METHOD FOR DETERMINING COMPLEX STRAIN AND STRESS STATE OF STRUCTURE UNDER STATIC LOADS AND DYNAMIC STRESS Russian patent published in 2012 - IPC G01B7/16 

FIELD: machine building.

SUBSTANCE: main and back-up resistance strain gauges are installed on surface of the structure, which is deformed with constant static load. The structure is loaded with temporary static load. Temporary static deformations are determined as per difference of measurements with additional resistance strain gauges under load and before it is applied. Temporary static load is released; deformations are measured again with additional resistance strain gauges. Material is cut around additional resistance strain gauges. Cutting depth corresponding to release of stressed state of the surface layer is determined, and deformation measurements are repeated again. As per difference of final and initial deformations there determined are surface deformations under constant static load and local temperature heating due to cutout. Additional resistance strain gauges are removed from the structure; material cutouts are completed with formation of cylindrical cavities to the specified depth. On the non-deformed structural member, material is cut out around active resistance strain gauge to the depth fixed on the structure. As per difference of measured deformations before and after cutting there determined are residual temperature deformations of the non-loaded structure. Cast-in transmitters of volumetric deformations are installed into cylindrical planes. Material integrity and continuity is restored as per the installation place. Main resistance strain gauges and resistance strain gauges of volumetric deformation transmitters are connected to strain-gauge bridge. The structure is loaded with dynamic load. As per the main resistance strain gauges there measured are maximum surface dynamic deformations, and as per spatial resistance strain gauges - components of volumetric dynamic deformations. Maximum surface and volumetric dynamic stresses and their dependence on loading rate are calculated as per the corresponding deformations.

EFFECT: simplification of the design; improvement of measurement accuracy and validity.

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