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Predictive Tool for Aging Effects on Performance of Phenolic-Based Thermal Protection Materials


OUSD (R&E) CRITICAL TECHNOLOGY AREA(S): Advanced Materials The technology within this topic is restricted under the International Traffic in Arms Regulation (ITAR), 22 CFR Parts 120-130, which controls the export and import of defense-related material and services, including export of sensitive technical data, or the Export Administration Regulation (EAR), 15 CFR Parts 730-774, which controls dual use items. Offerors must disclose any proposed use of foreign nationals (FNs), their country(ies) of origin, the type of visa or work permit possessed, and the statement of work (SOW) tasks intended for accomplishment by the FN(s) in accordance with the Announcement. Offerors are advised foreign nationals proposed to perform on this topic may be restricted due to the technical data under US Export Control Laws. OBJECTIVE: Develop an innovative approach for the prediction of performance vs. age of phenolic based composite thermal management materials such that the service life can be predicted. DESCRIPTION: Carbon/phenolic materials are very effective in providing thermal protection to underlying substrates in high heat flux, short life applications such as Submarine-launched Ballistic Missile (SLBM) Reentry Body heatshields, missile nozzle skirts, and Vertical Launch System liners. However, it is suspected that the physical/chemical characteristics of phenolic materials change with age (since manufacture) and that these changes may affect the performance of these materials in applications with extended storage/service lives prior to use. Performance of phenolic ablator materials in reentry and other Navy applications are evaluated with legacy ablation/decomposition codes such as CMA [Refs 4, 5], FIAT [Ref 6], or the more recent ICARUS [Ref 7]. These codes all operate with a single set of age = Zero physical, thermal, and chemical parameters for the base phenolic resin material. One key performance metric of the material is the back-side temperature rise at “time = t seconds” after exposure to “Heatflux = Q Btu/” with “age = T years after manufacture/deployment”. Also of interest is the prediction of change in physical and mechanical properties with depth or other location parameters. Changes that would predict or give insight into activation of accelerated ablation mechanisms or surface roughness development are particularly useful. It is also highly desirable to integrate the predictive methodology into a current generation Thermal Management System ablative/decomposition code of the type developed from the Charring Material Ablator (CMA) legacy code [Refs 4, 5]. The goal of this SBIR topic is to develop models, parameters, and algorithms that predict changes in these base parameters with age or storage life and other environmental conditions, and to embed or integrate these models, parameters, and algorithms into a current generation CMA code. It is expected that models should be able to predict age related performance effects up to 60 years after manufacture. The ability to predict changes in surface removal rates and changes to in-depth ablation mechanisms by effects such as ply separations, ply-lift or “cobra” effects is highly desired. Accelerated aging methods have recently been evaluated in order to gain insight into potential aging mechanisms [Ref 8]. Models and tools developed in the subject effort should identify possible accelerated or artificial aging mechanisms. Identification of an accelerated aging method(s) and execution of the code/tool against an accelerated aged material will be a key aspect of code validation. PHASE I: Seek to understand the phenolic aging phenomenon and identify basic aging mechanisms amenable to algorithm development. Identify a path forward for implementation of the algorithm(s) into one of the current or legacy CMA codes. PHASE II: Further develop the algorithms and identify underlying material physical/chemical/thermal parameters that are affected by age. A predictive performance tool based on age shall be developed and validated. It is anticipated that this tool will be based on one of the current or legacy CMA codes. However, if not, an alternate approach that is amenable for an age T=0 baseline/initial design purpose as well as predictive performance at T=XX years must be proposed. Accelerated aging methods may be utilized but must be proven as activating the appropriate phenolic aging mechanisms. Samples of Navy aged and unaged (non-tactical) materials may be made available to Phase II awardees for this purpose. Identification of a non-destructive, or in-situ assessment technique to go along with the predictive tool development would also be of interest. Demonstrate the predictive capability of the tool using contractor or Navy-supplied materials, an accelerated aging method, and laboratory or arc-jet ablation testing. PHASE III DUAL USE APPLICATIONS: Phase III opportunity to perform predictive age assessments of current fielded hardware in conjunction with an ongoing surveillance program or predictive age assessments of new build hardware for new programs and development/execution of an appropriate sampling strategy. Phenolic-based composite material thermal protection systems are used in commercial space applications and by NASA. These components will be subject to similar concerns with regard to performance after time in storage, or performance during planetary reentry after extended mission times. The overall commercial product from this activity is expected to be a plug-in for a legacy code or a re-write of an existing decomposing ablator code taking advantage of current computer coding developments. This plug-in or code would be attractive to many Navy/DoD components, such as Navy Strategic Systems Programs (SSP), and Primes developing phenolic composite heatshields for future applications as well as NASA and commercial Access-to-Space entities. Such a code would also be of interest to current programs seeking to extend the service life of their in-service materials. REFERENCES: 1. Navy Mk5 SLBM. 2. Lockheed Mk41 Vertical Launch System. Lockheed Martin, PIRA# MOR201903003, 2019. 3. Hall, W.B. et al. “Final Report: Standardization of the Carbon/Phenolic Materials and Processes, Volume 1.” NASA Technical Report, August 31, 1988. 4. Moyer, C.B. “User’s Manual for Aerothermal Charring Material Thermal Response and Ablation Program, Version 3, Volume I.” DTIC AD875062, April 1970. 5. Chan, C.C. “Modifications to the Aerothermal Charring Material Thermal Response and Ablation Program (CMA) for Carbon Ablation Analysis.” DTIC A211069, August 1989. 6. “Fully Implicit Ablation and Thermal Analysis Program, Version 3.” ARC-15779-1A, 2015. 7. Chen, Y-K and Milos, F.S. “Multidimensional Finite Volume Fully Implicit Ablation and Thermal Response Code.” , Journal of Spacecraft and Rockets, Vol. 55, No. 4, July–August 2018. 8. Manoj Abraham, D.S.; Kanagasabapathy, H. and Joselin,R. “Investigation of Accelerated Aging Effects in Phenolic Ablative Composites.” Appl. Math. Inf. Sci. 13, No. 3, 2019, pp. 461-469. KEYWORDS: Ablation, Phenolic, Aging Mechanisms, Composite Materials, Thermal Management Materials
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