This thesis presents the results of an investigation of bearing failure at a loaded hole in carbon fibre composite laminates. The investigation included finite element analysis and a program of experimental testing for quasi-isotropic laminates, uni-directional laminates and laminates with fibres steered along predefined trajectories. The investigation formed part of a research program in the Cooperative Research Centre for Advanced Composite Structures Ltd (CRC-ACS) support by the Office of Naval Research from the United States. Work in progress in the CRC includes research defined in this thesis including the addition of nano-particles to the resin to improve the bearing strength. The literature survey undertaken in this thesis identified that the micro-buckling theory proposed by Professor C.T. Sun from Purdue University, Indiana USA, is the best analysis procedure for initial bearing failure in pin-loaded laminates. This failure theory has therefore been implemented in a Fortran program using the results from a finite element analysis for the nonlinear contact problem of a pin bearing on a hole in a composite laminate. The finite element analysis is executed using the commercial finite element system MSC.MARC. The numerical predictions have been validated by a test of progressive failure with the aid of an acoustic emission monitoring system. The acoustic emission parametric and frequency analysis is performed using the acoustic emission software Vallen Systeme. Fast fourier transformation of the waveform have been achieved to distinguish and identify microfailure mode. Failure mechanisms have been verified by post-mortem microstructural examination. There are 3 failure mechanisms associated with bearing failure in carbon fibre reinforced epoxy composite, the first is fibre matrix interfacial failure, followed by fibre fracture, and subsequently matrix splitting. The application of AE technique has been applied successfully to characterise the development of failure.

Vibrating machinery must be isolated from a supporting structure if the vibration is likely to cause fatigue of components or annoyance to people due to direct vibration exposure or from the noise radiated by the vibrating structure. Active vibration isolation can be applied in these situations to extend the low frequency performance of passive vibration isolators. In this thesis, theoretical and experimental investigations are described for a vibrating rigid body that is passively and actively isolated from a beam and a cylinder, respectively. The focus of the work is to investigate the vibrational power transmitted by translational forces and rotational moments into the support structure. For the investigation of the simply supported beam, a classical mathematical model is examined and finite element modelling is used to predict the power transmission into the beam when active vibration control is used. The results show that power transmission by moments is significant and cannot be ignored when the vibrational power transmission into the support structure is actively controlled. To control the power transmission by translational forces and rotational moments, a novel six axis active vibration isolator and a novel six axis force transducer were constructed to be used in the experimental investigations. Using vibrational power transmission as a cost function to be minimized in active control experiments presents unique problems because negative values of translational power transmission are possible when power transmission from rotational moments is ignored or when phase errors occur in the transducer outputs. Active control attempts which converge the cost function to a negative value of power transmission along a particular axis can result in overall vibration levels in the structure which are greater than without active control. To prevent the increase in vibration levels, minimization of the squared value of power transmission is investigated as a potential cost function. A method is described to combine force and velocity signals into a signal which is proportional to the vibrational power transmission and is suitable for use with an existing filtered-x Least Mean Squares controller, so that the squared vibrational power transmission can be minimized. Experimental trials were performed to actively minimize the power transmission into a simply supported beam from a vibrating rigid body using a single axis and a six axis active vibration isolator. The purpose of the experimental work was to confirm the theoretical findings and to find a practical method to measure power transmitted by rotational moments. The vibrational power transmission from a vibrating rigid body that is passively and actively isolated from a cylinder was also investigated. The theoretical model of the cylinder was similar to the beam model, although the dynamics of the cylinder makes the solution more complicated. Two experimental trials were conducted to verify the theoretical model and involved the use of the single axis and the six axis active vibration isolators, respectively. / Thesis (Ph.D.)--School of Mechanical Engineering, 1999.

There are many situations in which contact between two bodies is at a single point so there can be no tensile (force). This form of contact only provides a single degree of restraint, and is defined as a unidirectional point contact. The analysis of Reuleaux shows that four suitably placed frictionless point contacts are required to completely restrain an object in a plane. The objective of the thesis is to allow user-placement of three contacts and to find acceptable range for placement of the fourth. If the fourth contact is anywhere in the range, the four forces fulfill the requirement for total planar restraint, i.e. all translations and rotations in a plane are prevented. This project considers the directions and placement allowed for the fourth force but does not take into consideration the magnitudes or friction coefficients of any of the four forces. In this research a program named Planar Restraint Design Assistant (PRDA) was developed to analyze positions of the four restraint forces. A planar object is first specified by the user; the program accepts AutoCAD images for more complex objects. For three given restraint forces PRDA determines a range of the fourth force such that total restraint is achieved. In addition, PRDA allows the user to arrange three restraint forces until a desired range of the fourth restraint force is obtained. Results are shown in visual form with accompanying graphs for numerical interpretation. A program user's guide and a program learning guide are provided as shown in the report with illustrative examples. Program source code in QuickBASIC is included in the report. / Graduation date: 1995

Graduation date: 1995

Thesis (Ph.D.)--Hong Kong University of Science and Technology, 2006. / Includes bibliographical references (leaves 112-125). Also available in electronic version.

Thesis (M.F.)--Oregon State University, 1977. / Typescript (photocopy). Includes bibliographical references (p. 48-49). Also available on the World Wide Web.

Abstract Taiwan is the 5th biggest export country of Plastics Machines, 4th one on export globally in 2005. With total employees around 8000 in 400 plants, Taiwan Plastics Machinery has built up their market position of comparable function in reasonable price level. With impact from end users¡¦ moving out of Taiwan, as well as China¡¦s macro-control on over-developed economic growth, the production volume of the whole industry is still on the growing trend. To be close to customers, following customers movement seems to be the direction for machine makers as well. However, for those small scale companies, to move out from home country is difficult due to lack of resources. The risk of investment in other region, e.g. China, is contrarily high. Export business is therefore the major factor for further business growth. And the results reveal that Taiwan Plastics Machine Makers has grown even under the weak situation. How could they make it? What is their core competence to keep the records? This study is to analyze the competence of the industry and furthermore to explore the relativity between competence and export growth. The study reveals that Taiwan Plastics Machinery export growth results mainly from the market demand. The competence is rather weak in consideration of the factors of production and competitiveness, especially from Mainland China and Korea. Therefore the growth on export volume of Taiwan Plastics Machinery has very limited relevant to its competence. To upgrade machinery¡¦s from the low price market, it is strongly recommended that improving on technology competence and innovation should be taken into strategic actions for future development.

Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1991. / Vita. Abstract. Includes bibliographical references (leaves 170-175). Also available via the Internet.

Thesis (Ph. D.)--West Virginia University, 2002. / Title from document title page. Document formatted into pages; contains xvii, 181 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 157-161).

Inaug.-diss.--Eidgenössische technische hochschule, Zürich. / Lebenslauf.