METHOD OF DETECTION OF FATIGUE MICRO-FRACTURES

摘要

FIELD: mining. ^ SUBSTANCE: metal film is applied on investigated surface. This film reacts to micro-shear deformation of basic metal in the process of cyclic deformation. Metal films, for example aluminium ones are attached to the structure. The structure with films is tested under operational regimes with 800-1000 cycles of loading. Reaction in form of elongated dark local zones is registered on surface of films; fractures are located directly under these zones. Moment of micro-fracture opening is determined by width of zone reaching 3-5 mcm without limit darkening. Obviously opened micro-fractures with broken metal continuity are determined by zones with their limit darkening of width of 10 mcm; length of micro-fractures is determined by length of dark zones of film minus 2-3 mcm. ^ EFFECT: reduced labour intensiveness. ^ 2 dwg