Vibration isolation is an important requirement for many engineering systems. In particular, in the context of vibration isolation for light-weight automotive vehicles that exhibit wide variation in sprung mass, several limitations are associated with passive isolation systems. Such passive systems cannot obtain wide variations in the suspension parameters which required for reliable performance. While these technical drawbacks can be overcome by implementing active systems, these are associated with an increase in complexity, cost and potentially negative impact on reliability. In this context, composite fluid materials, which combine different components in a way that enhances an isolator’s performance, could represent a possible alternative approach with promising potential. However, the application of composite fluid materials for vibration isolations is still an underdeveloped area. The composite fluid material that is the subject of this research is referred to as Foam Filled Fluid (FFFluid). It is composed of three components, namely compressible (foam) particles, a viscous carrier fluid and a packaging material. This composite material has recently been investigated for applications in impact energy management but is not understood in anti-vibration application. Thus, the objective of this research was to understand the mechanisms, to characterise design parameters and to predict the responses of such composite material when used for vibration isolation systems. A theoretical understanding of the working principle for a FFFluid-based isolator was first achieved. Then, experimental work was conducted to assess the performance of such a device. The characterisation of the composite material was carried out via a systematic study; this study was then validated by an experimental -ivprogramme based on a Design of Experiments approach. Finally, empirical prediction models of the system were extracted by analysing the obtained data statistically. The conducted research shows that a FFFluid-based isolator possesses several advantages over commonly used existing solutions. Its main benefit is the potential capability of adjusting stiffness and damping coefficients by changing one component or more of this composite material. It was shown that increasing the volume of the composite material led to increased stiffness and damping coefficients. Besides, increasing the ratio of fluid in the mixture caused to increase the stiffness coefficient. The most important parameters that have an influence on the response of FFFluid were: the size of foam, the ratio of foam to fluid, volume of the material and fluid viscosity. Therefore, empirical models were established based on these parameters, the accuracy of these models were 85% Through the study of this novel material, the application of the FFFluid concept as a vibration isolator solution was studied. In practice, the design parameters of such a system could be adjusted through a control mechanism, to provide an adaptive solution. This could represent a suitable means to bridge the gap between passive and active suspension system in the context of vibration isolation for light-weight vehicles.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:699355 |
| Date | January 2016 |
| Creators | Elderrat, Haithem |
| Publisher | Cardiff University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://orca.cf.ac.uk/95786/ |
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