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Julien Grandjean

Bio: Julien Grandjean is an academic researcher from University of Savoy. The author has contributed to research in topics: Surface roughness & Plane (geometry). The author has an hindex of 5, co-authored 9 publications receiving 109 citations. Previous affiliations of Julien Grandjean include University of Bordeaux & Polytech'Savoie.

Papers
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Journal ArticleDOI
TL;DR: In this paper, an original procedure is proposed to systematically analyze and quantify the assembly of parts with form and position defects and deformable contact surfaces. But this procedure is based on the traditional assumption that surfaces have no form defects and are rigid under external loads.
Abstract: Tolerancing activity is usually based on the traditional assumptions that surfaces have no form defects and are rigid under external loads. These assumptions tend to simplify the tolerance analysis of mechanical assemblies and hence the allocation of geometrical specifications. The present paper proposes an original procedure to systematically analyze and quantify the assembly of parts with form and position defects and deformable contact surfaces. Based on this procedure, stochastic simulations are performed by modifying the ratio between the position defects and form defects of surfaces. Even if the form defects are limited, they can lead to a non-compliant assembly. Clearly, the engineer's traditional approach, where form defects are assumed to have no influence, is generally not appropriate if we are to ensure that the expected performance is to be achieved on assembly.

40 citations

Journal ArticleDOI
TL;DR: In this paper, the role of surface defects on static flat seal efficiency is investigated on synthetic "turned-like" surfaces generated by combinations of the first 50 vibrational eigen modes determined from modal discrete decomposition.

38 citations

Journal ArticleDOI
TL;DR: In this article, the authors focus on surface defects of two plane surfaces of two carters assembly and propose a method to manage both form errors and sliding surfaces complexities in a Computer Aided Tolerancing process.

16 citations

Dissertation
29 Oct 2013
TL;DR: Marignier et al. as discussed by the authors developed a methode permettant d'etudier l'influence des defauts de forme on les performances of assemblages.
Abstract: La performance des mecanismes est intimement liee a la precision des surfaces qui composent les liaisons. La demarche habituelle de l’analyse de ces surfaces est basee sur des hypotheses fortes concernant leurs comportements. Ainsi, les defauts de forme et de rugosite sont negliges et les surfaces sont supposees infiniment rigides. L’objectif principal de ces travaux est de developper une methode permettant d’etudier l’influence des defauts de forme sur les performances des assemblages. Elle repose sur une methodologie et des outils pour l’identification des defauts qui vont optimiser ou penaliser les exigences fonctionnelles de l’assemblage. Dans ce manuscrit, deux cas d’etude sont proposes.Dans un premier temps, un montage de type bride (centrage court, appui plan) est etudie afin de valider l’ensemble de la demarche developpee. Les outils utilises reposent essentiellement sur la decomposition et composition modale des defauts, le concept de surface ecarts, la recherche de zone d’appui stable ainsi que la quantification des deformations de surfaces de contact basees sur des modeles analytiques ou numeriques. L’influence des defauts de forme sur la precision de mise en position est quantifiee par un domaine ecart de liaison. Une confrontation entre la demarche theorique et un dispositif experimental permet de valider l’approche. Par la suite, une liaison spherique est consideree constituant une prothese totale de hanche en materiau ceramique. Pour ce cas d’etude, l’objectif est d’identifier, au regard des typologies de defauts, leurs consequences sur l’apparition d’un phenomene sonore assimilable a du grincement appele le squeaking. La demarche reprend les memes etapes que celles utilisees avec l’etude de la bride. Differents dispositifs experimentaux sont mis en place confirmant la pertinence de cette approche. Des mesures specifiques apportent des elements d’analyse et de comprehension sur le comportement degrade de la liaison. Ce travail de these s’inscrit dans une collaboration entre 3 laboratoires : SYMME d’Annecy, I2M-IMC de Bordeaux-Talence, et la societe Tural localisee a Marignier (74), laboratoire de recherche industrielle qui travaille sur des implants medicaux.

12 citations

Journal ArticleDOI
TL;DR: This paper presents a metrological analysis of hip prosthesis components by highlighting the defects of form, waviness and roughness of these surfaces using a novel geometric parameterization (namely modal parameterization).
Abstract: This paper presents a metrological analysis of hip prosthesis components. When changing ceramic prostheses, the surgeon sometimes finds traces of alloy lying in the insert or the femoral head. These traces can be thin and accurate or as a wide band. From the measurements made on the contact areas of hip prosthesis components, we analyse these phenomena by highlighting the defects of form, waviness and roughness of these surfaces using a novel geometric parameterization (namely modal parameterization). The aim of this work is to isolate these defects to characterize the prostheses components. We show that this parameterization allows a multi-scale analysis of surfaces regardless of the type of wear of the prosthesis, and that the results offer some relevant explanations to the analysis of visible damage on the prostheses. In a later study, we are going to analyse the defects influence on the alteration of the performance of hip prostheses.

10 citations


Cited by
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Journal ArticleDOI
TL;DR: This work develops a semantic and theoretical framework and proposes a new system for organizing and designating multiscale analyses and characterizations of surface topographies from the engineering and scientific literature with an emphasis on production engineering research and design.
Abstract: This work studies multiscale analyses and characterizations of surface topographies from the engineering and scientific literature with an emphasis on production engineering research and design It highlights methods that provide strong correlations between topographies and performance or topographies and processes, and methods that can confidently discriminate topographies that were processed or that perform differently These methods have commonalities in geometric characterizations at certain scales, which are observable with statistics and measurements It also develops a semantic and theoretical framework and proposes a new system for organizing and designating multiscale analyses Finally, future possibilities for multiscale analyses are discussed

125 citations

Journal ArticleDOI
TL;DR: In this paper, a model composed of state-of-the-art models for the contact mechanics between rough metal surfaces and for the liquid flow through the rough aperture in-between them was developed.

74 citations

Journal ArticleDOI
TL;DR: In this article, the correlations between the topography of different damaged rough surfaces and process conditions were investigated by using Gaussian Filtering, Wavelet Transform and a more recent approach named Discrete Modal Decomposition.

62 citations

Journal ArticleDOI
TL;DR: A Metric Modal Decomposition (MMD) method is henceforth, developed to model the form defects of various parts in a mechanism, and the assemblies including form defects are further assessed using mathematical optimization.
Abstract: Tolerance analysis aims on checking whether specified tolerances enable functional and assembly requirements The tolerance analysis approaches discussed in literature are generally assumed without the consideration of parts’ form defects This paper presents a new model to consider the form defects in an assembly simulation A Metric Modal Decomposition (MMD) method is henceforth, developed to model the form defects of various parts in a mechanism The assemblies including form defects are further assessed using mathematical optimization The optimization involves two models of surfaces: real model and difference surface-base method, and introduces the concept of signed distance The optimization algorithms are then compared in terms of time consumption and accuracy To illustrate the methods and their respective applications, a simplified over-constrained industrial mechanism in three dimensions is also used as a case study

58 citations

Journal ArticleDOI
TL;DR: In this article, a geometrical quality assessment of an additive manufacturing product is presented, which includes a process oriented geometry model to predict the surface roughness and dimensional deviations, and a Geometrical simulation tool to assess the impacts of these deviations on the geometry of the joint.

49 citations