MATERIALS STRESS STATE EVALUATION METHOD Russian patent published in 2017 - IPC E21C39/00 

FIELD: measurement equipment.

SUBSTANCE: method involves samples testing till destruction. Samples are produced from the monoliths of the tested material, then they are test for monoaxial tension, compression, and in terms of triaxial stress state. These data are used to build a strength passport with envelope of Mohr's circle of stress limit. Main crack surface roughness (R_z) value is measured for each type of rock stress state based on which the roughness (R_z) change nomogram is constructed for the material destruction main crack surface, depending on the main normal stresses value σin the destruction crack zone. Then, a sample is taken from the area of the main crack of the building structure tested material destruction, and there roughness value R_z1 is measured of the destruction main crack surface through which, using a nomogram obtained, the value is determined of the maximum normal stresses σ_n.r. The point of the tested material limit state is determined, for which in the vertical axis of the material strength passport a value is set of the maximum normal stress acting in the zone of material destruction of σ_n.r. and from this point a perpendicular is put to the envelope of Mohr's circles of stress. Using the material limit state point, a Mohr's circle of stress is built for the tested sample of the destroyed structure element, and according to it, principal normal stress values σ_2p and σ_1p are determined and the material stress state type is defined in which the structure element was destroyed.

EFFECT: improved accuracy of stress state assessment of materials that make up the structure, improved reliability of its operation.

3 cl, 4 dwg