Fracture Resistance of Brittle Materials Under Local Loading by Scratching to Edge Chipping. Part. 1. Methodical Grounds of Research

Abstract

Methodical aspects of experimental investigation of brittle materials under local edge loading by scratching the specimen surface with a Rockwell indenter to its edge chipping (S+EF method) are detailed. The edge damage parameter range (fracture distance) had its basis in the literature data on numerical simulation of the stress-strain state in the local indentation zone of the material surface to its edge chipping. Fractographic analysis of tested edges revealed their damage behavior under given loading conditions. The paths of fracture crack propagation to the formation of “shell-like” chip scars, which are asymmetric quasi-conical crack traces, are studied. Partially formed or strained chips having a somewhat distorted fracture surface as compared to the “ideal” geometry of the edge chip were also found. The asymmetry of chip scars was established to have no effect on the fracture resistance of the material. The validity of empirical investigation results was achieved with a minimum test scope, determined by statistical data processing. This test method of low material intensity can be effectively applied to different lines of research.