J.W. Eischen and Y.G. Kim
Uses a general large displacement beam theory to formulate a finite element‐based numerical method for simulating fabric drape, manipulation and contact. Presents numerical…
Abstract
Uses a general large displacement beam theory to formulate a finite element‐based numerical method for simulating fabric drape, manipulation and contact. Presents numerical results corresponding to real fabric materials. Shows a broad class of fabric mechanics problems including how these effects can be solved.
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J. Ascough, H.E. Bez and A.M. Bricis
Uses Newmark’s method to carry out a time‐stepping finite element analysis to predict the behaviour of a cloth garment as it falls from an initial horizontal position to a final…
Abstract
Uses Newmark’s method to carry out a time‐stepping finite element analysis to predict the behaviour of a cloth garment as it falls from an initial horizontal position to a final position draped around a human body form. Bases the finite element model on a simple beam element, in order to minimize the computational time. Accounts for large displacement behaviour by including the element geometric stiffness. Bases the body form on anthropomorphic data produced by a shadow scanner. Enlists a novel scheme to model the contact between the cloth and the underlying body form. Uses the finite element model to provide data for an animated display and finds that it produces sufficiently realistic results for the garment designer’s purposes.
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Applies a sound theory to predict in‐plane bending deformation of flexible beams under large overall motions to predict the locus of the trailing end of the ply during wiping off…
Abstract
Applies a sound theory to predict in‐plane bending deformation of flexible beams under large overall motions to predict the locus of the trailing end of the ply during wiping off the conveyor surface of the layup machine. A computerized numerical solution was used to estimate the locus of the trailing end of the ply for seven woven fabrics of wide range of thickness, weight, and bending rigidity. The least square method was employed to obtain regression relationship between the horizontal and vertical displacement of the trailing end of the ply for each of the seven fabrics. The regression equations and the slat height were used to calculate the minimum gap between two slats of the stacking conveyor so that the fabric trailing end does not touch the top or the side surfaces of a slat during the layup process.
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S.D. McWaters, T.G. Clapp and J.W. Eischen
Introduces and evaluates a finite‐element computer model which predicts the bending behaviour of fabric in contact with a surface, in order to optimize the design of equipment…
Abstract
Introduces and evaluates a finite‐element computer model which predicts the bending behaviour of fabric in contact with a surface, in order to optimize the design of equipment used for automated processing of apparel. Describes how simulations were executed for all combinations of eight fabrics and three contact surfaces, and presents the experimental results obtained for similar conditions and fabrics. Proves the validity of the computer model by comparing the experimental results with those obtained by simulation. Describes how the computer model could be used to choose the optimum diameter of a fabric feeder picking roller.
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Donald H. House, Richard W. DeVaul and David E. Breen
Reviews a new approach being developed for modelling the dynamic behaviour of cloth. This work extends the cloth‐particle static draping model of Breen and House to include…
Abstract
Reviews a new approach being developed for modelling the dynamic behaviour of cloth. This work extends the cloth‐particle static draping model of Breen and House to include dynamics, and extends constrained dynamics simulation techniques developed by Witkin, Gleicher and Welch to yield performance enhancements. Fundamental to this approach is a new hierarchical approximation algorithm for constrained dynamics simulation which, it is hoped, will reduce the computational time demands of the algorithm to near real‐time range.
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Vincent Monchiet and Guy Bonnet
The paper deals with the development of an improved fast Fourier transform (FFT)-based numerical method for computing the effective properties of composite conductors. The…
Abstract
Purpose
The paper deals with the development of an improved fast Fourier transform (FFT)-based numerical method for computing the effective properties of composite conductors. The convergence of the basic FFT-based methods is recognized to depend drastically on the contrast between the phases. For instance, the primal formulation is not suited for solving the problems with high conductivity whereas the dual formulation is computationally costly for problems with high resistivity. Consequently, it raises the problem of computing the properties of composites containing both highly conductive and resistive inclusions.
Design/methodology/approach
In the present work, the authors' propose a new iterative scheme for solving that kind of problems which is formulated in term of the polarization.
Findings
The capability and relevance of this iterative scheme is illustrated through numerical implementation in the case of composites containing squared inclusions. It is shown that the rate of convergence is increased and thus, particularly when the case of high contrasts is considered. The predominance of the polarization based iterative scheme (PBIS) over existing ones is also illustrated in the case of a composite containing both highly conductive and highly resistive inclusions.
Originality/value
The method is easy to implement and uses the same ingredients as the basic schemes: the FFT and the exact expression of the Green tensor in the Fourier space. Moreover, its convergence conditions do not depend on the conductivity properties of the constituents, which then constitutes the main difference with other existing iterative schemes. The method can then be applied for computing the effective properties of composites conductors with arbitrary contrasts.
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Xiaoqun Dai, Takao Furukawa, Shigeru Mitsui, Masayuki Takatera and Yoshio Shimizu
Drape is a characteristic behaviour of flexible cloth, so it is important in modelling cloth. The paper introduces a novel method to model drape using a few shape parameters…
Abstract
Drape is a characteristic behaviour of flexible cloth, so it is important in modelling cloth. The paper introduces a novel method to model drape using a few shape parameters, predicted according to the pattern structure and mechanical properties of cloth. The technique is used to visualize the 3‐D drapeability of cloth and is then extended to simulation of a skirt. The general shape of a flared skirt of large deformation is predicted based on several shape parameters. Moreover, the constructed skirt model is used as pre‐draped initial shape for the popular physically‐based model – particle system. Kawabata Evaluation System (KES) plots of cloth are applied for accurate mechanical calculation. The simulated results show good agreement with actual cloth materials.
Jacek Ptaszny and Marcin Hatłas
The purpose of this paper is to evaluate the efficiency of the fast multipole boundary element method (FMBEM) in the analysis of stress and effective properties of 3D linear…
Abstract
Purpose
The purpose of this paper is to evaluate the efficiency of the fast multipole boundary element method (FMBEM) in the analysis of stress and effective properties of 3D linear elastic structures with cavities. In particular, a comparison between the FMBEM and the finite element method (FEM) is performed in terms of accuracy, model size and computation time.
Design/methodology/approach
The developed FMBEM uses eight-node Serendipity boundary elements with numerical integration based on the adaptive subdivision of elements. Multipole and local expansions and translations involve solid harmonics. The proposed model is used to analyse a solid body with two interacting spherical cavities, and to predict the homogenized response of a porous material under linear displacement boundary condition. The FEM results are generated in commercial codes Ansys and MSC Patran/Nastran, and the results are compared in terms of accuracy, model size and execution time. Analytical solutions available in the literature are also considered.
Findings
FMBEM and FEM approximate the geometry with similar accuracy and provide similar results. However, FMBEM requires a model size that is smaller by an order of magnitude in terms of the number of degrees of freedom. The problems under consideration can be solved by using FMBEM within the time comparable to the FEM with an iterative solver.
Research limitations/implications
The present results are limited to linear elasticity.
Originality/value
This work is a step towards a comprehensive efficiency evaluation of the FMBEM applied to selected problems of micromechanics, by comparison with the commercial FEM codes.
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Jie Xu, P.Y. Mok, C.W.M. Yuen and R.W.Y. Yee
To better respond to today’s volatile and changing fashion market, the purpose of this paper is to develop a web-based design support system that enables users to design realistic…
Abstract
Purpose
To better respond to today’s volatile and changing fashion market, the purpose of this paper is to develop a web-based design support system that enables users to design realistic and interesting skirts in the form of technical sketches over the internet.
Design/methodology/approach
The proposed system mainly consists of a sketch representation and composing method (SRCM), a graphic user interface (GUI) and a controller. The SRCM is implemented at the server end that generates technical sketches according to user defined parameters and features via the web-based GUI at the client side. The controller manages the workflows between the server and the clients.
Findings
To evaluate the effectiveness of the proposed system, a survey was conducted by inviting 30 subjects (professional designers or undergraduate students studying fashion design) to have trial run of the system in Hong Kong and in the USA. Positive comments and feedbacks were received, and valuable suggestions were also obtained in regard to the prototype system.
Originality/value
Compared with traditional computer-aided design (CAD) systems, the proposed system is more effective and easier to operate as users can create technical sketches in accurate proportions with simple computer operations in a few mouse clicks. Besides, the output sketches are fully compatible with most commercial CAD software. The system is developed based on web technologies, thus fashion sketches can be easily designed using any computer connected to the internet; it can be implemented on Android or iOS platform in the future.
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Z. Wu, C.K. Au and Matthew Yuen
Most of the cloth simulation and modelling techniques rely on the energy function of the system. The geometric deformation is related to the energy function by the fabric material…
Abstract
Most of the cloth simulation and modelling techniques rely on the energy function of the system. The geometric deformation is related to the energy function by the fabric material characteristics, which are usually difficult to measure directly. This paper discusses how the fabric material properties are related to the measurable mechanical properties of the fabric such as tensile modulus, Poisson's ratio etc. These properties are incorporated into a cloth simulator to produce draping results. The simulated image and real object are then compared to show the realism.