Made available in DSpace on 2014-12-17T14:57:58Z (GMT). No. of bitstreams: 1 MoacirBR_DISSERT.pdf: 4521415 bytes, checksum: c98edffad04a3e49fed259b6f659f5f2 (MD5) Previous issue date: 2009-12-04 / Universidade Federal do Rio Grande do Norte / In general, the designs of equipment takes into account the effects and processes of deterioration it will undergo and arrives at an approximate useful life. However, changes in operational processes and parameters, the action of external agents, the kind of maintenance conducted, the means of monitoring, and natural and accidental occurrences completely modify the desired performance of the equipment. The discontinuities that occur in anisotropic materials often and due to different factors evolve from being subcritical to critical acquiring the status of defect and compromising the physical integrity of the equipment. Increasingly sophisticated technological means of detection, monitoring and assessment of these discontinuities are required to respond ever more rapidly to the requirements of industry. This paper therefore presents a VPS (Virtual Pipe System) computational tool which uses the results of ultrasonic tests on equipment, plotting the discontinuities found in models created in the CAD and CAE systems, and then simulates the behavior of these defects in the structure to give an instantaneous view of the final behavior. This paper also presents an alternative method of conventional ultrasonic testing which correlates the integrity of an overlay (carbon steel and stainless steel attached by welding) and the reflection of ultrasonic waves coming from the interface between the two metals, thus making it possible to identify cracks in the casing and a shift of the overlay / Os projetos de equipamentos em geral j? contemplam os esfor?os e os mecanismos de de processo e de par?metros operacionais, a??o de agentes externos, esp?cie de manuten??o aplicada, forma de acompanhamento, ocorr?ncias naturais e acidentes modificam completamente deteriora??o a que estes est?o submetidos, prevendo aproximadamente sua vida ?til, por?m, mudan?as o comportamento esperado dos equipamentos. As descontinuidades em materiais anisotr?picos muitas vezes e, por diversos fatores, evoluem da condi??o de subcr?ticas para cr?ticas assumindo o status de defeito e comprometendo a integridade f?sica do equipamento. Meios de detec??o, monitora??o e avalia??o dessas descontinuidades, cada vez mais tecnol?gicos, s?o requeridos para responderem de forma mais eficaz ? exig?ncia da ind?stria. Assim, este trabalho apresenta uma ferramenta computacional VPS (Virtual Pipe System) que utiliza o resultado de ensaios de ultrassom em equipamentos plotando essas descontinuidades encontradas em modelos criados em sistemas CAD e CAE e, ainda, simula o comportamento desses defeitos na estrutura possibilitando a visualiza??o instant?nea do comportamento final. Apresenta-se ainda neste trabalho um m?todo alternativo de ensaio ultrass?nico convencional que correlaciona a integridade de um overlay (a?o carbono e a?o inoxid?vel depositado por solda) com as reflex?es de ondas de ultra-som provindas da interface entre os dois metais, possibilitando a identifica??o de trincas no revestimento e de descolamento do overlay

Made available in DSpace on 2014-12-17T14:58:15Z (GMT). No. of bitstreams: 1 LuzinarioGS_DISSERT.pdf: 1489197 bytes, checksum: c6a09807d24f35bd75cfbad03d10f90b (MD5) Previous issue date: 2012-03-05 / Currently there is still a high demand for quality control in manufacturing processes of mechanical parts. This keeps alive the need for the inspection activity of final products ranging from dimensional analysis to chemical composition of products. Usually this task may be done through various nondestructive and destructive methods that ensure the integrity of the parts. The result generated by these modern inspection tools ends up not being able to geometrically define the real damage and, therefore, cannot be properly displayed on a computing environment screen. Virtual 3D visualization may help identify damage that would hardly be detected by any other methods. One may find some commercial softwares that seek to address the stages of a design and simulation of mechanical parts in order to predict possible damages trying to diminish potential undesirable events. However, the challenge of developing softwares capable of integrating the various design activities, product inspection, results of non-destructive testing as well as the simulation of damage still needs the attention of researchers. This was the motivation to conduct a methodological study for implementation of a versatile CAD/CAE computer kernel capable of helping programmers in developing softwares applied to the activities of design and simulation of mechanics parts under stress. In this research it is presented interesting results obtained from the use of the developed kernel showing that it was successfully applied to case studies of design including parts presenting specific geometries, namely: mechanical prostheses, heat exchangers and piping of oil and gas. Finally, the conclusions regarding the experience of merging CAD and CAE theories to develop the kernel, so as to result in a tool adaptable to various applications of the metalworking industry are presented / Com o crescimento das exig?ncias do controle de qualidade na fabrica??o de pe?as mec?nicas, surgiu a atividade de inspe??o de produtos finais, que vai desde a an?lise dimensional ? composi??o qu?mica. Essa tarefa geralmente ? feita atrav?s de diversos m?todos de ensaios n?o destrutivos que minimizam a possibilidade de falhas das pe?as. Os resultados produzidos pelas ferramentas utilizadas nas inspe??es n?o s?o capazes de definir geometricamente um dano (trincas, microtrincas, defeitos de fabrica??o etc.) e, portanto, n?o s?o adequados para a visualiza??o na tela de um computador. Na verdade, t?cnicas de visualiza??o de objetos virtuais em 3D s?o capazes de identificar certos danos que dificilmente seriam detectados por outros m?todos tradicionais. Existem alguns softwares comerciais que buscam auxiliar as etapas de um projeto e simula??o de pe?as mec?nicas no intuito de prever poss?veis danos para tentar mitigar poss?veis eventos indesej?veis (rompimento de pe?as, quebra de equipamentos etc.). Entretanto, o desafio do desenvolvimento de softwares capazes de integrar as v?rias atividades de projeto, inspe??o de produtos, resultados de ensaios n?o destrutivos e simula??es de danos ainda precisa da aten??o de pesquisadores. Dessa forma, fez-se um estudo metodol?gico para a elabora??o de um kernel (n?cleo computacional) piloto do tipo CAD/CAE de grande versatilidade, capaz de auxiliar programadores no desenvolvimento de softwares que usam Engenharia Reversa como base aplicados ?s atividades de projeto e simula??o de casos em que pe?as mec?nicas s?o submetidas a solicita??es diversas. A cria??o do kernel deu-se atrav?s da aplica??o da Computa??o Gr?fica em conjunto com as teorias CAD e CAE e com o aux?lio da realidade virtual. Nesta disserta??o apresentam-se resultados em que o kernel desenvolvido foi aplicado com sucesso a estudos de casos de pe?as com geometrias espec?ficas, a saber: pr?teses mec?nicas, trocadores de calor e tubula??es de petr?leo e g?s. Finalmente, s?o apresentadas as conclus?es referentes ? experi?ncia da hibridiza??o das teorias CAD e CAE para o desenvolvimento do kernel, de forma a resultar numa ferramenta adapt?vel ?s mais diversas aplica??es da ind?stria metal-mec?nica

The semestral project will focus on using Computer Aided Engineering for analysis of the ESEM differential chamber. The instruments used for the analysis, evaluation and scrutiny of the given issue will be the CAD and CAE systems (Computer Aided Design and Computer Aided Engineering).

Aus der Einleitung: "Um Kosten in der Produktentwicklung weiter zu minimieren und gleichzeitig die Qualität der zu fertigenden Produkte zu gewährleisten, nehmen virtuelle Methoden in der Produktentwicklung einen immer größeren Stellenwert ein (Stelzer & Eigner, 2009). An die Maßhaltigkeit von umgeformten Blechteilen werden ständig höhere Anforderungen gestellt. Die Ursachen für Maßabweichungen an gefertigten Blechteilen resultieren maßgeblich aus den Berechnungsmodellen, die das System Werkzeug-Blechteil-Umformmaschine bisher in der Virtuellen Produktentwicklung noch nicht vollständig und exakt abbilden können. Mehrere Zyklen händischer Änderungen an den Umformwerkzeugen sind heute noch die Regel. Dieser Prozess wird bei der Blechumformung als Einarbeitungsphase bezeichnet und wird von Spezialisten des Werkzeugbaus unter Nutzung von unscharfem Erfahrungswissen durchgeführt. Der Zyklus der manuellen Einarbeitungsphase im Bereich des Werkzeugbaus steht den wirtschaftlichen Forderungen zum schnelleren Serienanlauf und zur Kostensenkung entgegen. Hier kann die Verkürzung des Einarbeitungsprozesses dienlich sein."

The relationship between Objective Metrics (OM) and Subjective Assessments (SA) has been analyzed by people using different methods. This paper continues Gaspar Gil Gómez’s research over test method development by use of SOM-GRNN, aiming to find correlations between OM and SA. In this paper, CAE simulation is performed to analyze the relationship between OM and vehicle parameters. First impression test is refined and one more dataset has been added in order to populate SOM-GRNN map. This paper also conducts analysis over SOM and GRNN algorithms, and explores several possible applications using SOM-GRNN map. Finally the whole SOM-GRNN system is integrated and a User Interface is built in GUI for future research and application. The system can still be improved by populating database, refining SA evaluation method and optimizing SOM-GRNN training algorithms. / Relationen mellan målmetri (OM) och subjektiv bedömning (SA) har analyserats av personer som använder olika metoder. I detta dokument fortsätter Gaspar Gil Gómezs forskning kring testmetodutveckling med hjälp av SOM-GRNN, som syftar till att finna korrelationer mellan OM och SA. I detta papper utförs CAE-simulering för att analysera förhållandet mellan OM och fordonsparametrar. Första intryckstestet är raffinerat och ytterligare en dataset har lagts till för att fylla i SOM-GRNN-kartan. I detta dokument analyseras även SOM- och GRNN-algoritmer, och undersöker flera möjliga tillämpningar med hjälp av SOM-GRNN kartan. Slutligen är hela SOM-GRNN-systemet integrerat och ett användargränssnitt är byggt i GUI för framtida forskning och tillämpning. Systemet kan fortfarande förbättras genom att fylla i databasen, förädla SA utvärderingsmetod och optimera SOM-GRNN träningsalgoritmer.

Aluminium har flera fördelar inom konstruktion och produktframtagning. Aimpoint AB har resonerat för kostnad samt viktreducering i sikteshuset Micro T-2. Syftet med rapporten var att undersöka möjligheterna att implementera polymera material som tillfredsställer framlagd kravspecifikation för Aimpoint AB. Målet med arbetet var att identifiera lämpligt material i form av polymer, med lämplig tillverkningsmetod som kan appliceras för sikteshuset utan att påverka de mekaniska egenskaperna negativt.  Lämpliga material som identifierades under litteraturstudien i arbetet var termoplasterna polyfenylensulfid (PPS) och polyetereterketon (PEEK) med implementerat kolfiber. Valet av polymerbaserade material utgjorde ett mindre omfång av lämpliga tillverkningsmetoder, som med hjälp av leverantörer och kostnadskalkylscenarier i Excel jämfördes.  Med hjälp av tredimensionella verktyg utfördes FEM-analyser i ABAQUS CAE® av det exemplifierade sikteshuset. Baserat på simuleringarna i ABAQUS CAE®, presenterar arbetet en jämförelse mellan befintligt sikteshus av Al6082-T6 och sikteshus av polymera material med implementerad förstärkning för modellen Micro T-2. Simuleringarna konstaterade deformation vid det dynamiska explicita fallet mot en konstruerad laminatskiva enligt standarden MIL-STD-810G.  För att bekräfta material och tillverkningsmetod krävs vidare undersökning. Detta för att med säkerhet besvara arbetets frågeställningar då FEM - analyser är en approximativ lösning. / SvenskaAluminum has several advantages in construction and product development. Aimpoint AB requires to reduce both the costs and the weight of their aluminum reflex sight of model Micro T-2.   The aim with the report was to investigate the possibility to implement polymeric materials as a substitute to aluminum that fulfills the requirements specification set by the manufacturer Aimpoint AB.   In addition to that, the aim was also to find suitable polymeric materials with an alternative production technique that is applicable for the reflex sight without compromising the mechanical integrity.  Suitable materials identified during the literature part of this report were two types of thermoplastic materials, polyphenylene sulfide (PPS) and polyetheretherketone (PEEK), both with addition of carbon fiber. The selection process of the polymeric materials was based on several factors and together with contractors, different cost estimation scenarios were compared in Excel. By help from three dimensional tools, FEM-analysis of the sight were performed in ABAQUS CAE®. Based on the results from the simulations performed in ABAQUS CAE®, the report presents a comparison between the original aluminum sight with the two types of carbon fiber reinforced thermoplastic sights. During the dynamic explicit case the simulation was performed as a drop test against a laminate board according to standard MIL-STD-810G. The results of the simulation presented a deformation of the tested sight. To confirm the material and manufacturing method, further investigation is required. This is necessary to address the questions posed in the current project since the FEM - analysis is an approximate solution. / <p>2023-06-28</p>

Gas turbines are today used in numerous industrial and aeronautical applications. To increase the specific power output and efficiency, a high turbine inlet gas temperature is desired. The high temperature leads to the need of cooling critical components in the hot gas path. Siemens Industrial Turbomachinery AB, SIT AB, in Finspång manufactures gas turbines where the internal cooling of critical components is done through serpentine channels. To utilize the cooling air as efficiently as possible, vortex creating objects are placed inside the channel which result in higher heat transfer. To compute the heat transfer in the channel, correlation based approaches that will give a uniform value for an entire channel are often used. This thesis contains two parts. First, investigating how an automated CAE process can be developed that is able to be incorporated into the SIT AB CAE process of today and with a future vision of a, basically, "one-click-CFD" approach for non-generic geometries. Secondly, how CFD simulations for predicting heat transfer levels inside the cooling channels with high accuracy and that captures local features of heat transfer can be performed. The suggested CAE approach involves the CAD-tool NX for geometry creation and for managing an entire CFD project the ANSYS software Workbench, combined with ANSYS Meshing for generation of computational grid, CFX-pre and CFX for pre-processing and solving and CFD-post for post-processing. This approach is suggested for generic geometries due to the simplicity in incorporating it into existing CAE processes. For the future vision of non-generic geometries, the inhouse developed project manager Concept is suggested. It allows for customized coupling between a broader range of available software tools. To validate the CFX model and to investigate how the CFD calculations should be performed, two cases were set up, one where the CFD model and the inhouse code was compared to experimental data of a generic geometry and one where the CFD model and the inhouse code were compared at engine-like conditions. The results for the experimental case resulted in heat transfer coefficients from the CFD model that were 30% off from experimental data, and the inhouse code maximum deviation was 10%. Compared to previous numerical studies this was considered to be of acceptable accuracy, and the location of data extraction points were considered to cause the deviation in the CFD model. For the engine-like case both CFD and inhouse code predicted the heat transfer level as expected. The simulations were performed in steady state mode on automatically generated meshes with the SST-Reattachment turbulence model. The Reynolds number varied from 10 000 to 80 000 and the meshes were around 4-10M elements in size.

This study was designed to ascertain, analyse and compare the perceptions of College Librarians and their associates about the role responsibility which College Librarians in libraries in New South Wales Colleges of Advanced Education (CAEs) were actually assuming and ideally should be assuming as part of their role as library managers. Using as its basis a theoretical framework of role and role-related concepts, as developed by social psychologists such as Kahn et al. (1964), a role set group of Principals, Registrars and Senior Library Staff was identified as the survey population. A review of the literature about CAEs and their libraries and overseas studies about the role of library managers assisted with the development of a role responsibility questionnaire. Data from the questionnaire was analysed in respect of actual and ideal role responsibility and any gaps between actual and ideal role responsibility. Gaps between perceptions of actual and ideal role responsibility between College Librarians and associates may indicate a potential for role conflict for persons enacting the role of College Librarian. This study found statistically significant results in respect of both actual and ideal role responsibility between College Librarians and Senior Library Staff, which indicated that there was not clear agreement between the two groups about either the role responsibility currently assumed by College Librarians and that which ideally should be assumed. In respect of the gap between actual and ideal role responsibility, however, there was no statistically significant result between College Librarians and associates, indicating that the potential for role conflict resulting from divergent perceptions between role set groups was not evident. This does not preclude the potential for role conflict from other sources.

This dissertation aims to advance the field of structural optimization by creating and demonstrating new methodologies for the explicit inclusion of manufacturing issues. The case of composite aerospace structures was a main focus of this work as that field provides some of the greatest complexities in manufacturing yet also provides the greatest incentives to optimize structural performance. Firstly, the possibilities for modifying existing FEA based structural optimization methods to better capture manufacturing constraints are investigated. Examples of brick-based topology optimization, shell-based topology optimization, parametric sizing optimization and manufacturing process optimization are given. From these examples, a number of fundamental limitations to these methods were observed and are discussed. The key limitation that was uncovered related to a dichotomy between analytical methods (such as FEA) and CAD-type methods. Based on these observations, a new Knowledge-Based framework for structural optimization was suggested whereby manufacturing issues are integrally linked to the more conventional structural issues. A prototype system to implement this new framework was developed and is discussed. Finally, the validity of the framework was demonstrated by application to a generic composite rib design problem.

Efficiency and innovative problem solving are contradictory requirements for productdevelopment (PD), and both requirements must be satisfied in companies that strive to remainor to become competitive. Efficiency is strongly related to ”doing things right”, whereasinnovative problem solving and creativity is focused on ”doing the right things”.Engineering design, which is a sub-process within PD, can be viewed as problem solving or adecision-making process. New technologies in computer science and new software tools openthe way to new approaches for the solution of mechanical problems. Product datamanagement (PDM) technology and tools can enable concurrent engineering (CE) bymanaging the formal product data, the relations between the individual data objects, and theirrelation to the PD process. Many engineering activities deal with the relation betweenbehavior and shape. Modern CAD systems are highly productive tools for conceptembodiment and detailing. The finite element (FE) method is a general tool used to study thephysical behavior of objects with arbitrary shapes. Since a modern CAD technology enablesdesign modification and change, it can support the innovative dimension of engineering aswell as the verification of physical properties and behavior. Concepts and detailed solutionshave traditionally been evaluated and verified with physical testing. Numerical modeling andsimulation is in many cases a far more time efficient method than testing to verify theproperties of an artifact. Numerical modeling can also support the innovative dimension ofproblem solving by enabling parameter studies and observations of real and syntheticbehavior. Simulation-driven design is defined as a design process where decisions related tothe behavior and performance of the artifact are significantly supported by computer-basedproduct modeling and simulation.A framework for product modeling, that is based on a modern CAD system with fullyintegrated FE modeling and simulation functionality provides the engineer with tools capableof supporting a number of engineering steps in all life-cycle phases of a product. Such aconceptual framework, that is based on a moderately coupled approach to integratecommercial PDM, CAD, and FE software, is presented. An object model and a supportingmodular modeling methodology are also presented. Two industrial cases are used to illustratethe possibilities and some of the opportunities given by simulation-driven design with thepresented methodology and framework. / QC 20100810