JPS62108130A - Synchronous photographing device for fatigue testing machine - Google Patents

Abstract

PURPOSE:To automatically photograph the state of a test piece at every prescribed cycle synchronously to the maximum load, by generating pulses at the moment when the maximum tensile load is applied to the test piece and actuating a photographing device. CONSTITUTION:A tensile pulse setter 5 is connected with an oscillator 1, actuated at the moment when the maximum tensile load is applied to a test piece, and generates pulses at every prescribed cycle of signals. On the other hand, a pulse generator 6 is connected in parallel with the tensile pulse setter 5 and generates pulses when a display lamp 4 is turned off or turned on. A compressed pulse setter 7 generates pulses at every prescribed frequency of generation of pulses of the pulse generator 6 and opens the shutter of a photographing device 8 so as to cause a stroboscope to emit light. In this manner, the pulse generator 6 generates pulses at the moment when the maximum compressive load is applied to the test piece and can actuate the photographing device 8. Therefore, cracks, etc., which occur and grow in a test piece can be photographed without any attendant in the night, etc.

Description

[Detailed description of the invention] [Technical field to which the invention pertains] The present invention relates to a fatigue testing machine that applies repeated loads to a test piece, and which photographs the condition of the test piece every predetermined cycle in synchronization with the maximum value of the load. Concerning a synchronized photographing device for a test machine.

[Prior art and its problems]

Fatigue of metallic materials progresses even if the cyclic stress applied to the material is much lower than the static fracture stress applied to the material, eventually leading to failure of the material.The larger the amplitude of the stress, the more fatigue It is known that the lifespan is shortened due to Furthermore, the life span of a metal material until it reaches fatigue failure is determined by the time it takes for a fatigue crack to occur and the time it takes for this crack to propagate. Therefore, when a fatigue crack is detected in a structure, the propagation characteristics of the fatigue crack are important in evaluating the remaining life of the structure, and it is desirable to accumulate data from sb fatigue tests. It is important to be able to measure and record the length of crack growth and the number of days the crack opens during the application of repeated stress. However, conventionally, photography during fatigue tests was done manually, and there was no known method, making it difficult to obtain sufficient measurement data.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a synchronized photographing device for a fatigue testing machine that synchronizes the state of a test piece during a fatigue test with the maximum load and automatically photographs the same at every predetermined cycle.

[Key points of the invention]

The present invention includes an oscillator that provides a cycle signal to a hydraulic servo that controls the cycle load of tension and compression applied to the test specimen, and an oscillator that is turned on from the maximum tensile load to the maximum compressive load, or when a weight is applied from the maximum compressive load. A synchronous photographing device for a fatigue testing machine that photographs the state of the test piece at the time,
a tensile pulse setting device that is connected to the oscillator and operates when the maximum tensile load is applied to the test piece and generates a pulse every predetermined cycle of the signal; and a tensile pulse setting device that is connected in parallel to the indicator light and turns off the indicator light. a pulse generator that generates a pulse to either turn on or turn on; a compression pulse setter that generates a pulse every predetermined number of pulses generated by this pulse generator; It consists of an imaging device that takes pictures one frame at a time using pulses, and the conventional fatigue tester controls the cycle load applied to the test piece by electrical signals and flashes an indicator light. The idea is to use this electrical signal to operate the imaging device in synchronization with the maximum load. If the pulse generator is not a circuit in which a capacitor is connected in series to a parallel circuit of a relay and a diode having a make contact, it is convenient to connect the make contact of the relay to a compression pulse setting device via a power source.

[Embodiments of the invention]

Fig. 1 is a block diagram showing one embodiment of the present invention. ◇ Here, 1 is an oscillator, and the signal from this oscillator 1 is used to send a signal to the hydraulic servo 2. A cycle load of tension and compression is applied to a test piece (not shown). control.

The oscillator 1f'i sends a signal to the hydraulic servo 2, and the counter 3 connected to the oscillator 1 counts the number of cycles of the load applied to the test piece. Further, the oscillator 1 is configured to turn on the indicator light 4 while the load applied to the test piece reaches from the maximum tensile load to the maximum compressive load. Depending on the testing machine, the indicator light 4 may be turned on from the maximum compressive load to the maximum tensile load. The synchronized imaging device is
The tension pulse setting device 5, the pulse generator 6, the compression pulse setting device 7, and the imaging device 8 are connected in parallel to the oscillator IK counter 3, and this output terminal is connected to the imaging device. is connected to operate the shutter. Then, at each predetermined cycle of the signal from the oscillator 1, a pulse is generated at the time when the maximum tensile load is applied to the test piece, the shutter of the camera 8 is opened, and the strobe light is emitted. 9 is a backflow prevention diode connected between the tension pulse setting device and the imaging device 8. As shown in FIG. 2, the pulse generator 6 has a capacitor 13 connected to a parallel circuit of a relay 11 having a make contact 11a and a diode 12, and this series-parallel circuit is connected in parallel to the indicator lamp 4.

The make contact 11a is connected to the compression pulse setting device 7 via the power source 14, and the output end of the compression pulse setting device 7 is connected to operate the shutter of the photographing device 8.

The operation of the pulse generator 6 is such that when the load on the test piece begins to decrease from the maximum tensile load, the indicator light 4 lights up and a voltage is generated on both sides of the indicator light 4. Then, at this voltage, diode 1
Capacitor 13 is charged via 2. At this time, since the voltage drop across the diode 12 is low, the relay 11 is not energized. At the point when the maximum load is applied to the test piece, the indicator light 4 goes out, and the voltage across the indicator light 4 disappears. At this time, the charge in the capacitor 13 is discharged through the relay 11 and the indicator light 4, and the relay 11 is activated. Then, the contact 11a closes and a pulse is applied to the compression pulse setter 7.

The compression pulse setter 7 generates a pulse every predetermined number of pulses generated by the pulse generator 6, opens the shutter of the camera 8, and causes the strobe to emit light. 10 is a backflow prevention diode. In this way, the pulse generator 6 generates a pulse at the moment when the maximum compressive load is applied to the test piece, and the imager 8 can be operated. Pulse generator 6 of Raku 2 figure
shows a wiring diagram connected to the indicator light 4 that lights up while the load applied to the test piece reaches from the maximum tensile load to the maximum compressive load. When connecting, the polarity of the diode 12 may be reversed. At this time, when the maximum compressive load is applied to the test piece, the indicator light 4 lights up, and if a voltage is generated during this time, the charging current of the capacitor 13 flows to the relay 11, and the relay 11 operates to close the contact 11a and the following happens. Works as described above. When indicator light 4 goes out, capacitor 1
The electric charge of 3 is discharged through the diode 12 and the indicator light 4 regardless of the relay 11. Note that the indicator light 4 is turned off or its lighting time is adjusted so that the shutter opens when the maximum strain is applied to the test piece, taking into account the application time of the maximum load that will be applied to the test piece. The figure shows a built-in strobe with an electromagnetic shutter that operates with pulses, but in the case of a push-button shutter, the electromagnets are operated with the pulses generated by both pulse generators. The shutter is opened by the moving force of a movable iron piece provided on the stone, and a strobe light is emitted by a contact provided on the photographing device 8.

〔Effect of the invention〕

According to the present invention, when a test piece installed in a fatigue testing machine is subjected to a cyclic load of tension and compression, the state of the test piece is automatically checked every predetermined cycle in synchronization when the maximum load is applied. It is possible to photograph cracks that occur and propagate in test specimens, as well as the opening amount of these cracks, even when unattended, such as at night. It can provide valuable materials for evaluation, and its effects are significant.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a synchronous photographing device for a fatigue testing machine according to the present invention, and FIG. 2 is a wiring diagram showing an embodiment of the pulse generator of FIG. 1. 1... Oscillator, 2... Hydraulic servo, 4
...Indicator light, 5...Tension pulse setter, 6...Pulse generator, 7...Compression pulse setter, 8...・Camera equipment, 11...
Relay, 12...Diode, 13, song, connector 20pa! 9 E6 pulse generator Figure 2

Claims (1)

[Claims] 1) An oscillator that provides a cycle signal to a hydraulic servo that controls the cycle load of tension and compression applied to the test specimen, and an oscillator that lights up from the maximum tensile load to the maximum compression load or from the maximum compression load. A synchronized photographing device for a fatigue testing machine that photographs the state of the test piece when the fatigue testing machine is equipped with an indicator light that lights up until the maximum tensile load and applies maximum tension and compression loads to the test piece. a tensile pulse setting device that is connected to the oscillator and operates when the maximum tensile load is applied to the test piece and generates a pulse every predetermined cycle of the signal; a pulse generator that generates a pulse when the light is turned off or turned on; a compression pulse setter that generates a pulse every predetermined number of pulses generated by the pulse generator; and a generator for both of the pulse setters. 1. A synchronous photographing device for a fatigue testing machine, comprising a photographing device that performs photographing operation frame by frame using pulses. 2) In the synchronized photographing device for a fatigue testing machine according to claim 1, the pulse generator is composed of a circuit in which a capacitor is connected in series to a parallel circuit of a relay and a diode having a make contact, and A synchronous photographing device for a fatigue testing machine, characterized in that a contact point is connected to a compression pulse setting device via a power source.