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The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material.Tue, 27 Feb 2024 21:27:15 GMT2024-02-27T21:27:15ZAK-ILS: An Active learning method based on Kriging for the Inspection of Large Surfaces
http://hdl.handle.net/10985/9294
AK-ILS: An Active learning method based on Kriging for the Inspection of Large Surfaces
DUMAS, Antoine; ECHARD, Benjamin; GAYTON, Nicolas; ROCHAT, Olivier; VAN DER VEEN, Sjoerd; DANTAN, Jean-Yves
Tolerance verification permits to check the product conformity and to verify assumptions made by the designer. For conformity assessment, the uncertainty associated with the values of the measurands must be known. In fact, to evaluate form characteristics of large aircraft structure workpieces, sampling is required, so a measurement error is present: exact estimation of form characteristics would require complete knowledge of the surface. To minimise this measurement error, this paper presents a Krigingbased procedure to identify the minimum of measured points to check the conformity with a given confidence level. The proposed method is validated on a simple example of orientation tolerance and then performed to inspect the form defect on three large aircraft workpieces.
Tue, 01 Jan 2013 00:00:00 GMThttp://hdl.handle.net/10985/92942013-01-01T00:00:00ZDUMAS, AntoineECHARD, BenjaminGAYTON, NicolasROCHAT, OlivierVAN DER VEEN, SjoerdDANTAN, Jean-YvesTolerance verification permits to check the product conformity and to verify assumptions made by the designer. For conformity assessment, the uncertainty associated with the values of the measurands must be known. In fact, to evaluate form characteristics of large aircraft structure workpieces, sampling is required, so a measurement error is present: exact estimation of form characteristics would require complete knowledge of the surface. To minimise this measurement error, this paper presents a Krigingbased procedure to identify the minimum of measured points to check the conformity with a given confidence level. The proposed method is validated on a simple example of orientation tolerance and then performed to inspect the form defect on three large aircraft workpieces.Impact of a behavior model linearization strategy on the tolerance analysis of over-constrained mechanisms
http://hdl.handle.net/10985/9291
Impact of a behavior model linearization strategy on the tolerance analysis of over-constrained mechanisms
DUMAS, Antoine; GAYTON, Nicolas; DANTAN, Jean-Yves
All manufactured products have geometrical variations which may impact their functional behavior. Tolerance analysis aims at analyzing the influence of these variations on product behavior, the goal being to evaluate the quality level of the product during its design stage. Analysis methods must verify whether specified tolerances enable the assembly and functional requirements. This paper first focuses on a literature overview of tolerance analysis methods which need to deal with a linearized model of the mechanical behavior. Secondly, the paper shows that the linearization impacts the computed quality level and thus may mislead the conclusion about the analysis. Different linearization strategies are considered, it is shown on an over-constrained mechanism in 3D that the strategy must be carefully chosen in order to not over-estimate the quality level. Finally, combining several strategies allows to define a confidence interval containing the true quality level.
Thu, 01 Jan 2015 00:00:00 GMThttp://hdl.handle.net/10985/92912015-01-01T00:00:00ZDUMAS, AntoineGAYTON, NicolasDANTAN, Jean-YvesAll manufactured products have geometrical variations which may impact their functional behavior. Tolerance analysis aims at analyzing the influence of these variations on product behavior, the goal being to evaluate the quality level of the product during its design stage. Analysis methods must verify whether specified tolerances enable the assembly and functional requirements. This paper first focuses on a literature overview of tolerance analysis methods which need to deal with a linearized model of the mechanical behavior. Secondly, the paper shows that the linearization impacts the computed quality level and thus may mislead the conclusion about the analysis. Different linearization strategies are considered, it is shown on an over-constrained mechanism in 3D that the strategy must be carefully chosen in order to not over-estimate the quality level. Finally, combining several strategies allows to define a confidence interval containing the true quality level.A new system formulation for the tolerance analysis of overconstrained mechanisms
http://hdl.handle.net/10985/17421
A new system formulation for the tolerance analysis of overconstrained mechanisms
DUMAS, Antoine; GAYTON, Nicolas; SUDRET, Bruno; DANTAN, Jean-Yves
The goal of tolerance analysis is to verify whether design tolerances enable a mechanism to be functional. The current method consists in computing a probability of failure using Monte Carlo simulation combined with an optimization scheme called at each iteration. This time consuming technique is not appropriate for complex overconstrained systems. This paper proposes a transformation of the current tolerance analysis problem formulation into a parallel system probability assessment problem using the Lagrange dual form of the optimization problem. The number of events being very large, a preliminary selective search algorithm is used to identify the most contributing events to the probability of failure value. The First Order Reliability Method (FORM) for systems is eventually applied to compute the probability of failure at low cost. The proposed method is tested on an overconstrained mechanism modeled in three dimensions. Results are consistent with those obtained with the Monte Carlo simulation and the computing time is significantly reduced.
Thu, 01 Jan 2015 00:00:00 GMThttp://hdl.handle.net/10985/174212015-01-01T00:00:00ZDUMAS, AntoineGAYTON, NicolasSUDRET, BrunoDANTAN, Jean-YvesThe goal of tolerance analysis is to verify whether design tolerances enable a mechanism to be functional. The current method consists in computing a probability of failure using Monte Carlo simulation combined with an optimization scheme called at each iteration. This time consuming technique is not appropriate for complex overconstrained systems. This paper proposes a transformation of the current tolerance analysis problem formulation into a parallel system probability assessment problem using the Lagrange dual form of the optimization problem. The number of events being very large, a preliminary selective search algorithm is used to identify the most contributing events to the probability of failure value. The First Order Reliability Method (FORM) for systems is eventually applied to compute the probability of failure at low cost. The proposed method is tested on an overconstrained mechanism modeled in three dimensions. Results are consistent with those obtained with the Monte Carlo simulation and the computing time is significantly reduced.An iterative statistical tolerance analysis procedure to deal with linearized behavior models
http://hdl.handle.net/10985/17422
An iterative statistical tolerance analysis procedure to deal with linearized behavior models
DUMAS, Antoine; GAYTON, Nicolas; BLES, Thomas; LOEBL, Robin; DANTAN, Jean-Yves
Tolerance analysis consists of analyzing the impact of variations on the mechanism behavior due to the manufacturing process. The goal is to predict its quality level at the design stage. The technique involves computing probabilities of failure of the mechanism in a mass production process. The various analysis methods have to consider the componentâ€™s variations as random variables and the worst configuration of gaps for over-constrained systems. This consideration varies in function by the type of mechanism behavior and is realized by an optimization scheme combined with a Monte Carlo simulation. To simplify the optimization step, it is necessary to linearize the mechanism behavior into several parts. This study aims at analyzing the impact of the linearization strategy on the probability of failure estimation; a highly over-constrained mechanism with two pins and five cotters is used as an illustration for this study. The purpose is to strike a balance among model error caused by the linearization, computing time, and result accuracy. In addition, an iterative procedure is proposed for the assembly requirement to provide accurate results without using the entire Monte Carlo simulation.
Thu, 01 Jan 2015 00:00:00 GMThttp://hdl.handle.net/10985/174222015-01-01T00:00:00ZDUMAS, AntoineGAYTON, NicolasBLES, ThomasLOEBL, RobinDANTAN, Jean-YvesTolerance analysis consists of analyzing the impact of variations on the mechanism behavior due to the manufacturing process. The goal is to predict its quality level at the design stage. The technique involves computing probabilities of failure of the mechanism in a mass production process. The various analysis methods have to consider the componentâ€™s variations as random variables and the worst configuration of gaps for over-constrained systems. This consideration varies in function by the type of mechanism behavior and is realized by an optimization scheme combined with a Monte Carlo simulation. To simplify the optimization step, it is necessary to linearize the mechanism behavior into several parts. This study aims at analyzing the impact of the linearization strategy on the probability of failure estimation; a highly over-constrained mechanism with two pins and five cotters is used as an illustration for this study. The purpose is to strike a balance among model error caused by the linearization, computing time, and result accuracy. In addition, an iterative procedure is proposed for the assembly requirement to provide accurate results without using the entire Monte Carlo simulation.Mathematical issues in mechanical tolerance analysis
http://hdl.handle.net/10985/6574
Mathematical issues in mechanical tolerance analysis
GAYTON, Nicolas; ETIENNE, Alain; QURESHI, Ahmed Jawad; DUMAS, Antoine; DANTAN, Jean-Yves
The aim of this paper is to provide an overview of tolerance analysis. Tolerancing decisions can profoundly impact the quality and cost of product. There is a strong need for increased attention to tolerance design to enable high-precision assemblies to be manufactured at lower costs. Indeed, tolerance analysis is a key element in industry for improving product quality. Designers want tight tolerances to assure product performance; manufacturers prefer loose tolerances to reduce cost. There is a critical need for a quantitative design tool for specifying tolerances. Tolerance analysis brings the engineering design requirements and manufacturing capabilities together in a common model, where the effects of tolerance specifications on both design and manufacturing requirements can be evaluated quantitatively. Significant amount of literature is related to tolerancing methods. Summaries of state of the art, the most recent developments, and the future trends in tolerancing research can be found. This paper provides a classification of the issues from a mathematical point of view.
Sun, 01 Jan 2012 00:00:00 GMThttp://hdl.handle.net/10985/65742012-01-01T00:00:00ZGAYTON, NicolasETIENNE, AlainQURESHI, Ahmed JawadDUMAS, AntoineDANTAN, Jean-YvesThe aim of this paper is to provide an overview of tolerance analysis. Tolerancing decisions can profoundly impact the quality and cost of product. There is a strong need for increased attention to tolerance design to enable high-precision assemblies to be manufactured at lower costs. Indeed, tolerance analysis is a key element in industry for improving product quality. Designers want tight tolerances to assure product performance; manufacturers prefer loose tolerances to reduce cost. There is a critical need for a quantitative design tool for specifying tolerances. Tolerance analysis brings the engineering design requirements and manufacturing capabilities together in a common model, where the effects of tolerance specifications on both design and manufacturing requirements can be evaluated quantitatively. Significant amount of literature is related to tolerancing methods. Summaries of state of the art, the most recent developments, and the future trends in tolerancing research can be found. This paper provides a classification of the issues from a mathematical point of view.