{"ddc":["000","620"],"doi":"10.15479/at:ista:12103","type":"dissertation","page":"138","has_accepted_license":"1","date_updated":"2024-02-28T12:57:46Z","oa_version":"Published Version","alternative_title":["ISTA Thesis"],"author":[{"full_name":"Sperl, Georg","id":"4DD40360-F248-11E8-B48F-1D18A9856A87","first_name":"Georg","last_name":"Sperl"}],"status":"public","publication_identifier":{"isbn":["978-3-99078-020-6"],"issn":["2663-337X"]},"year":"2022","month":"09","ec_funded":1,"citation":{"short":"G. Sperl, Homogenizing Yarn Simulations: Large-Scale Mechanics, Small-Scale Detail, and Quantitative Fitting, Institute of Science and Technology Austria, 2022.","mla":"Sperl, Georg. <i>Homogenizing Yarn Simulations: Large-Scale Mechanics, Small-Scale Detail, and Quantitative Fitting</i>. Institute of Science and Technology Austria, 2022, doi:<a href=\"https://doi.org/10.15479/at:ista:12103\">10.15479/at:ista:12103</a>.","ieee":"G. Sperl, “Homogenizing yarn simulations: Large-scale mechanics, small-scale detail, and quantitative fitting,” Institute of Science and Technology Austria, 2022.","ama":"Sperl G. Homogenizing yarn simulations: Large-scale mechanics, small-scale detail, and quantitative fitting. 2022. doi:<a href=\"https://doi.org/10.15479/at:ista:12103\">10.15479/at:ista:12103</a>","chicago":"Sperl, Georg. “Homogenizing Yarn Simulations: Large-Scale Mechanics, Small-Scale Detail, and Quantitative Fitting.” Institute of Science and Technology Austria, 2022. <a href=\"https://doi.org/10.15479/at:ista:12103\">https://doi.org/10.15479/at:ista:12103</a>.","ista":"Sperl G. 2022. Homogenizing yarn simulations: Large-scale mechanics, small-scale detail, and quantitative fitting. Institute of Science and Technology Austria.","apa":"Sperl, G. (2022). <i>Homogenizing yarn simulations: Large-scale mechanics, small-scale detail, and quantitative fitting</i>. Institute of Science and Technology Austria. <a href=\"https://doi.org/10.15479/at:ista:12103\">https://doi.org/10.15479/at:ista:12103</a>"},"date_published":"2022-09-22T00:00:00Z","project":[{"grant_number":"638176","_id":"2533E772-B435-11E9-9278-68D0E5697425","name":"Efficient Simulation of Natural Phenomena at Extremely Large Scales","call_identifier":"H2020"}],"title":"Homogenizing yarn simulations: Large-scale mechanics, small-scale detail, and quantitative fitting","related_material":{"record":[{"id":"11736","status":"public","relation":"part_of_dissertation"},{"id":"9818","status":"public","relation":"part_of_dissertation"},{"relation":"part_of_dissertation","status":"public","id":"8385"}]},"language":[{"iso":"eng"}],"publication_status":"published","oa":1,"_id":"12358","file_date_updated":"2023-02-02T09:39:25Z","abstract":[{"text":"The complex yarn structure of knitted and woven fabrics gives rise to both a mechanical and\r\nvisual complexity. The small-scale interactions of yarns colliding with and pulling on each\r\nother result in drastically different large-scale stretching and bending behavior, introducing\r\nanisotropy, curling, and more. While simulating cloth as individual yarns can reproduce this\r\ncomplexity and match the quality of real fabric, it may be too computationally expensive for\r\nlarge fabrics. On the other hand, continuum-based approaches do not need to discretize the\r\ncloth at a stitch-level, but it is non-trivial to find a material model that would replicate the\r\nlarge-scale behavior of yarn fabrics, and they discard the intricate visual detail. In this thesis,\r\nwe discuss three methods to try and bridge the gap between small-scale and large-scale yarn\r\nmechanics using numerical homogenization: fitting a continuum model to periodic yarn simulations, adding mechanics-aware yarn detail onto thin-shell simulations, and quantitatively\r\nfitting yarn parameters to physical measurements of real fabric.\r\nTo start, we present a method for animating yarn-level cloth effects using a thin-shell solver.\r\nWe first use a large number of periodic yarn-level simulations to build a model of the potential\r\nenergy density of the cloth, and then use it to compute forces in a thin-shell simulator. The\r\nresulting simulations faithfully reproduce expected effects like the stiffening of woven fabrics\r\nand the highly deformable nature and anisotropy of knitted fabrics at a fraction of the cost of\r\nfull yarn-level simulation.\r\nWhile our thin-shell simulations are able to capture large-scale yarn mechanics, they lack\r\nthe rich visual detail of yarn-level simulations. Therefore, we propose a method to animate\r\nyarn-level cloth geometry on top of an underlying deforming mesh in a mechanics-aware\r\nfashion in real time. Using triangle strains to interpolate precomputed yarn geometry, we are\r\nable to reproduce effects such as knit loops tightening under stretching at negligible cost.\r\nFinally, we introduce a methodology for inverse-modeling of yarn-level mechanics of cloth,\r\nbased on the mechanical response of fabrics in the real world. We compile a database from\r\nphysical tests of several knitted fabrics used in the textile industry spanning diverse physical\r\nproperties like stiffness, nonlinearity, and anisotropy. We then develop a system for approximating these mechanical responses with yarn-level cloth simulation, using homogenized\r\nshell models to speed up computation and adding some small-but-necessary extensions to\r\nyarn-level models used in computer graphics.\r\n","lang":"eng"}],"degree_awarded":"PhD","date_created":"2023-01-24T10:49:46Z","supervisor":[{"id":"3C61F1D2-F248-11E8-B48F-1D18A9856A87","full_name":"Wojtan, Christopher J","last_name":"Wojtan","first_name":"Christopher J","orcid":"0000-0001-6646-5546"}],"department":[{"_id":"GradSch"},{"_id":"ChWo"}],"day":"22","publisher":"Institute of Science and Technology Austria","article_processing_charge":"No","acknowledged_ssus":[{"_id":"SSU"}],"user_id":"8b945eb4-e2f2-11eb-945a-df72226e66a9","file":[{"file_size":104497530,"relation":"main_file","creator":"cchlebak","file_id":"12371","file_name":"thesis_gsperl.pdf","content_type":"application/pdf","date_updated":"2023-02-02T09:29:57Z","title":"Thesis","date_created":"2023-01-25T12:04:41Z","access_level":"open_access","description":"This is the main PDF file of the thesis. 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