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<p> An oblique four bar structural model with fixed member ends, being the most general building for space frames, is analysed under free and steady-state vibrations, using discrete mass method. </p> <p> Experimental techniques for measurement of free and steadystate vibrations are described. </p> <p> Experimental results have been compared against analytical ones. </p> / Thesis / Master of Engineering (MEngr)

The potential of filling carbon nanotubes in polymers has been widely acknowledged for composites with exceptional new properties owing to the high strength of carbon nanotubes. In the thesis, by employing Materials Studio 4.0 software, the buckling behaviour and vibration of polyethylene and carbon nanotube matrix composites are first discussed using molecular mechanics simulations. The research is aimed to acquire a high strength design of PE-CNT matrix with proper PE/CNT ratio as well as discovering the dynamic characteristics of the PE-CNT composites. Investigation results show that as the number of PE chains increases, the buckling strain and the resonance frequency will decrease. Van der Waals forces are collected to explain the relation of the PE chains to the buckling strain and the resonance frequency of the composites.

The potential of filling carbon nanotubes in polymers has been widely acknowledged for composites with exceptional new properties owing to the high strength of carbon nanotubes. In the thesis, by employing Materials Studio 4.0 software, the buckling behaviour and vibration of polyethylene and carbon nanotube matrix composites are first discussed using molecular mechanics simulations. The research is aimed to acquire a high strength design of PE-CNT matrix with proper PE/CNT ratio as well as discovering the dynamic characteristics of the PE-CNT composites. Investigation results show that as the number of PE chains increases, the buckling strain and the resonance frequency will decrease. Van der Waals forces are collected to explain the relation of the PE chains to the buckling strain and the resonance frequency of the composites.

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McMaster University in conjunction with an industrial partner has been designing wireless vibrational condition monitoring sensors for implementation on a vibrating screening machine used in mining applications. A limitation with the current sensor design is their dependency on battery power. In order for the sensors to provide real-time continuous streaming of acceleration data, an alternate power supply was required outside of traditional sources such as batteries or wired power. This thesis outlines the research and development of a power system that harvests the kinetic vibrational energy of a mining screen and converts it into electrical energy for use by a wireless sensor node. During development, multiple prototypes were built and evaluated under laboratory conditions. The core concept of the system is an eccentric pendulum mass excited by the external vibrations of the screening machine used to drive a stepper motor generator. The major design obstacle of the project was how to get the system to self initiate. Both a mechanical and an electrical solution were developed to solve this concern. The final prototype design is fully autonomous, able to react to the start up or shut-down of a screening machine, while also providing a continuous power supply to a wireless vibrational analysis sensor as tested in the lab. With minor optimization, this prototype can be turned into a commercial product for industrial implementation and sale. / Thesis / Master of Applied Science (MASc)

It is often needed to predict the behavior of structures. With the helpof an FE model, it is possible to see the motion of the structure. Inthis, Master thesis work time domain analyses were carried out on afinite element model representing a window attached by click-ins. Theaim was to establish an FE model which gives a good correlation withtest data. The finite element modelling was carried out in MSC Apex.MSC Nastran was utilised to analyze the FEA model and the resultwas post-processed in Simxpert. Different vibrational tests were made. A crane was used to exciteand support the wall together with the window and the responseswere recorded with tri-axial accelerometers. During the thesis, it wasfound that the FE model requires more work and accurate boundaryconditions to provide better resemblance with the test data.The results deviate from the measured. This opens future possibilities tocarry on the project.

The closed shell structures of certain all-carbon fragments originally observed in mass spectroscopy experiments leads to the enhanced stability of these species, known as fullerenes, which have excited sufficient interest amongst chemists and physicists over the last decade to warrant the award of the 1996 Nobel Prize for Chemistry to their discoverers. ¶ Studies of the stability, symmetry, and consequent remarkable properties of fullerenes began in earnest in 1991 with the development of a technique enabling the production and purification of macroscopic quantities of material. The best known and most widely studied fullerene is the truncated icosahedral C[subscript 60] molecule, which forms the basis of the present work. ¶ One important property of C[subscript 60] is that it forms salts with sufficiently electropositive species, such as the alkali metals. The resulting salts contain C[subscript 60] anions and are known as fullerides. Certain of these salts display metallic behaviour, and some superconduct at temperatures as high as 33 K. ¶ Three aspects of fulleride research are addressed in this work. These are: i) the preparation, crystal structure determination and superconductivity characterization of several new fullerides, particularly those including ammonia as an additional intercalant; ii) the electronic structure of the C[superscript n-, subscript 60] (n = 1 - 6) anions, as probed by solution-phase near infrared absorption spectroscopy; and iii) the molecular dynamics of a number of fullerides, superconducting and non-superconducting, by inelastic neutron scattering. ¶ This work has grown out of an Honours project also concerning C[subscript 60], the combined duration of the two studies covering essentially the entire history of this widely and competitively studied field.