Damage Model of a Two-Layer TiB/Ti-Based Ceramic-Metal Composite under Three-Point Loading

In this work, a model was developed for determining the critical load of a two-layer ceramic-metal composite under three-point loading based on the analysis of the local influence of distributed defects on the stress field. The stressed state is defined as the solution of a boundary value problem for a solid. The object of investigation was a two-layer TiB/Ti-based ceramic-metal composite obtained by free SHS (self-propagating high-temperature synthesis) compression. A method was developed for determining the statistical distribution of defects within a specimen based on metallographic cross-sectional analysis. The critical load was determined by the defect size probability density found from the experimental data. The cases of flat and sinusoidal interfaces between the composite layers were considered. A digital model of a two-layer beam deformed under three-point loading was built in Abaqus finite element software, which was used for numerical simulation of the stress field. Based on the numerical results, the stress field was corrected for the sinusoidal interface. The influence of the corrected stress field on the specimen strength was analyzed when the defect distribution pattern was similar to that in the composite with the flat interface. It was shown that the sinusoidal shape of the interface had no effect on the specimen strength, provided that the period and amplitude of deviation from the rectilinear shape were small relative to the linear size of the specimen.