In this paper the determination of pseudo Poisson’s ratio of woven fabric with a digital image co... more In this paper the determination of pseudo Poisson’s ratio of woven fabric with a digital image correlation method is presented. Measurements were performed on three cotton woven fabric samples which were prepared according the standard ISO 13934-1:1999. The fabric sample was exposed to tensile loading of 1% strain on a tensile test machine. Testing was simultaneous recording with a digital video camera. These video recordings were afterwards processed in the MATLAB program and the pseudo Poisson’s ratio determined according to the displacement in the x and y axis directions. The pseudo Poisson’s ratio was determined for three woven fabrics in the warp and weft directions. The results of the investigation show that the values of the pseudo Poisson’s ratio are in the range from 0.2 to 0.5, which agrees with results also found in the literature. According to the investigation it can be concluded that the value of the pseudo Poisson’s ratio depends on the weave type and the number of ya...
International Journal of Clothing Science and Technology, 2001
An investigation is presented of the impact of mechanical auxiliary devices on sewing-machines up... more An investigation is presented of the impact of mechanical auxiliary devices on sewing-machines upon the processing parameters of sewing operations. Processing parameters are investigated at an ergonomically designed workplace, on a modern sewing-machine, equipped with a processing microcomputer. Measuring samples are 300 to 1,000mm long, and stitching speeds are pre-programmed – 1,500 to 4,700rpm. Values for sewing operation processing parameters
International Journal of Clothing Science and Technology, 2007
PurposeThis paper aims to develop an efficient two‐variable minimisation algorithm and to apply i... more PurposeThis paper aims to develop an efficient two‐variable minimisation algorithm and to apply it in engineering optimisation of buttonhole reinforcements.Design/methodology/approachAn iterative extreme search is based on quadratic approximation of objective function, locating approximate solution at the minimum of corresponding elliptic paraboloid. Stress analysis is performed using plane stress finite element model. Optimal selection of geometrical parameters of buttonhole‐type reinforcement is done in terms of balance between maximum stress and material consumption.FindingsAdopted minimisation algorithm is assessed in a selected test example and proven to perform well in comparison with methods available in literature. In the selected case two local minima have been found within the predefined optimisation domain, with slight difference in objective function values.Research limitations/implicationsResearch is limited to homogeneous isotropic elastic model and a single representa...
International Journal of Clothing Science and Technology, 2003
A non-linear numerical simulation of a standard procedure for textile flexibility testing is perf... more A non-linear numerical simulation of a standard procedure for textile flexibility testing is performed using discretised beam bending model. Geometric non-linearity due to large deflections is traced using incremental method. Linear moment-curvature response is assumed, as well as constant curvature of a finite element of the beam. Numerical procedure is incorporated into a PC programme producing graphical results for the
International Journal of Clothing Science and Technology, 2005
Purpose – The purpose of this paper is to investigate and illustrate the possibilities of a syste... more Purpose – The purpose of this paper is to investigate and illustrate the possibilities of a systematic engineering approach in the design of mechanical reinforcements in garments. A mechanical reinforcement can be designed using optimisation strategies. Design/methodology/approach – In this work, an iterative algorithm for minimum search based on parabolic approximations is proposed and applied in the optimisation of mechanical reinforcement in a selected model problem of a buttonhole type. Findings – Optimisation algorithm based on parabolic approximations, in conjunction with the finite element analysis, offers some promising possibilities as support for the decision-making process in the design of mechanical reinforcements. The selection of optimisation criteria – influence parameters and corresponding weight factors – remains of course to be studied and implemented by the clothing engineering experts. Research limitations/implications – The intention in future work should be to optimise two or more geometric parameters simultaneously (multidimensional optimisation), and to produce a computer program for an automated optimum search. Practical implications – The contents of the paper could be useful for the experts in clothing engineering in the process of design or selection of the reinforcements of weak spots in textiles and garments. Originality/value – This paper provides optimisation routes to the weak sports of mechanical reinforcements in textiles and garments.
ABSTRACT Nonlinear tensile behavior of woven fabric is simulated using a simplified model of the ... more ABSTRACT Nonlinear tensile behavior of woven fabric is simulated using a simplified model of the basic cell in which tensile and bending resistances of the yarn are geometrically discretized. Geometry of the basic cell, which undergoes changes in the deformation process, is represented by the slope of the yarn. Geometric nonlinearity is accounted for by writing static equations in current configuration, and the corresponding nonlinear set of equations is solved incrementally. In order to compare the computed tensile curve with the one experimentally recorded in KES procedure of textile evaluation, residual deformation in unloading needs to be accounted for. This is done by introducing elastoplastic tensile response of the yarn into the nonlinear micromechanical model. In that way, the model covers both geometric and material nonlinearities in fabric deformation with a limited set of basic parameters. In order to refine the initial estimate of the parameters and make up for neglected secondary phenomena, the set of model parameters is optimized for best fit of computed and recorded tensile curves. The optimization is done using genetic algorithm. Very good accuracy is obtained, which seems promising for future engineering of woven fabrics.
ABSTRACT Nonlinear tensile behavior of woven fabric is simulated using a simplified model of the ... more ABSTRACT Nonlinear tensile behavior of woven fabric is simulated using a simplified model of the basic cell in which tensile and bending resistances of the yarn are geometrically discretized. Geometry of the basic cell, which undergoes changes in the deformation process, is represented by the slope of the yarn. Geometric nonlinearity is accounted for by writing static equations in current configuration, and the corresponding nonlinear set of equations is solved incrementally. In order to compare the computed tensile curve with the one experimentally recorded in KES procedure of textile evaluation, residual deformation in unloading needs to be accounted for. This is done by introducing elastoplastic tensile response of the yarn into the nonlinear micromechanical model. In that way, the model covers both geometric and material nonlinearities in fabric deformation with a limited set of basic parameters. In order to refine the initial estimate of the parameters and make up for neglected secondary phenomena, the set of model parameters is optimized for best fit of computed and recorded tensile curves. The optimization is done using genetic algorithm. Very good accuracy is obtained, which seems promising for future engineering of woven fabrics.
In this paper the determination of pseudo Poisson’s ratio of woven fabric with a digital image co... more In this paper the determination of pseudo Poisson’s ratio of woven fabric with a digital image correlation method is presented. Measurements were performed on three cotton woven fabric samples which were prepared according the standard ISO 13934-1:1999. The fabric sample was exposed to tensile loading of 1% strain on a tensile test machine. Testing was simultaneous recording with a digital video camera. These video recordings were afterwards processed in the MATLAB program and the pseudo Poisson’s ratio determined according to the displacement in the x and y axis directions. The pseudo Poisson’s ratio was determined for three woven fabrics in the warp and weft directions. The results of the investigation show that the values of the pseudo Poisson’s ratio are in the range from 0.2 to 0.5, which agrees with results also found in the literature. According to the investigation it can be concluded that the value of the pseudo Poisson’s ratio depends on the weave type and the number of ya...
International Journal of Clothing Science and Technology, 2001
An investigation is presented of the impact of mechanical auxiliary devices on sewing-machines up... more An investigation is presented of the impact of mechanical auxiliary devices on sewing-machines upon the processing parameters of sewing operations. Processing parameters are investigated at an ergonomically designed workplace, on a modern sewing-machine, equipped with a processing microcomputer. Measuring samples are 300 to 1,000mm long, and stitching speeds are pre-programmed – 1,500 to 4,700rpm. Values for sewing operation processing parameters
International Journal of Clothing Science and Technology, 2007
PurposeThis paper aims to develop an efficient two‐variable minimisation algorithm and to apply i... more PurposeThis paper aims to develop an efficient two‐variable minimisation algorithm and to apply it in engineering optimisation of buttonhole reinforcements.Design/methodology/approachAn iterative extreme search is based on quadratic approximation of objective function, locating approximate solution at the minimum of corresponding elliptic paraboloid. Stress analysis is performed using plane stress finite element model. Optimal selection of geometrical parameters of buttonhole‐type reinforcement is done in terms of balance between maximum stress and material consumption.FindingsAdopted minimisation algorithm is assessed in a selected test example and proven to perform well in comparison with methods available in literature. In the selected case two local minima have been found within the predefined optimisation domain, with slight difference in objective function values.Research limitations/implicationsResearch is limited to homogeneous isotropic elastic model and a single representa...
International Journal of Clothing Science and Technology, 2003
A non-linear numerical simulation of a standard procedure for textile flexibility testing is perf... more A non-linear numerical simulation of a standard procedure for textile flexibility testing is performed using discretised beam bending model. Geometric non-linearity due to large deflections is traced using incremental method. Linear moment-curvature response is assumed, as well as constant curvature of a finite element of the beam. Numerical procedure is incorporated into a PC programme producing graphical results for the
International Journal of Clothing Science and Technology, 2005
Purpose – The purpose of this paper is to investigate and illustrate the possibilities of a syste... more Purpose – The purpose of this paper is to investigate and illustrate the possibilities of a systematic engineering approach in the design of mechanical reinforcements in garments. A mechanical reinforcement can be designed using optimisation strategies. Design/methodology/approach – In this work, an iterative algorithm for minimum search based on parabolic approximations is proposed and applied in the optimisation of mechanical reinforcement in a selected model problem of a buttonhole type. Findings – Optimisation algorithm based on parabolic approximations, in conjunction with the finite element analysis, offers some promising possibilities as support for the decision-making process in the design of mechanical reinforcements. The selection of optimisation criteria – influence parameters and corresponding weight factors – remains of course to be studied and implemented by the clothing engineering experts. Research limitations/implications – The intention in future work should be to optimise two or more geometric parameters simultaneously (multidimensional optimisation), and to produce a computer program for an automated optimum search. Practical implications – The contents of the paper could be useful for the experts in clothing engineering in the process of design or selection of the reinforcements of weak spots in textiles and garments. Originality/value – This paper provides optimisation routes to the weak sports of mechanical reinforcements in textiles and garments.
ABSTRACT Nonlinear tensile behavior of woven fabric is simulated using a simplified model of the ... more ABSTRACT Nonlinear tensile behavior of woven fabric is simulated using a simplified model of the basic cell in which tensile and bending resistances of the yarn are geometrically discretized. Geometry of the basic cell, which undergoes changes in the deformation process, is represented by the slope of the yarn. Geometric nonlinearity is accounted for by writing static equations in current configuration, and the corresponding nonlinear set of equations is solved incrementally. In order to compare the computed tensile curve with the one experimentally recorded in KES procedure of textile evaluation, residual deformation in unloading needs to be accounted for. This is done by introducing elastoplastic tensile response of the yarn into the nonlinear micromechanical model. In that way, the model covers both geometric and material nonlinearities in fabric deformation with a limited set of basic parameters. In order to refine the initial estimate of the parameters and make up for neglected secondary phenomena, the set of model parameters is optimized for best fit of computed and recorded tensile curves. The optimization is done using genetic algorithm. Very good accuracy is obtained, which seems promising for future engineering of woven fabrics.
ABSTRACT Nonlinear tensile behavior of woven fabric is simulated using a simplified model of the ... more ABSTRACT Nonlinear tensile behavior of woven fabric is simulated using a simplified model of the basic cell in which tensile and bending resistances of the yarn are geometrically discretized. Geometry of the basic cell, which undergoes changes in the deformation process, is represented by the slope of the yarn. Geometric nonlinearity is accounted for by writing static equations in current configuration, and the corresponding nonlinear set of equations is solved incrementally. In order to compare the computed tensile curve with the one experimentally recorded in KES procedure of textile evaluation, residual deformation in unloading needs to be accounted for. This is done by introducing elastoplastic tensile response of the yarn into the nonlinear micromechanical model. In that way, the model covers both geometric and material nonlinearities in fabric deformation with a limited set of basic parameters. In order to refine the initial estimate of the parameters and make up for neglected secondary phenomena, the set of model parameters is optimized for best fit of computed and recorded tensile curves. The optimization is done using genetic algorithm. Very good accuracy is obtained, which seems promising for future engineering of woven fabrics.
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