Research on bend strength of brittle materials based on statistical fracture theory

Based on statistical fracture theory, the expect strength and failure probability of brittle materials relating 3-point bending test and 4-point bending test are developed. The relation of the expect strength in the above stress states is studied. According to the analysis results, the followings may be concluded: (1)The expect strength in bending stress states is greater than that in the stress state of uniform uniaxial tension; (2) The expect strength in 3-point bending stress state is greater than that in 4-point bending stress state; (3) In 4-point bending stress state, the bigger the distance of the load working points is, the less the expect strength is or, the bigger the failure probability of the structure in the same stress state is. All these conclusions may possess important guiding meanings to practice project.