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Bhouri Naoufel - One of the best experts on this subject based on the ideXlab platform.
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Thermodynamic and dimensional behavior of textile materials under climatic variations
2009Co-Authors: Bhouri NaoufelAbstract:Ce travail constitue une contribution à l'étude de l'influence de la déformation libre des fibres textiles sous l'effet des contraintes hydriques sur la structure globale d'un tricot Jersey et d'un tissu Toile en coton, ayant subi les mêmes traitements de finition. Une comparaison entre les capacités de sorption du Jersey et des fils défilés de leur structure montre que le serrage géométrique limite les capacités de sorption du Jersey. Les coefficients du tenseur déformation plane du Jersey sous l'effet d'un cycle d'adsorption/désorption montre un gonflement croissant en fonction de l'humidité au moment de l'adsorption et un rétrécissement presque linéaire au moment de la désorption pour reprendre ses valeurs initiales marquant ainsi l'effet mémoire de l'état relaxé de la structure. L'influence du repassage sur le comportement de la Toile en coton sous l'effet de deux cycles continus successifs d'adsorption/désorption est étudiée. Les résultats montrent que l'aplatissement des fils dans la structure génère une amplification de la déformation plane résultante. Un deuxième cycle d'adsorption successif montre l'annulation complète de l'effet de repassage. Une comparaison entre les isothermes d'adsorption et de désorption d'un tissu Toile repassé et non repassé montre que les isothermes de sorption de la Toile repassée et non repassée se collent dés la troisième zone de l'isotherme du premier cycle d'adsorption, ce qui explique que l'encombrement stérique des molécules d'eau dans la structure de la Toile repassée génère un réarrangement stéréochimique de la structure supramoléculaire pour reprendre une forme similaire à la Toile non repassée.The 2D deformation of bleached plain weave and Jersey cotton ready to wear clothing was measured during adsorption and desorption cycles. The strain along warp and weft directions and the shear deformation were evaluated by image correlation Process. The dimensional variations are explained by geometrical consideration of the structure at microscopic (fibers scale) and macroscopic levels (yarns scale). Indeed, the reaction between water vapor molecules and material enlightens two steps. At first, the swelling fibers fill the micro pores inside the yarns. Then, the yarns swell and push on their neighbors to fill up the macro pores and cause the macroscopic swelling of the overall structure. During the desorption phase, the fibers shrink to create a free space inside the plain weave structure that will be relaxed to find its initial state. The shear deformation is related to the cohesion by twist between cotton fibers. The Ironing generates flattened yarns and increases their friction which amplifies the deformation during the first adsorption cycle. However, this effect is cancelled at the end of the first adsorption / desorption cycle with no memory effect of the Ironing Process. These results are confirmed by comparison between sorption isotherms of ironed and not ironed plain weave samples. A comparison between the sorption capacity of Jersey and yarn made of the same structure shows that the geometric form decreases the sorption capacity of jersey especially at high humidity. Then knitting infects the swelling of yarns and decreases their sorption capacity
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Comportement thermodynamique et dimensionnel des matériaux textiles soumis à des variations des conditions climatiques
2009Co-Authors: Bhouri Naoufel, Perre Patrick, Ben Nasrallah SassiAbstract:Ce travail constitue une contribution à l'étude de l'influence de la déformation libre des fibres textiles sous l'effet des contraintes hydriques sur la structure globale d'un tricot Jersey et d'un tissu Toile en coton, ayant subi les mêmes traitements de finition. Une comparaison entre les capacités de sorption du Jersey et des fils défilés de leur structure montre que le serrage géométrique limite les capacités de sorption du Jersey. Les coefficients du tenseur déformation plane du Jersey sous l'effet d'un cycle d'adsorption/désorption montre un gonflement croissant en fonction de l'humidité au moment de l'adsorption et un rétrécissement presque linéaire au moment de la désorption pour reprendre ses valeurs initiales marquant ainsi l'effet mémoire de l'état relaxé de la structure. L'influence du repassage sur le comportement de la Toile en coton sous l'effet de deux cycles continus successifs d'adsorption/désorption est étudiée. Les résultats montrent que l'aplatissement des fils dans la structure génère une amplification de la déformation plane résultante. Un deuxième cycle d'adsorption successif montre l'annulation complète de l'effet de repassage. Une comparaison entre les isothermes d'adsorption et de désorption d'un tissu Toile repassé et non repassé montre que les isothermes de sorption de la Toile repassée et non repassée se collent dés la troisième zone de l'isotherme du premier cycle d'adsorption, ce qui explique que l'encombrement stérique des molécules d'eau dans la structure de la Toile repassée génère un réarrangement stéréochimique de la structure supramoléculaire pour reprendre une forme similaire à la Toile non repassée.The 2D deformation of bleached plain weave and Jersey cotton ready to wear clothing was measured during adsorption and desorption cycles. The strain along warp and weft directions and the shear deformation were evaluated by image correlation Process. The dimensional variations are explained by geometrical consideration of the structure at microscopic (fibers scale) and macroscopic levels (yarns scale). Indeed, the reaction between water vapor molecules and material enlightens two steps. At first, the swelling fibers fill the micro pores inside the yarns. Then, the yarns swell and push on their neighbors to fill up the macro pores and cause the macroscopic swelling of the overall structure. During the desorption phase, the fibers shrink to create a free space inside the plain weave structure that will be relaxed to find its initial state. The shear deformation is related to the cohesion by twist between cotton fibers. The Ironing generates flattened yarns and increases their friction which amplifies the deformation during the first adsorption cycle. However, this effect is cancelled at the end of the first adsorption / desorption cycle with no memory effect of the Ironing Process. These results are confirmed by comparison between sorption isotherms of ironed and not ironed plain weave samples. A comparison between the sorption capacity of Jersey and yarn made of the same structure shows that the geometric form decreases the sorption capacity of jersey especially at high humidity. Then knitting infects the swelling of yarns and decreases their sorption capacity.NANCY1-Bib. numérique (543959902) / SudocSudocFranceF
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Comportement thermodynamique et dimensionnel des matériaux textiles soumis à des variations des conditions climatiques
HAL CCSD, 2009Co-Authors: Bhouri NaoufelAbstract:The 2D deformation of bleached plain weave and Jersey cotton ready to wear clothing was measured during adsorption and desorption cycles. The strain along warp and weft directions and the shear deformation were evaluated by image correlation Process. The dimensional variations are explained by geometrical consideration of the structure at microscopic (fibers scale) and macroscopic levels (yarns scale). Indeed, the reaction between water vapor molecules and material enlightens two steps. At first, the swelling fibers fill the micro pores inside the yarns. Then, the yarns swell and push on their neighbors to fill up the macro pores and cause the macroscopic swelling of the overall structure. During the desorption phase, the fibers shrink to create a free space inside the plain weave structure that will be relaxed to find its initial state. The shear deformation is related to the cohesion by twist between cotton fibers. The Ironing generates flattened yarns and increases their friction which amplifies the deformation during the first adsorption cycle. However, this effect is cancelled at the end of the first adsorption / desorption cycle with no memory effect of the Ironing Process. These results are confirmed by comparison between sorption isotherms of ironed and not ironed plain weave samples. A comparison between the sorption capacity of Jersey and yarn made of the same structure shows that the geometric form decreases the sorption capacity of jersey especially at high humidity. Then knitting infects the swelling of yarns and decreases their sorption capacity.Ce travail constitue une contribution à l'étude de l'influence de la déformation libre des fibres textiles sous l'effet des contraintes hydriques sur la structure globale d'un tricot Jersey et d'un tissu Toile en coton, ayant subi les mêmes traitements de finition. Une comparaison entre les capacités de sorption du Jersey et des fils défilés de leur structure montre que le serrage géométrique limite les capacités de sorption du Jersey. Les coefficients du tenseur déformation plane du Jersey sous l'effet d'un cycle d'adsorption/désorption montre un gonflement croissant en fonction de l'humidité au moment de l'adsorption et un rétrécissement presque linéaire au moment de la désorption pour reprendre ses valeurs initiales marquant ainsi l'effet mémoire de l'état relaxé de la structure. L'influence du repassage sur le comportement de la Toile en coton sous l'effet de deux cycles continus successifs d'adsorption/désorption est étudiée. Les résultats montrent que l'aplatissement des fils dans la structure génère une amplification de la déformation plane résultante. Un deuxième cycle d'adsorption successif montre l'annulation complète de l'effet de repassage. Une comparaison entre les isothermes d'adsorption et de désorption d'un tissu Toile repassé et non repassé montre que les isothermes de sorption de la Toile repassée et non repassée se collent dès la troisième zone de l'isotherme du premier cycle d'adsorption, ce qui explique que l'encombrement stérique des molécules d'eau dans la structure de la Toile repassée génère un réarrangement stéréochimique de la structure supramoléculaire pour reprendre une forme similaire à la Toile non repassée
W. J. Van Veenen - One of the best experts on this subject based on the ideXlab platform.
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Experimental and numerical study of the wall Ironing Process of polymer coated sheet metal
Mechanics of Materials, 2000Co-Authors: H. C.e. Van Der Aa, Maaike A. Van Der Aa, Paul J. Schreurs, Frank P T Baaijens, W. J. Van VeenenAbstract:In the traditional manufacturing Process for metal food and beverage containers, a food contact-safe lacquer is sprayed onto the can before filling. This time consuming and therefore expensive Process can be eliminated using a polymer coated sheet metal provided that the polymer will survive the manufacturing operations. The most critical stage in can making is the Ironing Process because of the large deformations that occur. This paper presents experimental and numerical results regarding the Ironing Process of polymer coated aluminum and polymer coated steel. A plane strain strip Ironing device has been constructed to investigate the influence of the Ironing reduction, velocity and die angle on the Process forces and friction. Furthermore, an in-situ study of the displacement and strain fields has been performed in the strip Ironing experiments using a digital image correlation technique. Simulations of the Process have been performed using an arbitrary Lagrange Euler method based on an operator splitting procedure (OS-ALE). The constitutive behaviour of metal and polymer has been modelled with a generalized compressible Leonov model with a Bodner-Partom and an Eyring viscosity function, respectively. The experimental results are in good agreement with numerical simulations.
Fpt Frank Baaijens - One of the best experts on this subject based on the ideXlab platform.
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modelling of the wall Ironing Process of polymer coated sheet metal
Mechanics of Materials, 2001Co-Authors: Pjg Piet Schreurs, Fpt Frank BaaijensAbstract:A numerical tool has been developed to analyse the wall Ironing Process of sheet metal coated with a polymer layer. Under industrial Processing condition, both sheet metal and polymer coating exhibit elasto-viscoplastic behaviour. The constitutive relations are incorporated in an Arbitrary Lagrange Euler (ALE) method, which is based on an operator splitting procedure. The convective part of this formulation is handled by the 6 Discontinuous Galerkin (DG) method. Simulation results of the forming Process are shown.
Hoon Huh - One of the best experts on this subject based on the ideXlab platform.
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tool design in a multi stage drawing and Ironing Process of a rectangular cup with a large aspect ratio using finite element analysis
International Journal of Machine Tools & Manufacture, 2002Co-Authors: Seho Kim, Seungho Kim, Hoon HuhAbstract:Tool design is carried out for a multi-stage deep drawing and Ironing Process of a rectangular cup with the large aspect ratio using the result of the finite element analysis. The analysis incorporates three-dimensional continuum elements for an elasto-plastic finite element method with the explicit time integration scheme using LS-DYNA3D. The analysis simulates the five-stage deep drawing and Ironing Process with the thickness control of the cup wall. Simulation is performed in order to investigate the failure by tearing during the forming Process at the initial state of tool design. The analysis reveals that the difference of the drawing ratio within the cross section induces non-uniform metal flow which causes severe local extension. The irregular contact condition between the blank and the die also induces non-uniform metal flow which causes local wrinkling. This paper identifies such unfavorable mechanism in the rectangular cup drawing with Ironing and proposes a new tool design with the guideline for modification in the design of the Process and the sequential tool shape. The finite element analysis result with the improved tool design confirms that the proposed design not only reduces the possibility of failure but also improves the quality of a deep-drawn product. The numerical result shows fair coincidence with the experimental result.
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optimum tool design in a multi stage rectangular cup drawing and Ironing Process with the large aspect ratio by the finite element analysis
Transactions of The Korean Society of Mechanical Engineers A, 2002Co-Authors: Seho Kim, Seungho Kim, Hoon HuhAbstract:Optimum tool design is carried out fur a multi-stage rectangular cup deep-drawing and Ironing Process with the large aspect ratio. Finite element simulation is carried out to investigate deformation mechanisms with the initial design made by an expert. The analysis considers the deep drawing Process with Ironing for the thickness control in the cup wall. The analysis reveals that the difference of the drawing ratio within the cross section and the irregular contact condition produce non-uniform metal flow to cause wrinkling and severe extension. For remedy, the modification guideline is proposed in the design of the tool and the Process. Analysis results confirm that the modified tool design not only improves the quality of a deep-drawn product but also reduces the possibility of failure. The numerical result shows fair coincidence with the experimental one. After tryouts of the tool shape, the rectangular cup has been produced in the transfer press.
Bao Meng - One of the best experts on this subject based on the ideXlab platform.
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deformation characteristic and geometrical size effect in continuous manufacturing of cylindrical and variable thickness flanged microparts
Journal of Materials Processing Technology, 2018Co-Authors: Bao Meng, Sanqiang ShiAbstract:Abstract The most critical issues in microforming technologies are tailoring the desirable product quality and ensuring the high productivity from application perspective. This is also the case for fabrication of cylindrical micro-pin and flanged micropart with nonuniform thickness. To realize continuous micromanufacturing of the hollow flanged micropart with variable thickness, an efficient progressive microforming method is proposed by using an integrated hole flanging-Ironing Process. In this Process, size effect and its affected deformation behavior and forming quality of the micropart are still not well known and knowing of them well is crucial in forming of the accurate shape and geometry of the microparts, tailoring the needed product properties and assuring the required qualities. This study thus aims at addressing these issues in terms of deformation load, forming kinematics, dimensional accuracy, defect formation and microstructural evolution based on an unequal-thickness flanged micropart produced by the developed progressive microforming system in which shearing, hole flanging-Ironing and blanking operations are realized progressively. The experimental results reveal that the length of the flanged micropart is reduced with the increasing grain size, while both the tapering angle and its scatter present an opposite tendency, which could be explained by the coupled model of free surface roughening and open-closed lubricant pockets. Furthermore, the dimensional accuracy, surface appearance and the defects including curved profile, singularity, wrinkling and irregularity are closely related to the initial material microstructure. Through realization and examination of the developed progressive microforming system and the finished microparts, the progressive hole flanging-Ironing Process is proven to be promising and efficient for continuous micromanufacturing of micro-scaled hollow geometries with higher flange and variable thickness.