- Composite Materials and Structures, Finite Element Analysis (Engineering), Polymer Engineering, Heat Transfer, Textile Engineering, Composites, and 9 morePolymer Composites, Thermal Analysis, Chemical Shrinkage, Cure Behavior, Thermosetting Resins, Rheometer, Moulding behaviour, Multilayer Interlock Fabric, and Carbon Compositesedit
- A PhD in Mechanical Engineering with focus on composite materials from Université de Nantes France, have experience o... moreA PhD in Mechanical Engineering with focus on composite materials from Université de Nantes France, have experience of working with known European industrial groups dealing with composite materials and ONERA (The French Aerospace Lab). Currently working as an Assistant Professor, teaching undergraduate, MS and PhD level classes and doing research on 2D, 3D textile fabrics, finite element analysis and composite materials.edit
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ABSTRACT In this article, numerical simulation of suspension (particles filled-resin) flow through a fibrous media taking into account dual scale porosity in LCM (Liquid Composite Molding) processes is presented. During the flow, a strong... more
ABSTRACT In this article, numerical simulation of suspension (particles filled-resin) flow through a fibrous media taking into account dual scale porosity in LCM (Liquid Composite Molding) processes is presented. During the flow, a strong interaction between the particle motion and the fluid flow takes place at the porous media wall (the fiber bundle surface). In this study, the Stokes–Darcy coupling is used to describe the resin flow at mesoscopic scale to treat the particles in suspension. A “fluid” model to describe the suspension flow, a “filtration” model to describe the particle capture and a “solid” model dedicated to the modeling of mass particles dynamics was used. The “solid” model is also operated to identify the particles retention.
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The aim of this study was to investigate the effect of elastane linear density, thread density, and weave float on the stretch, recovery, and compression properties of bi-stretch woven fabrics for compression garments. Fabric samples were... more
The aim of this study was to investigate the effect of elastane linear density, thread density, and weave float on the
stretch, recovery, and compression properties of bi-stretch woven fabrics for compression garments. Fabric samples were
produced using elastane core-spun cotton yarns both in the warp and weft. The elastane linear density, fabric thread
density, and weave float size were used as input variables while fabric contraction, subgarment pressure, fabric stretch,
and recovery were taken as response variables. Two different elastane linear densities, i.e. 44 and 78 dtex, two different
thread densities, and three different weave designs, i.e. 1/1 plain, 2/2 z-twill, and 3/3 z-twill were used. The results of
fabric samples were analyzed in Minitab statistical software. The coefficients of determinations (R-sq values) of the
regression equations showed good prediction ability of the developed statistical models. The findings of the study may
be helpful in deciding appropriate manufacturing specifications of bi-stretch fabrics to attain specific stretch, recovery,
and compression properties.
stretch, recovery, and compression properties of bi-stretch woven fabrics for compression garments. Fabric samples were
produced using elastane core-spun cotton yarns both in the warp and weft. The elastane linear density, fabric thread
density, and weave float size were used as input variables while fabric contraction, subgarment pressure, fabric stretch,
and recovery were taken as response variables. Two different elastane linear densities, i.e. 44 and 78 dtex, two different
thread densities, and three different weave designs, i.e. 1/1 plain, 2/2 z-twill, and 3/3 z-twill were used. The results of
fabric samples were analyzed in Minitab statistical software. The coefficients of determinations (R-sq values) of the
regression equations showed good prediction ability of the developed statistical models. The findings of the study may
be helpful in deciding appropriate manufacturing specifications of bi-stretch fabrics to attain specific stretch, recovery,
and compression properties.
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ABSTRACT Seersucker is a thin puckered woven fabric in which some threads bunched together, giving a wrinkled appearance in place. Conventionally seersucker fabric is produced on weaving machines with some special warp tensioning devices.... more
ABSTRACT Seersucker is a thin puckered woven fabric in which some threads bunched together, giving a wrinkled appearance in place. Conventionally seersucker fabric is produced on weaving machines with some special warp tensioning devices. The aim of this work was to develop knitted seersucker fabric on single cylinder weft knitting machine using plain jersey structure. Core spun cotton yarn and cotton plain yarn of same linear density were fed at regular intervals to the feeders on the machine. The produced sample has a regular puckering stripe along the width of the fabric with same height. Air permeability and moisture management tests of wet processed samples were performed. The results indicated that the knitted seersucker fabric has good comfort properties as well as better aesthetic appearance
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Control and optimization of curing process is very important for the production of high quality composite parts. Crosslinking of molecules of thermoset resin occurs in this phase, which involves exothermy of reaction, chemical shrinkage... more
Control and optimization of curing process is very important for the production of high quality composite parts. Crosslinking of molecules of thermoset resin occurs in this phase, which involves exothermy of reaction, chemical shrinkage (Sh) and development of thermo-physical and thermo-mechanical properties. Exact knowledge of the evolution of all these parameters is required for the better understanding and improvement of the fabrication process. Sh is one such property of thermoset matrix, which is difficult to characterize due to its coupling with thermal expansion/contraction. A number of techniques have been used to determine volume Sh of thermoset matrix, which later on has been used to find tensor of Sh for the simulation of residual stresses and shape distortion of composite part, etc. Direct characterization of volume Sh of composites has also been made by some authors. Though not much, but some work has also been reported to determine the Sh of composite part in a specific direction. In this article, all the techniques used in the literature for the characterization of Sh of resin and composite are reported briefly with their respective advantages, disadvantage and important results.
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Thermal expansion is an important property to define the end use application, and to model residual stresses and related problems in a composite part. Thus its accurate determination is essential. In laminated composites, this parameter... more
Thermal expansion is an important property to define the end use application, and to model residual stresses and related problems in a composite part. Thus its accurate determination is essential. In laminated composites, this parameter depends largely on the orientation of fibres, fibre fraction, type of resin and reinforcement, etc. In this article, numerical results on the coefficients of thermal expansion (CTE) at different angles in the composite plates (having different stacking sequences of plies) found using finite element analysis are presented. Experimental values of these coefficients for [0/90] are found in satisfactory agreement with the simulations. Finally, a mathematical model is proposed for modelling these coefficients.
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The use of thermoset composites has increased remarkably during the recent past in naval, automobile and aeronautical applications. Despite superior mechanical behaviour, certain problems, e.g. shape distortion, fibre buckling and matrix... more
The use of thermoset composites has increased remarkably during the recent past in naval, automobile and aeronautical applications. Despite superior mechanical behaviour, certain problems, e.g. shape distortion, fibre buckling and matrix cracking, are induced in composite part, especially during fabrication due to the heterogeneous nature of such materials. Excellent control of the curing process is required for production of a composite part with required shape and properties. For an accurate simulation of the curing process, exact knowledge of cure-dependent polymer properties and heat transfer is needed. Several instruments are required to identify these parameters, which is time consuming, and costly. In the present study, results on the simultaneous characterization of bulk modulus, chemical shrinkage and degree of cure of vinylester resin using PVT-α device are presented. Determination of cure and temperature-dependent thermal conductivity of the matrix using the same device is also discussed. The obtained results are compared with the available literature results.
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Multilayer woven reinforcements are increasingly employed in the domain of composite materials. Delamination occurrence and resultant failure of a laminated composite piece subjected to high vibrations, is an issue of much concern in... more
Multilayer woven reinforcements are increasingly employed in the domain of composite materials. Delamination occurrence and resultant failure of a laminated composite piece subjected to high vibrations, is an issue of much concern in aeronautics. The situation becomes more complex in case of bended/curved pieces. In order to improve through the thickness mechanical properties, 3D-woven multilayer interlock fabric is used as composite reinforcement. Structural changes, i.e. thickness change, relative slippage of layers, change in tow aspect ratio and change of orientation of the tows columns, etc. occur in such fabrics during the forming process. These changes may lead to the gradient of the resin amount in composite, internal stresses and variations of mechanical properties in the piece. No significant research has been conducted on this aspect. Lack of knowledge or neglecting these changes may lead to prejudicial estimations of ultimate mechanical properties and fracture analysis. In the present article, the changes that occurred in 5-layer and 13-layer 3D-woven multilayer interlock fabrics have been studied, when moulded at five different angles and two different bending radii. A significant change in thickness, tow aspect ratio, tow orientation and relative layer slippage is observed.
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Quantification and understanding of the evolution of chemical shrinkage of thermoset polymers is of crucial importance for modelling of residual strains and stresses. Thermal properties of resin and the strong coupling between chemical... more
Quantification and understanding of the evolution of chemical shrinkage of thermoset polymers is of crucial importance for modelling of residual strains and stresses. Thermal properties of resin and the strong coupling between chemical reactions and thermal fields lead to non-negligible thermal and curing degree gradients in the part. In this paper, modelling of the volume chemical shrinkages of an unsaturated epoxy vinylester resin and associated glass fibre composites is proposed, by taking into account the coupling between volume variation and thermal gradients. Modelling is also compared with the measurements done with a home-made instrument (PVT–α). Results suggest that chemical shrinkage is non linear as a function of degree of cure. Moreover, for an equal mass of resin, chemical shrinkage of resin carrying fibres is lesser than the neat resin.
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Residual deformations and stresses formation in the thermoset-laminated composite is a frequently studied subject in the recent years. During fabrication, the laminated composites undergo chemical deformation during cross-linking and... more
Residual deformations and stresses formation in the thermoset-laminated composite is a frequently studied subject in the recent years. During fabrication, the laminated composites undergo chemical deformation during cross-linking and thermal deformation while cooling. In thin laminates, due to large displacements and complex evolution of shape, these deformations can only be explained by using nonlinear strain–displacement relationship. In the present article, we calculated together for the first time, the thermal and chemical deformations occurring in carbon/epoxy laminates by considering a nonlinear geometrical approach to understand the evolution of shape and hence residual stresses induced during fabrication process. The effect of fibre fraction on the chemical and thermal deformations is studied as well.