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<p dir="ltr">There are 150 fatal occupational injuries on average per year due to exposure to electricity in the United States (U.S.) [1]. Power utility workers are exposed to electrical hazards when restoring power service to utility customers, who experience an average of 2 hours of power outages per year in the U.S. [2]. Utility companies struggle to keep qualified workers from quitting during the highest ever-recorded voluntary turnover in the U.S. with 55 million people quitting their jobs in 2022, raising the risk of safety incidents [3].</p><p dir="ltr">This research studies the department responsible for the operations in the power distribution system, Distribution Dispatch Center (DDC), based on a case study of a power company called Ohm-Sweet-Ohm (OSO) Inc. This thesis proposes a 12-step methodology and approach to assess the efficiency of OSO DDC by using a variation of the Collective System Design methodology for the design of enterprises [4].</p><p dir="ltr">The methodology consists of developing a system design decomposition that defines the functions and improvements to existing solutions of OSO DDC. The decomposition addresses the inconsistencies of the functions identified without a solution in the current state of OSO DDC.</p><p dir="ltr">The proposed methodology's impact is safety improvements in power distribution operations and the potential cost benefit for OSO Inc. of almost four million dollars a year. The measurements to evaluate the success of the proposed solutions are the number of safety incidents per year, the time taken to restore utility customers after power outages, and the voluntary turnover rate in the OSO DDC.</p>

The goal when applying robust engineering design methods is to improve a system's quality by reducing its sensitivity to uncertainty that has influence on the performance of the product. In the Robust Concept Exploration Method (RCEM) this approach is facilitated with additionally giving the designer the possibility to search for a compromise between the desired performance and a satisfying robustness. The current version of the RCEM, however, has some limitations that render it inapplicable for nonlinear design problems. These limitations, which are demonstrated in this thesis, are mainly connected to the application of global response surfaces and the Taylor series for variance estimations. In order to analyze the limitation of the robustness estimation, several alternative methods are developed, assessed and introduced to a modified RCEM. The developed Multiple Point Method is based on the Sensitivity Index (SI) and improves the variance estimation in RCEM significantly, especially for nonlinear problems. This approach is applicable to design problems, for which the performance functions are known explicitly. For problems that require simulations for the performance estimation, the simulation-based RCEM is developed by introducing the Probabilistic Collocation Method (PCM) to robust concept exploration. The PCM is a surrogate model approach, which generates local response models around the points of interests with a minimum number of simulation runs. Those models are utilized in the modified-RCEM for the uncertainty analysis of the system's performance. The proposed methods are tested with two examples each. The modified RCEM is validated with an artificial design problem as well as the design of a robust pressure vessel. The simulation-based RCEM is validated using the same artificial design problem and the design of a robust multifunctional Linear Cellular Alloy (LCA) heat exchanger for lightweight applications such as mobile computing. The structure of the theoretical and empirical validation of the methods follows the validation square.

The need of exploring efficient solutions to today’s engineering problems is becoming essential in the current market development. Soil Steel composite bridges (SSCB) are considered well competitive in terms of their feasibility and constructability. The primary objective of this study is to provide a comprehensive comparison study for two known design methods of SSCB, which are the Pettersson-Sundquist design method (developed in Sweden) and the Klöppel &amp; Glock design method (developed in Germany). Moreover, in the goal of having better behaviour understanding for SSCBs, the study also include finite element modelling (FEM) using PLAXIS 2D of three case studies and compare model results with field measurements.   The design comparison deals with the design concepts, assumptions and limitations for both design methods, where full design procedures are implemented and compared for a defined case study.   The results of the FEM analysis show rational outcome to the field measurements for structural response during backfilling and close results for ordinary loading as well. While the design comparison shows how the different approach in both design methods in limitations and design assumptions has important impact on the results, where soil failure in the Klöppel &amp; Glock design method can be controlling the design for low heights of cover, whereas formation of crown plastic hinge is more controlling in the Pettersson-Sundquist design method. However, and in general, the Pettersson-Sundquist design method require more steel in low heights of cover while it is less demanding for higher soil covers compared to the Klöppel &amp; Glock design method.

The work described provides the development, implementation and evaluation of engineering product design guidelines suitable for engineering product designers. The motivation arises from collaborative efforts that continue to be made by the Least Economically Developed Countries (LDC) and the Most Economically Developed Countries (MDC) towards the development of the engineering design field. It is argued here that product design guidelines which are derived from existing product design methods enhance the capability of engineering designers to shorten time to market, deal adequately with product design constraints and boost supply chains. The sample for the proposed study is comprised of companies in Botswana (a least economically developed country) and the United Kingdom (a most economically developed country). The research has been conducted using a mixed qualitative research approach comprised of aspects from the framework method, cluster analysis and Kolb's model. The findings have identified five themes central to the product design process which are incorporated into the engineering product design guidelines. Case study work was conducted to validate the approach. The following claims are made for contributions to knowledge: 1. A conceptual framework which is a graphical co-ordinate system of engineering and management techniques required by nine engineering product design methods. The conceptual framework is arranged according to two orthogonal axes that describe the structure of the product design process and incorporate the need function form structure, the divergent convergent structure, the product design drivers, product realisation process and product development lifecycles. 2. The product design method notation which is a register of the expressions derived from the conceptual framework and is used to communicate and aid in the selection of a group of techniques being implemented, or intended for implementation by design teams; and 3. The configuration scheme which provides a clear link between components, subassemblies, products, projects, programmes and policies. The critical point put forward by this work is that the conceptual framework is only comprehensible today because the engineering product design methods in the public domain have imparted knowledge about the functions of physical products (described here as part of the need function form structure) at the expense of human needs and the interactive forms of human responses to physical products. The contributions of this research provide a holistic and coherent means of integrating design methodologies for the benefit of design teams in Botswana. The approach is, however, universal and may also be beneficial for design projects in the most economically developed countries.

The European standard Eurocode 5, a design method for timber structures,is currently under revision. In this study the draft for a reviseddesign method for vibrations in timber floors was compared to the currentmethod. The hypothesis of the thesis was that the revised designmethod might force some changes to the present construction practiceand that these changes may carry with them increased costs for the industry.Six common floor structures used in Sweden today were identifiedand for these floors design calculations were made according to the currentand the revised design method. It was checked whether the floorspassed the criteria in the two design methods and a comparison was madefor the only criterion which could be compared between the methods, thepoint load deflection. Floor structures could pass or fail the current designmethod based on two criteria, the point load deflection and the unitimpulse velocity response. All floors passed the current design methodexcept one which had a fundamental frequency below 8 Hz, because ofthe low frequency the current design method was not applicable to thefloor structure. In the revised design method the final result is a responsefactor and based on the response factor floors are given floor performancelevels. The seven step scale for the floor performance level go from I toVII where I is excellent and VII is unacceptable. All floor structures excepttwo achieved an acceptable floor performance level according to therevised design method. The two floors which failed were floors commonlyused in single family houses, they failed for a span length commonly usedtoday. A limited parametric study was performed where it was found thatthe modal mass used had a larger impact on the floor performance levelthan the mass per square meter included. For floors with a fundamentalfrequency above 8 Hz, including a higher mass per square meter resultedin a lower, i.e. better, response factor in all cases except one. For floorswith a fundamental frequency between 4.5 and 8 Hz, a higher mass resultedin a higher, i.e. worse, response factor. The study found that notall floor structures used in Sweden today are acceptable according to therevised design method therefore changes may have to be implemented andthese changes could result in an increased cost.

Les procédés de fabrication additive sont en pleine essor ces dernières années. De nombreux industriels cherchent à évaluer leur potentiel et leurs avantages. Ces nouvelles technologies impliquent des changements au niveau des manières de fabriquer mais également au niveau des manières de concevoir. Ce travail de thèse s’est intéressé à ce second aspect et apporte plus particulièrement des réponses à la question de recherche suivante :Quel guide méthodologique suivre pour une étude dont le but est de reconcevoir des pièces afin de s’approcher de l’optimum en termes de masse ?Pour traiter cette question, le problème a été abordé au regard de plusieurs questions sous-jacentes afin de combler les manques identifiés dans l’état de l’art réalisé que ce soit sur les problématiques du paramétrage de l’optimisation topologique ou sur celles des techniques de reconstruction. Nous avons réalisé plusieurs études de cas afin de pouvoir répondre à ces différentes questions et pouvoir ainsi lister les points critiques. Ce travail de thèse a été réalisé en partenariat avec un acteur de l’aéronautique : Zodiac Seats France. Ceci nous a permis de réaliser des études de cas sur des pièces existantes qui possédaient un certain niveau de complexité. Parmi ces études de cas, nous avons distingué deux types d’étude :- Une étude élémentaire pour effectuer des boucles rapides en faisant varier les choix et- Une série d’études industrielles pour regarder s’il y a convergence ou divergence entre les conclusions de l’étude élémentaire et des cas d’applications plus complexes.Puis, nous avons donné une description détaillée d’une méthode de conception pour la fabrication additive basée sur 5 grandes phases :- l’évaluation de la pièce candidate ou des pièces,- la modélisation,- l’optimisation topologique : obtention d’une forme de géométrie,- la reconstruction de la pièce à partir du résultat de l’optimisation topologique et intégration des contraintes de fabrication- l’optimisation dimensionnelle : affiner les dimensions de la géométrie reconstruite.A ces phases, viennent s’ajouter des étapes de contrôle via des analyses éléments finis. Cette démarche s’est construite autour d’observations faites lors du déroulement des études de cas. Pour chacune de ces phases, un ensemble de recommandations a été défini pour aider le concepteur dans l’obtention d’une pièce optimale en termes de masse. Enfin, nous avons donné ce descriptif de la méthode à un concepteur relativement novice pour avoir un nouveau regard sur celle-ci et pouvoir ainsi identifier des points à améliorer. A l’issue de ce travail de conception, ce concepteur a pointé plusieurs points manquants ainsi que plusieurs faiblesses dans l’argumentaire du guide méthodologique. Ses observations et son opinion, nous ont permis de prendre du recul vis-à-vis de notre travail.Les apports majeurs de ce travail de thèse sont :- La description détaillée d’une méthode composée de 5 grandes phases- Dans cette démarche, nous avons dénombré plusieurs étapes clés : une étape préliminaire d’évaluation du potentiel des pièces à reconcevoir au regard de la fabrication additive et plusieurs phases d’optimisation complémentaires (topologie et dimensions),- La mise en avant de l’importance de bien délimiter le périmètre de l’étude (pièce isolée ou dans le mécanisme),- L’identification des étapes au cours desquelles les contraintes de fabrication devront être intégrées- Le positionnement du concepteur au cœur de la méthode : les outils numériques permettent de ne réaliser qu’une partie du travail de conception. / Additive manufacturing processes have been growing in recent years. Many industries seek to assess their potentials. These new technologies involve changes in terms of manufacturing but also in terms of designing. This work is interested in this second aspect. It brings answers to the following research question:What methodological guide to follow for a study whose goal is to redesign pieces in order to approach the optimum in terms of mass?To answer to this question, the problem is decomposed into several sub questions. These questions must fill the identified lacks in the state of the art, and deal with topological optimization parameters or reconstructions techniques for example. Several case studies are realized to answer to these sub questions and to list the critical points. This work is realized in partnership with an aerospace company: Zodiac Seats France. This allowed us to work on existing parts which have a certain complexity level. Two types of studies can be distinguished:- Basic study: to experiment different strategies and to make variation on the parameter choices rapidly.- Practical study: to check on more complex cases if there is a convergence with basic study conclusions.Then, a detailed description of a design method for additive manufacturing is provided. It is composed in 5 phases:- Evaluation of parts potential.- Model of parts.- Optimization of parts with topological optimization tools: obtaining the shape of the parts.- Reconstruction of parts from the topological result: integration of manufacturing constraints.- Optimization of reconstructed parts with dimensional optimization tools: refinement of the dimensions of reconstructed parts.Between these phases, checked step are added, based on finite element analysis. This method is built on practical observations obtained from the different case studies. For each phase, a set of recommendations is provided to help designers to design lightweight parts. Finally, this descriptive method is given to a novice designer to have the method tested. The aim of this test is having a new vision on this detailed method and identifying points to be improved. At the achievement of this design work, the designer noticed several missing points as well as several weaknesses in the method argument. His observations and his opinions gave us to take a step back from our work.The major contributions of this work are:- The description of a detailed method in 5 large phases.- In this method, there are several key steps : 1 step of evaluation of parts potential with regard to additive manufacturing as well as two complementary steps of optimization (shape and dimensions)- The perimeter of the parts study must be delimited clearly (isolated parts or in the mechanism),- The identification of the stages in which the manufacturing constraints have to be integrated- The position of the designer to the method heart: digital tools realize only one part of the design work.

Hyundai, Toyota and GM automobile factory were committed to provide more speed planetary gear automatic transmission research and development in order to improve the transmission performance and fuel efficiency. To set embedded clutch into planetary gear mechanism is an effective way to get more speed ratio, its call an epicyclic-type automatic transmission with embedded clutches, referred to the embedded-type automatic transmission. For the development of automatic transmission with eight or more speed ratios, an efficient design methodology is urgently needed and still not available. Therefore, the purpose of this article is to develop a systematic method for the design of automatic transmission with embedded clutches. First, the features and requirements of the automatic transmissions with embedded clutches are investigated and the corresponding design requirements are induced. Next, the theory of the analysis of kinematic for automatic transmissions with embedded clutches is derived based on the concept of lever analogy. Then, the design theory of automatic transmissions with embedded clutches is developed based on the analysis theory. Finally, the complete atlas of automatic transmissions with embedded clutches can be systematically synthesized from the data of given speed ratios. In this article, the innovative and patentable seven-speed and eight-speed automatic transmissions with embedded clutches have been done. This proposed design method can also be applied to the development and design of ten-speed automatic transmissions with embedded clutches.

Small size of electronic product with high layout density is the future trend in today¡¦s high speed digital circuit design. A circuit designer is obliged to optimize the best solution of circuit layout in a limited area in order to both keep a good signal integrity¡]SI¡^, and save the layout space. Meander delay line is one of the challenging topic in high-speed circuit. In this dissertation, a effective method is provided to design a meander delay line, and FDTD and HFSS are matched up to predict the behavior and the character of the meander delay line; the differential meander delay line is compared with the single meander delay line, and the behavior and phenomena of the differential meander delay line are discussed. To reduce couple power, the differential meander line of design would be a new thinking. The most important point in this thesis, the complete flows of designing single meander lines and differential meander lines are provided, and designer could follow the steps of the proposed method to design a perfect and practical meander line with both keeping good SI and using least layout space. The effect of the design parameters of the meander line on the signal quality both in time-domain and frequency-domain is theoretically and experimentally investigated. FDTD method and the commercial tool HFSS are employed for the numerical study in this work.

A new receiver concept utilizing impinging jet cooling technology has been developed for a small scale solar dish-Brayton system. In a typical impinging receiver design, the jet nozzles are distributed evenly around the cylindrical absorber wall above the solar peak flux region for managing the temperature at an acceptable level. The absorbed solar irradiation is partially lost to the ambient by radiation and natural convection heat transfer, the major part is conducted through the wall and taken away by the impingement jets to drive a gas turbine. Since the thermal power requirement of a 5 kWe Compower® micro gas turbine (MGT) perfectly matches with the power collected by the EuroDish when the design Direct Normal Irradiance (DNI) input is 800 W/m2, the boundary conditions for the impinging receiver design in this work are based on the combination of the Compower®MGT and the EuroDish system. In order to quickly find feasible receiver geometries and impinging jet nozzle arrangements for achieving acceptable temperature level and temperature distributions on the absorber cavity wall, a novel inverse design method (IDM) has been developed based on a combination of a ray-tracing model and a heat transfer analytical model. In this design method, a heat transfer model of the absorber wall is used for analyzing the main heat transfer process between the cavity wall outer surface, the inner surface and the working fluid. A ray-tracing model is utilized for obtaining the solar radiative boundary conditions for the heat transfer model. Furthermore, the minimum stagnation heat transfer coefficient, the jet pitch and the maximum pressure drop governing equations are used for narrowing down the possible nozzle arrangements. Finally, the curves for the required total heat transfer coefficient distribution are obtained and compared with different selected impinging arrangements on the working fluid side, and candidate design configurations are obtained. Furthermore, a numerical conjugate heat transfer model combined with a ray-tracing model was developed validating the inverse design method and for studying the thermal performance of an impinging receiver in detail. With the help of the modified inverse design method and the numerical conjugate heat transfer model, two impinging receivers based on sintered α-SiC (SSiC) and stainless steel 253 MA material have been successfully designed. The detailed analyses show that for the 253 MA impinging receiver, the average air temperature at the outlet and the thermal efficiency can reach 1071.5 K and 82.7% at a DNI level of 800 W/m2 matching the system requirements well. Furthermore, the local temperature differences on the absorber can be reduced to 130 K and 149 K for two different DNI levels, which is a significant reduction and improvement compared with earlier published cavity receiver designs. The inverse design method has also been verified to be an efficient way in reducing the calculation costs during the design procedure. For the validation and demonstration of the receiver designs, a unique experimental facility was designed and constructed. The facility is a novel high flux solar simulator utilizing for the first time Fresnel lenses to concentrate the light of 12 commercial high power Xenon-arc lamps. Finally, a prototype of a 253 MA based impinging was experimentally studied with the help of the 84 kWe Fresnel lens based high flux solar simulator in KTH. / <p>QC 20151123</p> / Optimised Microturbine Solar Power System , OMSOP