METHOD FOR DETERMINATION OF STRESS INTENSITY FACTORS FOR CRACKS Russian patent published in 2018 - IPC G01L1/24 G01N3/08 

FIELD: test technology.

SUBSTANCE: invention relates to the field of experimental mechanics and is intended to determine stress intensity factors for cracks occurring in operation of elements of aircraft structures. Essence:test sample is installed, which loaded with external forces and / or containing internal stresses, in optical scheme of interferometer, registration of initial state of speckle pattern of surface by a high resolution video camera, increase in crack length by a small increment, registration of speckle pattern of the deformed state of sample surface due to crack propagation, visualization of interference patterns by numerically subtracting of two images obtained earlier, determination of the crack opening at beginning point of increment of its length and at central point of this increment, calculation of stress intensity factors by formulas that follow from correlation of linear fracture mechanics.

EFFECT: improved measurement accuracy of stress intensity factors under influence of external and, especially, internal stresses, which is necessary to increase working life and reliability of elements of aircraft structures due to development of parameters of failure mechanics due to cyclic loading.

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