METHOD OF ESTABLISHING PRE-BREAKDOWN STATE OF STRUCTURAL ARTICLE Russian patent published in 2017 - IPC G01N23/20 

FIELD: physics, measurement technology.

SUBSTANCE: invention relates to inspection equipment and can be used in nondestructive inspection laboratories, design and scientific research organisations for diagnosing cracking in structural materials and predicting the pre-breakdown state of a structure. Method comprises performing deformation, plotting a characteristic curve and establishing the pre-breakdown state. To this end, the method includes preparing a reference from the structural article, subjecting said reference to cyclic deformation and, based on the resultant change in the parameter of the elementary crystal lattice, determining the value of internal stress I of the type . A curve of change in internal stress I of the type versus cyclic deformation pressure P_i is plotted, from which the value of maximum stress and the moment of emergence of cracks are determined after safe stress. The pre-breakdown state parameter K_s.p. is calculated. A sample is prepared from the breakdown area of the structural article which is most likely based on the operating condition, and the value of internal stress I of the type is determined in said sample. The ratio of the value of internal stress I to the value of the maximum stress is compared with the pre-breakdown state parameter K_p.s., thereby establishing the possibility of further operation of the structural article.

EFFECT: invention enables to establish the pre-breakdown state of a structural article operating in both steady-state and transient thermal conditions.

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