-2D. Esses resultados preliminares podem fornecer aos projetistas informações importantes sobre as respostas aeroelásticas de um sistema aeronáutico com variação da linha de arqueamento, permitindo estabelecer um quadro adequado para futuras investigações de controle aeroelástico de sistema aeronáutico de geometria variável. / Recent developments on aircraft variable geometry technologies have been mainly motivated by the need for improving the flight performance. The morphing wing concept, by means of variable camber, represents an alternative towards more efficient lifting surfaces. However, for higher performance aircraft, this technology may lead to designs that create unsteady loads, which may result in adverse aeroelastic responses, which represents an important and limiting issue. Proper understanding of the aeroelastic behavior, particularly in transonic flight regimes, due to variations in camber comprises an important matter. This work is a primary study of aeroelastic consequences of an real-time adaptive aircraft. The objective of this work is to investigate prescribed variations to airfoil camberline and their influence to the aeroelastic response in transonic flight regime. The methodology is based on computational simulations of typical section with unsteady transonic aerodynamics solved with a Computational Fluid Dynamics (CFD) code. The time integration of the aeroelastic system is obtained by Runge-Kutta fourth order. The unsteady transonic flow was computed by a CFD code based on the 2D-Euler equations with unstructured mesh. Prescribed camber variation of a symmetrical airfoil is transferred to the CFD mesh, and aeroelastic responses and loading is assessed. These preliminary results may provide the designers valuable information on the interaction between changes in camber during airfoil aeroelastic reactions, allowing establishing an adequate framework for further aeroelastic control investigations of morphing wings.
30

Návrh souboru zařízení pro seřízení podvozku závodního automobilu / Design of alignment and chassis setup equipment

Vajdák, Martin January 2017 (has links)
Diplomová práce se zabývá návrhem zařízení pro měření parametrů podvozku závodního vozidla (sbíhavost/rozbíhavost, příklon/odklon, světlá výška vozu, rozložení hmotnosti), které následně slouží pro jeho seřízení. Úvodní teoretická část uvádí přehled nejdůležitějších parametrů podvozku, které mají podstatný vliv na chování a ovladatelnost vozu a které jsou tak nejčastěji předmětem zájmu. Následující kapitola shrnuje metody a zařízení, které se dnes pro měření parametrů podvozku využívají a uvádí jejich výhody a nevýhody. Předposlední kapitola teoretické části je věnována obecným doporučením pro měření parametrů podvozku vozidla a jeho seřizování. Poslední kapitola teoretické části uvádí požadavky na zařízení, jehož návrh je předmětem této práce. Úvod praktické části práce je věnován popisu konstrukce dvou navržených variant pro měření parametrů podvozku vozidla. Následující kapitola pak popisuje přípravu a průběh měření s využitím navržených souborů zařízení. Další kapitola je věnována výběru snímačů a zařízení pro měření. Závěr této kapitoly pak shrnuje přibližné celkové náklady na výrobu obou navržených variant. Poslední kapitolou je napěťová a deformační analýza navržené podpěry automobilu, která podepírá automobil namísto jeho kol. Závěr diplomové práce shrnuje dosažené cíle a zároveň uvádí návrhy a doporučení dalšího vývoje navržených zařízení.

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