Material development and multi-scale analysis of nonlinear vibrations with damping of composite blades
File(s)
Author(s)
Tufekci, Mertol
Type
Thesis
Abstract
This work focuses on manufacturing, characterisation, with a particular focus on the vibration damping capabilities, and modelling of nanocomposites that can be used as an improved matrix for designing composite aero-engine fan blades. For this purpose, epoxy is selected as the matrix material as it is one of the most commonly used matrix materials. The main improvement in the mechanical properties is achieved with the addition of various nanoreinforcements into the epoxy matrix which are namely fumed silica (FS), halloysite nanotube (HNT), silica and rubber nanoparticles. To characterise and model the effects of the nanoparticle reinforcements on the resultant composite structure, first, the effects of friction on the experimental test setups are investigated analytically. Then, the necessary samples are manufactured. The manufactured composite samples are put through experimental characterisation procedures, including scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), three-point bend tests, dynamic mechanical analysis (DMA) and Charpy impact tests. To understand the mechanisms behind the change in the mechanical behaviour of the composites with different reinforcing particles, numerical simulations are carried out. Initially, mean-field homogenisation (MFH) with Mori-Tanaka is performed to estimate the elastic properties of the nanoreinforcements, as their experimental characterisations are not possible in a straightforward and conventional way. Then finite element (FE) analyses are conducted on representative volume elements (RVE) for a more detailed, in-depth analysis of the mechanics of the composites. Considering these conventional methods do not take the size effects into account, the nonlocal continuum theory is employed to calculate the nonlocal stresses to investigate the size effects of the reinforcements. As another example, a fan blade made of material of nonlocal characteristics is presented...
Version
Open Access
Date Issued
2022-08-31
Date Awarded
01/02/2023
License URL
Advisor
Dear, John
Salles, Loic
Renson, Ludovic
Sponsor
Türkiye Bilimsel ve Teknolojik Araştırma Kurumu
Grant Number
BIDEB 2213 A 2016/2
Publisher Department
Mechanical Engineering
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)