Papers by Author: Emőke Rudnayová

Abstract: Mechanical and fracture properties of unidirectional composites reinforced with R-glass fibres and utilizing various commercially available polysiloxane resins as matrix precursors were investigated. As the matrix becomes more brittle after the pyrolysis the impact toughness and flexural strength of the composites fall. On the other hand, the shear modulus rises after the pyrolysis as the matrix becomes stiffer in shear. The appearance of fracture surfaces generated during the flexural strength at room temperature (RT) and elevated temperatures is discussed.

Abstract: Irregular evolution of friction coefficient, recorded during the ball-on-disc test on Si3N4 based ceramic materials, was analysed by means of fractal geometry methods. Tests were carried out at room temperature, in air and without any lubricant. It was proven that the friction coefficient trace, considered as a geometric object, has the property of a fractal curve. The fractal dimension of this curve increased with increasing wear rate measured in a corresponding wear test. This could indicate the possible correlation between the wear rate and the fractal dimension of friction coefficient as a function of sliding distance (time).