Investigation on non-uniform strains of a 2.5D woven ceramic matrix composite under in-plane tensile stress

Abstract

In this study, the digital image correlation technique and strain gauges were applied to the in-plane tensile tests of a 2.5D woven ceramic matrix composite for the purpose of characterizing deformation and strain distribution features. The test results indicate a strong influence of the weave architecture on the strain distribution of the material. Mesoscale finite element models were established based on the weave architecture of the material. The experimental and simulation results show that: the strain distributions are periodic and fluctuating; the maximum strain fluctuation on the surface is about 30%, but the deviation of average strain decreases rapidly with the calculated area increase. The strain measurement methods were proposed to obtain the accurate average strain: the size of measurement/calculated area should be twice larger than the unit cell size; much more accurate result could be obtained when the area size is an integer multiple of the unit cell size.