Study of damping behaviour of graphene based nano-composite materials
Loading...
Date
2024-07-11
Authors
Τσουλβατζή, Γεωργία Παρασκευή
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Vibration reduction is essential for many aspects of life. Structures, machines, and objects due to vibrations can succumb to defects or even complete destruction. These defects can be catastrophic when occurred while operating and can cause losses, even in human lives. To overcome that issue, scientists turn their research on damping materials. Elastomers can be extremely good damping agents but have weak mechanical properties and are used in some composite compositions but usually the enhancement is only in one or two dimensions of the material. In order to have a more isotropic effect, research has turned towards stronger polymers, like epoxy resin, with mediocre damping properties which can be however enhanced by incorporating nano-inclusions. This is a promising field of study that already has shown some good results in carbon nanotubes composites, so this study has turned to other carbon-based inclusions.
Specifically epoxy composites were fabricated with the inclusion of graphene nanoplatelets (GNPs) and expanded graphite (EG) with three different mixing methods (sonication, three-roll-milling and shear mixing) and a broad inclusion concentration. The composites that were fabricated were mechanically tested with an MTS machine in a three-point-bending configuration. Then to test their damping properties the specimens were tested in a free oscillation arrangement and then for the materials with the better damping ratios also forced oscillation was tested with the use of a DMA machine.
In essence, this study suggests that minimizing agglomerations, maintaining good flake aspect ratios, and maximizing strength without risking failure are the key for good results. Among the inclusion types tested, graphene nanoplatelets (GNP) yielded the most promising results. The epoxy composite containing 0.125% w/w GNP, produced via the three-roll milling method with an 80 μm final roll distance, exhibited significant improvements. This material demonstrated a 56.4% increase in damping ratio, along with enhanced flexural strength (9.3%) and flexural modulus (24%), while maintaining a similar strain at break compared to clear epoxy.
Description
Keywords
Epoxy composites, Composites, Damping ratio, Mechanical characterisation, Graphene nanoplatelets, Expanded graphite, Three-roll-milling, Shear mixing, Sonication, Free oscillation, DMA