| This dissertation is a study of the thermal physical properties of a single fiber to be used as a key part of an HTS tunable filter. Eight classes of candidate fibers were narrowed down to carbon and borosilicate fibers for more study. Novel measurement methods were used in this project that overcame the shortcomings of literature methods, which can only measure the properties at room temperature. The experimental apparatus was designed and built, and measurements were made of Young's modulus, tensile strength, ultimate strain, torsional modulus and thermal linear expansion of both types of fibers at both room temperature and 95K. The errors of the measurement, including random variations in fiber diameter, were analyzed statistically to determine error bounds.; The measurement results were used to determine the mechanical performance of each of the fibers when applied to suspending the toractor system. Based on the working conditions of both carbon fiber and borosilicate fiber, the borosilicate fiber was chosen for this purpose. The performance margin of the fiber suspending system was estimated by using a statistical model.; A new model was proposed to demonstrate the relationship of the cross-section structure of Polyacrylonitrile (PAN)-based carbon fiber and its mechanical properties. The theoretical predictions on the properties of PAN-based carbon fiber based on this model agree very well with the experimental data. The Young's modulus and tensile strength of PAN-based carbon fiber with known diameter can be calculated by a simple equation without taking time to do an experimental measurement. |
