Non-linear deformation behaviour of anisotropic fibre reinforced ceramics

The composite properties of anisotropic reinforced silicon-carbide ceramics produced using different techniques, were determined in tension, compression and shear tests. Besides a distinct anisotropic material behaviour of some fibre ceramics, especially the technically important bi-directional reinforced ceramics indicate a strong non-linear stress strain behaviour and different properties for tension and compression load. The influence of those material mechanical phenomena on the structural behaviour of fibre ceramic composites under flexural load has been analysed in flexural tests using a novel optical field method to measure the induced strain fields. On the basis of the experimental investigations a numerical FEA simulation concept for the calculation of fibre ceramics under flexural load was applied. This model considers the realistic non-linear structural behaviour realistically. The performed theoretical and practical examinations make very clear, that the material adapted structural phenomena have considerable influences on the stress and strain fields of fibre reinforced ceramics under flexural loads and can not be neglected.