JPS6129735A - Display device for stress image - Google Patents

Abstract

PURPOSE:To obtain a stress image without experience by matching the timing of sampling with the timing at which a tensile and a compressive load are maximum. CONSTITUTION:A detection signal obtained by placing a load on an object body 1 by a loading testing machine 2 is converted by a processing circuit 7 into a temperature signal, which is sent to gates 9a and 9b, which turn on and off with a gate signal from a timing circuit 16. When the temperature signal obtained when the gates 9a and 9b turn on with sampling signals from one-shot circuits 20a and 20b is data in compressive loading and data in tensile loading, outputs of integration circuits 12a and 12b when the timing of sampling coincides with the timing at which loading is maximum are maximum and minimum respectively and the output of a difference detecting circuit 14 is maximum. For the purpose, the phase of sampling is varied gradually and the output of the circuit 14 is monitored to know the timing at which the loading is maximum, thereby matching the timing of the sampling automatically.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a stress image display device that utilizes thermoelastic effects, and in particular to a stress image display device that can automatically set sampling timing to an optimum state. Regarding.

[Prior Art] A device has been proposed that uses the thermoelastic effect to measure and display stress distribution in a short time without contact. This proposed device focuses on the fact that the surface temperature of the stress concentration area of the test object increases when a compressive load is applied, and conversely decreases when a tensile load is applied. (or Onto distribution)
A stress distribution image is obtained by subtracting the temperature (or temperature distribution) when no load is applied or when a reverse load is applied.

[Problems to be solved by the invention] At this time, in order to obtain a high-quality image, it is necessary to sample the surface temperature of the specimen when the tensile and compressive loads are at their maximum. Since A Bellator was making adjustments, red test and maturity were necessary. The present invention has been made in view of this point, and an object of the present invention is to provide a device that can automatically adjust the timing of leanbring.

[Configuration for Solving Problems] In order to achieve this objective, in the present invention, a subject subjected to a heavy load of 61 times with repeated fluctuations is
f! A stress image display device that obtains and displays a stress distribution image based on two types of lagoon data of a subject obtained by scanning with an infrared detector at the timing of ? 7, means for generating a first non-pulling signal having a repetition period equal to the greening period of the cart load; means for generating the second numbering signal; means for sampling the melon distribution data obtained by scanning the object with an infrared detector in synchronization with the respective sampling signals; and means in synchronization with the first sampling signal. A first integrating means that integrates the sampled smallpox distribution data, a second integrating means that integrates the sampled temperature distribution data in synchronization with the second sampling signal, and a difference between the outputs of the respective integrating means. means for determining the first
and a phase variable means for changing the phase of the second sampling signal with respect to the weighted load over a plurality of stages, and an output of the difference detection means is monitored, and the output is the thickest.
A detection means for detecting a phase when > is provided, and the phases of the first and second sampling signals are fixed to the phase detected by the detection means.

[Function] Temperature data sampled in synchronization with the first sampling signal is j: ta when compressive load is applied, and temperature data sampled in synchronization with the second quantity sampling signal is data under tensile load. If so, when the sampling timing coincides with the timing of the maximum load, the first
Since the output value of the second integrating means is the largest and the output value of the second integrating means is the smallest, the output of the time difference detecting means is the largest. Therefore, by monitoring the output of the difference detection means while gradually changing the sampling phase with respect to the weighted load, it is possible to know the timing when the load reaches its maximum.
The sampling timing can be adjusted automatically.

[Example] Hereinafter, one embodiment of the present invention will be explained in detail using the drawings.

FIG. 1 is a block diagram showing an example of a stress image display device embodying the present invention. In the figure, 1 is a test object, 2 is a load tester that applies a load to the test object 1, 3 is an infrared detector for detecting infrared rays generated from the test object 1, and 4 is an object that detects the image spot of the infrared detector 3. An optical scanner is used to focus on the specimen 1 and scan the image spot on the specimen 1, and 5 is a blackbody furnace that generates reference infrared rays.

A detection signal obtained from the detector 3 as the optical gap 1/4 scans is sent via an amplifier 6 to a processing circuit 7 including a clamp circuit, a linearizer, etc., and converted into a temperature signal having a linear relationship with temperature. converted. The temperature signal obtained is A
- After being converted into a digital signal by the D converter 8, it is taken out via the gate 9a or 9b, and the computer 10
and stored in the attached memory lla or 11b. Integrating circuits 12a, 12b and registers 13a, 1 to which signals taken out through the gates 9a, 9b are supplied.
3b and the difference detection circuit 14 are the characteristic parts of the present invention, and the output signal of the difference detection circuit 14 is sent to the computer 10 and stored in the attached sampling timing adjustment memory 15.

Reference numeral 16 denotes a timing circuit that generates a gate signal to turn ON and OFF the gates 9a and 9b, and a zero-cross detection circuit 17 to which a load signal from the load testing machine 2 is supplied, detects a zero-cross at a specified time from Compico 10. circuit 1
A variable delay circuit 18 that delays the pulse signal from the optical scanner 4, a distributor 19 that distributes the pulse signal from the variable delay circuit 18 into two systems, and a pulse signal from the distributor 19 and a horizontal synchronization signal from the optical scanner 4 one-shot circuits 20a and 2 that generate a gate signal with a length of one horizontal scan based on the
0b. Reference numeral 21 denotes a frequency divider that divides the frequency of the sampling sent to the gate 9b, and the divided output is sent to the vertical scanning step input terminal (2) of the optical scanner 4 via the switch 22.

A continuous step pulse SP from a pulse generator (not shown) can be supplied to this input terminal V via a switch 22.

In the above-described configuration, the optical scanner 4 repeatedly performs horizontal scanning, for example, 120 times per second, and when the switch 22 is turned to the contact C side, a step pulse is sent to the vertical scan step input terminal. Step scanning is performed in the vertical direction by SP. Therefore, when the vertical scanning of the optical scanner 17-4 reaches an appropriate position, if the switch 22 is switched to contact O and the supply of stepping pulses is stopped, the optical scanner 4 will stop vertical scanning at that position. Performs line scanning in which only horizontal scanning is repeated.

When adjusting the sampling timing, the operator
For example, the optical scanner 4 is set to perform line scanning at the center of the field of view. FIG. 2(a) shows the load signal generated by the load test line 2, and it can be seen that in this example, the load is repeatedly applied in a sinusoidal waveform at a period of 5 Q Q m5eo (21-1z). The zero-cross detection circuit 17 to which this cart signal is supplied outputs a pulse signal P 1a with a period half the load application period, as shown in FIG. 2(b).
P 1b, P 2a, P 2b.

p 3a, p 3b, ... are obtained. The variable delay circuit 18 uses two pulses as one pulse, and adjusts the phase of each set by 6° as shown in FIG. 2(C).
(500m5ecx 6'/360"
':;8.3IllSeC) step and sends it to the distribution circuit 19. The distribution circuit 19 selects the previous pulses pla, p2a, p3a, among the two pulses included in each set.
・-- goes to the one-shot circuit 20a, the subsequent pulse p
ib.

P2b, P3b, ... are one-shot circuits 20
B is distributed as shown in FIGS. 2(d) and (e).

Figure 2 (f) and (G) are P I of Figure 2 (d) and (e).
Parts a, P Ib, and P2a are shown enlarged from time to time, and there are also ICs. Figure 2 (h) shows the horizontal synchronization signal synchronized with 120 horizontal scans per second generated from the optical scanner 4, and Figure 2 (i) shows the temperature signal obtained by the horizontal scan. The shot circuit 2' Oa is connected to the pulse No. 245 P1a, 1) 2a, ... (Fig. 2 ([)) sent from the distribution circuit 19 and the horizontal synchronization signal (Fig. 2 (h)). Based on this, a sampling signal (FIG. 2 (J)) corresponding to one horizontal scanning period ``1'' which is performed first after occurrence of p la and p 2a is generated and sent to the goo-98.

The one-shot circuit 20 [) also performs the first horizontal scanning period II I I after Plb occurs.
A 1 non-shilling signal that becomes + (FIG. 2(k)) is generated and sent to the gate 9b.

Goo 1-9a, 9b is υplink trust +3 Ka” 1
'', the temperature signal Sa1 is taken out from the gate 9a based on Pl, and the temperature signal Sold is taken out from the gate 9b based on P2, and the integration circuit 12a.

12b and are integrated. Then, the obtained integral value ia1. lbl is held in the registers 13a and 13b until the gates 9a and 9b are opened next, and during that time, the difference detection circuit 14 obtains difference data 1 between Ial and Tb1 and sends it to the computer 10.

Computer 10 stores this 11 in memory 15.

Next, in exactly the same way, a temperature signal S82. is generated based on P3 and P4. Sb2 is sampled and each integral (iQ
Ia2. The difference 2 of Ib2 is determined by the difference detection circuit 14, sent to the computer 10, and stored in the memory 1.
Thereafter, in exactly the same way, data 13 to I30 of the difference between the integral values of the temperature signals obtained at timings in which the phase relative to the load application is sequentially shifted by 6 degrees are obtained by the difference detection circuit 14, and stored in the memory 15. They are stored sequentially.

By the way, as mentioned above, the surface temperature of the test object is highest when the compressive load applied to the test object is maximum, and is lowest when the tensile load is maximum. Therefore, the integral value of the temperature signal obtained by scanning when the shrinkage load is at its maximum is greater than the integral value of the humidity signal obtained by scanning at the peak timing, and the integral value of the temperature signal obtained by scanning when the tensile load is at its maximum is On the contrary, the integral value of the obtained temperature signal becomes the smallest. Therefore, 2
The difference between the two integral values reaches its maximum value when both are at their maximum timing.

Therefore, the computer 10 calculates the maximum value 0 from 11 to 130 stored in the meter 15, and calculates the delay time of the variable delay circuit 18 as 500m5ecx n
Set to 6°/360' (6°xn in phase). It goes without saying that the timing given by this delay time is the timing at which the compression and tensile loads are at their maximum.

Then, the A-berator manually or the computer automatically moves the switch 22 to the contact C side.
TIj: i The scan is returned to the scan start position (usually the upper end of the field of view) [l], and then switched to the contact side, the frequency divider 21 is reset, and stress distribution image measurement is started. Since one sampling signal to the gate 9b is generated per cycle of load application, if the frequency division ratio of the frequency divider 21 is 1/64, the sampling signal is 64.
The vertical scanning of the optical scanner 4 is advanced by one step each time a load is applied, and the measurement is completed when a predetermined step, for example, 240 steps is reached, assuming that the number of scanning lines in one screen is 240.

In each step, the temperature signal for one line at the maximum compressive load sampled through the gate 9a every 64 times of load application is integrated into a predetermined part of the memory 11a, and similarly every 64 times the load is applied through the gate 9b. The temperature signal for one line at the time of maximum tensile load sampled through
It is integrated into a predetermined portion of the memory 11b. When a total of 240 steps of measurement were completed in this way,
The memory Ila stores temperature image data obtained by integrating 64 times the temperature signals of 240 lines for one screen sampled at the timing of maximum compressive load, and the memory 11b stores temperature image data of 240 lines for one screen sampled at the timing of maximum tensile load. Temperature image data obtained by integrating line temperature signals 64 times will be stored. And computer 10
extracts the data so as to find the difference between the humidity image at the maximum compressive load and the humidity image at the maximum tensile load, and sends it to a display device (not shown) to display it as a stress distribution image.

In the above embodiment, two integration circuits are used, but since they do not perform integration operations at the same time, it is also possible to use one integration circuit and distribute the results to two registers (1).

[Effects of the Invention] As detailed above, according to the present invention, the timing of sampling can be automatically adjusted to the timing when the tensile and compressive loads are at their maximum, so that high-quality samples can always be obtained without the need for experience or skill. It is possible to obtain stress distribution images.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention, and FIG. 2 is a timing diagram for explaining the operation of the embodiment. 1: Test object 2: Multiple tester 3: Infrared detector 4: Optical scanner 7: Processing circuit 8: A-D converter 9a, 9b: Gate 10: Computer 11a, llb, 15: Me-E IJ 12a, 12b: Integration circuit 13a, 13b: Register 14: Difference detection circuit 16: Timing circuit 17: Zero cross detection circuit 18: Variable delay circuit 19: Distributor 20a, 20b: ')', y short y time 'N21: Frequency division Device 22: Switch

Claims (1)

[Claims] A stress distribution image is calculated and displayed based on two types of temperature distribution data of the test object obtained by scanning the test object, which is subjected to a repeatedly fluctuating load, with an infrared detector at two different timings of the load application. In the image display device,
A first having the same repetition period as the repetition period of the load application.
means for generating a sampling signal of the first sampling signal; means for generating a second sampling signal delayed from the first sampling signal by a period of half the repetition period of the load application; means for sampling the temperature distribution data sampled in synchronization with the respective sampling signals, first integration means for integrating the sampled temperature distribution data in synchronization with the first sampling signal, and synchronization with the second sampling signal. a second integrating means for integrating the sampled humidity distribution data; a means for determining the difference between the outputs of the respective integrating means; and changing the phase of the first and second sampling signals with respect to the weighted load over a plurality of stages. and detecting means for monitoring the output of the difference detecting means and detecting the phase when the output becomes the largest, and adding the phase detected by the detecting means to the first and second A stress image display device characterized in that the phase of a sampling signal is fixed.