{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/129948"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/129948","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Modeling the oxidation, ablation, and mechanics of carbon fiber preform in thermal protection systems","abstract":"Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2025-10-20 without embargo terms","abstract_html":"Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2025-10-20 without embargo terms","abstract_has_math":false,"creators":["Arias, Victoria"],"institution":"University of Illinois Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Mechanical Engineering","degree_department":null,"school":null,"contributors":["Johnson, Harley T.","Stephani, Kelly A","Panerai, Francesco","Chew, Huck Beng","Haskins, Justin B."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2025,"date_issued":"2025-07-18","date_published":"2025-07-18","updated_at":"2026-07-22T22:25:06Z","subjects":["Cabon Oxidation","Direct Simulation Monte Carlo","Molecular Dynamics","Porous Carbon","Elastic Behavior"],"languages":["en","eng"],"rights":["Copyright 2025 Victoria Arias"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://hdl.handle.net/2142/129948","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Johnson, Harley T.","Stephani, Kelly A","Panerai, Francesco","Chew, Huck Beng","Haskins, Justin B."]},{"key":"dc:creator","label":"Author","values":["Arias, Victoria"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2025-07-18","2025-08"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Mechanical Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Cabon Oxidation","Direct Simulation Monte Carlo","Molecular Dynamics","Porous Carbon","Elastic Behavior"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en","eng"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2025 Victoria Arias"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://hdl.handle.net/2142/129948"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2025-10-20 without embargo terms","The student, Victoria Arias, accepted the attached license on 2025-07-15 at 23:48.","The student, Victoria Arias, submitted this Dissertation for approval on 2025-07-16 at 00:16.","This Dissertation was approved for publication on 2025-07-18 at 09:32.","DSpace SAF Submission Ingestion Package generated from Vireo submission #22594 on 2025-10-20 at 20:15:20","The focus of this thesis is modeling the response of ablative, carbon-based thermal protection system (TPS) materials undergoing extreme heat and mechanical loading during atmospheric Earth reentry. The current state-of-the-art material is a carbon fiber reinforced phenolic composite called PICA, or phenolic-impregnated carbon ablator. Ablation of the phenolic matrix is key to transporting heat away from the shield, whereas the porous carbon-bonded carbon fiber substrate, called FiberForm, provides rigidity while still being lightweight and oxidation resistant. However, once the phenolic begins to pyrolyze, the exposed FiberForm will oxidize and become more susceptible to mass loss and mechanical degradation. Within FiberForm, there exists a porous network of carbon fibers which are bonded and fused together by a carbonaceous binder material. The challenge we address in this work is how to more accurately model oxidation and oxidation-induced mechanical response of both the fiber and binder phases in FiberForm. First, we perform molecular dynamics (MD) simulations to predict the effect of oxidation-induced pitting on the tensile behavior of carbon fiber and amorphous carbon (to represent the binder phase). In this work, we demonstrate a method to extract pit data from micrographs and superimpose them on the computational domain, and we find a significant reduction in tensile modulus for all pitted structures. We also use SPARTA, a direct-simulation Monte Carlo (DSMC) code, to develop a 1D multilayer oxidation model that can capture the competition between reaction and advection in layers of graphene. In addition, we develop and parallelize an oxidation-driven surface recession framework in SPARTA. We verify our implementation for different ablating and non-ablating test geometries in 2D and 3D. Lastly, we apply our framework to model the ablation of realistic carbon fiber geometries at flight-relevant conditions. We demonstrate its ability to accurately recreate the carbon fiber response observed for different flow regimes during reentry."]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Modeling the oxidation, ablation, and mechanics of carbon fiber preform in thermal protection systems"]}]}],"canonical_facts":{"dc:contributor":["Johnson, Harley T.","Stephani, Kelly A","Panerai, Francesco","Chew, Huck Beng","Haskins, Justin B."],"dc:creator":["Arias, Victoria"],"dc:date":["2025-07-18","2025-08"],"dc:description":["Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2025-10-20 without embargo terms","The student, Victoria Arias, accepted the attached license on 2025-07-15 at 23:48.","The student, Victoria Arias, submitted this Dissertation for approval on 2025-07-16 at 00:16.","This Dissertation was approved for publication on 2025-07-18 at 09:32.","DSpace SAF Submission Ingestion Package generated from Vireo submission #22594 on 2025-10-20 at 20:15:20","The focus of this thesis is modeling the response of ablative, carbon-based thermal protection system (TPS) materials undergoing extreme heat and mechanical loading during atmospheric Earth reentry. The current state-of-the-art material is a carbon fiber reinforced phenolic composite called PICA, or phenolic-impregnated carbon ablator. Ablation of the phenolic matrix is key to transporting heat away from the shield, whereas the porous carbon-bonded carbon fiber substrate, called FiberForm, provides rigidity while still being lightweight and oxidation resistant. However, once the phenolic begins to pyrolyze, the exposed FiberForm will oxidize and become more susceptible to mass loss and mechanical degradation. Within FiberForm, there exists a porous network of carbon fibers which are bonded and fused together by a carbonaceous binder material. The challenge we address in this work is how to more accurately model oxidation and oxidation-induced mechanical response of both the fiber and binder phases in FiberForm. First, we perform molecular dynamics (MD) simulations to predict the effect of oxidation-induced pitting on the tensile behavior of carbon fiber and amorphous carbon (to represent the binder phase). In this work, we demonstrate a method to extract pit data from micrographs and superimpose them on the computational domain, and we find a significant reduction in tensile modulus for all pitted structures. We also use SPARTA, a direct-simulation Monte Carlo (DSMC) code, to develop a 1D multilayer oxidation model that can capture the competition between reaction and advection in layers of graphene. In addition, we develop and parallelize an oxidation-driven surface recession framework in SPARTA. We verify our implementation for different ablating and non-ablating test geometries in 2D and 3D. Lastly, we apply our framework to model the ablation of realistic carbon fiber geometries at flight-relevant conditions. We demonstrate its ability to accurately recreate the carbon fiber response observed for different flow regimes during reentry."],"dc:format":["application/pdf"],"dc:identifier":["https://hdl.handle.net/2142/129948"],"dc:language":["en","eng"],"dc:rights":["Copyright 2025 Victoria Arias"],"dc:subject":["Cabon Oxidation","Direct Simulation Monte Carlo","Molecular Dynamics","Porous Carbon","Elastic Behavior"],"dc:title":["Modeling the oxidation, ablation, and mechanics of carbon fiber preform in thermal protection systems"],"dc:type":["text"],"thesis:degree_discipline":["Mechanical Engineering"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois Urbana-Champaign"]},"updated_at":"2026-07-22T22:25:06Z"}