Abstract

Our software tool TexMath is a modular program for simulating mechanical material properties and optimizing textile products as well as multi-scale problems for textile applications. With MeshUp we create periodic textile structures of all kinds (woven fabrics, knitted warp and weft fabrics, spacer textiles) according to the respective machine control with complex weaves/knitting looping diagrams. A graphical user interface is being developed which allows simple usage of MeshUp with industry standards of textile pattern definition. In addition to pattern generation this includes intuitive definition of boundary conditions and keeps all patterns, machines and materials as well as simulation results in a database. With FiberFEM, woven and braided textiles, spacer fabrics, scrims and trusses can be calculated and optimized regarding their effective mechanical material properties. A special feature of FiberFEM is that, in addition to tensile and shear properties, effective bending and torsional properties of textiles can also be determined based on their textile structure and yarn properties. As input variables FiberFEM requires the microstructure description from MeshUp, the fiber cross-section geometry, as well as mechanical fiber properties such as tensile stiffness and friction. As output the effective mechanical textile quantities are calculated. Besides the calculation of the effective mechanical material properties for already existing woven or knitted textiles for technical and medical applications, the approach also offers the potential for the targeted design and optimization of new textiles with a given mechanical property profile. The tool FIFST is specialized for dynamic simulations of stretchable knitted fabrics and teir production. For example, the knitting process can be simulated, the pull-off from the knitting machine, the shrinkage to a relaxed textile and also the further deformation during tightening can be calculated. This means that the design of the knitted fabric can also be adapted to predefined tension profiles and individualized machine control is possible for the production of personalized textiles or product-specific designs. The numerical implementation uses the finite element method with non-linear truss elements, which has been extended for contact problems by an additional internal variable - the sliding of threads at contact nodes. The friction law is implemented with the Euler-Eutelwein model, which was extended by an additional adhesion term. Adhesion thus allows different pre-strains in the respective meshes. The elastic energy is calculated directly from the yarn force-elongation curves. All tools have interfaces to each other and also to GeoDict (optionally to Ansys/Abaqus as IGES-formats) in order to perform further fluid mechanical simulations on the textiles, e.g. to determine their permeability in any elongation state. An interface with FeelMath allows further detailed three-dimensional mechanical simulations at specific yarn or contact points, so that strength and durability can also be investigated.