Graph models for engineering design : Model encoding, and fidelity evaluation based on dataset and other sources of knowledge

Automatically extracting knowledge from small datasets with a valid causal ordering is a challenge for current state-of-The-Art methods in machine learning. Extracting other type of knowledge is important but challenging for multiple engineering fields where data are scarce and difficult to collect. This research aims to address this problem by presenting a machine learning-based modeling framework leveraging the knowledge available in fundamental units of the variables recorded from data samples, to develop parsimonious, explainable, and graph-based simulation models during the early design stages. The developed approach is exemplified using an engineering design case study of a spherical body moving in a fluid. For the system of interest, two types of intricated models are generated by (1) using an automated selection of variables from datasets and (2) combining the automated extraction with supplementary knowledge about functions and dimensional homogeneity associated with the variables of the system. The effect of design, data, model, and simulation specifications on model fidelity are investigated. The study discusses the interrelationships between fidelity levels, variables, functions, and the available knowledge. The research contributes to the development of a fidelity measurement theory by presenting the premises of a standardized, modeling approach for transforming data into measurable level of fidelities for the produced models. This research shows that structured model building with a focus on model fidelity can support early design reasoning and decision making using for example the dimensional analysis conceptual modeling (DACM) framework.publishedVersionPeer reviewe

Modélisation intégrée produit-process à l'aide d'une approche de méta-modélisation reposant sur une représentation sous forme de graphes: Application à la fabrication additive

Additive manufacturing (AM) has created a paradigm shift in product design and manufacturing sector due to its unique capabilities. However, the integration of AM technologies in mainstream production faces the challenge of ensuring reliable production and repeatable quality of parts. Toward this end, modeling and simulation play a significant role to enhance the understanding of the complex multi-physics nature of AM processes. In addition, a central issue in modeling AM technologies is the integration of different models and concurrent consideration of the AM process and the part to be manufactured. Hence, the ultimate goal of this research is to present and apply a modeling approach to develop integrated modelingin AM. Accordingly, the thesis oversees the product development process and presents the Dimensional Analysis Conceptual Modeling (DACM) framework to model the product and manufacturing processes at the design stages of the product development process. The framework aims at providing simulation capabilities and systematic search for weaknesses and contradictions to the models for the early evaluation of solution variants. The developed methodology is applied in multiple case studies to present models integrating AM processes and the parts to be manufactured. This thesis results show that the proposed modeling framework is not only able to model the product and manufacturing process but also provide the capability to concurrently model product and manufacturing process, and also integrate existing theoretical and experimental models. The DACM framework contributes to the design for additive manufacturing and helps the designer to anticipate limitations of the AM process and part design earlier in the design stage. In particular, it enables the designer to make informed decisions on potential designalterations and AM machine redesign, and optimized part design or process parameter settings. DACM framework shows potentials to be used as ametamodeling approach for additive manufacturing.La fabrication additive (FA) a initié un changement de paradigme dans le secteur de la conception et de la fabrication des produits grâce à ses capacités uniques. Cependant, l'intégration des technologies de fabrication additive dans la productique traditionnelle doit permettre d'assurer une production fiable et une qualité reproductible des pièces. Dans cette optique, la modélisation et la simulation jouent un rôle essentiel pour améliorer la compréhension de la nature complexe et multi-physique des procédés de fabrication additive. De plus, l’intégration simultanée de différents modèles multi-physiques et de la prise en compte du procédé utilisé et de la pièce constituent toujours un défi pour la modélisation de ces technologies. L’objectif final de cette recherche est de développer et d’appliquer une approche de modélisation permettant une modélisation intégrée de la fabrication additive. Cette thèse analyse le processus de développement du produit et présente une méthodologie innovante intitulée ‘Dimensional Analysis Conceptual Modeling’ (DACM) pour modéliser les produits et les procédés de fabrication aux différentes étapes de conception. La méthode a été développée pour permettre la simulation de modèles multi-physiques. Elle intègre également une recherche systématique de faiblesses et de contradictions dans une première évaluation des solutions potentielles au problème. La méthodologie développée est appliquée dans plusieurs études de cas afin de présenter des modèles intégrant les processus de fabrication additive et les pièces à fabriquer. Les résultats montrent que la méthodologie DACM permet de modéliser distinctement et simultanément le produit et le processus de fabrication. Cette méthodologie permet aussi d'intégrer les modèles théoriques et expérimentaux déjà existants. Elle contribue à la conception pour la fabrication additive et aide le concepteur à anticiper les limites des procédés et de la conception plus tôt dans les premières étapes de développement du produit. En particulier, cela permet de prendre les bonnes décisions selon les différentes possibilités d'optimiser la conception des pièces et le paramétrage des machines de fabrication additive pour aboutir à la solution la plus adaptée. La méthode permet également de détecter la nécessité de reconcevoir des machines existantes en détectant les faiblesses de celles-ci. Cette thèse montre que la méthode DACM peut être potentiellement utilisée comme une approche de méta-modélisation pour la fabrication additive

The Effects of Illicit Drug Trade on Stabilizing Macro-economy

Annaul production of more than 5000 tons of opiates in Afghanistan and the necessity of its traffic into other countries, affects on Iran’s economy as one of the Afghanistan’s neighboring countries. It is more imprtant when drug traffickers joined to new organized crime groups and run different kinds of criminal acts. On this basis, in this article the effects of illicit drug trade and other criminal acts on macro-economy is studied by by using experiences of some countries. Although some researchers believe that funding the criminal acts in countries which have broad financial activities is more than other economies, there are signs that other countries are not protected from this issue. Illicit drug trade consists %20 of money supply in Colombia where central bank officials are faced with some problems. Owing to the special conditions of Iran where is passing through economical period, in this article the experiences of the countries that have been faced with fund-related criminal acts in implementing their reforms and stabilizing policies are addressed. Such experiences indicate that in economical reforming process, informal markets are emerged and informal (underground) economical sections neuteralize governmental policies. In Russia, for example, the lack of an effective banking system and specified exchange market as well as a legal risk-taking system have resulted in arise of an informal system. In one hand, informal systems which obtain their financial resources through criminal acts, keep the faced prices in a high level and in the other hand, influence heavily over financial policies through increasing interest rates and loaning in informal markets. The experiences of reforming economies indicate that the behaviour of their governments is not under control and they promote informal system (underground economy) by serious interventions or unlimited loaning. This article is also contemplating privitization and liberating policies in the conditions that informal economy acts under the support of criminal organizations

Product-process integrated meta-modeling using a graph-based approach : Application to additive manufacturing

La fabrication additive (FA) a initié un changement de paradigme dans le secteur de la conception et de la fabrication des produits grâce à ses capacités uniques. Cependant, l'intégration des technologies de fabrication additive dans la productique traditionnelle doit permettre d'assurer une production fiable et une qualité reproductible des pièces. Dans cette optique, la modélisation et la simulation jouent un rôle essentiel pour améliorer la compréhension de la nature complexe et multi-physique des procédés de fabrication additive. De plus, l’intégration simultanée de différents modèles multi-physiques et de la prise en compte du procédé utilisé et de la pièce constituent toujours un défi pour la modélisation de ces technologies. L’objectif final de cette recherche est de développer et d’appliquer une approche de modélisation permettant une modélisation intégrée de la fabrication additive. Cette thèse analyse le processus de développement du produit et présente une méthodologie innovante intitulée ‘Dimensional Analysis Conceptual Modeling’ (DACM) pour modéliser les produits et les procédés de fabrication aux différentes étapes de conception. La méthode a été développée pour permettre la simulation de modèles multi-physiques. Elle intègre également une recherche systématique de faiblesses et de contradictions dans une première évaluation des solutions potentielles au problème. La méthodologie développée est appliquée dans plusieurs études de cas afin de présenter des modèles intégrant les processus de fabrication additive et les pièces à fabriquer. Les résultats montrent que la méthodologie DACM permet de modéliser distinctement et simultanément le produit et le processus de fabrication. Cette méthodologie permet aussi d'intégrer les modèles théoriques et expérimentaux déjà existants. Elle contribue à la conception pour la fabrication additive et aide le concepteur à anticiper les limites des procédés et de la conception plus tôt dans les premières étapes de développement du produit. En particulier, cela permet de prendre les bonnes décisions selon les différentes possibilités d'optimiser la conception des pièces et le paramétrage des machines de fabrication additive pour aboutir à la solution la plus adaptée. La méthode permet également de détecter la nécessité de reconcevoir des machines existantes en détectant les faiblesses de celles-ci. Cette thèse montre que la méthode DACM peut être potentiellement utilisée comme une approche de méta-modélisation pour la fabrication additive.Mots-clés: Fabrication Additive, Conception Pour la Fabrication Additive, Modélisation Intégrée, Développement de Produit, Dimensional Analysis Conceptual Modeling FrameworkAdditive manufacturing (AM) has created a paradigm shift in product design and manufacturing sector due to its unique capabilities. However, the integration of AM technologies in the mainstream production faces the challenge of ensuring reliable production and repeatable quality of parts. Toward this end, Modeling and simulation play a significant role to enhance the understanding of the complex multi-physics nature of AM processes. In addition, a central issue in modeling AM technologies is the integration of different models and concurrent consideration of the AM process and the part to be manufactured. Hence, the ultimate goal of this research is to present and apply a modeling approach to develop integrated modeling in additive manufacturing. Accordingly, the thesis oversees the product development process and presents the Dimensional Analysis Conceptual Modeling (DACM) Framework to model the product and manufacturing processes at the design stages of product development process. The Framework aims at providing simulation capabilities and systematic search for weaknesses and contradictions to the models for the early evaluation of solution variants. The developed methodology is applied in multiple case studies to present models integrating AM processes and the parts to be manufactured. This thesis results show that the proposed modeling framework is not only able to model the product and manufacturing process but also provide the capability to concurrently model product and manufacturing process, and also integrate existing theoretical and experimental models. The DACM framework contributes to the design for additive manufacturing and helps the designer to anticipate limitations of the AM process and part design earlier in the design stage. In particular, it enables the designer to make informed decisions on potential design alterations and AM machine redesign, and optimized part design or process parameter settings. DACM Framework shows potentials to be used as a metamodeling approach for additive manufacturing

Function modelling combined with physics-based reasoning for assessing design options and supporting innovative ideation

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Modeling of the Process Parameters Influencing Cold Metal Transfer (CMT): Development of an Approach Based in Causal Networks

The new Additive Manufacturing technologies combined with other transformations such as increasing digitalization and automation are creating new opportunities and associated challenges. For all the AM technologies, both functional and topological design of parts need to be completely reconsidered, for example, it becomes possible to integrate multiple functions into a single part. From the manufacturing process outlook, the links between process parameters and design requirements have to be unveiled. Discovering those links is a challenging process because of the existence of cross-impacts. The nature of the relationships is also probably highly nonlinear in some cases. Using a traditional design of experiment approach to discover those links might be time-consuming and the number of parameters to test might be enormous. This article applies an approach based on SI metrics combined with the functional representation of the manufacturing process to form causal-graphs. Those graphs are used in a preliminary phase to generate models of the interrelations between manufacturing and design parameters. Those models are also used to guide the experimental process and to minimize the amount of experiments to be conducted to validate the model. The approach is applied to the Cold Metal Transfer (CMT) technology currently in test in our laboratorypublishedVersio

Identification of fundamental requirements for ideal metamodeling framework in additive manufacturing

publishedVersio

An Investigation of the Influence of Viscosity and Printing Parameters on the Extrudate Geometry in the Material Extrusion Process

The material extrusion process is one of the most popular additive manufacturing processes. The presence of porosity in the MEX printed parts, which ultimately deteriorates the mechanical properties, is one of the main drawbacks of the MEX process. The porosity in the structure is related to the shape of the adjacent beads and overlapping during the material deposition. Due to the deposition nature of the MEX process, the porosity cannot be entirely removed from the printed parts. Understanding the influence of process parameters on material deposition and the rheological properties is crucial to improving the quality of the final product. In this study, the two-phase-flow numerical approach with the level-set equations has been used for the first time to model the material deposition on the moving platform in 3D. The influence of the viscosity and printing parameters, including travel speed, inlet velocity, viscosity, nozzle diameter, and layer height, on the width of the deposited bead has been investigated. The simulation results are validated against experimental measurements with an average error of 5.92%. The width measured by the experimental study shows good agreement with the results of the numerical simulation. The comparison between the results of the 3D numerical simulation and 2D simulation reveals that the 2D simulation is not appropriate and accurate enough to predict the geometry of the deposited bead with the given set of parameter settings. The key novelty of this research paper is the application of the level-set method in a 3D context for material deposition on a moving substrate