SU894372A1 - Meter of crack propagation rate in metal - Google Patents

Description

(5) SPEED DISTRIBUTION METER FOR CRACKING IN METAL

one

The invention relates to the testing of materials and products, more specifically to photoelectronic devices for measuring parameters of deformation and destruction of metals, and can be used on testing machines as an attachment device for determining the rate of crack development in a metal.

A device for measuring the rate of crack development in a metal is known, comprising a block of a tension mechanism with grips for a sample, a force sensor and a recorder.

The device has a low accuracy of measuring the rate of crack development.

Closest to the present invention is a measuring instrument of the rate of propagation of a crack in a metal, comprising a block of a stretching mechanism with grips for a sample, a photovoltaic system analyzing radiation from a sample surface in time.

force sensor, recorder electrically connected to the C2- photovoltaic system.

A disadvantage of the known crack propagation velocity meter in a metal is the low accuracy of the measurement of the crack propagation rate in brittle fracture.

The purpose of the invention is to increase accuracy.

Claims (2)

To achieve this goal, a device containing a stretching mechanism block with grips for the sample and a sensor, a photoelectric system, a time analyzing radiation from the sample surface, a recorder electrically connected to the photovoltaic system, electrical contacts connected to the unit stretching mechanism with grips for a sample, a threshold device and a pulse duration meter, while the electrical system output through the specified electrical contacts and threshold device TVO is connected to the meter pulse duration. The drawing shows a block diagram of the device. The crack propagation velocity meter in the metal contains a block 1 of the stretching mechanism with grips for the sample, a photoelectric system 2 analyzing in time the radiation from the surface of the sample electrically connected with the recorder 3 and through the electrical contacts k connected to the block 1 of the stretching mechanism with grips for the sample, threshold device 5 with a pulse width meter 6, force sensor 7 connected to recorder 3 and mechanically connected to the gripper for the sample. The drawing also shows the test sample 8. The device operates as follows. A tensile force P is applied to sample 8, which is recorded by force sensor 7 by the recorder 3. At the same time, the photoelectric system 2, sensitive to the infrared spectrum, records a change in the intensity of electromagnetic radiation, which monotonously decreases to the elastic deformation region. At the time of the occurrence of a crack in the sample 8, the radiation intensity of the sample increases sharply. The threshold device 5 is triggered by a certain excess of the signal above its average level. The moment of operation corresponds to the moment of occurrence of the crack and is recorded by the recorder 3 and the pulse duration meter 6. After the crack reaches the edge of the sample, it is separated into two parts. At this moment, the threshold device 5 is triggered, the pulse width meter 6 measures the response time of the threshold device 5, which corresponds to the time of crack development in the sample 8. Taking into account the known distance that the crack passes, the rate of its propagation is determined. If it is necessary to determine the measurement of the crack velocity in the process of its development on the recorder, which in this case uses an oscilloscope, record the signal proportional to the instantaneous value of the crack velocity. every moment of time. The end of the crash in this case is recorded by the pulse width meter 6. The proposed meter can significantly improve the accuracy of measuring the rate of crack propagation during brittle fracture of metals by using the property of metals to radiate a pulse of electromagnetic radiation, starting from the infrared radiation region at the moment of rupture. Invention A crack propagation velocity meter in a metal comprising a stretch mechanism block with grips for a sample, a photoelectric system analyzing radiation from the sample surface in time, a recorder electrically connected to the photovoltaic system, and an force sensor characterized in that increase the accuracy, electrical contacts connected to the grips for the sample, a threshold device and a pulse duration meter are introduced into it, and the output of the photoelectric system through The electrical contacts and the horn device are connected to a pulse width meter. Sources of information taken into account during the examination 1. US Patent N °, pp. 01 J l / iA, published.19b3. 2. David K. Wilborn. Tempereture rofiles Observed in Tensile Spesiens Duruny Physial Tsst. - Materials valuation, 1977, M ° 3, P.28-30.