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PuMA and Multiscale Modeling

AMS Seminar Series

Speakers: Federico Semeraro & Krishnan Swaminathan Gopalan, Science and Technology Corporation / NASA Ames Research Center

Presentation

Seminar Slide Deck (PDF-12.2MB)

Abstract

This presentation discusses the capabilities and modeling approach of the Porous Microstructure Analysis (PuMA) software, a computational framework to extract material properties and simulate material response. The three main components of the software, i.e., domain generation, image processing and the computation of effective material properties, will be discussed.

The presentation also motivates the need of developing such framework for the analysis of ablative Thermal Protection Systems (TPS) used for atmospheric entry in NASA missions. In order to accurately inform material response simulations on full-size heatshield designs, their properties are computed on high-fidelity microstructures obtained from micro-CT reconstructions. One of the main focuses of the presentation is the importance of considering the local anisotropy of the carbon fiber composites used as TPS. This involves the knowledge of the constituent property, which must be aligned with the local material orientation. The relevant PuMA modules for this analysis are presented, including the algorithms for automatic detection of the fiber orientation, and the numerical methods to estimate the effective thermal conductivity and elasticity.

Another application of PuMA is presented, displaying the construction of finite-rate surface chemistry for materials with complex microstructures. The ability to accurately represent the microstructure using micro-CT data provides a detailed framework to represent the material recession through surface reactions. This application was used to model oxidation, which is the primary source of ablation at lower temperatures for carbon-based TPS materials. PuMA was also used to reproduce molecular beam experiments and obtain detailed information regarding the rates of different products of surface carbon oxidation. This information is used to develop accurate finite-rate representations at the micro-scale, which can be further extended to the macro-scale using effective models.

Biography

Photo of Federico Semeraro
Federico Semeraro is a research scientist for the Science and Technology Corporation working in the NASA Advanced Supercomputing Division at NASA Ames Research Center. He originally joined the Predictive Materials Modeling (PMM) group in January 2018 as a student intern. He obtained his M.S. in Aerospace Engineering from Imperial College London in July 2018 and is currently working part-time towards his second M.S. in Computer Science from the Georgia Institute of Technology. In August 2018, he rejoined the PMM group and has since been working as a developer of the Porous Microstructure Analysis (PuMA) software. His work focuses on developing and implementing numerical methods for the computation of material properties (e.g., fiber orientation, conductivity, elasticity) based on X-ray tomographic reconstructions of fibrous microstructures.

Photo of Krishnan Swaminathan Gopalan
Krishnan Swaminathan Gopalan is a research scientist for the Science and Technology Corporation working in the Computational Physics Branch of the NASA Advanced Supercomputing Division at NASA Ames Research Center. Swaminathan Gopalan obtained his Ph.D. in mechanical engineering from the University of Illinois at Urbana Champaign (UIUC) under the supervision of Prof. Kelly Stephani. He also has an M.S. in mechanical engineering from UIUC. Since he joined NASA in 2019, his work has been focused on porous material modeling at the micro-scale, including constructing surface chemistry models for carbon oxidation and developing machine learning algorithms for segmentation of carbon weaves.