The Micro-constitutive Model Of Knitted Fabric And Buckling Analysis Of Fabric

The simulating techniques of deformation and buckling of fabric have extensive applications in many fields, such as CAD for garments, virtual clothing stores, virtual reality, computer cartoons, and computer games. Since the eighties of the twentieth century, many researchers have devoted their works on the numerical simulations of the draping and buckling of woven fabric. The woven fabric was modeled as the orthotropic continuum. Based on the models the draping and buckling of woven fabric were numerically simulated. It was found that the simulations did not well agree with the experiment observations, and some buckling deformations can't even been predicted. Supported by the National Nature Science Foundation of China, the micro-mechanical model for woven fabric was proposed and, based on the model, some buckling phenomena of woven fabric sheet under tension and simple shear were analytically predicted successfully.In contrast with the research on woven fabric, there are little works reported in literature. In this thesis the micro-mechanical constitutive model for knitted fabric is proposed, the analytical and numerical studies of draping and buckling of knitted fabric are carried out, and finally, the buckling of woven fabric is simulated numerically. The works in this thesis are briefly listed below.1. The micro-mechanical constitutive model for knitted fabric is proposed that describes the special mechanical properties due to the micro-knitting structure.2. Based on the micro-constitutive model of knitted fabric and the well-established theory of small deformation superimposed on large deformation, the buckling of knitted fabric sheets under uniaxial tension along wale direction is investigated. It is shown that only the flexural buckling mode is possible, that is in good agreement with the experiment observation.3. Based on the micro-constitutive model of knitted fabric the buckling of knitted fabric sheets under uniaxial tension along course direction is analyzed. It is proved that the knitted fabric sheets don't buckle, that is also in good agreement with the experiment observation.4. The experiments of knitted fabric subjected tension are carried out, and the elastic moduli is measured.5. Based on the micro-constitutive model of knitted fabric the draping and buckling of knitted fabric sheets are simulated numerically by using the curved shell element for large deformation. The simulated result agrees well with the image of buckled knitted fabric sheets.6. Based on the micro-constitutive model of woven fabric the draping and buckling of woven fabric sheets are simulated numerically by using the curved shell element for large deformation and the finite element method. The important effect of compress moduli on the buckling analysis is analyzed. The simulated result agrees well with the image of buckled woven fabric sheets.