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AIAA Science and Technology Forum and Exposition, AIAA SciTech Forum 2025

作者： Spiegel, Seth C. Yoder, Dennis A. Debonis, James R. Huynh, H.T. Heinlein, Gregory S. Borghi, Michael R. Georgiadis, Nicholas J. Inlets and Nozzles Branch NASA Glenn Research Center ClevelandOH44135 United States Multiscale and Multiphysics Modeling Branch NASA Glenn Research Center ClevelandOH44135 United States Turbomachinery and Turboelectric Systems Branch NASA Glenn Research Center ClevelandOH44135 United States

ISBN: (数字)9781624107238

ISBN: (纸本)9781624107238

The Glenn Flux Reconstruction (GFR) code is a computational fluid dynamics (CFD) code under development at NASA Glenn Research Center. GFR is based on the high-order flux reconstruction (FR) method and provides a large-eddy simulation (LES) capability that is both accurate and efficient for complex aeropropulsion flows. Three significant new capabilities have been added to the code that improve its performance and functionality. First, a variety of explicit Runge-Kutta methods, including some with adaptive time stepping, were added to GFR with two methods offering a 33% improvement in time-to-solution. Second, GFR can now utilize fully unstructured, mixed-element meshes to more easily facilitate the grid generation process for complex geometries. Finally, a rotating reference frame capability has been added to GFR for solving rotating turbomachinery problems. A selection of results demonstrating these new capabilities are presented in this work. The Taylor-Green vortex problem is used to verify the new unstructured capability by showing similar accuracy and resolution for all element types. LES of the Turbulent Heat Flux Phase III (THX3) experiment with comparison to another high-order LES code and a popular Reynolds-averaged Navier-Stokes (RANS) code demonstrates the accuracy of the code for complex aeropropulsion flows. Finally, LES of a spacecraft cabin ventilation fan shows the ability of GFR to efficiently establish a fan performance map and identify operating points for further analysis at high orders of accuracy. © 2025, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.

关键词： Computational fluid dynamics

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COMPARISON OF MICROMECHANICS THEORIES FOR modeling CHOPPED CARBON FIBER POLYMER MATRIX COMPOSITES 23

COMPARISON OF MICROMECHANICS THEORIES FOR MODELING CHOPPED C...

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23rd International Conference on Composite Materials, ICCM 2023

作者： Pineda, Evan J. Kaleel, Ibrahim Bednarcyk, Brett A. Miller, Sandi G. Multiscale and Multiphysics Modeling Branch NASA Glenn Research Center Cleveland United States NASA Postdoctoral Program Oak Ridge Associated Universities Cleveland United States Ceramic and Polymer Composites Branch NASA Glenn Research Center Cleveland United States

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Damage Initiation of Continuous Fiber Laminated Thermoplastic Composites 38

Damage Initiation of Continuous Fiber Laminated Thermoplasti...

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38th Technical Conference of the American Society for Composites, ASC 2023

作者： Buenrostro, Javier Miller, Sandi G. Ricks, Trenton M. Periera, J. Michael Universities Space Research Association ClevelandOH44135 United States Ceramic and Polymer Composites Branch NASA Glenn Research Center ClevelandOH44135 United States Multiscale and Multiphysics Modeling Branch NASA Glenn Research Center ClevelandOH44135 United States Structural Dynamics Branch NASA Glenn Research Center ClevelandOH44135 United States

ISBN: (纸本)9781605956916

The use of advanced thermoplastic composites (TPC) for structural applications in the aerospace and automotive industries has grown increasingly popular due to their high performance, high manufactured part output, and sustainability. Advanced manufacturing processes of thermoplastic composites allow for the building of complex optimized structural geometries with both continuous and discontinuous fibers. With more complex parts and processes comes the need for established qualification methodologies. Characterization of damage evolution from different manufacturing processes needs to be further explored to better understand the behavior of TPC for aerospace environments. Investigation into the differences in the damage behavior of continuous and discontinuous laminated TPC in tension and compression is important for aerospace applications where impact and crush damage is likely. Experiments using continuous fiber laminated IM7/PEKK TPC, [±45]4s specimens loaded in tension and [90/0]3s specimens loaded in compression, are performed to obtain stress vs strain curves with Digital Image Correlation (DIC) and acoustic emission (AE) transducers to monitor damage initiation and evolution. Next, interrupted low-cycle mechanical tests are performed on [±45]4s laminates with optical microscopy in between cycles to support characterization and understanding of the relevant damage mechanisms needed for material models. The damage mechanisms in laminated composites are of interest to better understand the effects of different fiber architectures on the laminate scale behavior, which can be used to calibrate continuum damage mechanics models. © 2023 by DEStech Publications, Inc. and American Society for Composites. All rights reserved.

关键词： Laminated composites

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Multi-Scale Experimental Characterization for LS-DYNA MAT213 modeling of Composite Structures under High Strain Rate

arXiv

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arXiv 2024年

作者： Black, Jackob Premo, Ryan Goldberg, Robert K. Asce, F. Ricks, Trenton M. Lyons, Troy Kim, Han-Gyu Mississippi State University Department of Aerospace Engineering Mississippi StateMS39762 United States NASA Glenn Research Center Ceramic and Polymer Composites Branch ClevelandOH44135 United States NASA Glenn Research Center Multiscale and Multiphysics Modeling Branch ClevelandOH44135 United States NASA Glenn Research Center Structural Dynamics Branch ClevelandOH44135 United States

Aerospace structures often experience high strain rate events such as ballistic impact, crash, or crush. A material model has been developed that enhances the capability to simulate the dynamic response of composite materials under these loading conditions. The material model has been implemented into the commercially available transient dynamic finite element code LS-DYNA as MAT213. The model can simulate the nonlinear deformation, damage, and failure that takes place in a composite under dynamic loading conditions. The specific goal of this work is to characterize the MAT213 input for the representative material. The specific composite material being examined consists of T700G unidirectional carbon fibers and a low-melt PolyArylEtherKetone (LMPAEK) thermoplastic resin system. It is formally referred to as Toray TC1225 LMPAEK T700G. As the initial part of this work, this paper is focused on characterizing the material parameters for the MAT213 deformation model based on results obtained from multi-scale experimentation. The effort concentrated on characterizing the in-plane material response suitable for use with thin shell elements. For shell elements within MAT213, tabulated stress-strain results from tension and compression tests in the longitudinal and transverse directions and in-plane shear tests are required. Due to the difficulty of measuring small strains in the transverse direction, a multi-scale testing method was developed. Macro-scale testing is performed per the typical ASTM methods while micro-scale testing uses a microscope along with smaller coupon sizes to obtain the smaller strains in the transverse direction of each test. For both testing methods, a VIC-2D camera and software for DIC (Digital Image Correlation) analysis are used. Using the DIC combined with each test fixture, reliable stress and strain data are collected. This material was characterized based on this data. Single-element simulations are then executed to validate that the results

关键词： Dynamic response

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multiscale failure analysis of a 3D woven composite containing manufacturing induced voids and disbonds

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Composites Part A: Applied Science and Manufacturing 2022年第0期156卷 106844-106844页

作者： Pineda, Evan J. Bednarcyk, Brett A. Ricks, Trenton M. Farrokh, Babak Jackson, Wade Multiscale and Multiphysics Modeling Branch NASA Glenn Research Center ClevelandOH44135 United States Mechanical Systems Analysis and Simulation Branch NASA Goddard Space Flight Center GreenbeltMD20771 United States Damage Tolerance and Reliability Branch NASA Langley Research Center HamptonVA23681 United States

multiscale failure simulations of a three-dimensional woven composite repeating unit cell considering six scales, spanning the woven composite mesoscale to the sub-microscale voids, have been performed. The multiscale recursive micromechanics approach, which enables recursive integration of general micromechanics theories over an arbitrary number of length scales, has been employed within the NASA multiscale Analysis Tool. The multiscale model uses both the generalized method of cells and Mori-Tanaka micromechanics theories and considers failure in the constituent materials using a simple damage model. Baseline results, from a model of a composite containing distributed voids, are compared to uniaxial experimental data for an AS4 carbon fiber/ RTM6 epoxy matrix orthogonal three-dimensional woven composite with good agreement in terms of global stiffness and global failure stress. The multiscale model is then used to examine the nonlinear response of the material to other loading conditions. Case studies, motivated by X-ray computed tomography data, are presented on the effects of manufacturing induced voids and cracks. © 2022

关键词： Computerized tomography

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Hybrid experimental and numerical characterization of the 3D response of woven polymer matrix composites 36

Hybrid experimental and numerical characterization of the 3D...

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36th Technical Conference of the American Society for Composites 2021: Composites Ingenuity Taking on Challenges in Environment-Energy-Economy, ASC 2021

作者： Buenrostro, Javier Kim, Hyonny Goldberg, Robert K. Ricks, Trenton M. Department of Structural Engineering University of California San Diego 9500 Gilman Drive La Jolla CA92093 United States Ceramic and Polymer Composites Branch NASA Glenn Research Center ClevelandOH44135 United States Multiscale and Multiphysics Modeling Branch NASA Glenn Research Center ClevelandOH44135 United States

ISBN: (纸本)9781713837596

The need for advanced material models to simulate the deformation, damage, and failure of polymer matrix composites under impact conditions is becoming critical as these materials are gaining increased usage in the aerospace and automotive industries. The purpose of this work is to characterize carbon epoxy fabrics for composite material models that rely on a large number of input parameters to define their nonlinear and 3D response;e.g. elastic continuum damage mechanics models or plasticity damage models [1, 2]. It is challenging to obtain large sets of experimental stress-strain curves, therefore, careful selection of physical experiments that exhibit nonlinear behavior is done to significantly reduce the cost of generating three-dimensional material databases. For this work, plain weave carbon fabrics with 3k and 12k tows are manufactured by VARTM. Testing is done using MTS hydraulic test frames and 2D digital image correlation (DIC) to obtain experimental stress-strain curves for in-plane tension and shear as well as transverse shear. For cases where actual experimental data is either not available or difficult to obtain, the required model input is virtually generated using the NASA Glenn developed Micromechanics Analysis Method/Generalized Method of Cells (MAC/GMC) code. A viscoplastic polymer model is calibrated and utilized to model the matrix constituent within a repeating unit cell (RUC) of a plain weave carbon fiber fabric. Verification and validation of this approach is done using MAT213, a tabulated orthotropic material model in the finite element code LS-DYNA, which relies on 12 input stress-strain curves in various coordinate directions [2]. Based on the model input generated by the micromechanics analyses in combination with available experimental data, a series of coupon level verification and validation analyses are carried out using the MAT 213 composite model. © 2021 36th Technical Conference of the American Society for Composites 2021: Composit

关键词： Stress-strain curves

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multiscale failure analysis of a 3D woven unit cell containing defects 35

Multiscale failure analysis of a 3D woven unit cell containi...

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35th Annual American Society for Composites Technical Conference, ASC 2020

作者： Pineda, Evan J. Bednarcyk, Brett A. Ricks, Trent M. Farrokh, Babak Jackson, Wade Multiphysics and Multiscale Modeling NASA Glenn Research Center ClevelandOH44135 United States Mechanical Systems Analysis and Simulation Branch NASA Goddard Space Flight Center GreenbeltMD20771 United States Durability Damage Tolerance Reliability Branch NASA Langley Research Center HamptonVA23681 United States

ISBN: (纸本)9781605956657

multiscale failure simulations have been performed for a Three-dimensional woven composite unit cell considering five, or more, length scales spanning the woven composite mesoscale to the sub-microscale voids. The multiscale recursive micromechanics approach, which enables recursive integration of general micromechanics theories over an arbitrary number of length scales, has been employed within the NASA multiscale Analysis Tool. The multiscale model uses both the generalized method of cells and Mori-Tanaka micromechanics theories, and considers failure in the constituent materials using a simple damage model. Baseline results, containing distributed voids, are compared to uniaxial experimental data for an AS4 carbon fiber/ RTM6 epoxy matrix 3D orthogonal woven composite with good agreement in terms of global stiffness and global failure stress. The simulations demonstrate that the 3D woven composite exhibits damage tolerance through sustaining increasing axial load far beyond the first initiation of damage. The multiscale model is used to examine the nonlinear response of the material to other loading conditions. Case studies, motivated by X-ray computed tomography data, are presented on the effects of manufacturing induced voids and cracks. © ASC 2020.

关键词： NASA

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modeling of the influence of a damaged thermally grown oxide (TGO) layer in an environmental barrier coating system 34

Modeling of the influence of a damaged thermally grown oxide...

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34th Technical Conference of the American Society for Composites, ASC 2019

作者： Mital, Subodh K. Ricks, Trenton M. Arnold, Steven M. Harder, Bryan J. University of Toledo ToledoOH43606 United States Multiscale and Multiphysics Modeling Branch NASA Glenn Research Center ClevelandOH44135 United States Environmental Effects and Coatings Branch NASA Glenn Research Center ClevelandOH44135 United States

ISBN: (纸本)9781605956022

Environmental barrier coatings (EBC) are an enabling technology for the successful application of ceramic matrix composites (CMCs) in air-breathing gas turbine engines. EBCs are susceptible to a number of failure modes including oxidation/delamination, recessions, chemical attack and dissolution, thermomechanical degradation, erosion, and foreign object impact damage in a combustion environment. Spallation of environmental barrier coating (EBC), induced by a thermally grown oxide (TGO) layer, is a key EBC failure mode. The TGO layer, resulting from steam oxidation, grows either from a silicon bond coat layer (if present) or from a silicon carbide (SiC) based substrate itself. The TGO layer evolves (i.e., thickness increases with time) as water vapor and oxygen gradually diffuse through the EBC, and the EBC spalls off once the TGO layer reaches some critical thickness. The critical thickness of the TGO layer for failure is in the range of 20-30 microns, but it can vary due to exposure temperature, microstructure etc. Current work at NASA Glenn Research Center, under the Revolutionary Tools and Methods (RTM) subproject is aimed at addressing associated failure modes in EBC systems and developing robust analysis tools to aid in the design/analysis of these systems. The objective of the current work is to conduct a sensitivity study to examine the influence of uniformly and non-uniformly grown oxide layers on the associated driving forces leading to spallation of the EBC when subjected to isothermal loading. The effect of damage in the TGO layer on the resulting stress states is also assessed both in uniform and non-uniform TGO layers. © 2019 by DEStech Publications, Inc. and American Society for Composites. All rights reserved.

关键词： Failure modes

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Coupled thermo-mechanical micromechanics modeling of the influence of thermally grown oxide layer in an environmental barrier coating system 33

Coupled thermo-mechanical micromechanics modeling of the inf...

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33rd Technical Conference of the American Society for Composites 2018

作者： Ricks, Trenton M. Arnold, Steven M. Harder, Bryan J. Multiscale and Multiphysics Modeling Branch NASA Glenn Research Center ClevelandOH44135 United States Environmental Effects and Coatings Branch NASA Glenn Research Center ClevelandOH44135 United States

ISBN: (纸本)9781510872073

Environmental Barrier Coatings (EBCs) have emerged as a promising means of protecting silicon based ceramic matrix composite (CMC) components for high temperature applications (e.g., aircraft engines). EBCs are often used to protect an underlying material (substrate) such as silicon carbide from extreme thermal/chemical environments. In a typical CMC/EBC system, an EBC may or may not be adhered to an underlying substrate with a bond coat (e.g., silicon). Irrespective, systems that utilize EBCs are susceptible to a number of failure modes including oxidation/delamination, recession, chemical attack and dissolution, thermomechanical degradation, erosion, and foreign object damage. Current work at NASA Glenn Research Center is aimed at addressing these failure modes in EBC systems and developing robust analysis tools to aid in the design process. The Higher-Order Theory for Functionally Graded Materials (HOTFGM), a precursor to the High-Fidelity Generalized Method of Cells micromechanics approach, was developed to investigate the coupled thermo-mechanical behavior of functionally graded composites and will be used herein to assess the development and growth of a low-stiffness thermally grown oxide (TGO) layer in EBC/CMC systems without a silicon bond coat. To accomplish this a sensitivity study is conducted to examine the influence of uniformly and nonuniformly grown oxide layer on the associated driving forces leading to mechanical failure (spallation) of EBC layer when subjected to isothermal loading. Copyright © (2018) by DEStech Publications, *** rights reserved.

关键词： Ceramic matrix composites

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Laser displacement measurements of fan blades in resonance and flutter during the boundary layer ingesting inlet and distortion-tolerant fan test

Laser displacement measurements of fan blades in resonance a...

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AIAA Aerospace Sciences Meeting, 2018

作者： Duffy, Kirsten P. Provenza, Andrew J. Bakhle, Milind A. Min, James B. Abdul-Aziz, Ali University of Toledo Department of Mechanical Industrial and Manufacturing Engineering ToledoOH43606 United States NASA Glenn Research Center Multiscale and Multiphysics Modeling Branch ClevelandOH44135 United States Kent State University College of Aeronautics and Engineering KentOH44240 United States

ISBN: (数字)9781624105241

ISBN: (纸本)9781624105241

NASA’s Advanced Air Transport Technology Project is investigating boundary layer ingesting propulsors for future subsonic commercial aircraft to improve aircraft efficiency, thereby reducing fuel burn. To that end, a boundary layer ingesting inlet and distortion-tolerant fan stage were designed, fabricated, and tested within the 8’x6’ Supersonic Wind Tunnel at NASA Glenn Research Center. Because of the distortion in the air flow ingested by the fan, the blades were designed to withstand a much higher aerodynamic forcing than for a typical clean flow. The blade response for several resonance modes was measured during start-up and shutdown, as well as at near 85% design speed. Flutter in the first bending mode was also observed in the fan at the design speed, at an off-design condition, although instabilities were difficult to instigate with this fan in general. Blade vibrations were monitored through twelve laser displacement probes that were placed around the inner circumference of the casing, at the blade leading and trailing edges. These probes captured the movement of all the blades during the entire test. In addition to blade vibration results, benefits and disadvantages of laser displacement probe measurements versus strain gage measurements are discussed. © 2018, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.

关键词： Boundary layers

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