Diagram Design of Weaving Process for Touch-Feel Estimation of Plain-Woven Fabrics by Finite Element Method

Digital evaluation of touch-feel in textiles is useful to design fundamental functions of clothing. Here, it is necessary to design textiles for detail evaluation of the sensitivity in human’s feelings to consider the life-style creation in various aspects. Then, the objective of this paper is to propose a design method for plain-woven fabrics by touch-feel estimation considering the weaving process with the constitutive relations of yarn. Here, a diagram for control weaving is defined by the diameter of the yarn and displacement quantity of the weaving and the cramping by defining the theoretical thickness. For the effective design to consider various processes, unit-cell of plain-woven structures are fundamentally classified as open set models and closed set models. One of the unit-cell models in the finite element method (FEM) for the plain-woven structure is adopted because the adopted model can consider initial-stress distribution in the weaving process. Here, LS-DYNA, which is a general-purpose finite element software, has been utilized by displacement boundary, fixed boundary and a function of the global constraint on boundary conditions, and then the analysis of periodic structures like plain-woven structures can be realized by satisfying a geometric continuity. Construction of woven structure has two types of axisymmetric deformation with absolute and relative characteristics in the middle section on yarns.  It can be modeled by using the constraint equations that are referred to each node condition, displacement quantity, the direction in the global coordinate system and coefficient of constraint. In this software (version R9.1.0), it had a functional restriction of duplicated definitions because displacement boundaries and global constraint boundaries include the equality degrees-of-freedom of constraint equations. Then, a technique that can avoid conflicts with other conditions of the boundary was introduced for considering the initial-stress distribution of plain-woven structures to ease the finite element analysis by defining the weaving quantities. Whereas, a former version of the software that has functional restriction has brought discussions on the mechanics of yarn in plain-woven fabrics. It expects that it is used for a design tool by inputting various constitutive relations. For touch-feel estimation, an analysis model is constructed by warp, weft, and plungers that cramps the woven structure. A series of diagrams to compress with plungers is shown after constructing a plain-woven structure. As for analyzing the weaving process and the touch-feel estimation in one model, realization of the effective engineering is enabled. This procedure yields that the relationship between the displacement and simulation time suggests for consideration of initial-stress.