Alternating bending load behaviour of unidirectionally fibre-reinforced glasses

Abstract

Alternating bending load experiments are described and applied on SiC- and carbon-fibre-reinforced alkaline earth borosilicate glass samples. The mechanical properties (strength, bendover stress, Young's modulus) were determined by the three point bending method after 1000 strain-controlled alternations of load and compared with those of non-pretreated samples. It could be shown that all composites can be treated by an alternating bending load up to their elastic proportionahty limit (bendover stress) without failure or without any loss of their mechanical properties. Alternating bending loads above the bendover stress lead to a rapid fatigue of the SiC-fibre-reinforced glass composites while the carbon-fibre-reinforced composites show a great toleration of damage under the applied experimental conditions. In the case of the carbon-fibre-reinforced glass the homogeneity of the fibre distribution is of special importance for high bendover stresses and strengths during cyclic bending load experiments.