Inspection of geometry influence and fiber orientation to characteristic value for short fiber reinforced ceramic matrix composite under bending load

For use of short fiber reinforced ceramics the knowledge of the influence of coupon geometry on the failure mode and the determined resistance in bending tests is necessary. In contrast to the continuous fiber reinforced ceramic matrix composites (CMC), for short fiber reinforced CMC there are only few studies and no standard on consideration of size effects. In the present work, the influence of coupon geometry and test conditions on the average value and distribution of flexural strength has been investigated. Two short fiber CMCs with different fiber length were examined under four point bending load. Moreover, the relationship between fiber orientation in the loaded area, failure location and measured flexural strength was investigated through high resolution X-ray computer tomography (mCT) and SEM. The presented outputs will be proposed to a future standard for bending test of short fiber reinforced CMC materials with different fiber length.