SU1392408A1 - Method of calibrating strain gauge equipment for measuring a signal from a high-temperature resistance strain gauge mounted on an investigated object - Google Patents

Abstract

This invention relates to a measurement technique. The purpose of the invention is to improve the measurement accuracy. The method is implemented by a device where the calibration beam 9 is mounted on the shaker 10. The strain gages 11 and 12 are electrically connected through the switch 13 to the input of the amplifier 14. The maximum values of the deformations must correspond to the expected deformations of the object under study. 2 Il.

Description

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The invention relates to a measurement technique and is intended for the calibration of strain gauge instrumentation, working with high temperature film strain gauges, used to measure dynamic deformations of machine parts at high (up to 1100 ° C) temperatures, for example, cooled turbine blades, crop chambers, aircraft GTDs and more .d

The aim of the invention is to improve the measurement accuracy.

FIG. 1 is a diagram of the calibration of measuring equipment; in fig. 2 is a scheme for determining the ratio of output signals from a high-temperature film and precision strain gauges.

At the test site 1, a high-temperature film strain-resistor 2, electrically connected to a theisometric equipment, consisting of a strain-gauge amplifier 3 and recorders of a light-beam oscilloscope 4, an electronic oscilloscope 5, and an equipment 6 of an accurate magnetic recording, is installed. On the elastic element 7 (tuning fork) of the calibration device precision strain gauge 8.

The diagram (Fig. 2) shows a graduation beam 9 from a heat-resistant alloy, a vibrating bench 10, a high-temperature film strain gauge

11, a precision strain gauge 12, a switch 13, and a strain gauge amplifier 14, complete with a recording device 1 of 15.

Graduation of strain gauge equipment consists of the following operations.

A calibration beam 9 (Fig. 2) made of a heat-resistant alloy and representing, for example, a rectangular console beam, is installed and thermo-processed, a high-temperature film strain gauge 11, identical to the strain gauge 2, installed on the object under study 1 (FIG. one). In the immediate vicinity of the high-temperature film strain gauge 11 in the same cross-section of the calibration beam 9, a precision strain gauge 12 (identical to the precision strain gauge 8) is installed, which does not require a high-temperature heat treatment installation. Main requirement

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To the strain gages, taken for precision, the minimum sensitivity spread in the party. For example, commercially available foil strain gauges of type KF5P1 can be used as precision ones.

Then install the calibration beam 9 on the shaker 10, the strain gauges 11 and 12 through the switch 13 is electrically connected to the input of the strain gauge 14 complete with a recording device 15, for example an AC voltmeter.

At constant values of dynamic deformations, output signals from high-temperature 11 and precision 12 strain gages are recorded and their ratio is determined.

A precision strain gauge 8 from a batch taken to determine the ratio of output signals is installed on the elastic element 7 of the calibration device and electrically connected to the input of the strain gauge amplifier Z. On the elastic element 7 in steps, starting from zero and up to the maximum value, dynamic deformations are set, The maximum values of the specified deformations must correspond to the expected deformations of the object under study. At each stage of the specified deformations, the output signal is recorded on recording devices, for example, on a light beam oscilloscope 4, an electronic oscilloscope 5 and equipment 6 of an accurate magnetic recording.

When calibrating, precision strain gauges with high metrological characteristics are used, and the accuracy of the ratio of output signals of high-temperature film and precision strain gauges can be quite high due to an increase in the number of strain gauges investigated to determine this ratio, therefore the accuracy is improved. In addition, there are no additional errors caused by the determination of this ratio, therefore, the accuracy is improved. connecting lines on resistance, capacity of assembly connections at graduation and When measuring the strain on the object.

Claims (1)

Invention Formula Calibration method of strain gauge instrumentation for signal measurement a high-temperature strain gauge mounted on the object under study, consisting in installing a strain gauge; - a resistor on the elastic element of the grading device, connecting it to the input of the strain gauge equipment, specifying the deformation strain elastic element and measuring the output signal of the strain gauge equipment, about that, in order to increase accuracy, is pre-installed on an additional elastic element in the form of a calibration beam from a heat-resistant alloy, first high-15 Peripheral, and then precision strain gauge resistors, connect them to strain gauge measuring equipment and, setting the calibration beam deformation, determine the ratio of the sensitivity of the strain gauges, then on the elastic element of the graduation gauge install a precision strain gauge identical to the pattern of the calibration pattern, which is identical to the pattern of the calibration pattern, which is applied to the calibration pattern, is identical to the pattern of the calibration pattern, and the temperature pattern is applied to the calibration pattern, which is identical to the pattern of the calibration pattern and the temperature pattern that is applied to the calibration pattern of the calibration pattern, the temperature pattern that is identical to the pattern of the calibration pattern and the temperature pattern that is applied to the temperature pattern, is identical to the temperature pattern of the calibration pattern, which is identical to the temperature gauge, and the temperature gauge will be applied to the strain gauge, which is identical to the temperature gauge. graduation of strain gauge instrumentation in a known manner, taking into account the obtained sensitivity ratio. Phi.1