SU1549273A1 - Method of checking quality of glueing of resistance strain gauge - Google Patents

Abstract

This invention relates to a measurement technique, namely strain gauge. The purpose of the invention is to improve the accuracy of gluing quality control by reducing the 1 / - error due to differences in the temperature characteristics of the resistance of the resistance strain gages being compared. For this, the controllable and reference (high quality glued) resistance strain gages are subjected to a test current with a constant instantaneous power, an input current with a constant instant power and compare the increments of their resistances in the time interval 3 Tn - TNN, where Tn is the constant heating time of the reference the resistance strain gage, and the TNC - constant heating time of a fully non-glued strain gage of the same batch

Description

This invention relates to a measurement technique, namely strain gauge.

The aim of the invention is to improve the control accuracy by reducing the error due to differences in temperature characteristics of the resistance of the resistance strain gages compared.

The method is carried out as follows.

Proceeding from the condition of maintaining the performance and the metrological quality of the strain gauge, choose the value of the test electric current with a constant instantaneous amplitude, which can be considered either a constant or alternating current, the amplitude of which instantaneously increases at the moment of switching from zero to maximum, the modulus of which remains unchanged. The constant heating time of such a current (current of constant instantaneous power and abruptly supplied to the conductor) of a completely non-adhered tensor resistor from the controlled batch, i.e., the resistive-belt surrounded by air from all sides, is preliminarily determined. For this purpose, a test current is applied to the non-glued strain gauge and the dependence (T) of the temporal change in the resistance increment of the glued-resistant strain gauge is determined, which is used to determine the heating time constant. Type of non-glued strain gauge, i.e., the time for which the main temperature change of its resistance (63% of maximum value) Next, on a sample of the material of the structure to be strain-gauge, paste a strain gauge from the selected controlled batch and under the action of a test current pulse with a post constant instantaneous amplitude and duration T ,, n recorded DTG graph of y (t) of time varying increments resistance strain gauge. which is then subjected to the quality test of gluing by one of the known destructive methods, for example, current heating before charring

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the basics. If the destructive method shows high sticking quality, the DDI relationship (t) is taken as the reference for this batch of controlled strain resistors and for this KOMCI operation material, which determines the steady-state heating time Ti of the reference, high-quality glued resistor. For each controlled i-th strain gauge of the same batch, glued to the structure of the same material, a test current pulse with a constant instantaneous amplitude and duration Tin is applied, and the time dependence ARi fy (t) is recorded, which is compared with the reference AR2 p ( t). Regardless of the temperature characteristic of the resistance, all resistance strain gages of the controlled batch that do not have a defect sticker will have the same constant heating time equal to Tn, and during the current time with a constant instantaneous amplitude equal to ZTN, approximately 97% of the temperature increment of their resistance will occur. For poorly glued strain gauges, i.e. having a non-glue base, characterized by an increased value of the heating time, as compared to Tn, tending to Tick-in as the non-platelet area grows. Therefore, to assess the quality of gluing, the dependence is not completely compared.

Claims (1)

  $ (g) with dependenceD f (g). and only the increments of resistance of each 1st strain gauge and the reference one in the time interval ZTz - TNN. As a result of such a comparison of a controlled strain gauge with a reference, the residual systematic error in determining the quality of gluing will not exceed 3% of the maximum variation of the temperature characteristics of the resistance strain gauges in the batch. Claims The method of quality control of gluing strain gauges is that test and reference quality glued strain gauges are applied to a test pulse of electric current, during which changes in resistance of the strain gauges are recorded, the results of which are compared to determine the quality of gluing of the monitored strain gauge, which differs. that, in order to increase the control accuracy by reducing the error due to differences in temperature characteristics of the resistance of the resistance strain gages compared. The strain gages are supplied with a current pulse with a constant instantaneous amplitude and a long duration equal to the previously definite constant heating time of this current with the intensity of the non-adhered resistor.