Date of Award

2023

Document Type

Open Access Dissertation

Degree Name

Doctor of Philosophy in Mechanical Engineering-Engineering Mechanics (PhD)

Administrative Home Department

Department of Mechanical Engineering-Engineering Mechanics

Advisor 1

Gregory M. Odegard

Committee Member 1

Trisha Sain

Committee Member 2

Ranjit Pati

Committee Member 3

Gowtham

Abstract

Polymer matrix composite materials are widely used as structural materials in aerospace and aeronautical vehicles. Resin/reinforcement wetting and the effect of polymerization on the thermo-mechanical properties of the resin are key parameters in the manufacturing of aerospace composite materials. Determining the contact angle between combinations of liquid resin and reinforcement surfaces is a common method for quantifying wettability. It is challenging to determine contact angle values experimentally of high-performance resins on CNT materials such as CNT, graphene, bundles or yarns, and BNNT surfaces. It is also experimentally difficult to determine the effect of polymerization reaction on material properties of a resin. Fortunately, molecular dynamics-based simulations provide accurate predictions for interfacial properties between polymer and reinforcement materials, and predictions of thermo-mechanical properties of polymer materials.

A molecular dynamics framework to predict the contact angle values of polymers on reinforcement surfaces is developed. Several aerospace-grade polymers are simulated to predict the contact angle values of CNT and BNNT surfaces. The results show that the contact angle values depend upon the processing temperatures, functional groups in the polymers, monomer chain length, and atomic charges. Comparison of the wettability of different surfaces is provided. The effect of functional groups and charges is quantified by interaction energy analysis between polymer and surface. Results indicate that the cyanate esters and BMI polymers show better wettability are suggested to use for composite manufacturing to result in better resin infusion.

Further, Elium thermoplastic material was modeled. The polymerization reaction was simulated to create polymerized models. The physical, thermal, and mechanical properties are predicted as a function of the extent of the polymerization reaction. The predicted material properties are compared with experimentally measured material properties from the literature. The use of IFF-R forcefield is validated for accurate material properties predictions for a thermoplastic material.

Creative Commons License

Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.

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