Generating virtual specimens for complex non-periodic woven structures by converting machine instructions into topological ordering rules. (1st May 2016) - Cox, Brian N.
Abstract: We describe the generation of geometrical models of complex, non-periodic, three-dimensional (3D) textile structures, which combine reinforcing tows and open spaces formed by the use of fugitive tows or alloy rods. Modeling begins with the machine instructions that are executed on the weaving loom to create a 3D textile architecture, including instructions for unusual machine operations that create functional features such as holes or joints. Data include only simple specifications of the nature of each tow, such as its cross-sectional area and approximate stiffness. The weave architecture is defined by sets of bounded integers, an ideal input data structure for computational design optimization. Models are generated automatically via simple algorithms based on topological ordering rules. Diverse outcomes are illustrated by a sandwich structure and a cooled airfoil component. The generation of complex structures that are built from very many machine instructions is simplified by identifying "design instructions", which consist of repeated patterns of machine instructions that can be entered into the input deck very quickly, rather than by entering each machine instruction separately. Yet symmetry, including periodicity, is not necessarily present: the airfoil exemplar demonstrates the use of design instructions to form an asymmetric structure along whose length the number of tows and their interlacing pattern both vary.