This thesis presents a study into the feasibility of applying a Knowledge Based Engineering System to the manufacture and prescription of custom contoured seating. The custom contoured seats are designed to meet the needs of clients of Cardiff and Vale University Health Board’s Rehabilitation Engineering Unit who have neurological, musculoskeletal and/or other conditions that result in limited movement, complex body shapes and poor posture. The custom contoured seats provide accommodation or correction for poor posture whilst improving the client’s function and comfort level, minimising risk to the client and in some cases providing therapeutic benefits such as improving the client’s unsupported posture. The literature review showed that there is not currently a technique in development or envisaged that would perform the task of the system being investigated in this thesis. Three techniques were identified, two for the prescription of wheelchairs based on a series of extensive questions, the output of which is a wheelchair with no custom contoured seating. The third technique converts pressure readings of clients with low complexity conditions sitting on a flat surface into a custom contoured seat. The client group being investigated in this study are unable to sit unsupported and would not be able to provide a meaningful pressure reading when held in position due to the shape of most of the clients’ bodies. Algorithms were developed to extract useful features from Cardiff and Vale University Health Board’s Rehabilitation Engineering Unit’s mechanical shape sensor; which is called the Cardiff Body Match. The features extracted from the measurements were designed to reduce the dimensionality of the data and inform a clinical engineer as to the anthropometry of the client seated in the Cardiff Body Match mechanical shape sensor. The algorithms developed were able to correct errors in measurements, estimate the location of pelvic landmarks and provide a classification of the curvature of the back. Engineering rules were elicited from clinical engineers at Cardiff and Vale University Health Board’s Rehabilitation Engineering Unit and from the literature. The engineering rules were described in plain English and represented using a novel approach based on notations used in predicate calculus. The engineering rules’ application was tested and the shape of a custom contoured seat that could be produced with the Knowledge Based Engineering System was demonstrated. This study has shown that through further research a Knowledge Based Engineering System for the manufacture and prescription of custom contoured seating for clients of Cardiff and Vale University Health Board’s Rehabilitation Engineering Unit is possible. This thesis contributes to the knowledge by demonstrating the feasibility of the Knowledge Based Engineering System, developing the bespoke algorithms and the novel collection of knowledge through elicitation.

In diesem Beitrag wird am Beispiel von Flanschverbindungen dargestellt, wie Simulations- und Berechnungsmodelle wissensbasiert aufgebaut und verknüpft werden können. Dies führt zu einer teilautomatisierten Auslegung. In einem weiteren Schritt wird eine Methode zur Optimierung der Flanschverbindung vorgestellt. Hierbei wurden Parameter identifiziert, die zur Optimierung geeignet sind. Die prototypische Implementierung der beiden Methoden erfolgte im CAD-System Siemens NX10 (Siemens PLM Software).

This thesis work is mainly focused on the processes involved in manufacturing of aircraft engine components. The processes are especially about welding and welding methods. The basics of welding and the thesis support has been taken from the GKN Aerospace Sweden AB, a global aerospace product supplier.  The basic objective of this thesis work is to improve the usability of an automation system which is developed for evaluating the weldability of a part. A long run maintainability aspect of this automation system has been considered. The thesis work addresses the problems arising during the usage of a computerised automated system such as process transparency, recognisability, details traceability and other maintenance aspects such as maintainability and upgradability of the system in the course of time. The action research methodology has been used to address these problems.  Different approaches have been tried to finding the solution to those problems. A rule based manufacturability analysis system has been attempted to analyse the weldability of a component in terms of different welding technics. The software “Howtomation” has been used to improve the transparency of this analysis system. User recognisability and details tractability have been taken into account during the usage of a ruled based analysis system. The system attributes such as maintainability, upgradability, adaptiveness to modern welding methods has been addressed. The system suitability for large scale analysis has been considered.

This PhD project aims to develop a cost modelling system to support lean product and process development. The system enables the designers to assess the design along with associated manufacturing processes and provides decision support at an early development stage. Design assessment at early development stage can help designers to take proactive decisions, eliminate mistakes and enhance product value. The developed cost modelling system to support lean product and process development incorporates three lean product and process development enablers, namely set-based concurrent engineering, knowledge-based engineering, and mistake-proofing (poka-yoke). To facilitate above explained lean enablers, the system architecture contains six modules, six separate groups of database, a CAD modelling system, and a user interface. The system modules are: (i) value identification; (ii) manufacturing process/machines selection; (iii) material selection; (iv) geometric features specification; (v) geometric features and manufacturability assessment; and (vi) manufacturing time and cost estimation. The group of database includes: (i) geometric features database, (ii) material database, (iii) machine database, (iv) geometric features assessment database, (v) manufacturability assessment database, and (vi) previous projects cost database. A number of activities have been accomplished to develop the cost modelling system. Firstly, an extensive literature review related to cost estimation, and lean product and process development was performed. Secondly, a field study in European industry and a case study analysis were carried out to identify current industrial practices and challenges. Thirdly, a cost modelling system to support lean product and process development was developed. Finally, validation of the system was carried out using real life industrial case studies. The system provides a number of benefits, as it enables designers to incorporate lean thinking in cost estimation. It takes into consideration downstream manufacturable process information at an early upstream stage of the design and as a result the designer performs the process concurrently and makes decisions quickly. Moreover, the system helps to avoid mistakes during product features design, material and manufacturing process selection, and process parameters generation; hence it guides toward a mistake-proof product development. The main feature of the system, in addition to manufacturing cost estimation, is set-based concurrent engineering support; because the system provides a number of design values for alternative design concepts to identify the feasible design region. The major contribution of the developed system is the identification and incorporation of three major lean product and process development enablers, namely set-based concurrent engineering, knowledge-based engineering and poka-yoke (mistake-proofing) in the cost modelling system. A quantification method has been proposed to eliminate the weaker solution among several alternatives; therefore only the feasible or strong solution is selected. In addition, a new cost estimation process to support lean product and process development has been developed which assists above explained three lean product and process development enablers.

When building aircrafts, structural components must be designed for high strength, low cost, and easy assembly.To meet these conditions structural components are often based upon previous designs, even if a new component is developed.Refining previous designs can be a good way of preserving knowledge but can also limit the exploration of new design concepts. Currently the design process for structural aircraft components at SAAB is managed by design engineers. The design engineer is responsible for ensuring the design meets requirements from several different disciplines such as structural analysis, manufacturing, tool design, and assembly.Therefore, the design engineer needs to have good communication with all disciplines and an effective flow of information. The previous design is refined, it is then reviewed and approved by adjacent disciplines.Reviewing designs is an iterative process, and when several disciplines are involved it quickly becomes time consuming.Any time the design is altered it has to be reviewed once more by all disciplines to ensure the change is acceptable.So there is a need for further customizing the design concept to decrease the number of iterations when reviewing. Design Space Exploration DSE is a well known method to explore design alternatives before implementation and is used to find new concepts.This thesis investigates if DSE can be used to facilitate the design process of structural aircraft components and if it can support the flow of information between different disciplines.To find a suitable discipline to connect with design a prestudy is conducted, investigating what information affect structural design and how it is managed.The information flow is concluded in a schematic diagram where structural analysis is chosen as additional discipline. By using topology optimization in a DSE, design and structural analysis are connected.The design space can be explored with regards to structural constraints.The thesis highlights the possibilities of using DSE with topology optimization for developing structural components and proposes a method for including it in the design process.

Dans un processus traditionnel de conception de produits mécaniques, l’organisation classique est la conception du produit puis son dimensionnement et enfin son optimisation. Les concepteurs prennent des risques en n’évaluant les performances du produit que dans les dernières phases du processus, et l’étape d’optimisation est bien souvent mise de côté, faute de temps ou à cause du retard pris sur les autres phases. La phase de conception préliminaire est une étape délicate car les décisions doivent y être prises dans un contexte imprécis ou peu de choses sont définies. Il n’existe pas d’outils informatiques adaptés et l’étude de plusieurs concepts multiplie les tâches routinières et les pertes de temps associées. Le concepteur prend donc des risques en réduisant le nombre de concepts développés. Le dimensionnement de produits comporte également un certain nombre de difficultés, comme un positionnement tardif dans le processus, entraînant des étapes de pré et post traitement lourdes ainsi que des simulations longues. L’analyse d’aide à la décision est prometteuse mais elle reste marginale, faute de modèles simplifiés disponibles dans les phases amont du processus de conception.Cette thèse expose la synthèse de nos travaux de recherche portant sur l’optimisation en conception de systèmes mécaniques. L’étude proposée s’intègre dans une démarche d’ingénierie hautement productive de systèmes mécaniques et comporte plusieurs facettes : conception fonctionnelle paramétrique, application d’ingénierie à base de connaissances, outils de simulation numérique et d’optimisation. Nous proposons une méthodologie permettant d’introduire au plus tôt dans le processus de conception, une étape d’optimisation couplée à des simulations d’aide à la décision, en vue d’identifier des architectures optimales inédites, présentant les meilleurs compromis vis-à-vis d’objectifs multiples relatifs au comportement mécanique. L’objectif du travail de recherche est de développer des modèles, des méthodes et des outils dédiés à la génération semi-automatique de modèles géométriques tridimensionnels multiples identifiés comme solutions les plus performantes dans un cadre de conception collaborative de produits mécaniques. Notre méthodologie est ensuite expérimentée sur plusieurs projets de conception de systèmes mécaniques relevant de la mécanique des structures, en analyses statique et dynamique. Il s’agit en particulier de la conception d’organes du véhicule de l’UTBM participant au trophée SIA. / In a traditional process of design of mechanical products, the traditional organization is the product design and the sizing and finally optimization. The designers take risks in failing to assess product performance in the final stages of the process, and the optimization step is often ignored because of time or due to delays on other phases. The preliminary design is a delicate step because decisions must be taken in a little vague or defined. There are no adequate data tools and the study of several concepts multiply routine tasks and wasted time associated. The designer is therefore taking risks by reducing the number of concepts developed. The design of products also includes a number of difficulties, such as positioning late in the process, resulting in steps of pre and post processing of heavy and long simulations. An analysis of decision support is promising but remains marginal due to lack of simplified models available in the early phases of the design process.This thesis describes the synthesis of our research on design optimization of mechanical systems. The proposed study is part of a highly productive process engineering of mechanical systems and multi-faceted: parametric functional design, application engineering knowledge base, simulation tools and optimization. We propose a methodology to introduce at the earliest in the design process, an optimization step coupled with simulations of decision support, to identify optimal architectures novel, the three best compromise vis- -vis multiple objectives related to the mechanical behavior. The objective of the research is to develop models, methods and tools dedicated to the semi-automatic generation of multi-dimensional geometric models identified as most effective solutions in a collaborative design of mechanical products. Our methodology is then tested on several projects of design of mechanical systems within the mechanical structures in static and dynamic analysis. This is especially the design of the vehicle components of the UTBM MLS participant trophy.

This thesis report presents the work of analysing current challenges in Multidisciplinary Analysis systems. Exemplary the system of an aerospace supplier, GKN Aerospace Sweden AB, is examined and several suggestions for improve- ment are implemented. The Multidisciplinary Analysis system, with company internal name Engineering Workbench, employs a set-based approach in exploring the design-space for jet engine components. A number of design cases with varied geometrical and environmental parameters is generated using Design of Experiment sampling methods. Each design case is then subjected to a set of analyses. Using the analyses results, a surrogate model of the parts behaviour in relation to the input parameters is created. This enables the product developer to get a general view of the model’s behaviour and also to react to changes in product requirements. Design research methodology is applied to further develop the Engineering Workbench into a versatile design support system and expand the functionality to include producibility assessment. In its original state, the execution of a study requires explicit domain knowledge and programming skills in several disciplines. The execution of a study is often halted by minor process errors. Several methods to improve this status are suggested and tested. Among those are the introduction of an interface to improve the usability and expand the range of possible users. Further the integration of a four level system architecture supporting a modular structure. Producibility assessment is enabled by developing an expert system where geometrical and simulation results can be caught, analysed and evaluated to produce producibility metrics. Evaluation of the implemented solutions indicate a step in the right direction. Further development towards Multidisciplinary Optimisation, involving experts in information technologies as well as case- based reasoning techniques is suggested and discussed.

An evolving set of modern physics-based, multi-disciplinary conceptual design methods seek to explore the feasibility of a new generation of systems, with new capabilities, capable of missions that conventional vehicles cannot be empirically redesigned to perform. These methods provide a more complete understanding of a concept's design space, forecasting the feasibility of uncertain systems, but are often computationally expensive and time consuming to prepare. This trend creates a unique and critical need to identify a manageable number of capable concept alternatives early in the design process. Ongoing efforts attempting to stretch capability through new architectures, like the U.S. Army's Future Vertical Lift effort and DARPA's Vertical Takeoff and Landing (VTOL) X-plane program highlight this need. The process of identifying and selecting a concept configuration is often given insufficient attention, especially when a small subset of favorable concept families is not immediately apparent. Commonly utilized methods for concept generation, like filtered morphological analysis, often identify an exponential number of alternatives. Simple approaches to concept selection then rely on designers to identify a relatively small subset of alternatives for comparison through simple methods regularly related to decision matrices (Pugh, TOPSIS, AHP, etc.). More in-depth approaches utilize modeling and simulation to compare concepts with techniques such as stochastic optimization or probabilistic decision making, but a complicated setup limits these approaches to just a discrete few alternatives. A new framework to identify and select promising, robust concept configurations utilizing fuzzy methods is proposed in this research and applied to the example problem of concept selection for DARPA's VTOL Xplane program. The framework leverages fuzzy systems in conjunction with morphological analysis to assess large design spaces of potential architecture alternatives while capturing the inherent uncertainty and ambiguity in the evaluation of these early concepts. Experiments show how various fuzzy systems can be utilized for evaluating criteria of interest across disparate architectures by modeling expert knowledge as well as simple physics-based data. The models are integrated into a single environment and variations on multi-criteria optimization are tested to demonstrate an ability to identify a non-dominated set of architectural families in a large combinatorial design space. The resulting framework is shown to provide an approach to quickly identify promising concepts in the face of uncertainty early in the design process.An evolving set of modern physics-based, multi-disciplinary conceptual design methods seek to explore the feasibility of a new generation of systems, with new capabilities, capable of missions that conventional vehicles cannot be empirically redesigned to perform. These methods provide a more complete understanding of a concept's design space, forecasting the feasibility of uncertain systems, but are often computationally expensive and time consuming to prepare. This trend creates a unique and critical need to identify a manageable number of capable concept alternatives early in the design process. Ongoing efforts attempting to stretch capability through new architectures, like the U.S. Army's Future Vertical Lift effort and DARPA's Vertical Takeoff and Landing (VTOL) X-plane program highlight this need. The process of identifying and selecting a concept configuration is often given insufficient attention, especially when a small subset of favorable concept families is not immediately apparent. Commonly utilized methods for concept generation, like filtered morphological analysis, often identify an exponential number of alternatives. Simple approaches to concept selection then rely on designers to identify a relatively small subset of alternatives for comparison through simple methods regularly related to decision matrices (Pugh, TOPSIS, AHP, etc.). More in-depth approaches utilize modeling and simulation to compare concepts with techniques such as stochastic optimization or probabilistic decision making, but a complicated setup limits these approaches to just a discrete few alternatives. A new framework to identify and select promising, robust concept configurations utilizing fuzzy methods is proposed in this research and applied to the example problem of concept selection for DARPA's VTOL Xplane program. The framework leverages fuzzy systems in conjunction with morphological analysis to assess large design spaces of potential architecture alternatives while capturing the inherent uncertainty and ambiguity in the evaluation of these early concepts. Experiments show how various fuzzy systems can be utilized for evaluating criteria of interest across disparate architectures by modeling expert knowledge as well as simple physics-based data. The models are integrated into a single environment and variations on multi-criteria optimization are tested to demonstrate an ability to identify a non-dominated set of architectural families in a large combinatorial design space. The resulting framework is shown to provide an approach to quickly identify promising concepts in the face of uncertainty early in the design process.

M.Ing. (Engineering Management) / The growing need for customized solutions and faster product delivery obliges the product development industry to develop new strategies that can enable the rapid and flexible design of products. Several design approaches have been developed to address this issue: one such is Knowledge-Based Engineering (KBE), which is a design technique that enables the automation of the design process. This approach consists of using computational intelligence to capture the design rules related to a product family in order to generate automatically customized designs adapted to particular customer requirements. Knowledge-Based Engineering is also used to facilitate the performance of design evaluation activities such as finite element analysis (FEA) and computational fluid dynamics (CFD) as part of multi-disciplinary design optimization (MDO). The application of this approach led to impressive results mostly in the automotive and aeronautical industry. Owing to this method, some companies manage to reduce the duration of the design process by 90%. Despite the excellent results obtained through the use of Knowledge-Based Engineering, there are still very few companies that make use of this approach in their design process. The review of the relevant literature showed that the lack of a standard easy-to-use methodology of implementation is one of the major obstacles to the expansion of Knowledge-Based Engineering. The knowledge processing phase constitutes one of the main challenges of the KBE implementation process. This phase consists of extracting and documenting the knowledge embedded in the design team in order to convert it in a programming code. Available methodologies such as MOKA and KNOMAD do not seem to provide easy-to-use methods to represent the design knowledge in a form that makes it easy to be programmed. The lack of a preliminary stage that justifies the adequacy of KBE for a particular design process is also an important gap identified in the literature.This dissertation discusses a detailed method that addresses issues related to knowledge processing and suitability analysis in KBE implementation. The knowledge processing method suggested is based on the Work Breakdown Structure (WBS) which is used widely in the system engineering approach and consists of a very logical classification of the design knowledge. The strength of this method lies in its ability to represent the design knowledge in a form that makes it understandable for both engineers and programmers. Appropriate representation of this sort shortens the duration of the knowledge processing and facilitates the knowledge programming phase. Regarding the rationale for choosing of KBE, a detailed suitability assessment method is proposed.

Siemens Energy develops, manufactures, and provides service of products utilized for production of green energy. This thesis has been conducted at Siemens Energy in Finspång and the department of steam turbine design. A major part of the work at the department includes service and updates of operating steam turbines located all around the world. The tasks of updating and service are short and require quick answers as the plant is waiting to be started. In order to adapt to the rapid development time required, the department of steam turbine design has developed a CAD automation process for drawing production of steam turbine diaphragms. The automation process is developed in an older CAD system that the department long have relied on. This CAD software and thus the automation process will soon be retired and taken out of service since the company is switching to the modern CAD software NX. This thesis is aimed at investigating the current development process at the department and propose and develop a new CAD automation process in NX for steam turbine diaphragms. The work was initiated by performing an analysis of the current situation where the collection of data constituted a solid ground for the rest of the thesis. The data lay the basis for the creation of a design specification which later served as a starting point for both the search and development of solution proposals regarding CAD automation. During the concept generation, it became clear that the development process embodied the scope of concepts, a form of application programming interface to achieve design automation was considered evident. This implied a more area-focused concept generation leading up to multiple solution concepts. After the generated solutions had been sorted and ranked, the solution to proceed with was based on NX integrated tool Knowledge Fusion to achieve CAD automation in NX. The development of the automation process and associated models utilized theories such as the MOKA methodology, high level cad templates and on explicit reference modeling. Resulting in a CAD automation process with possibilities to deliver both CAD models and technical drawings within a timeframe that reduces development time. It was concluded that the developed CAD automation process and associated models assured quality and reliability of the CAD material produced. Furthermore, the developed solution fit in the existing diaphragm development process and showed potential to significantly reduce the development time of steam turbine diaphragms.