METHOD TO DETECT RESIDUAL STRESSES IN COMPOSITE MATERIALS Russian patent published in 2016 - IPC G01L1/06 

FIELD: measurement equipment.

SUBSTANCE: method to determine residual stresses in a part material includes installation of a sample in the form of a rectangular plate into an optical circuit of an interferometer, registration of a speckle structure on sample surface in the initial condition by a high-resolution video camera, removal of the sample from the optical circuit of the interferometer, drilling of a probing hole, return of the sample into the initial position, registration of the speckle-structure of the deformed sample surface, visualisation of patterns of interference strips by numerical subtraction of two previously produced images, detection of increment of probing holes diameters in direction of main residual stresses, calculation of components of main residual stresses by formulas arising from the theoretical solution on stress concentration on the contour of the through round hole in the plate during its stretching in arbitrary direction towards the main axes of anisotropy.

EFFECT: increased accuracy of measurement of residual stresses, increased resource and reliability of elements of structures during their operation due to taking into account of residual stresses contribution into general stressed-deformed state.

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