SU579541A1 - Arrangement for determining variation of specimen diameter - Google Patents

Description

This invention relates to a test apparatus for measuring sample dimensions under strain, loading, etc. optical method.

A device containing an illuminator, an optical system with an aperture diaphragm, a photodetector, a scanning disk, an electronic transducer, and a measuring or recording device in which an intermediate linear-to-angular transducer is installed is known.

The disadvantage of this device is that it is not possible to determine the location of the thinning and to measure the dimensions of the diameter of the sample when it breaks. In the case of strength testing.

Closest to the invention to the technical essence is a device for measuring deformations, comprising an illuminator, a photodetector, an optical system interposed between them, two recorders and a plotter L2 connected to their outputs.

Its disadvantage is the low measurement accuracy determined by the sensitivity of the carriage to movement and the accuracy of the rheochord movement sensor.

In order to improve the measurement accuracy, the proposed device is equipped with a scale unit and connected in series by a switch, an assembly element and a voltage meter, the photodetector of the same type cells of which have outputs connected to the switch inputs, the input of the scale unit is connected off

output of one mz of photodetector cells, and its output - with the second input of the voltage meter "voltage, the output of which is connected to the second recorder, and the output of the switch is connected to the input

first registrar.

The drawing shows a block diagram of the proposed device.

The device contains the illuminator G, the optical system 2, the photodetector 3,

located behind. the optical system 2, the switch 4, the inputs of which are connected to the outputs of the cells of the photodetector 3, an assembly element 5 connected to the output of the switch 4, a logometer 6

Claims (2)

voltage, the input of which is connected to the output of the assembly element 5, recorders 7, 8, whose inputs are connected to the outputs of the switch 4 and voltage logometer 6, plotter 9 connected to the outputs of the recorders 7, 8, scale unit 10 whose input is connected through a switch 11 with the output of one of the cells of the photodetector 3, and the output with the input of the voltage meter 6 voltages. The device works as follows. When a sample 1 is illuminated by the illuminator 1, the shadow image of the sample is projected by means of the optical system 2 onto the photodetector 3, which is made of individual plates of the same type. In this case, the all-optical part of the device is adjusted in such a way that the shadow image of the test sample is located between the electrodes of each cell of the photodetector 3. As a result of the total background illumination of the photodetector 3, a voltage is formed proportional to the light flux incident on photodetector 3. Thus, the larger the shadow image (diameter) of the test sample, the less the illumination of the cells of the photodetector 3 and the lower the voltage at their output electrodes. : At the output of the cells of the photodetector 3, located in the shadow of the lower end of the test specimen (shaded in the drawing), the voltage is zero, since these cells of the photodetector are not illuminated. As the test specimen is lengthened, the shadow boundary shifts downward and a voltage appears at the output electrodes of the next cells. Before applying a loading force to the sample, the switch 11 closes, and the voltage from the output electrodes of the first cell of the photodetector 3, proportional to the original diameter of the test sample, is fed to the scale unit 10, where it is memorized. After fixing the voltage proportional to the initial diameter of the test sample, the switch.11 opens and applies the load to the sample. Switch 4 alternately connects the output electrodes of the cells of the photodetector 3 to the element 5 of the Assembly. Element 5 of the assembly selects the largest from the switched signals. If the diameter of the test sample decreases evenly along the entire length of the sample, the signals arriving at the input of the assembly element 5 are the same. When a localized thinning is formed in any place of the sample, which, upon further loading, causes the sample to break at that location, a voltage appears on the output electrodes of the corresponding cell that exceeds the value of the voltages at the outputs of the remaining cells. The assembly element 5 selects this voltage from all the others and supplies it to one of the inputs of the voltage meter 6, the other input of which is supplied from the scale unit 10 proportional to the initial diameter of the test specimen. Logometer 6 voltage allows to determine the ratio of the two voltages applied to its inputs, i.e. ultimately, the ratio of the initial diameter to the thinning diameter of the test sample. In this case, at the moment when the beginning of the formation of a thinning of the sample diameter is recorded, the recorder 7 of the photo receiver cell number records the cell number of the photo receiver, corresponding to the coordinate of the thinning location. The co-ordinate location of the thinning of the diameter of the test sample is plotted on the tape of plotter 9 along the X axis, and the value of the relative change of the diameter of the sample is recorded by the recorder 8 and is marked on the tape of plotter 9 along the y axis. The accuracy of recording the area where the sample diameter is thinned increases with an increase in the number of partitions of the photodetector into cells. Claims - Device for determining the relative change in the sample diameter for strength tests, containing an illuminator, a photodetector, an optical system located between them, two recorders and a plotter connected to their outputs, in order to improve the Measurement accuracy, it equipped with a large-scale block.1 and a switch connected in series, an element of the assembly and a voltage meter; the photodetector is made of the same type cells, the outputs of which are connected to the inputs of the switch Dr, the scale unit input is connected via a switch with the output of one of the cells of the photodetector and its output - to the second input logmetra voltage whose output is connected to the second recorder, and the switch output is connected to the input of the first DVR. Sources of information taken into account in the examination: 1. USSR Copyright Certificate 230488, CL. &Amp; 01 B 11/16, 1969. 2. USSR author's certificate 326454, cl. Cr 01 B 11/16, 1972.