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2. Bayesian Inference of Fiber Orientation and Polymer Properties in Short Fiber-Reinforced Polymer Composites

Author

Thomas, Akshay J., Barocio, Eduardo, Bilionis, Ilias, and Pipes, R. Byron

Subjects
Condensed Matter - Materials Science, Statistics - Applications
Abstract

We present a Bayesian methodology to infer the elastic modulus of the constituent polymer and the fiber orientation state in a short-fiber reinforced polymer composite (SFRP). The properties are inversely determined using only a few experimental tests. Developing composite manufacturing digital twins for SFRP composite processes, including injection molding and extrusion deposition additive manufacturing (EDAM) requires extensive experimental material characterization. In particular, characterizing the composite mechanical properties is time consuming and therefore, micromechanics models are used to fully identify the elasticity tensor. Hence, the objective of this paper is to infer the fiber orientation and the effective polymer modulus and therefore, identify the elasticity tensor of the composite with minimal experimental tests. To that end, we develop a hierarchical Bayesian model coupled with a micromechanics model to infer the fiber orientation and the polymer elastic modulus simultaneously which we then use to estimate the composite elasticity tensor. We motivate and demonstrate the methodology for the EDAM process but the development is such that it is applicable to other SFRP composites processed via other methods. Our results demonstrate that the approach provides a reliable framework for the inference, with as few as three tensile tests, while accounting for epistemic and aleatory uncertainty. Posterior predictive checks show that the model is able to recreate the experimental data well. The ability of the Bayesian approach to calibrate the material properties and its associated uncertainties, make it a promising tool for enabling a probabilistic predictive framework for composites manufacturing digital twins., Comment: 33 pages, 13 figures, 3 tables

Published
2022
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20. Manufacturing of Stretchable Wavy-Patterned Fiber-Reinforced Elastomer Composites and Its Behaviors Under Tensile Loading Conditions.

Author

Kim, Garam, Su, Roy, Lee, Harry, Tackett, Drake, Barocio, Eduardo, Ropp, Timothy D., and Pipes, R. Byron

Subjects
FIBROUS composites, CARBON fibers, MANUFACTURING processes, TENSILE tests, MOLDS (Casts & casting)
Abstract

The wavy-patterned carbon fiber reinforced elastomer composites that offered both the elongation characteristic of the elastomer and the stiffness of the fiber reinforcement before the elastomer reached its elongation at failure was introduced in this study. The goal of this study was to develop and demonstrate the manufacturing process of the wavy-patterned fiber-reinforced elastomer composites and investigate its behaviors under tensile loading conditions. A carbon fiber tow was impregnated with a silicone elastomer and placed in the test specimen manufacturing mold with a specific pattern using a wavy-patterned fiber placing jig. The silicone elastomer was then poured into the mold to cast test specimens. Various wavy-patterned fiber-reinforced elastomer composites, each with different allowed elongation levels and different amount of fiber, were designed and fabricated. Due to fiber slippage during the tensile test with the traditional test grip fixture, a roller grip fixture was used for the tensile test. The test results showed a unique behavior of the wavy-patterned fiber reinforced elastomer composites that elongated until the patterned fiber became straightened, providing additional stiffness to the test specimen under tensile loading. It was observed that the maximum strength and elongation at failure varied with different patterns and amounts of fiber. The unique failure mechanisms of the fiber-reinforced elastomer composite during the tensile test were analyzed and discussed. Despite the fiber being fully impregnated with the elastomer, weak adhesion between the fiber and elastomer led to disbonding between them. [ABSTRACT FROM AUTHOR]

Published
2024
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28. Contributors

Author

Adam, Laurent, primary, Aleksenko, Vladislav O., additional, Barocio, Eduardo, additional, Bochkareva, Svetlana A., additional, Bogdanor, Michael, additional, Brenken, Bastian, additional, Buslovich, Dmitry G., additional, Chang, Li, additional, Doghri, Issam, additional, Domm, Matthias, additional, Dontsov, Yuri V., additional, Dul, Sithiprumnea, additional, Fambri, Luca, additional, Favaloro, Anthony, additional, Fei, Guoxia, additional, Friedrich, Klaus, additional, Gan, Xinpeng, additional, Gardan, Julien, additional, Gao, Xia, additional, Ghasemi Nejhad, Mehrdad N., additional, Grohens, Yves, additional, Gurka, Martin, additional, He, Qinghao, additional, James, Jemy, additional, Jia, Xin, additional, Joseph, Blessy, additional, Kalarikkal, Nandakumar, additional, Kornienko, Lyudmila A., additional, Kunc, Vlastimil, additional, Lavorgna, Marino, additional, Li, Jing, additional, Lietaer, Olivier, additional, Liu, Peng, additional, Lyukshin, Boris A., additional, Man, Ziyan, additional, Mathieu, Sylvain, additional, Panin, Sergey V., additional, Pegoretti, Alessandro, additional, Pipes, R. Byron, additional, Selzer, Ralf, additional, Shilko, Sergey V., additional, Thomas, Sabu, additional, Walter, Rolf, additional, Wang, Jinzhi, additional, Wang, Xiaolong, additional, Wang, Zhanhua, additional, Xia, Hesheng, additional, Ye, Lin, additional, Yu, Ning, additional, Zachary Trimble, A, additional, and Zhang, Xiaoqin, additional

Published
2020
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42. Structural Framework for Flight I: NASA’s Role in Development of Advanced Composite Materials for Aircraft and Space Structures

Author

Tenney, Darrel R, Davis, John G., Jr, Johnston, Norman J, Pipes, R. Byron, and McGuire, Jack F

Subjects
Structural Mechanics, Composite Materials
Abstract

This monograph is organized to look at: the successful application of composites on aircraft and space launch vehicles, the role of NASA in enabling these applications for each different class of flight vehicles, and a discussion of the major advancements made in discipline areas of research. In each section, key personnel and selected references are included. These references are intended to provide additional information for technical specialists and others who desire a more in-depth discussion of the contributions. Also in each section, lessons learned and future challenges are highlighted to help guide technical personnel either in the conduct or management of current and future research projects related to advanced composite materials.

Published
2019

45. FIBER REINFORCED THERMOPLASTICS: Compression Molding of Hybrid Continuous and Discontinuous Fiber Reinforced Thermoplastics for Enhancing Strength Characteristics.

Author

Barocio, Eduardo, Eichenhofer, Martin, Kalman, Jordan, Fjeld, Ludvik M., Kirchhoff, Joseph, Kim, Garam, and Pipes, R. Byron

Abstract

Compression molding with long discontinuous fiber-reinforced thermoplastics enables replacing traditionally machined metallic components with geometrical complexity and with reductions in weight and potential enhancements in structural characteristics like durability, fatigue, and serviceability. Fiber length is critical in fiber-reinforced composites. While long continuous fibers limit the geometrical complexity that can be fabricated but provide exceptional mechanical properties, discontinuous fibers provide manufacturing flexibility but with a penalty in strength. This work demonstrates enhancement in strength and reduction in strength variability achieved by compression molding of long discontinuous fiber platelets and continuous fiber preforms. This approach was demonstrated for an overhead bin pin bracket geometry. Continuous fiber preforms were manufactured with 60% by volume of carbon fiber-reinforced Poly Ether Ketone Ketone (PEKK) using the 9T Labs continuous fiber Additive Fusion Technology (AFT). Similarly, fiber platelets with 60% by volume of carbon fiber reinforced PEKK were utilized. Continuous fiber preforms were designed considering both the concurrent flow of continuous and discontinuous fibers with the desired mesostructure of continuous and discontinuous fibers. The results presented in this work showed an increase of 99.6% in the load at the onset of failure by reinforcing the pin bracket with about 17% by weight of continuous fiber preforms. Similarly, the coefficient of variance of the load at the onset of failure decreased by 46%. Finally, reinforcing the pin bracket with continuous fiber preforms not only enhanced the strength characteristics but also decreased the variability in strength characteristics. [ABSTRACT FROM AUTHOR]

Published
2023
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