During early stages of the design process, designers investigate the design alternatives by consi... more During early stages of the design process, designers investigate the design alternatives by considering several criteria and their own experience. There is a lack of tools to support decision, so a trial and error iterative design process is commonly used. Design choices are relating to continuous and discrete design variables. Therefore, the design space appears to be very broad and quite difficult to explore. In this paper, after a rapid summery of existing technique based on CSP coupled to interval analysis solver, a framework for the reliable exploration of design space is proposed. It is shown that there is different level of taking into account the reliability aspect in preliminary design. Then, the study of the reliability of a solution is proposed. In this case, it consists in defining a link between the design variables and the product to be designed. Then, the concept of flexibility in the constraint relations is defined, in the aim to find solutions which are less sensiti...
International Journal on Interactive Design and Manufacturing (IJIDeM), 2011
Abstract In the industrial design process,“trial-and-error” loops are usually used between design... more Abstract In the industrial design process,“trial-and-error” loops are usually used between design departments and simulation departments, to design and validate a candidate solution. Such a solution is defined by instantiated design variables, characterizing the ...
The interactive product design is of major economic and strategic importance in the development o... more The interactive product design is of major economic and strategic importance in the development of new and innovative industrial products and processes. Designers have to deal with new constraints coming from the increasing customer requirements, the new environmental constraints (fuel consumption, emission of dioxide of carbon…), the constant mutation of the product and the continuous needed of specialist employees to drive and realize such products and processes. The research in interactive product design is related ...
Advances in Integrated Design and Manufacturing in Mechanical Engineering II, 2007
The deep drawing process consists in realizing parts with complex shapes like different kind of b... more The deep drawing process consists in realizing parts with complex shapes like different kind of boxes, cups, etc., from a metal sheet. These parts are obtained through one or several stamping steps. The tool setup motion of the stamping process is difficult to obtain. It requires practice and special knowledge on the process. The design is long and difficult to optimize. It is expensive in machining tool operations because it needs many trials and modifications on the tool before obtaining the right shape and the good working of the tool. The mains reasons of these difficulties come from the strain heterogeneity, the spring back after the tool removing and the decrease of thickness. There are many influent parameters for this kind of process. They modify directly the shape of the part. These parameters can be listed in three different categories: Firstly, the parameters linked to the tool geometry like the die enter radius, the punch diameter and the clearance between die and punch. Secondly, the parameters linked to the manufacturing conditions like the stamping speed, the lubricant and the blank holder force. And thirdly, the parameters linked to the flank geometry.
International Journal on Interactive Design and Manufacturing (IJIDeM), 2011
ABSTRACT During the early phases of design processes, designers have to take the best decisions i... more ABSTRACT During the early phases of design processes, designers have to take the best decisions in order to converge quickly toward the most preferred design solution. More precisely, in a preliminary design context, the phase of embodiment design consists in determining the best values for the main dimensioning parameters of the system to improve its performances. In general, these performances must satisfy functional or technical requirements related to design objectives. The balancing act between the satisfaction of constraints and objectives can be treat as a multiobjective optimization problem. Although designers often face to a qualitative evaluation of design solutions, difficulty arises from his ability to express preferences and expectations throughout the objective function of the multiobjective optimization problem. Illustrated through the preliminary design of a two stage flash evaporator, the purpose of this article aims to develop a methodology to formulate both constraints and preferences into the optimization model. Thus design solutions are evaluated with a single global indicator of confidence. Flash evaporators are thermal systems which are mainly used for flash cooling and juice concentration applications. The design of such a system has to respect specific constraints related to these areas of applications and should meet multiple design objectives. Several goal-oriented design solutions are discussed, in particular when low design sensitivity is expected.
2013 International Conference on Advanced Logistics and Transport, 2013
The integration of the environmental dimension is crucial in industrial activity. Designers shoul... more 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 finally on a 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.
This paper deals with tolerancing analysis, deterministic calculation and fiabilist approaches. T... more This paper deals with tolerancing analysis, deterministic calculation and fiabilist approaches. The analysis of the rotor/stator clearance at the tip of the blades of a turboshaft engine of helicopter is proposed. Deterministic approach allows to quantify the clearance value in the worst case. A probabilist calculation is applied and allows to quantify the failure probability of the engine, when the calculated value is outside of the requirements in the worst case. Then, the different calculations based on reliable sensitivity analysis and associated results can aid the designer to determine geometrical specifications in order to define a more robust engine.
This article describes tolerance analysis using a reliability-based approach to ensuring that a f... more This article describes tolerance analysis using a reliability-based approach to ensuring that a functional condition is satisfied. A particular feature of this procedure is that it defines the combined effects of geometric and dimensional ISO specifications for product parts, and the architectural parameters that define the relative positions of parts in contact. In the first part, we describe configuring the product parameters by geometric deviations and from this a global model is produced to characterise the variation in rotor/stator clearance in a turboshaft engine turbine. This model relies on tolerance zone dimensions, dimensional tolerances and architectural parameters. When clearance is examined using the reliability-based approach, links emerge between the turbine's architectural parameters and its geometric and dimensional specifications. Indicators can then be deduced which guide the designer in selecting the optimum turbine architectures.
In this paper, an experimental and a model study of a stamping operation are presented. The exper... more In this paper, an experimental and a model study of a stamping operation are presented. The experiment gives local information, thanks to strain and temperature fields measures obtained by a visible and an infrared camera observing the blank side during the forming operation. Temperature variations close to +10K were measured in the front free blank side, at the final forming stage. A simplified, adiabatic, thermomechanical finite element model of the forming step is proposed. It leads to admissible load and local strain fields in regards to the experimental data. The temperature variations, in qualitative agreement, are over-estimated, because of the hypothesis of adiabaticity. However, they give an upper bound of the temperature variations.
Controlling variability and process optimization are major issues of manufacturing processes whic... more Controlling variability and process optimization are major issues of manufacturing processes which should be tackled together since optimal processes must be robust. There is a lack of numerical tool combining optimization and robustness. In this paper, a complete approach starting from modelling and leading to the selection of robust optimal process parameters is proposed. A model of stamping part is developed through Finite Element simulation codes and validated by experimental methods. The search for optimal tool configurations is performed by optimizing a desirability function and by means of a genetic algorithm based optimization code. Several tool configurations are selected from the resulting solutions and are observed through robustness analysis. Noise parameters relating to friction and material mechanical properties are taken into consideration during this analysis. A quadratic response surface developed with Design Of Experiments (DOE) links noise parameters to geometrical variations of parts. For every optimal configuration, the rate of non-conform parts which don't satisfy the design requirements is assessed and the more robust tool configuration is selected. Finally, a sensitivity analysis is performed on this ultimate configuration to observe the respective influence of noise parameters on the process scattering. The method has been applied on a U shape parts.
Journal of Manufacturing Science and Engineering, 2007
This work is a development from the INETFORSMEP European project. It was proposed to realize a gl... more This work is a development from the INETFORSMEP European project. It was proposed to realize a global optimization of a deep drawing industrial progression (made of several stages) for a cup manufacture. The objectives of the process were the thickness decrease and the geometrical parameters (especially the height). This paper completes this previous work in the aim of mastering the contour defect. From the optimal configuration, we are looking for minimizing the needed material and the number of forming operations. Our action is focused on the appearance of undesirable undulations (ears) located in the rim of the cups during forming, due to non-uniform crystallographic texture. These undulations can cause a significant amount of scrap, productivity loss and undesired cost during manufacture. In this paper, this phenomenon causes the use of five forming operations for the cup manufacture. The focus is to cut down from five to two forming stages by defining an optimal blank (size and shape). The advantage is to reduce the cost of the tool manufacturing and to minimize the needed material (by suppressing the part flange). The envisaged approach consists in defining a particular description of the ears' part by modal decomposition and then simulating several blank shapes and sizes generated by discrete cosine transformation (DCT). The use of a numerical simulation for the forming operation and the design of experiment technique allows to find mathematical links between the ears' formation and the DCT coefficients. An optimization is then possible by using mathematical links. This original approach leads to reduce the ears' amplitude by ten, with only fifteen numerical experiments. Moreover, we have downsized the number of forming stages from five to two with minimal material use.
During early stages of the design process, designers investigate the design alternatives by consi... more During early stages of the design process, designers investigate the design alternatives by considering several criteria and their own experience. There is a lack of tools to support decision, so a trial and error iterative design process is commonly used. Design choices are relating to continuous and discrete design variables. Therefore, the design space appears to be very broad and quite difficult to explore. In this paper, after a rapid summery of existing technique based on CSP coupled to interval analysis solver, a framework for the reliable exploration of design space is proposed. It is shown that there is different level of taking into account the reliability aspect in preliminary design. Then, the study of the reliability of a solution is proposed. In this case, it consists in defining a link between the design variables and the product to be designed. Then, the concept of flexibility in the constraint relations is defined, in the aim to find solutions which are less sensiti...
International Journal on Interactive Design and Manufacturing (IJIDeM), 2011
Abstract In the industrial design process,“trial-and-error” loops are usually used between design... more Abstract In the industrial design process,“trial-and-error” loops are usually used between design departments and simulation departments, to design and validate a candidate solution. Such a solution is defined by instantiated design variables, characterizing the ...
The interactive product design is of major economic and strategic importance in the development o... more The interactive product design is of major economic and strategic importance in the development of new and innovative industrial products and processes. Designers have to deal with new constraints coming from the increasing customer requirements, the new environmental constraints (fuel consumption, emission of dioxide of carbon…), the constant mutation of the product and the continuous needed of specialist employees to drive and realize such products and processes. The research in interactive product design is related ...
Advances in Integrated Design and Manufacturing in Mechanical Engineering II, 2007
The deep drawing process consists in realizing parts with complex shapes like different kind of b... more The deep drawing process consists in realizing parts with complex shapes like different kind of boxes, cups, etc., from a metal sheet. These parts are obtained through one or several stamping steps. The tool setup motion of the stamping process is difficult to obtain. It requires practice and special knowledge on the process. The design is long and difficult to optimize. It is expensive in machining tool operations because it needs many trials and modifications on the tool before obtaining the right shape and the good working of the tool. The mains reasons of these difficulties come from the strain heterogeneity, the spring back after the tool removing and the decrease of thickness. There are many influent parameters for this kind of process. They modify directly the shape of the part. These parameters can be listed in three different categories: Firstly, the parameters linked to the tool geometry like the die enter radius, the punch diameter and the clearance between die and punch. Secondly, the parameters linked to the manufacturing conditions like the stamping speed, the lubricant and the blank holder force. And thirdly, the parameters linked to the flank geometry.
International Journal on Interactive Design and Manufacturing (IJIDeM), 2011
ABSTRACT During the early phases of design processes, designers have to take the best decisions i... more ABSTRACT During the early phases of design processes, designers have to take the best decisions in order to converge quickly toward the most preferred design solution. More precisely, in a preliminary design context, the phase of embodiment design consists in determining the best values for the main dimensioning parameters of the system to improve its performances. In general, these performances must satisfy functional or technical requirements related to design objectives. The balancing act between the satisfaction of constraints and objectives can be treat as a multiobjective optimization problem. Although designers often face to a qualitative evaluation of design solutions, difficulty arises from his ability to express preferences and expectations throughout the objective function of the multiobjective optimization problem. Illustrated through the preliminary design of a two stage flash evaporator, the purpose of this article aims to develop a methodology to formulate both constraints and preferences into the optimization model. Thus design solutions are evaluated with a single global indicator of confidence. Flash evaporators are thermal systems which are mainly used for flash cooling and juice concentration applications. The design of such a system has to respect specific constraints related to these areas of applications and should meet multiple design objectives. Several goal-oriented design solutions are discussed, in particular when low design sensitivity is expected.
2013 International Conference on Advanced Logistics and Transport, 2013
The integration of the environmental dimension is crucial in industrial activity. Designers shoul... more 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 finally on a 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.
This paper deals with tolerancing analysis, deterministic calculation and fiabilist approaches. T... more This paper deals with tolerancing analysis, deterministic calculation and fiabilist approaches. The analysis of the rotor/stator clearance at the tip of the blades of a turboshaft engine of helicopter is proposed. Deterministic approach allows to quantify the clearance value in the worst case. A probabilist calculation is applied and allows to quantify the failure probability of the engine, when the calculated value is outside of the requirements in the worst case. Then, the different calculations based on reliable sensitivity analysis and associated results can aid the designer to determine geometrical specifications in order to define a more robust engine.
This article describes tolerance analysis using a reliability-based approach to ensuring that a f... more This article describes tolerance analysis using a reliability-based approach to ensuring that a functional condition is satisfied. A particular feature of this procedure is that it defines the combined effects of geometric and dimensional ISO specifications for product parts, and the architectural parameters that define the relative positions of parts in contact. In the first part, we describe configuring the product parameters by geometric deviations and from this a global model is produced to characterise the variation in rotor/stator clearance in a turboshaft engine turbine. This model relies on tolerance zone dimensions, dimensional tolerances and architectural parameters. When clearance is examined using the reliability-based approach, links emerge between the turbine's architectural parameters and its geometric and dimensional specifications. Indicators can then be deduced which guide the designer in selecting the optimum turbine architectures.
In this paper, an experimental and a model study of a stamping operation are presented. The exper... more In this paper, an experimental and a model study of a stamping operation are presented. The experiment gives local information, thanks to strain and temperature fields measures obtained by a visible and an infrared camera observing the blank side during the forming operation. Temperature variations close to +10K were measured in the front free blank side, at the final forming stage. A simplified, adiabatic, thermomechanical finite element model of the forming step is proposed. It leads to admissible load and local strain fields in regards to the experimental data. The temperature variations, in qualitative agreement, are over-estimated, because of the hypothesis of adiabaticity. However, they give an upper bound of the temperature variations.
Controlling variability and process optimization are major issues of manufacturing processes whic... more Controlling variability and process optimization are major issues of manufacturing processes which should be tackled together since optimal processes must be robust. There is a lack of numerical tool combining optimization and robustness. In this paper, a complete approach starting from modelling and leading to the selection of robust optimal process parameters is proposed. A model of stamping part is developed through Finite Element simulation codes and validated by experimental methods. The search for optimal tool configurations is performed by optimizing a desirability function and by means of a genetic algorithm based optimization code. Several tool configurations are selected from the resulting solutions and are observed through robustness analysis. Noise parameters relating to friction and material mechanical properties are taken into consideration during this analysis. A quadratic response surface developed with Design Of Experiments (DOE) links noise parameters to geometrical variations of parts. For every optimal configuration, the rate of non-conform parts which don't satisfy the design requirements is assessed and the more robust tool configuration is selected. Finally, a sensitivity analysis is performed on this ultimate configuration to observe the respective influence of noise parameters on the process scattering. The method has been applied on a U shape parts.
Journal of Manufacturing Science and Engineering, 2007
This work is a development from the INETFORSMEP European project. It was proposed to realize a gl... more This work is a development from the INETFORSMEP European project. It was proposed to realize a global optimization of a deep drawing industrial progression (made of several stages) for a cup manufacture. The objectives of the process were the thickness decrease and the geometrical parameters (especially the height). This paper completes this previous work in the aim of mastering the contour defect. From the optimal configuration, we are looking for minimizing the needed material and the number of forming operations. Our action is focused on the appearance of undesirable undulations (ears) located in the rim of the cups during forming, due to non-uniform crystallographic texture. These undulations can cause a significant amount of scrap, productivity loss and undesired cost during manufacture. In this paper, this phenomenon causes the use of five forming operations for the cup manufacture. The focus is to cut down from five to two forming stages by defining an optimal blank (size and shape). The advantage is to reduce the cost of the tool manufacturing and to minimize the needed material (by suppressing the part flange). The envisaged approach consists in defining a particular description of the ears' part by modal decomposition and then simulating several blank shapes and sizes generated by discrete cosine transformation (DCT). The use of a numerical simulation for the forming operation and the design of experiment technique allows to find mathematical links between the ears' formation and the DCT coefficients. An optimization is then possible by using mathematical links. This original approach leads to reduce the ears' amplitude by ten, with only fifteen numerical experiments. Moreover, we have downsized the number of forming stages from five to two with minimal material use.
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Papers by Yann Ledoux