METHOD FOR DETERMINING RESIDUAL STRESSES IN PRODUCTS FROM POLYMER COMPOSITE MATERIALS Russian patent published in 2023 - IPC G01N29/07 

FIELD: constructional engineering.

SUBSTANCE: determining residual stresses in the structural material of products at various stages of their life cycle and can be used in constructional engineering, including after their manufacture to determine the quality of curing polymer composite materials, materials obtained by additive process, but also during their operation. An impulse load is applied to the diagnosed object in the installation area of one of the vibroacoustic sensor to create a wave field in the object and it is fixed with the help of vibroacoustic sensors installed at a certain distance along the product from the sensor, in the zone of which the vibroacoustic field was excited. Based on the results of simultaneous processing from all sensors, the local speed of sound in the object between the sensors, the phase angle of the displacement in the front of the vibroacoustic wave between the sensors and the spectrum of the wave front of all sensors are determined, which makes it possible to determine the shift between the integral natural frequency of the object and the local modal (natural) frequencies in the installation area of the vibroacoustic sensor, the value of residual stresses at local points of installation of sensors on the object.

EFFECT: expanding the possibilities of process diagnostics of the physical and mechanical properties of an object using nondestructive methods with the assessment of residual stresses in local areas of the product material while simplifying the method, reducing labor intensity and increasing the accuracy of determining residual stresses.

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