Linking objective and subjective modeling in engineering design through arc-elastic dominance

Engineering design in mechanics is a complex activity taking into account both objective modeling processes derived from physical analysis and designers’ subjective reasoning. This paper introduces arc-elastic dominance as a suitable concept for ranking design solutions according to a combination of objective and subjective models. Objective models lead to the aggregation of information derived from physics, economics or eco-environmental analysis into a performance indicator. Subjective models result in a confidence indicator for the solutions’ feasibility. Arc-elastic dominant design solutions achieve an optimal compromise between gain in performance and degradation in confidence. Due to the definition of arc-elasticity, this compromise value is expressive and easy for designers to interpret despite the difference in the nature of the objective and subjective models. From the investigation of arc-elasticity mathematical properties, a filtering algorithm of Pareto-efficient solutions is proposed and illustrated through a design knowledge modeling framework. This framework notably takes into account Harrington’s desirability functions and Derringer’s aggregation method. It is carried out through the re-design of a geothermal air conditioning system

Eco-innovative Method to Improve the Distribution Phase of Product

The integration of the environmental dimension is crucial in industrial activity. Designers should integrate the new environmental constraints to adapt their approaches and methodologies in the framework of eco-innovation of industrial products and consumer goods. This paper proposes a new method integrating ecological aspects into the innovation process composed of three main stages: an analysis and structuring of the product, the formalization of the problem and the resolution phase. According to the structuring and the design objectives, actions can be selected and allow to guide the design to the most relevant modification to perform on the product. An illustration of the approach is applied on the optimization of the environmental impacts related to the logistical aspects

Optimizing the Architecture of a Dynamic Spinal Implant for Customized Mechanical Behavior

Non-fusion technology in spine surgery reduces surgical morbidity and degeneration of the adjacent levels by the insertion of dynamic spinal implants. Despite these advantages, a dynamic spinal implant (DSI) generates complications which require clinical follow-up, the continuous development of constructive solutions and structured optimization of the implant architecture using current mechanical design methods. This study structures this optimization process of a DSI concept by incorporating the mechanical behavior of the device, design variables and functional requirements into a global design model. The geometric (descriptive anatomy) and mechanical (materials, components, etc.) characteristics are obtained from a literature review. By combining these parameters, variables and requirements, appropriate values can be determined. The resulting mathematical model is then used to design and implement a device that is suitably adapted in movements and stiffness. The model assumes linear or non-linear behavior. We describe the optimization of the design variables to ensure the correct functioning of the mechanism when adapted to the patient. The optimization purpose is to determine the architecture of the implant, the choice of materials and the geometric parameters of implantation. An optimized implant model corresponding to specific degrees of degeneration in the intervertebral joint can then be envisaged

Influence des défauts de forme sur les performances d'assemblages (application aux prothèses totales de hanche)

La performance des mécanismes est intimement liée à la précision des surfaces qui composent les liaisons. La démarche habituelle de l analyse de ces surfaces est basée sur des hypothèses fortes concernant leurs comportements. Ainsi, les défauts de forme et de rugosité sont négligés et les surfaces sont supposées infiniment rigides. L objectif principal de ces travaux est de développer une méthode permettant d étudier l influence des défauts de forme sur les performances des assemblages. Elle repose sur une méthodologie et des outils pour l identification des défauts qui vont optimiser ou pénaliser les exigences fonctionnelles de l assemblage. Dans ce manuscrit, deux cas d étude sont proposés.Dans un premier temps, un montage de type bride (centrage court, appui plan) est étudié afin de valider l ensemble de la démarche développée. Les outils utilisés reposent essentiellement sur la décomposition et composition modale des défauts, le concept de surface écarts, la recherche de zone d appui stable ainsi que la quantification des déformations de surfaces de contact basées sur des modèles analytiques ou numériques. L influence des défauts de forme sur la précision de mise en position est quantifiée par un domaine écart de liaison. Une confrontation entre la démarche théorique et un dispositif expérimental permet de valider l approche. Par la suite, une liaison sphérique est considérée constituant une prothèse totale de hanche en matériau céramique. Pour ce cas d étude, l objectif est d identifier, au regard des typologies de défauts, leurs conséquences sur l apparition d un phénomène sonore assimilable à du grincement appelé le squeaking. La démarche reprend les mêmes étapes que celles utilisées avec l étude de la bride. Différents dispositifs expérimentaux sont mis en place confirmant la pertinence de cette approche. Des mesures spécifiques apportent des éléments d analyse et de compréhension sur le comportement dégradé de la liaison. Ce travail de thèse s inscrit dans une collaboration entre 3 laboratoires : SYMME d Annecy, I2M-IMC de Bordeaux-Talence, et la société Tural localisée à Marignier (74), laboratoire de recherche industrielle qui travaille sur des implants médicaux.The performance of a mechanism is closely correlated with the accuracy of the surfaces that make up the mechanical joint. The most common approach used to study these surfaces is based on strong assumptions about their behavior. Form errors and roughness are neglected and the surfaces are assumed infinitely rigid. The main objective of this work is to develop an original approach to study the impact of form errors on the assemblies. It is mainly based on a methodology and associated tools to predict which defects will optimize or penalize the functional requirements of the assembly. In this manuscript, two case studies are proposed. In a first step, a plate flange (ball and cylinder joints added to a planar joint) is designed to validate the overall approach. Modal decomposition of defects, sum-surface concept, the determination of a stable contact area and quantification of contact deformation of surfaces correspond to the main theoretical tools used in this framework. The influence of form errors on the positioning accuracy is quantified by a clearance domain. Comparisons between theoretical approach and experimental setup are used to validate the models. Subsequently, a spherical joint is considered corresponding to a total hip implant with ceramic material. The objective of this study is to identify which type of form errors can impact the appearance of the squeaking phenomena. The same procedure is followed as for the first example. In parallel, several experimental devices are designed to validate the relevance of this approach. Specific measurements provide some key elements to understand the behavior of the implant subject to squeaking. This work is part of a collaboration between three laboratories : SYMME Annecy, I2M-IMC Bordeaux, and Tural company located in Marignier (74), an industrial research laboratory working on medical implants.SAVOIE-SCD - Bib.électronique (730659901) / SudocGRENOBLE1/INP-Bib.électronique (384210012) / SudocGRENOBLE2/3-Bib.électronique (384219901) / SudocSudocFranceF

Influence des défauts de forme dans les assemblages de surfaces planes

Ce papier propose de se focaliser sur les déformations locales des liaisons particulière de type appui plan centrage court couramment utilisée pour la jonction entre deux carters (corps de pompe, turbomoteur ). L'approche proposée permet de mettre en évidence sur un cas simple l'importance de la prise en compte des défauts de forme dans le comportement des liaisons et d'étudier l'influence des déformations locales sur la performance finale d'un mécanisme. Le niveau de performance sera exprimé en fonction du taux de non conformité d'une spécification fonctionnelle de l'assemblage

Influence des défauts de forme sur le comportement des liaisons (étude expérimentale et théorique)

L objectif de l étude est d identifier le comportement des liaisons d un mécanisme du point de vue des déplacements en fonction des défauts de forme et des jeux. Le sujet est abordé selon une approche théorique et une approche expérimentale.La partie théorique montre la dualité entre les deux concepts utilisés : le domaine jeu et la surface convexe des différences. Elle montre également la typologie des domaines et l influence des incertitudes de forme sur ces domaines.En parallèle, un dispositif expérimental est développé. Il permet, non seulement, de réaliser la mesure des déplacements dans la liaison avec l exactitude nécessaire, mais aussi, de valider les résultats par une simulation de l assemblage à partir de la mesure 3D des surfaces en contact. L expérimentation porte sur plusieurs couples de surfaces comportant des défauts de forme de différents types. L'influence d'un chargement mécanique est étudiée afin de quantifier les déformations locales de surfaces de contact et l'évolution des écarts de position entre les pièces.The aim of the study is to identify, in terms of displacements, the joint behavior of a mechanism in function of form defects and gaps. Two approaches are proposed : a theoretical approach and an experimental one.The theoretical part presents the duality between the two concepts used in the experimental approach : gap hull and convex difference surface. It outlines also the typology of gap hulls and the influence of the form uncertainties on gap hulls.In parallel, an experimental device is developed. It allows, not only, to carry out the measure of displacements in the joint with the necessary accuracy, but also, to validate the results by an assembly simulation from the 3D measurement of the surfaces in contact. The experimentation involves several pairs of surfaces with different types of form defects. The influence of mechanical loads is studied in order to quantify the local deformation of the surfaces in contact and the evolution of location deviations between these surfaces.BORDEAUX1-Bib.electronique (335229901) / SudocSudocFranceF

Chemical characterization and in vitro toxicity on human bronchial epithelial cells BEAS-2B of PM2.5_{2.5} from an urban site under industrial emission influence

Particulate Matter (PM) is one of the most relevant environment-related health issues all over the world. In 2013, the International Agency for Research on Cancer (IARC) has classified air pollution and PM as a carcinogen for humans [1]. However, the mechanisms involved in the toxicity of these particles remains poorly understood, mainly because PM are uniquely complex owing to their physicochemical characteristics. In this study, fine particles were collected in the city center of Dunkirk, northern France using a 5 stages high volume cascade impactor (Staplex® 235, 68m3/h) and a Digitel DA80 high volume sampler (30m3/h).Samples were extensively characterized for their physico-chemical properties, including trace metals, water-soluble ions and organic species. Normal human bronchial epithelial cells (BEAS-2B) were used as cell model for toxicological analysis. Cytotoxicity, PAHs-metabolizing enzymes gene expression and genotoxic alterations were evaluated after 24, 48 or 72 h of exposure considering increasing concentrations of PM$_{2.5-0.3}$, organic extracts (OE) and water-soluble fraction (WF) of PM$_{2.5-0.3}$ and PM$_{2.5}$. Several sources such as road traffic, industrial activities mainly related to steelmaking, marine emissions including sea-salts and shipping, as well as soil resuspension were found to contribute to the PM$_{2.5}$ composition. Cytotoxicity assessment results showed time and dose dependent responses, with effects mainly related to PAH compounds in PM$_{2.5}$ OE in which their content were 12 times higher than in PM$_{2.5-0.3}$ one [2]. Differences in the induction of CYP1A1, CYP1B1 and NQO1 genes expression involved in the metabolic activation of organic compounds, as well as genotoxic effects (oxidative DNA adducts, H2A.X phosphorylation) were also evidenced after cells exposure to OE and PM$_{2.5-0.3}$ [3]. These results confirm the major effect of organic compounds on toxic effects, but also the potential contribution of the inorganic fraction of the PM which maintains longer the effects in exposed cells

Parsimonious analysis for eco-innovation of products

The integration of the environmental dimension is crucial in industrial activity. Designers should integrate the new environmental constraints to adapt their approaches and methodologies in the framework of eco-innovation of industrial products and consumer goods. This paper proposes a new method integrating ecological aspects into the innovation process. We analyze different tools proposed in the literature to determine the relevant parameters to consider for assuring an efficient methodology. Relevant parameters are related to different phases in the lifecycle of the product and it is proposed to link them to different impacts on the environment. Actions are set up to guide engineers in the early phase of concept generation for eco-innovation. The methodology is essentially based on functional analysis, energy analysis and physical analysis of products and problem solving tools stemming from Triz theory

Typology of geometrical defects in Electron Beam Melting

Quality control in terms of material health, texture and workpiece geometry is not assured in additive manufacturing. Many literature studies address quality issues on a scale of less than one millimeter. On the other hand, few works concern geometrical defects at the level of the piece as a whole (form and dimension), on a scale therefore greater than several millimeters. From the existing bibliography and the authors’ experience, the objective of the article is to list the typologies of geometrical defects usually encountered and the configurations in which they appear.Maîtrise géométrique des pièces produites par fabrication additive métalliqu

Analyse de la variation géométrique des pièces produites en fabrication additive EBM - Cas de pièces avec volume surplombant

National audienceL'étude proposée consiste à étudier les types de défauts obtenus en fabrication additive EBM (Electron Beam Melting) pour cela, une géométrie particulière a été choisie avec un volume en surplomb. Les défauts géométriques les plus importants se sont localisés sur la face avant (perte de bord) et le dessous de la pièce (variation d'épaisseur). Afin de caractériser la forme des défauts, une Analyse en Composantes Principales (ACP) a été mise en oeuvre et permet d'identifier les modes les plus significatifs de chacun des lots de pièces produits. A partir de ces analyses, il en ressort que les défauts dépendent de la stratégie de fabrication et que les pièces placées sur la périphérie du plateau présentent des défauts de grandes amplitudes