A new geometric modeling approach of anisotropic yarn structure | |
| Author | Keartisak Sriprateep |
| Call Number | AIT Diss. no.ISE-07-03 |
| Subject(s) | Computer-aided design Computer-aided engineering |
| Note | A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Engineering in Design and Manufacture Engineering, School of Engineering and Technology |
| Publisher | Asian Institute of Technology |
| Series Statement | Dissertation ; no. ISE-07-03 |
| Abstract | Recent computer aided design (CAD) and computer aided engineering (CAE) systems have become capable and more and more popular in design and analysis. In textile, yam application, most of the previous works regarding geometrical modeling of yam structure are based on single line yam path. The main objective in this study is to develop a model of yam as assemblies of many fibers by twisting using computer-aided design. Virtual simulation of yam structures based on process parameters for conventional ring spinning system is investigated. Also prediction of the stress-strain curves of yam structures based on the new assembly model is done. In the first part, an algorithm for 3D modeling of fibers assemblies has been developed. The method uses a concept of 'virtual location with circle shape model' for simulation of fiber in yams cross-section. Yam is simulated with sine waves of different magnitude, frequency and initial phase. A series of cross-sections at equal intervals along the yam length is given. Each cross-section is rotated by a pre-determined amount relative to the previous one, to allow for the yam twist and parameters of fibers migration. The fibers curve in each interval between two successive cross-section is approximated by NURBS. Each fiber is created by sweeping a closed curve along a centerline path. The simulated yams structure using the new algorithm described can model a wider variety and yields an improved visual representation of real yam structure. Stress distributions are also computed to predict the behavior of final yam structure under extension, compression and bending conditions of fibers assembly model. In the second part, a new computer geometric modeling approach for 3D yam structures produced by the conventional ring spinning system is presented. The concept of virtual locations for modeling yam cross-section is extended. Virtual locations are ring configuration with ellipsoid shapes defined by yam-twist level in each ring layer. The new theoretical curves of the fiber migration model have been developed to represent the relationship between equivalent migration amplitude and relative tension. A new mathematical model based on migrating helix is developed. Fiber migration is governed by geometric and tension mechanisms. The migration parameters include twisting tension, migration period and amplitude. The initial phase and frequency of migration pattern are used as the parameters of fiber migration. Based on the results obtained from the new virtual locations concept, new migrating fiber model and new theoretical curves, a CAD modeling approach for fiber assembly is presented for geometric and visual simulation of yam structures. The new model is validated by using real process parameters of spun rayon yam. In the last part, nonlinear FEM with new fiber assembly model is presented to predict tensile behavior for continuous filament yams. Linear and non-linear material properties are considered. The geometry of ideal and migrating yam are modeled by different twist angles and then nonlinear FEM is used to simulate the stress-strain curve of fibers and yam. The shape of the elements is ten node tetrahedral. In the calculation process, one end of the yam model is fixed and the other end is extended along the length. The fibers are considered bonded to each other. The results observed from nonlinear FEM with new geometric model shows good agreement with experiment. The migrating yam has little influence on tensile properties |
| Year | 2007 |
| Corresponding Series Added Entry | Asian Institute of Technology. Dissertation ; no. ISE-07-3 |
| Type | Dissertation |
| School | School of Engineering and Technology (SET) |
| Department | Department of Industrial Systems Engineering (DISE) |
| Academic Program/FoS | Industrial Systems Engineering (ISE) |
| Chairperson(s) | Bohez, Erik L. J.; |
| Examination Committee(s) | Guha, Sumanta ;Pisut Koomsap ;Naraporn Rungsimuntakul; |
| Scholarship Donor(s) | Ministry of University Affairs and Mahasarakham University, Thailand; |
| Degree | Thesis (Ph.D.) - Asian Institute of Technology, 2007 |