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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.
61

An integrated approach to environmentally conscious design and manufacturing

Goan, Meng-Jong Kuan 03 October 2007 (has links)
The problem addressed in this research was to develop an approach for the simultaneous green design of products and associated manufacturing processes including demanufacturing concerns. We propose a generic approach called Integrated Environmentally Conscious Design and Manufacturing (IECDM) which can be applied to address problems in the ECDM domain. IECDM incorporates environmental considerations into the engineering design process, thereby increasing a product's total life-cycle value (including its end-of-life value) as experienced by the customer, manufacturer, and society, while simultaneously reducing impacts on the environment caused by that product and its manufacturing processes. IECDM is a novel integration of Quality Function Deployment (QFD), Life-Cycle Assessment (LCA), Multiple Criteria Decision-Making (MCDM), and Cost-Benefit Assessment (CBA). The focus is on process, based on modification of the traditional QFD methodology to incorporate environmental issues and green product-design decisions through the life cycle design activities of synthesis, analysis, and evaluation. This dissertation presents a QFD-based IECDM approach, a mathematical CBA model, and an IDDS (Integrated Design Decision-Support) framework with a design-flow-chart application for incorporating environmental criteria into product and process eco-design. The IECDM problem is defined as: given the customer and environmental requirements, develop an integrated approach for green product design that results in maximization of the product's total life-cycle value (TLCV). Initially. through investigation in the field of ECDM, we specified a clear ECDM domain within Industrial Ecology. Then. we proposed various state-of-the-art techniques that were used to implement ECDM in the literature. After we defined the IECDM problem. we developed an integrated approach that led to a generic QFD-IECDM methodology for dealing with problems in the ECDM domain. Finally, for implementing the proposed methodology, we developed a tentative IODS framework to encourage long-term development followed by an example. / Ph. D.
62

Development of a suspension system for a forklift cabin : A design project at Kalmar innovation centre

Schäring, Isabelle, Forssell, Johan January 2024 (has links)
A suspension system is to be made to increase driver comfort and ergonomics. This kind of system is widely used in a variety of vehicles, such as tractors and trucks, but is not yet standard for forklifts. The purpose of the case study is to design a fully mechanical, passive suspension system that can be retrofitted to a particular forklift without any cabin or chassis modification. The main focus will be on the linkages used to limit unwanted movement of the cabin. A concept utilizing 2 sets of parallel linkages is chosen to continue develop with the application of design for environment and design for manufacturing. This manages to reduce the total number of component sneeded for the system down to 33 from 43 in the first draft of the concept. The design needs to be dimensioned and further tested before a prototype is built. If the system then is implemented, it will have lasting effects on the forklift industry and the ergonomics of operators.
63

Contribución metodológica en técnicas de diseñar para fabricación

Ferrer Real, Inés 23 April 2007 (has links)
En el proceso de diseño se toman decisiones que pueden afectar a la fabricabilidad del producto. Cuando el diseñador es experto, considera las limitaciones, las propiedades y el coste de fabricación en la fase de materialización o de detalle. El problema surge cuando el diseñador no es experto o cuando no hay suficiente información y conocimiento de fabricación disponible. Tomando como referencia la teoría de Diseño Axiomático y las técnicas de DFM, se propone una metodología para identificar, definir y formalizar la información de fabricación que debería estar disponible en el diseño para diseñar para fabricar (DFM). También se propone un prototipo de modelo de información para desarrollar una futura herramienta informática que facilitaría la aplicación de esta metodología y que permitiría guiar al diseñador durante el diseño. La metodología ha sido aplicada a una biela de un motor de combustión interna alternativo (MCIA), y a los procesos que se están usando actualmente para fabricarla: forja en matriz cerrada y forja de polvo de metal. / Experience and knowledge of the designer are key elements during the design process. In the embodiment and detailed design phases is when the expert designers take into account the manufacturing process constraints, capabilities and costs. A problem arises when the designer is inexpert or when not enough manufacturing information and knowledge is available. This work presents a methodology, based on the Axiomatic Design Theory and on DFM techniques, to determine the explicit manufacturing process knowledge that the designer should have to design for manufacturing. This methodology has been the basis to develop the model information approach. This model is the first step to develop software to assist in the methodology application and to guide the designer during the design process. The methodology has been applied to a particular component (connecting rod). The manufacturing processes considered are forging and powder metallurgy, which are the main processes currently used in the manufacturing of connecting rods.
64

Produktutformning och materialval för formsprutning : beträffande polymera material / Product design and material selection for injection molding : concerning polymer materials

Johansson, Hanna, Sundin, Maria January 2015 (has links)
Formsprutning är en tillverkningsmetod somställer krav på produkters utformning. För att göra en lämplig ingötsplacering räcker inte alltid riktlinjer utan en produktspecifik analys kan vara nödvändig. Materialval kräver en tydlig kravspecifikation och kan med fördel göras i samråd med en materialexpert. Riktlinjer för Design for manufacturing and assembly inkluderar bland annat rekommendationer för formgivning. Detta kandidatarbete strävar efter att hjälpa produktutvecklare att tidigt i produktutvecklingsprocessen ta hänsyn till tillverkningsaspekter. Baserat på litteraturstudier, intervjuer och fallstudier har riktlinjer tagits fram för materialval, design for manufacturing and assembly och formgivning för formsprutning. Arbetet är avgränsat till att endast titta på formsprutningsbara termoplaster. Arbetet, som genomförts vid Linköpings universitet, är en del av projektet Säkra monteringsverktyg som resulterade i ett portabelt dödmansgrepp. Defallstudier som genomfördes inom projektetbehandlar värdering av koncept utifrån produktionsperspektiv, materialval och formsprutningsanalyser i programmet Moldflow. Arbetet resulterade i riktlinjer för applicering av metoden design for manufacturing and assembly, formsprutningsanpassning samt materialval. Fallstudien i Säkra monteringsverktyg utmynnade ien värdering av koncept utifrån produktionsaspekter, ett materialval baserat på projektets kravspecifikation och rekommendationer för produktens utformning med syfte att optimera dess tillverkning. En slutsats av arbetet är att produktionsanpassning av produktens utformning bör ske tidigt i utvecklingsprocessen. En annan slutsats är att besök i industrin, hos exempelvis ett formsprutningsföretag, leder till bättre förståelse av vilka krav som behöver uppfyllas för att en produkt ska vara möjlig att producera. Om simuleringsprogram för formsprutning finns bör det användas i kombination med riktlinjer för produktutformning. Ytterligare en slutsats som gjorts är att materialval underlättas genom tidig kontakt med materialleverantörer. Materialvalet baseras på kravspecifikationen och därför bör kraven tydliggöras och dess rimlighet kontrolleras innan materialvalet sker. / Injection molding is a manufacturing method that requires specific features to attain manufacturability. Gating suitability requires analysis and mere guidelines do not always provide the correct gate placement. Material selection requires a pronounced specification and is preferably supervised by an expert. Guidelines concerning design for manufacturing and assembly include, among other things, recommendations directly affecting the shape of the product. The aim for this bachelor thesis is to aid product developers and designers in taking manufacturing aspects into account early in the product development process. This is achieved by providing them with guidelines regarding material selection, injection molding, as well as design for manufacturing and assembly. The thesis is limited to thermoplastic materials suitable for injection molding and its results are based off thorough literature research, interviews and case studies. This bachelor thesis project, which is conducted at Linköping University,is a part of a project calledSafe manual assembly tools, and the resulting portable enabling device developed in Safe manual assembly toolsis used as case studies in this thesis. The case studies include: evaluation of concepts concerning manufacturability; material selection; and injection molding analysis through the software Moldflow. The thesis results in guidelines concerning design for manufacturing and assembly, injection molding and material selection. The case study is requited with concept selection suggestions, a selection of material that meets the specification of requirements stated in Safe manual assembly tools and design recommendations that aim to improve the manufacturability of the concept. This bachelor thesis concludes that design alterations striving to meet requirements for manufacturability should be made early in the devolpment process. Visiting the polymer-based product manufacturing industry offers better insight into which requirements that need to be fulfilled to make a product producible. Injection molding simulation software, if such is available, should be used in combination with design guidelines.The thesis also concludes that material selection is simplified through early contact with suppliers of material. Material selection is based off the specification of requirements and therefore requirements specified in the specification should be clarified and have their plausibility confirmed before the selection takes place.
65

Contribution to interoperable products design and manufacturing information : application to plastic injection products manufacturing / Contribution à l'interopérabilité des informations de conception et de fabrication de produits : application à la fabrication par injection de produits plastiques

Szejka, Anderson Luis 14 October 2016 (has links)
La compétitivité toujours plus importante et la mondialisation ont mis l'industrie manufacturière au défi de rationaliser les différentes façons de mettre sur le marché de nouveaux produits dans un délai court, avec des prix compétitifs tout en assurant des niveaux de qualité élevés. Le PDP moderne exige simultanément la collaboration de plusieurs groupes de travail qui assurent la création et l’échange d’information avec des points de vue multiples dans et à travers les frontières institutionnelles. Dans ce contexte, des problèmes d’interopérabilité sémantique ont été identifiés en raison de l'hétérogénéité des informations liées à des points de vue différents et leurs relations pour le développement de produits. Le travail présenté dans ce mémoire propose un cadre conceptuel d’interopération pour la conception et la fabrication de produits. Ce cadre est basé sur un ensemble d’ontologies clés, de base d’ingénierie et sur des approches de cartographie sémantique. Le cadre soutient les mécanismes qui permettent la conciliation sémantique en termes de partage, conversion et traduction, tout en améliorant la capacité de partage des connaissances entre les domaines hétérogènes qui doivent interopérer. La recherche a particulièrement porté sur la conception et la fabrication de produits tournants en plastique et explore les points particuliers de la malléabilité - la conception et la fabrication de moules. Un système expérimental a été proposé à l’aide de l'outil Protégé pour modéliser des ontologies de base et d’une plateforme Java intégrée à Jena pour développer l'interface avec l'utilisateur. Le concept et la mise en œuvre de cette recherche ont été testés par des expériences en utilisant des produits tournants en plastiques. Les résultats ont montré que l'information et ses relations rigoureusement définies peuvent assurer l'efficacité de la conception et la fabrication du produit dans un processus de développement de produits moderne et collaboratif / Global competitiveness has challenged manufacturing industry to rationalise different ways of bringing to the market new products in a short lead-time with competitive prices while ensuring higher quality levels. Modern PDP has required simultaneously collaborations of multiple groups, producing and exchanging information from multi-perspectives within and across institutional boundaries. However, it has been identified semantic interoperability issues in view of the information heterogeneity from multiple perspectives and their relationships across product development. This research proposes a conceptual framework of an Interoperable Product Design and Manufacturing based on a set of core ontological foundations and semantic mapping approaches. This framework has been particularly instantiated for the design and manufacturing of plastic injection moulded rotational products and has explored the particular viewpoints of moldability, mould design and manufacturing. The research approach explored particular information structures to support Design and Manufacture application. Subsequently, the relationships between these information structures have been investigated and the semantics reconciliation has been designed through mechanisms to convert, share and translate information from the multi-perspectives. An experimental system has been performed using the Protégé tool to model the core ontologies and the Java platform integrated with the Jena to develop the interface with the user. The conceptual framework proposed in this research has been tested through experiments using rotational plastic products. Therefore, this research has shown that information rigorously-defined and their well-defined relationships can ensure the effectiveness of product design and manufacturing in a modern and collaborative PDP
66

Développement d'une méthodologie de réduction des défauts géométriques : application à l'usinage 5-axes de composants de turbomachine

Chaves-Jacob, Julien 28 September 2009 (has links) (PDF)
Ces travaux contribuent à l'amélioration de la fabrication de pièces complexes de turbomachine. Elles sont principalement composées de veines fluides souvent délimitées par des pales, dont la fonction première est de transférer de l'énergie entre un fluide et une partie mécanique. Dans ce cas précis, la géométrie de ces pièces est essentielle pour obtenir un bon rendement du mécanisme. Cependant, lors de l'usinage, les flexions des pales et/ou de l'outil ainsi que les interférences locales occasionnent des défauts géométriques pouvant nuire à l'efficacité du système. Dans le but de résoudre cette problématique, une approche globale est utilisée dans ce mémoire. Elle débute par l'étude de la conception de ces pièces, en introduisant des concepts de Design For Manufacturing, utilisables grâce à la proposition d'indicateurs de fabricabilité par usinage 5-axes de pièces de turbomachine. Cette démarche permet donc de garantir que les pièces conçues sont économiquement réalisables. Les travaux ont continué avec la mise en place d'une méthodologie d'aide au choix de la meilleure stratégie d'usinage basée sur des critères de respect des besoins fonctionnels de la pièce et des critères économiques. La seconde partie de ce mémoire est consacrée à l'étude d'une approche novatrice permettant la réduction des interférences locales lors de l'usinage par le flanc de surfaces non développables. Cette méthode, baptisée Computation of Adapted Tool Shape, optimise la forme de l'outil, pour une trajectoire et une surface données, afin d'obtenir un meilleur respect des besoins fonctionnels de la pièce. La dernière partie de ces travaux définit le domaine d'application de cette nouvelle méthode par sa mise en oeuvre sur des études de cas académiques et industriels.
67

協同設計創新對於半導體價值鏈之影響 - 以 DFM 為例 / Impact of Design Collaboration Innovation for Semiconductor Value Chain: Take DFM (Design for Manufacturing) as Case

申雲勇, Shen, Yun-Yong Unknown Date (has links)
隨著奈米積體電路時代的來臨, 在微影技術,半導體製造技術和電路設計技術的進步已導致新的機會來整合大部份在系統中被使用到的電子功能。例如經過SoC技術提供的單晶片解決方案 - 由可重複使用的矽智財共同構成的單晶片系統 (舉例來說: 微處理器矽智財、數位信號處理矽智財、記憶體矽智財和其他的明星矽智財共同構成的單晶片系統) 可以和其他的整合系統溝通。這種包括多項技術的整合方式漸漸增加DFM 的要求, 進而創造在半導體價值鏈之中新虛擬的整合鏈模式。 對於先進產品發展, 經由現存的分解方式價值鏈﹐從每個單一鏈節 (無晶圓設計,矽智財,電路設計自動化, 設計服務,光罩製造,晶圓製造和封裝/測試)所創造的聯合價值無法在短時間超越IDM (舉例來說: 無法提供較早的上市時間)。因此針對先進產品突破性的發展,整合每個單一鏈節變成重要的主題。本研究針對這一個整合議題提供一個新的設計合作平台作為解決方案。 研究將以 DFM議題在半導體價值鏈中的影響作為分析。針對公司和公司間的溝通界面, 設計合作平台將會提供更多的併進價值鏈知識整合。 / Advances in lithography, semiconductor processes and circuit design techniques at the nanometer IC era have led to new opportunities to integrate most of the electronic functions encountered in systems. The single-chip solution through System on Chip (SoC) which comprises reusable Silicon IP (SIP) such as Microprocessor, Digital Signal Processing (DSP), Memory and other Star SIPs enabling the system to communicate with other systems. This multidisciplinary approach calls for increasing Design for Manufacturing (DFM) needs among semiconductor value chain to enable a whole new virtual integrated chain. Through the existing disintegrated value chain, the synergized value contributed from each single node (fabless, SIP provider, EDA, design service, mask foundry, wafer foundry and assembly/test) could not fulfill the time-to-market benefit as the IDM provides for advanced product development. To integrate each single chain node becomes the important topic for advanced product breakthrough. A new design collaboration platform is proposed to address this integration issue. Study was conducted among this semiconductor value chain for the DFM (Design for Manufacturing) issue. The design collaboration platform addresses the inter-firm communication interface among the value chain to provide more concurrent value chain knowledge integration. By applying Fine’s double helix model with the evidence from DFM case, I successfully predict the re-integration trend of semiconductor industry post the disintegration model.
68

Analysis of Vehicle Dynamics and Control of Occupant Biodynamics using a Novel Multi-Occupant Vehicle Model

Joshi, Divyanshu January 2016 (has links)
Due to the detrimental effects of ride vibrations on occupants and increasing safety concerns, improvement in vehicle dynamic characteristics has become a key focus of researchers. Typically, ride and handling problems have been dealt with independently. There is a dearth of vehicle models capable of capturing occupant biodynamics and its implication on vehicle ride and handling. Also in general, the objective of conventional control systems has been to attenuate vertical dynamic response of the sprung mass of a vehicle. Feedback control based algorithms are predominantly used in active/semi-active suspensions that ignore the biodynamics of occupants. In the current work, a new 50 degree-of-freedom (DOF) combined nonlinear multi-occupant vehicle model is developed using the lumped parameter modelling (LPM) approach. The current model provides a platform for performing a combined study of ride, handling and occupant biodynamics. The model is capable of simulating the combined effect of sitting occupancies, road inputs and driving maneuvers on biodynamic responses. It is analyzed using MATLAB/SIMULINK functionalities and validated by independently correlating the computed responses with existing experimental results. A study is performed on ride behavior of a vehicle-occupant system under two different transient road inputs. In addition, the effect of road roughness on vehicle ride is also studied. Random road profiles are generated from road roughness spectrum given in the ISO 8608:1995 manual. Insights are developed into the ride dynamics of a vehicle traversing over roads of classes A, B, C and D at given test velocities. The effect of sitting occupancies and vehicle velocities on lateral dynamics is also studied. Results underscore the need for considering sitting occupancies while analyzing vehicle dynamics and also highlight the potential of the current model. Furthermore, a Moore-Penrose Pseudoinverse based feed-forward controller is developed and implemented in an independently acting semi-active seat suspension system. Feasibility of feed-forward control in primary suspensions is also investigated. Finally, issues of stability, performance and limitation of the controller are discussed.
69

Advanced Numerical Approaches for Analysis of Vehicle Ride Comfort, Wheel Bearings and Steering Control

Mahala, Manoj Kumar January 2015 (has links) (PDF)
Suspension systems and wheels play a critical role in vehicle dynamics performance of a car in areas such as ride comfort and handling. Lumped parameter models (LPMs) are commonly used for assessing the performance of vehicle suspension systems. However, there is a lack of clarity with regard to the relative capabilities of different LPM configurations. A comprehensive comparative study of three most commonly used LPMs of increasing complexity has been carried out in the current work. The study reported here has yielded insights into the capabilities of the considered LPMs in predicting response time histories which may be used for assessing ride comfort. A shortcoming of available suspension system models appears to be in representation of harsh situations such as jounce movement which cause full compression of springs leading to ‘jerks’ manifested as high values of rate of change of acceleration of sprung mass riding on a wheel. In the current research work, a modified nonlinear quarter-car model is proposed to account for the contact force that results in jerk-type response. The numerical solution algorithm is validated through the simulation of an impact test on a car McPherson strut in a Drop Weight Impact Testing Tower developed in CAR Laboratory, CPDM. This is followed by a detailed comparison of HCM and QCM to examine their suitability for such analysis. For decades, wheel bearings in vehicles have been designed using simplified analytical approaches based on Hertz contact theory and test data. In the present work, a hybrid approach has been developed for assessing the load bearing capacity of a wheel ball bearing set. According to this approach, the amplitude of dynamic wheel load can be obtained from a lumped parameter analysis of a suspension system, which can then be used for detailed static finite element analysis of a wheel bearing system. The finite element modelling approach has been validated by successfully predicting the load bearing capacity of an SKF ball bearing set for an acceptable fatigue life. For the first time, using a powerful commercial explicit finite element analysis tool, a detailed dynamic analysis has been carried of a deep groove ball bearing with a rotating inner race. The analysis has led to a consistent representation of complex motions consisting of rotations and revolutions of rolling elements, and generated insights into the stresses developed in the various components such as balls and races. In conclusion, a simple yet effective fuzzy logic-based yaw control algorithm has been presented in the current research. According to this algorithm, two inputs i.e. a yaw rate error and a driver steering angle are used for generating an output in the form of an additive steering angle which potentially can aid a driver in avoiding straying from an intended path.
70

The Effect of Mismatch of Total Knee Replacement Components with Knee Joint : A Finite Element Analysis

Kanyal, Rahul January 2016 (has links) (PDF)
It has been noticed that the need for total knee replacement surgery is increasing for Asian region. A total knee replacement is a permanent surgical solution for a patient having debilitating pain in knee joint suffering from arthritis. In this surgery, knee joint is replaced with components made up of bio-compatible materials after which the patient can resume the normal day to day activities. Western population has bigger build compared to Asian population. Most of the total knee replacement prosthesis are designed for western population. When these total knee prosthesis are used for Asian population, they cause a mismatch leading to various clinical complications such as reduced range of motion and pain. The studies have been limited to clinical complications caused by the mismatch. To address this limitation, current study is aimed to find the mechanical implications such as stress distribution, maximum stresses, maximum displacements etc., caused by mismatch of total knee replacement components with knee. A surgeon selects total knee components for a patient based on some critical dimensions of femur and tibia bone of knee. In addition, a method to accurately calculate these dimensions of the femur and tibia bone of a real knee was developed in the current study. This method calculated the points of curvature greater than a threshold (decided based on the radius of the curvature) found out using the formula of curvature. Further, the highest point was calculated based on maximum height from a line drawn between initial and final point within the captured points, also the extreme points were calculated based on the sign change in slope of points within the captured points, giving multiple points on the boundary of bones extracted in an MRI image of a patient. The distance between two selected farthest points, out of these points, in specific direction was the basis for selection of the TKR components. Total knee replacement components were modeled in Geomatics Studio 12 software, bones were modeled in Rhinoceros 5 software, assembly of bones and total knee replacements components was done in Solid works 2013 software, the finite element model of the assembly was developed in Hyper mesh 11 software and, the stress analysis and post processing was done in ABAQUS 6.13 software. A static, implicit non linear analysis was performed. Simulations were performed for two conditions: at standing (0o of flexion) and at hyper-flexed (120o of flexion). In order to figure out if there were any mechanical implications of mismatch, the full model of assembly consisting of femur, tibia and fibula bones assembled with total knee replacement components, and the reduced model consisting of only total knee replacement components were simulated separately, results of which have been discussed in the current thesis. In this work, the effect of change of length of ligaments at 120o of flexion in detail was also studied. This study brought out various outcomes of contact mechanics and kinematics between the components of total knee replacement prosthesis.

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