JPH0648234B2 - AE measuring device - Google Patents

Description

Detailed Description of the Invention A. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an AE (acoustic emission) measuring device, and more particularly to an AE measuring device suitable for use in repeated tests.

B. Prior Art In order to accurately measure the fatigue state of a member to be inspected by measuring the AE wave generated in the member to be inspected in a repeated test,
AE at which phase of the repeated stress applied to the inspected member
It is necessary to determine whether a wave is generated or to measure the stress value when the AE wave is generated. In the conventional AE measuring devices, the excitation waveform voltage signal corresponding to the repeated stress applied to the inspected member by the shaker is input to a plurality of comparators having different reference voltages, and the repeated stress is thereby obtained. By setting the level region, it is measured at which stress level region the AE wave starts to occur.

C. Problems to be Solved by the Invention In such a conventional AE measuring apparatus, a plurality of comparators are required, the circuit becomes complicated, and in addition, whether the AE wave is generated at the rise of the repeated stress or not Sometimes it cannot be discriminated whether the AE wave is generated. In addition, it is impossible to measure how the stress value changes when the AE wave is generated as the number of repetitions increases.

D. Means for Solving the Problems In the present invention, in order to measure at which phase of the repeated stress the AE wave is generated and the stress value at the time of the generation of the AE wave, each signal according to the repeated stress applied to the inspected member is measured. Detecting means for detecting the reference position of the cycle, phase information measuring means for starting measurement of the phase information of the repetitive stress in response to detection of the reference position, and AE wave for detecting the AE wave in the member to be inspected A sensor that outputs a signal, a phase information reading unit that is connected to the sensor and the phase information measuring unit, and that reads a measurement value of the phase information measuring unit at the time of rising of the AE signal, and a stress that reads a stress value from the stress signal. The reading unit includes a reading unit and a discriminating unit that discriminates which region of the cycle divided into at least four phase regions includes the phase information.

E. Action In the present invention, the detecting means detects the reference position of each cycle of the stress signal, and in response to the detection, the phase information measuring means sequentially starts measuring the phase information of the stress signal. And
The phase information reading means reads the phase information at the rising edge of the AE signal, and the stress reading means reads the stress value at the rising edge of the AE signal. Further, it is determined in which region of the stress cycle the measured phase information is divided into at least four phase regions.

F. Embodiment FIG. 1 shows an embodiment of the present invention, in which a stress signal is input to one terminal of the comparator 1. The stress signal is a voltage level signal corresponding to the amplitude and frequency of the repeated stress applied to the member to be inspected, and is, for example, the second signal.
As shown in the figure (a), the maximum stress σmax and the minimum stress σ
It is a voltage signal that repeats with an amplitude according to min and a cycle corresponding to one cycle of repeated stress. The threshold voltage signal TH is input to the other terminal of the comparator 1. The comparator 1 is followed by the one-shot multi-valve 3 whose output is connected to the reset terminal of the counter 5. The counter 5 is connected to the output of an oscillator 7 which outputs a pulse signal of a reference frequency, and the counter 5 is followed by a latch 9. The latch 9 has an AE
The output of the AE sensor 11 that detects the wave and outputs the AE signal is connected, and the input signal of the latch 9 is changed in response to the incoming AE signal in response to the AE wave from the AE sensor 11. It is configured to be latched and output. Here, the oscillator 7 and the counter 5 correspond to the phase information measuring means.

On the other hand, the stress signal is also input to the A / D converter 13, converted into a digital value, and the digital value is sequentially supplied to the microprocessor 15. The output of the latch 9 is also connected to the microprocessor 15. Furthermore, the microprocessor 15 is followed by a data recorder 17.

The operation will be described with reference to FIGS. 2 (a) to 2 (d).

When the stress signal shown in FIG. 2A is input to the comparator 1, the comparator 1 outputs a high level signal to the one-shot multivibrator 3 only while the stress signal is larger than the threshold value TH. The rising of the high level signal of the conoparator 1 triggers the multivibrator 3 to obtain a one-shot pulse at the times t1 and t2. As shown in FIG. 2 (d), the counter 5 is set by the one-shot pulse and its content becomes "0".
Then, in response to the pulse from the oscillator 7, the counter 5 advances by "+1" as shown in FIG. 2 (d). When the AE signal is output from the sensor 11 at time t3 in FIG. 2 (c), the contents of the counter 5 are latched at the start of rising thereof (see FIG. 2 (d)). Therefore, the count value itself of the counter 5 latched by the latch 9 is the AE
It indicates the phase information of the repeating stress at the time when the wave is generated. For example, if the frequency of the repeating stress is 1 Hz and the frequency of the output pulse of the oscillator 7 is 1 KHz, the count value of the counter 5 is 250 at the maximum stress σmax and 750 at the minimum stress σmin.

The microprocessor 15 outputs the phase and the stress value when the AE wave is generated from the signal indicating the stress value based on the program shown in FIG. That is, when the program shown in FIG. 3 is started by a predetermined interrupt signal, in step S1, the frequency TS of the repeating stress is increased.
And read the reference frequency TR of the output pulse of the oscillator.
These values can be manually set by the operator. In step S2, the stress value in response to the rise of the AE signal, that is, the digital signal from the A / D converter 13 is read. Next, in step S3, it is determined whether or not TR / TS is 4 or more. If it is less than 4, the process jumps to step S12 to output an error signal. If it is 4 or more, it is determined in which step of each cycle of the repeated stress the count value from the latch 9 is included in each of steps S4 to S7. The phase region is divided into four phase regions 1 to 4 every 90 degrees as shown in FIG. 4, for example. If a positive determination is made in any of steps S4 to S7, steps S8 to S
The contents of the corresponding step among 11 are executed, and this program ends. The data of the phase region and the stress value thus obtained are sent to the data recorder 17 and recorded.

In this embodiment, the starting point of each cycle of the stress signal is set as the reference position, but it is not limited to the starting point of each cycle, and it goes without saying that the intermediate point may be set as the reference position.

G. EFFECTS OF THE INVENTION According to the present invention, the phase information is sequentially measured and reset for each cycle of repeated stress, and in which phase region the AE wave is generated from the phase information at the time of the generation of the AE wave. Whether or not there is a determination is made, and the value of the repeated stress at that time is output. Therefore, in which phase region of the repeated stress the AE wave is generated in the repeated test, and the stress value at that time can be measured.

Further, according to the present embodiment, even if the frequency of the repeated stress is increased with respect to the reference frequency of the oscillator output pulse and the resolution as the count value is reduced, the AE wave is generated at least in four phase regions of the stress cycle. Since the occurrence of stress and the stress value at that time can be measured, accurate measurement is possible even when the frequency of repeated stress is relatively high.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention, FIGS. 2 (a) to 2 (d) are waveform diagrams showing output waveforms of respective portions, and FIG.
FIG. 4 is a flow chart showing an example of a program for calculating the phase region and stress value, and FIG. 4 is an explanatory diagram of the phase region. 1: Comparator 3: One-shot multivalve 5: Counter 7: Oscillator 9: Latch 11: Sensor 13: A / D converter 15: Microprocessor 17: Data recorder

Claims (1)

[Claims] 1. A detecting means for detecting a reference position of each cycle of a signal corresponding to a repeating stress applied to a member to be inspected, and a phase for starting measurement of phase information of the repeating stress in response to the detection of the reference position. An information measuring unit and a sensor that detects an AE wave in the member to be inspected and outputs an AE signal;
Connected to the sensor and the phase information measuring means,
Phase information reading means for reading the measured value of the phase information measuring means at the rise of the E signal, stress reading means for reading the stress value from the stress signal, and which area of the cycle divided into at least four phase areas An AE measuring device, comprising: a determining unit that determines whether the phase information is included.