• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 46
  • 8
  • 7
  • 5
  • 4
  • 2
  • 2
  • Tagged with
  • 97
  • 97
  • 24
  • 24
  • 22
  • 16
  • 14
  • 14
  • 14
  • 12
  • 10
  • 10
  • 10
  • 10
  • 10
  • 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.
81

Human-centred automation : with application to the fighter aircraft domain

Helldin, Tove January 2012 (has links)
The working situation of fighter pilots is often very challenging. The pilots are requested to perform their tasks and make decisions in situations characterised by time-pressure, huge amounts of data and high workload, knowing that wrong decisions might result in fatal consequences. To aid the pilots, several automatic support systems have been implemented in modern fighter aircraft and will continue to be implemented in pace with technological advancements and new demands posed on the pilots. For example, innovations within the information fusion (IF) domain have made it possible to fuse large amounts of data, stemming from different sensors, databases etc., to create a better foundation for making decisions and act than would have been possible if the information sources had been used separately. However, there are both positive and negative effects of automation, such as decreased workload and improved situation awareness on the one hand, but skill degradation and complacent behaviour on the other. To avoid the possible negative consequences of automation, while at the same time ameliorating the positive ones, a human-centred automation (HCA) approach to system design has been proposed as a way of optimizing the collaboration between the human and the machine. As a design approach, HCA stresses the importance of a cooperative human-machine relationship, where the operator is kept in the automation loop. However, how to introduce HCA within the fighter aircraft domain as well as its implications for the interface and automation design of support systems within the field has not been investigated. This thesis investigates the implications of introducing HCA into the fighter aircraft domain. Through literature surveys and empirical investigations, general and domain specific HCA guidelines have been identified. These advocate, for example, that an indication of the reliability of the information and the recommendations provided by the different aircraft support systems must be given as well as that support for appropriate updates of the pilots’ individual and team awareness of the situation must be provided. A demonstrator, mirroring some of the identified guidelines, has been implemented and used to evaluate the guidelines together with system developers within the domain. The evaluation indicated that system developers of modern fighter aircraft implicitly incorporate many of the identified HCA guidelines when designing. However, the evaluation further revealed that to explicitly incorporate these guidelines into the development approach, preferably through the development of a domain specific style guide, would aid the system developers design automated support systems that provide appropriate support for the pilots. The results presented in this thesis are expected to aid developers of modern fighter aircraft support systems by incorporating HCA into the traditional simulator-based design (SBD) approach. This approach is frequently used within the field and stresses early and frequent user-involvement when designing, in which complementary HCA evaluations could be performed to further improve the support systems implemented from an automation perspective. Furthermore, it is expected that the results presented in this thesis will contribute to the research regarding how to incorporate the human operator in the information fusion processes, which has been recognised as a research gap within the IF field. Thus, a further contribution of this thesis is the suggestion of how the HCA development approach could be of aid when improving the interaction between the operator and the automated fusion system. / Arbetssituationen för stridspiloter är ofta mycket utmanande. Piloterna måste utföra sina uppgifter och fatta beslut i stressiga situationer med stora informationsmängder och hög arbetsbörda, samtidigt som val av fel beslut kan leda till allvarliga konsekvenser. För att hjälpa piloterna har flera automatiska stödsystem implementerats i moderna stridsflygplan. Denna trend kommer att fortsätta i takt med nya tekniska framgångar och nya krav som ställs på piloterna. Forskning inom informationsfusion (IF) har bland annat gjort det möjligt att fusionera stora mängder data som härstammar från olika sensorer, databaser m.m. för att på så sätt skapa en bättre grund för att fatta beslut och agera än vad som hade varit möjligt om informationskällorna hade använts separat. Dock har både positiva och negativa effekter av automatisering rapporterats, såsom minskad arbetsbörda och förbättrad situationsuppfattning men även försämrad pilotprestation till följd av att de automatiska systemens prestanda inte övervakas. För att undvika negativa effekter av automation samtidigt som de positiva effekterna stärks har den så kallade människo centrerade automationen (HCA) lyfts fram som en möjlig väg att designa system där samverkan mellan automationen och den mänskliga operatören optimeras. Som en designapproach fokuserar HCA på viken av en samverkande människamaskin relation, där operatören hålls kvar i automatiseringsloopen. Men hur HCA kan introduceras inom stridsflygdomänen och dess implikationer för gränssnitts- och automationsdesign av stödsystem inom domänen har inte undersökts. Denna licentiatavhandling undersöker möjliga implikationer av att introducera HCA inom stridsflygdomänen. Genom litteraturundersökningar och empiriska studier har generalla och domänspecifika HCA riktlinjer identifierats, såsom att piloterna måste erbjudas en indikation angående tillförlitligheten hos den information och de rekommendationer som de olika implementerade stödsystemen i flygplanet har genererat, samt att stöd för att uppdatera piloternas individuella och gemensamma uppfattning av situationen måste ges. En demonstrator, som återspeglar några av de identifierade HCA riktlinjerna, har implementerats och använts för att utvärdera riktlinjerna tillsammans med systemutvecklare inom domänen. Denna utvärdering påvisade att systemutvecklare inom stridsflygdomänen implicit använder sig av många av de identifierade HCA riktlinjerna under designprocessen, men att explicit inkludera dessa i en domänspecifik design guide skulle kunna hjälpa dem att designa automatiska system som erbjuder lämpligt stöd för piloterna. De resultat som presenteras i denna licentiatavhandling förväntas kunna hjälpa utvecklare av moderna stridsflygsystem genom att inkludera HCA i den traditionella simulator-baserade designapproachen (SBD). Denna approach används flitigt inom området och fokuserar på tidigt och återkommande användardeltagande vid designarbetet, där komplementära HCA utvärderingar skulle kunna genomföras för att förbättra de stödsystem som implementeras från ett automationsperspektiv. Det förväntas även att de resultat som presenteras i denna avhandling kommer att bidra till forskningen kring hur operatörer kan påverka fusionsprocessen, vilket har identifierats som ett område där mer forskning behövs inom IF området. Ytterligare ett bidrag av denna avhandling är därför det förslag som ges på hur HCA utvecklingsprocessen skulle kunna användas för att förbättra interaktionen mellan operatören och det automatiska fusionssystemet.
82

Experimental and Analytical Methodologies for Predicting Peak Loads on Building Envelopes and Roofing Systems

Asghari Mooneghi, Maryam 09 December 2014 (has links)
The performance of building envelopes and roofing systems significantly depends on accurate knowledge of wind loads and the response of envelope components under realistic wind conditions. Wind tunnel testing is a well-established practice to determine wind loads on structures. For small structures much larger model scales are needed than for large structures, to maintain modeling accuracy and minimize Reynolds number effects. In these circumstances the ability to obtain a large enough turbulence integral scale is usually compromised by the limited dimensions of the wind tunnel meaning that it is not possible to simulate the low frequency end of the turbulence spectrum. Such flows are called flows with Partial Turbulence Simulation. In this dissertation, the test procedure and scaling requirements for tests in partial turbulence simulation are discussed. A theoretical method is proposed for including the effects of low-frequency turbulences in the post-test analysis. In this theory the turbulence spectrum is divided into two distinct statistical processes, one at high frequencies which can be simulated in the wind tunnel, and one at low frequencies which can be treated in a quasi-steady manner. The joint probability of load resulting from the two processes is derived from which full-scale equivalent peak pressure coefficients can be obtained. The efficacy of the method is proved by comparing predicted data derived from tests on large-scale models of the Silsoe Cube and Texas-Tech University buildings in Wall of Wind facility at Florida International University with the available full-scale data. For multi-layer building envelopes such as rain-screen walls, roof pavers, and vented energy efficient walls not only peak wind loads but also their spatial gradients are important. Wind permeable roof claddings like roof pavers are not well dealt with in many existing building codes and standards. Large-scale experiments were carried out to investigate the wind loading on concrete pavers including wind blow-off tests and pressure measurements. Simplified guidelines were developed for design of loose-laid roof pavers against wind uplift. The guidelines are formatted so that use can be made of the existing information in codes and standards such as ASCE 7-10 on pressure coefficients on components and cladding.
83

Visualisierung von Service-Frontends in einem Werkzeug zur präsentationsorientierten Komposition annotierter Dienste

Dannecker, Lars 16 November 2009 (has links)
Das Ziel des ServFace Projektes ist es Endnutzern ohne umfangreiche IT-Kenntnisse das einfache Erstellen von servicebasierten Anwendungen zu ermöglichen. Dazu wird ein Kompositions- werkzeug mit dem Namen “ServFace Builder“ verwendet. Das Werkzeug erlaubt es Endnutzern, interaktive Anwendungen durch die Komposition von Service-Operationen zu erstellen. Dafür ist eine grafische Repräsentation der Service-Operationen durch UI-Fragmente notwendig. Die UI-Fragmente werden im ServFace-Umfeld als Frontends bezeichnet. In der vorliegenden Arbeit wird ein Konzept zur automatischen Visualisierung dieser Frontends vorgestellt. Um das Ergebnis der Visualisierung zu verbessern, nutzt der Visualisierungsprozess neben der Service-Beschreibung weitere Informationen in Form von Annotationen und Gestaltungsempfehlungen. Konkret werden die folgenden Aspekte in dieser Arbeit beschrieben: • Visualisierung von Frontends zur Repräsentation von Service-Operationen auf Basis von Service-Beschreibungen, Annotationen, Plattformspezifikationen und Gestaltungsempfehlungen unter der Maßgabe der Gebrauchstauglichkeit und Nutzbarkeit. • Integration der Frontends in die jeweils aktuelle Instanzen des gegebenen Anwendungsmodells. • Technische Umsetzung und Evaluation der entwickelten Konzepte / The aim of the ServFace Project is to enable users with limited IT skills to easily create service-based applications. In order to do so, a tool called "ServFace Builder" has been developed. This tool allows users to build a composite application by combining several service operations. An important part of the ServFace Builder is the graphical representation of those service operations through user interfaces. This thesis describes an approach to automatically generate user interfaces for service operations. To enhance the graphical representation, the user interface generation process of the ServFace Builder comprises annotations and design recommendations next to the common service descriptions to enhance the result of the generation process. This thesis discusses: • Graphical representation of service operations on the basis of service descriptions, annotations, plattform specifications and design recommendations. • Integration of the graphical representation into the actual instance of the given application model. • Implementation and evaluation of the presented concepts.
84

Isolerad och ledsen, hur mHealth kan designas för psykisk ohälsa relaterad till isolering : Hur design kan ge fler möjligheter att få hjälp / Isolated and sad, how an mHealth application can be designed to help with mental health related issues during isolation : How design can offer more possibilities to get help

Bratt, Ellen, Broman, Elvira January 2021 (has links)
Syftet med uppsatsen var att undersöka hur man med hjälp av digital design kan stödja den psykiska hälsan hos individer i USA under Covid-19 pandemin. Covid-19 är den första pandemin som utspelar sig i ett utvecklat digitalt samhälle där både mHealth/telehealth-design är välstuderat. Studien undersöker specifikt hur designelement för en mHealth-applikation kanen mHealth-applikation kan stödja en stor grupp användare under en global pandemi. Uppsatsen undersöker hur design kan öka användandet av mHealth för att söka hjälp mot psykisk ohälsa, som uppstått på grund av isolering till följd av den amerikanska statens riktlinjer under Covid-19 pandemin. Med hjälp av tidigare forskning gällande designriktlinjer för mHealth-applikationer, inkluderande design och element att tänka på när man designar applikationer för psykisk ohälsa, framtogs en prototyp av en mHealth-applikation. Denna prototyp testades därefter av sex respondenter som alla lider av depression till följd av isolering. Efter think aloud-observation under testandet av prototypen genomfördes en kvalitativ intervju för att undersöka respondenternas upplevelse av applikationen. Resultatet av studien påpekar vikten av användarens integritet, inkluderande design och element som efterfrågats i tidigare studier av mHealth-applikationer. Dessa resultat stödjer också de åtaganden tidigare forskninglagt fram och i sin tur visar denna studie att en mobilapplikation kan designas föratt stödja människor med deras psykiska ohälsa i relation till Covid-19 isoleringen. / The goal of this thesis was to investigate how the use of digital design could help people with their mental health during the covid-19 pandemic. Covid-19 is the first and only pandemic where both mHealth and telehealth design has been well developed. Our thesis explores how design elements can increase the will of users to use mHealth applications, especially for users whose mental health has been impacted by covid-19 restrictions in the United States. Based on the scientific articles regarding mHealth design, a prototype was made. This includes inclusive design and design elements focused on people with mental health struggles. The prototype was tested by six users who all reported feeling down because of isolation during covid-19. During the study, users were asked to test the prototype and ‘think aloud’, followed by a qualitative interview to better understand the user’s experience, feelings, and thoughts on the prototype. The results show the importance of a patient's integrity, the importance of inclusive design, and the appreciation of certain design elements. The results are in line with results from previous research and offer evidence on how to design a mHealth application to support people with their mental health during a pandemic.
85

Environmental Design Research and the Design of Urban Open Space: A Study of Current Practice in Landscape Architecture

Masters, Jennifer 01 January 2012 (has links) (PDF)
A large and growing body of research exists on how the design of the environment can positively or negatively affect people’s health and well-being, as well as influence their behavior. Researchers in this field, known as “environmental design research,” have long acknowledged the challenge of translating their findings into formats that are accepted and used by practitioners. This study explores how environmental design research on urban open space and the practice-oriented translations of it are used by landscape architects who have been recognized in the profession for their designs of parks, plazas, and streets in urban areas. Through interviews with practitioners, an understanding emerges of the impact of environmental design research on contemporary practice, leading to recommendations that could enhance it in the future. Key findings of the study indicate that translations of the research, specifically in the form of design guidelines, while intended to inform practice, are not widely used by designers. Rather, to understand how design impacts human behavior, practitioners rely primarily on what they refer to as intuition, largely informed by their own direct observations of people in public space. The quality of their personal observations, therefore, is critical to their depth of understanding of human behavior and the environment. The study concludes with recommendations that could improve the skills of design students and practitioners to conduct, interpret, and apply their own direct observations in their designs, using methods and findings from the field of environmental design research to inform and enrich this process.
86

Translucent concrete in product design : Implementation of a new segment of design products through Strategic branding / Translucent betong i produktdesign : Implementering av ett nytt segment av designprodukter genom strategiskt varumärkesbyggande

CASSEL, JULIA, ÖSTEVIK, AGNES January 2018 (has links)
The company Butong is based on a patented process of casting concrete between two layers of bubble wrap, resulting in panels of translucent concrete. This material is mainly applied as panels in vertical gardens and light installations. Today, the business is based on projects that require custom made designs. Alongside these projects, products with a standardised manufacturing process are desired to extend the company towards the consumer market and fill the workflow gaps existing in their current production. Through strategic branding, this project aimed to create a new business segment of standardised design products and the framework needed for Butong to enter the consumer market. From analysing the company and its values, understanding the possibilities and limitations of the material and from investigating the opportunities on the market, the brand position for the segment was determined. A strategy to establish the business on the targeted market was developed, including a brand identity and design guidelines for the new segment. To exemplify the usage of the guidelines, several concepts were produced, of which one was further developed to be the flagship product of the segment. The segment was directed to target both Butong’s current market and the consumer market in order to facilitate its establishment and to reach a larger public. It is developed to consist of products that clearly display the properties of the material and are aligned to the identity of the brand. Following the set guidelines, the developed concepts confirm its value and potential by communicating coherency and the expressions desired. With a standardised manufacturing process, the production can be engaged at any time to make use of the existing workflow gaps and complement Butong’s existing business without obstructing it. / Företaget Butong bygger sin verksamhet på sin patenterade tillverkningsmetod av att gjuta betong mellan två lager av bubbelplast, vilken resulterar i paneler av translucent betong. Detta material används framförallt till att skapa vertikala trädgårdar och effektfulla ljusinstallationer. Idag är verksamheten projektbaserad vilket kräver skräddarsydda lösningar. Ett sortiment bestående av produkter med en standardiserad tillverkningsprocess skulle kunna komplettera den befintliga produktionen genom att fylla de luckor som uppstår i det projektbaserade arbetet. Ett sådant sortiment ses även som en möjlighet för att utöka den nuvarande verksamheten mot en konsumentmarknad. Genom strategiskt varumärkesbyggande var målet med detta projekt att skapa ett nytt affärssegment bestående av standardiserade produkter och det strategiska ramverk som krävs för att kunna etablera Butong på konsumentmarknaden. Av att analysera företaget och dess värderingar, förstå materialets möjligheter och begränsningar samt undersöka marknaden, kunde positioneringen av segmentet bestämmas. En strategi skapades för att etablera segmentet på den tänkta marknaden tillsammans med en varumärkesidentitet och riktlinjer för produktutvecklingen inom segmentet. För att exemplifiera användandet av dessa riktlinjer skapades flera koncept, varav ett vidareutvecklades som en första produkt att representera varumärket med. För att underlätta etableringen av segmentet och utöka verksamheten, valdes både Butongs nuvarande marknad och konsumentmarknaden som målgrupp. Produkterna inom segmentet har ett formspråk som både demonstrerar materialets egenskaper och följer företagets nuvarande identitet. Värdet och potentialen i de framtagna riktlinjerna bekräftas av de uttryck och det genomgående formspråk som de skapade koncepten kommunicerar. Med en standardiserad produktion, kan tillverkningen av produkterna tas vid när som helst och ta till vara på luckorna i arbetsflödet och på så sätt komplettera Butongs nuvarande verksamhet utan att påverka den.
87

Low-impact user interfaces: How can we create a climate-smart approach toward front-end mobile application design? : Evaluation and proposed improvement of existing guidelines – Focused on Online Food Delivery sector.

Sundqvist, Isabella, Zurawska, Kinga Joanna January 2023 (has links)
The use of the Internet and digital services has increased significantly during recent years, and as Human-Computer Interaction (HCI) field keeps on expanding, it is influencing aspects of our daily lives, though not always for the better. Researchers and practitioners, including a small number of designers, are addressing the growing concerns about the Internet’s environmental impact, such as electronic waste, increased energy use, resource depletion, and carbon footprint, which have emerged in recent years, and are calling for a more environment-friendly approach to web and app design. However, it is still a relatively new area of concern. This study evaluates existing guidelines for designing low-impact user interfaces in the mobile food delivery sector. First, the study investigates users’ food delivery habits and their impressions of low-impact interfaces. The findings from this section are then used to design a low-impact food delivery application (FDA) prototype and are tested with users to see how to make low-impact interfaces attractive for a possible change in user behaviors. This thesis builds on previous research about sustainable web design, but the focus area of this study is to investigate whether applied guidelines and low-impact design features are desired by users on mobile screens as well. The research reveals that low-impact features are indeed useful on smaller screens as well and users are generally open-minded and acceptive of front-end changes that have a more positive impact on the environment. However, it is crucial to communicate clearly about any low-impact modifications made to an application, due to the current low level of user awareness and knowledge in this field.
88

TOWARDS A DESIGN FRAMEWORK FOR EVALUATING BOOKING SYSTEMS : A Comprehensive Examination

Gulliksson, Emmy January 2023 (has links)
This master’s thesis investigates the usability challenges in current booking systems and proposes a new design framework to address these challenges. The research encompasses an in-depth analysis of the usability issues associated with booking systems used to create the design guidelines for the framework. The framework is evaluated using a heuristic evaluation approach for evaluation. 25 individual booking systems were individually assessed by a single evaluator, with a focus on finding usability issues using the framework. The heuristic evaluation process took approximately 30 minutes to an hour per system evaluation, following the heuristic evaluation methodology. Identified issues and corresponding recommendations were compiled in a diagram, while the comprehensive testing document is included in the appendix of this paper. The heuristic evaluation revealed a total of 438 identified issues across the 25 booking systems, with the identified issues per system ranging from 3 to 9. The average number of issues identified using the new framework stood at 6.08.  The research answers the first research question: ”What are the key usability challenges in current booking systems?” by conducting an extensive literature review and creating a comprehensive list of 13 distinct usability challenges in booking systems. The amount of identified challenges demonstrates the necessity for a dedicated framework. The challenges encompass a wide spectrum, spanning from user adoption of the interface to practical aspects like booking cancellation and customer service.  Addressing the second research question, which describes the utilization of the new design framework to tackle usability challenges, the study employs the heuristic evaluation results to determine the efficacy of the framework. An average of 6.08 identified usability issues per system validates the framework’s usefulness for evaluators of booking systems. The discussion also underscores the potential for increased effectiveness with the recommended three to five evaluators.  Despite certain limitations, including the lack of detailed evaluation results due to confidentiality agreements, and the inability to complete booking procedures due to resource constraints, the framework’s effectiveness is established. The framework proves to be a valuable addition to existing design guidelines, serving as a comprehensive tool for evaluating booking systems. In conclusion, this master’s thesis completely addresses the research questions, underscoring the need for dedicated design guidelines for booking systems and demonstrating the effectiveness of the proposed framework in enhancing usability. The study also identifies areas for future work and recommends enhancements for a more holistic evaluation of booking systems. / Denna masteruppsats undersöker användbarhetsutmaningarna i nuvarande bokningssystem och föreslår ett nytt designramverk för att bemöta dessa utmaningar. Forskningen omfattar en djupgående analys av nuvarande användbarhetsutmaningar hos bokningssystem vilka sedan används för att skapa designriktlinjer för ett nytt designramverk. Det nya designramverket för bokningssystem utvärderas sedan med hjälp av en heuristisk utvärderingsmetod. 25 individuella bokningssystem utvärderades individuellt av en utvärderare, med fokus på att hitta användbarhetsproblem med hjälp av ramverket. Den heuristiska utvärderingsprocessen tog cirka 30 minuter till en timme per systemutvärdering, utförda enligt den heuristiska utvärderingsmetoden. Identifierade problem och motsvarande rekommendationer sammanställdes i ett diagram, medan det omfattande testdokumentet finns med i bilagan till detta dokument. Den heuristiska utvärderingen resulterade i totalt 438 identifierade problem hos de 25 bokningssystemen, där identifierade problem per system varierade från 3 till 9. Det genomsnittliga antalet identifierade problem med hjäp av det nya ramverket var 6,08.  Den första forskningsfrågan: ”Vilka är de viktigaste användbarhetsutmaningarna i nuvarande bokningssystem?” besvarades genom en omfattande litteraturundersökning som resulterade i en lista innehållande 13 distinkta användarvänlighetsutmaningar hos bokningssystem. Mängden identifierade utmaningar visade på noödvändigheten av ett dedikerat ramverk för bokningssystem. Utmaningarna täcker ett brett spektrum, från att användaren använder gränssnittet till praktiska aspekter som avbokning och kundservice.  För att besvara den andra forskningsfrågan, som handlar om det nya designramverkets möjlighet att tackla användbarhetsutmaningar, användes en heuristisk utvärdering vars resultat fastställde ramverkets effektivitet. Det resulterade i genomsnitt av 6,08 identifierade användbarhetsproblem per system, vilket validerar ramverkets användbarhet för utvärderare av bokningssystem. Diskussionen understryker också potentialen för ökad effektivitet med de rekommenderade tre till fem utvärderarna istället för en.  Trots vissa begränsningar, såsom bristen på detaljerade utvärderingsresultat på grund av sekretessavtal och oförmågan att slutföra bokningsprocedurer på grund av resursbegränsningar, har ramverkets effektivitet fastställts. Ramverket visade sig vara en värdefull ersättning till befintliga designriktlinjer och fungerar som ett omfattande verktyg för att utvärdera bokningssystem. Sammanfattningsvis adresserar denna masteruppsats forskningsfrågorna och understryker behovet av dedikerade designriktlinjer för bokningssystem samt visar effektiviteten hos det föreslagna ramverket för att förbättra användbarheten. Studien identifierar också områden för framtida arbete och rekommenderar förbättringar för en mer holistisk utvärdering av bokningssystem.
89

Experimental and Analytical Collapse Evaluation of an Existing Building

Akah, Ebiji Anthony 15 October 2015 (has links)
No description available.
90

Multidisziplinäre Formoptimierung modularer Grundgeometrien für Druckgussbauteile mit strömungs- und strukturmechanischen Zielfunktionen / Multidisciplinary shape optimization of modular basic geometries for high pressure die castings with fluid dynamic and structural mechanic objective functions

Maurer, Simon Alexander 18 February 2016 (has links) (PDF)
Am Anfang des Entwicklungsprozesses eines Gussbauteils für die Automobilbranche steht klassischerweise die konstruktive Ausarbeitung und die Auslegung auf Zielgrößen, wie Festigkeit, Steifigkeit bzw. die Erfüllung der Crashlasten. Im nächsten Entwicklungsschritt wird, oftmals in Zusammenarbeit mit externen Lieferanten, das Werkzeugkonzept entwickelt und die Herstellbarkeit mit Hilfe von Gießsimulationen abgesichert. Bei der Fertigung verursachen streuende Prozessgrößen, wie etwa Geschwindigkeits- oder Temperaturniveaus, Schwankungen in der Leistungsfähigkeit des Endprodukts (z. B. lokale Bruchdehnung oder Zugfestigkeit). Maßnahmen zur Erhöhung der Prozessstabilität und zur Reduktion des Verschleißes konzentrieren sich oftmals auf die erfahrungsbasierte Verbesserung des Fertigungsprozesses und Anpassungen des Anguss- und Überlaufsystems. Größere Änderungen der Bauteilgeometrie sind häufig aus zeitlichen Gründen nicht mehr möglich. Das Ziel dieser Arbeit ist es daher, optimierte modularisierte Grundgeometrien, wie Rippen oder Umlenkungen, mit Hilfe von numerischen Formoptimierungen zu entwickeln, um diese schon von Anfang an in der Bauteilentwicklung zu berücksichtigen. Als Zielfunktionen dienen strömungs- und strukturmechanische Kenngrößen, um einerseits verschleißfördernde Mechanismen und füllungsbedingte Defekte zu reduzieren und andererseits die Beanspruchbarkeit zu erhöhen. Bei den Untersuchungen wird zusätzlich die Robustheit des Ergebnisses analysiert, um Verbesserungspotenziale auch bei streuenden Randbedingungen realisieren zu können. / The virtual development process of an automotive casting part usually begins with classical design tasks and analyses of material strength, stiffness and crash load cases. In the next step, often in cooperation with external suppliers, the tooling concept is developed and casting simulations are used to ensure manufacturability. During manufacturing there is a scatter in process parameters, such as flow velocity or temperature levels, which in turn cause a scatter in the performance of the final product (e.g. local elongation at fracture or ultimate tensile strength). Means to increase process stability and yield are often limited to knowledge-based improvements of the manufacturing process parameters and adaptations of the gating and overflow system. Major changes to the part geometry are usually no longer possible due to project time constraints. Therefore it is the goal of this thesis to optimize modularized basic geometries, like ribs or bends, by using numerical shape optimizations and employ them right from the beginning of the part development process. For the objective functions of the optimizations the disciplines of fluid dynamic filling and the resulting structural behaviour are considered. In addition, the resulting shape is analyzed with regards to robustness towards scatter in manufacturing operating conditions. By using these new modularized geometries the overall robustness of the final product is expected to be increased.

Page generated in 0.0943 seconds