Electrospun nanofibrous interleaves in composite laminate materials

Palazzetti, Roberto (2013) Electrospun nanofibrous interleaves in composite laminate materials, [Dissertation thesis], Alma Mater Studiorum Università di Bologna. Dottorato di ricerca in Meccanica e scienze avanzate dell'ingegneria: progetto n. 4 "Meccanica dei materiali e processi tecnologici", 25 Ciclo. DOI 10.6092/unibo/amsdottorato/5245.
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Abstract

The present work aims for investigate the influence of electrospun Nylon 6,6 nanofibrous mat on the behavior of composite laminates. The main idea is that nanofibrous interleaved into particular ply-to-ply interfaces of a laminate can lead to significant improvements of mechanical properties and delamination/damage resistance. Experimental campaigns were performed to investigate how nanofibers affect both the static and dynamic behavior of the laminate in which they are interleaved. Fracture mechanics tests were initially performed on virgin and 8 different configuration of nanomodified specimens. The purposes of this first step of the work are to understand which geometrical parameters of the nanointerleave influence the behavior of the laminate and, to find the optimal architecture of the nanofibrous mat in order to obtain the best reinforcement. In particular, 3 morphological parameters are investigated: nanofibers diameter, nanofibers orientation and thickness of the reinforce. Two different values for each parameter have been used, and it leads to 8 different configurations of nanoreinforce. Acoustic Emission technique is also used to monitor the tests. Once the optimum configuration has been found, attention is focused on the mechanism of reinforce played by the nanofibers during static and dynamic tests. Low velocity impacts and free decay tests are performed to attest the effect of nanointerlayers and the reinforce mechanism during the dynamic loads. Bump tests are performed before and after the impact on virgin and two different nanomodified laminates configurations. The authors focused their attention on: vibrational behavior, low velocity impact response and post-impact vibration behavior of the nano-interleaved laminates with respect to the response of non-nanomodified ones. Experiments attest that nanofibers significantly strength the delamination resistance of the laminates and increase some mechanical properties. It is demonstrated that the nanofibers are capable to continue to carry on the loads even when the matrix around them is broken.

Abstract
Tipologia del documento
Tesi di dottorato
Autore
Palazzetti, Roberto
Supervisore
Co-supervisore
Dottorato di ricerca
Scuola di dottorato
Ingegneria industriale
Ciclo
25
Coordinatore
Settore disciplinare
Settore concorsuale
Parole chiave
Electrospinning, Polymeric Nanofibers, Composite Material, Interlaminar Stress, Delamination Resistance
URN:NBN
DOI
10.6092/unibo/amsdottorato/5245
Data di discussione
22 Aprile 2013
URI

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