Оn the structure of the device for measuring residual stresses

Abstract

Тhe article deals with a relevant problem – improvement of the accuracy of measurement of residual stresses in the elements of machines and structures with the use of attachable transducers.Analysis of flexible current-vortex transducers designed in the form of a single-layer coil has been performed. To solve the problem, the method of eddy currents is proposed, which can be used to set the calibration value of the magnetic resistance of the air gap between the transducer and the object.This method implementation based on the scheme of the oscillator with a reactive circuit has been demonstrated. The design of the residual stress measurement unit in the form of «capacitive three-point» self-excited oscillator has been substantiated. The structure of the device for measuring stresses has been proposed. The core element of the calibration value setting unit is a self-excited oscillator with a reactive frequency oscillating circuit, the inductance thereof been the excitation coil of the current-vortex transducer.Magnetic resistance of the gap is measured by moving the transducer vertically versus the surface of the object in the measurement area. The circuit of the proposed device consists of a block for setting the gap magnetic resistance, eddy-current transducer, electron-counting frequency meter, and residual stress measuring unit.