Characterization of Mechanical Properties under Shear Load of a Short-Carbon-Fiber-Reinforced C/SiC Ceramic

Kurzfassung

The main objective of this work is the evaluation of the mechanical shear properties of a short-carbon-fiber-reinforced ceramic, which shows strong non-homogeneity in its microstructure and anisotropy through different fiber orientations. In this work, the shear modulus (G-modulus) and shear strength of this material were determined with the Iosipescu shear test and the Asymmetric-Four-Point-Bend shear test (AFPB test) at room temperature. Both test methods provide a nearly pure shear stress state in the shear plane and are therefore suitable for determination of the mechanical properties under shear load. Different notch opening angles with θ = 0° or θ = 110° and sample sizes for both methods are discussed. For strain measurement, strain gauge rosettes are applied on two sides of the test specimens. Because of the limited size of basic material, for the Iosipescu test small specimens were bonded onto aluminum tabs, which induced different failure mechanisms. Therefore the Iosipescu results are only valid for determination of shear modulus but not for evaluation of shear strength.