SiC- and carbon-fibre-reinforced glass under alternating bending stress loadings
Date
Authors
Volume
Issue
Journal
Series Titel
Book Title
Publisher
Link to publishers version
Abstract
Alternating bending stress experiments are described which were performed with various fibre/DURAN-glass composites reinforced by Nicalon NL 202 SiC fibres and by two different types of carbon fibres, a high-tensile strength (ht) and a high-modulus (hm) fibre. Also the influence of unidirectionally homogeneous and inhomogeneous fibre distribution as well as the bidirectional 0°/90° ply distribution are studied. In contrast to previously investigated strain-controlled experiments the present stress-controlled experiments show after the pretreatment of 1000 alternating tensile-compressive stress cycles fatigue (beginning damage) already at amplitudes below the limit of pure elasticity (below bendover stress) of a simple bending-load experiment. Despite of this difference the "training effect" of the previous investigation, the increase of the bendover stress with increasing stress amphtude after 1000 alternating-load cycles, is found to be similar and can be established also for the present experiments. The carbon-fibre-reinforced composites show a better tolerance of damage due to their smaller fibre diameters than the SiC-fibre-reinforced composites.