Dissertation/Thesis Abstract

Interlayer Toughening of Carbon Fiber Composites Using Non-woven Veils and Multi-Walled Carbon Nanotubes
by Denk, Jack, M.S., California State University, Long Beach, 2020, 79; 27735439
Abstract (Summary)

Carbon fiber composites are becoming increasingly popular in the aerospace and automotive industries due to their excellent mechanical properties and low weight. Vehicles that are manufactured using composite materials have the potential to save money and resources due to the decreased amount of fuel they consume. Although carbon fiber composites have strong in-plane properties, they are vulnerable to out-of-plane impacts that can have detrimental effects on their load bearing capability. Impacts can initiate delamination in the interlayers of a composite that are hard to detect, possibly resulting in a catastrophic failure of structure. The interlaminar fracture toughness can be increased in composites through the use of materials such as thermoplastics, rubbers, and carbon nanotubes amongst others. Increasing the interlaminar toughness while maintaining a lightweight, high strength composite has become an area of high interest.

There are two primary objectives of this study. The first objective is to investigate how interleaving by a non-woven polyamide veil affects the mode I and mode II interlaminar fracture toughness of a benzoxazine/carbon fiber woven prepreg when cured at different pressures. The second objective is to study how interleaving by multi-walled carbon nanotubes can affect the mode I and mode II interlaminar fracture toughness, as well as the residual compressive strength in an epoxy/carbon fiber woven prepreg.

The results of the first study showed that the polyamide veil was successful in increasing mode I and mode II interlaminar fracture toughness of composites when cured at low pressures. High curing pressures were found to have a negative effect on the fracture toughness of the interleaved composites, however the non-interleaved composites were essentially unaffected by the pressure. Multi-walled carbon nanotubes as an interleaf had a negative effect on the mode I fracture toughness of composites, however they did not have an effect on the mode II interlaminar toughness or the residual compressive strength.

Indexing (document details)
Advisor: Barjasteh, Ehsan
Commitee: Yavari, Parviz, Tehrani, Mehran
School: California State University, Long Beach
Department: Mechanical and Aerospace Engineering
School Location: United States -- California
Source: MAI 81/9(E), Masters Abstracts International
Subjects: Mechanical engineering
Keywords: Carbon fiber, Composites, Interlaminar, Mode I, Mode II, Nanotubes
Publication Number: 27735439
ISBN: 9781658443500
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