JPS61271449A - Ae measuring apparatus - Google Patents

Abstract

PURPOSE:To enable the determination of the phase of a repeating stress at which an AE (acoustic emission) wave is generated, by performing and resetting the measurement of phase information of the repeating stress at each cycle thereof to output the value thereof at the time when the AE wave is generated. CONSTITUTION:When a stress signal is inputted into a comparator 1, a high level signal is outputted to a one-shot multivibrator 3 only while it is larger than threshold TH and the multivibrator 3 is triggered with the rising of the signal to obtain a one-shot pulse. The counter 5 is reset by the pulse to turn the contents thereof to zero and advances by '+1' in response to a pulse from an oscillator 7. As an AE signal is outputted from a sensor 11, the contents of the counter 5 are latched at the start of rising thereof to indicate phase information of a repeating stress at the time when an AE wave is generated and a CPU 15 outputs the phase and the stress value thereof when the AE wave is generated from the signal indicating the stress value.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to an AE (acoustic one-emitter) measuring device, and particularly to an AE measuring device suitable for use in repeated tests.

B. Prior art In order to accurately measure the fatigue state of the inspected member by measuring the AE waves generated in the inspected member during repeated tests,
AE at which phase of repeated stress applied to the inspected member
It is necessary to determine whether a wave is generated or to measure the stress value when an AE wave is generated. In conventional AE measuring devices, an excitation waveform voltage signal corresponding to the repeated stress applied to the inspected member by a vibrator is inputted to multiple comparators each having a different reference voltage, and thereby The stress level region is set to measure the stress level region in which AE waves begin to occur.Problems that the C0 invention is trying to solve: Conventional AE measuring devices like this require multiple comparators. Yes 1
In addition to making the circuit complicated, it is also impossible to distinguish whether AE waves are generated at the rise or fall of repeated stress. Furthermore, as the number of repetitions increases, it is also impossible to measure how the stress value changes when AE waves are generated.

Means for Solving the D0 Problem The present invention uses a signal that corresponds to the repeated stress applied to the member to be inspected in order to measure in which phase of the repeated stress the AE wave is generated and the stress value when the AE wave is generated. a detection means for detecting a reference position of each cycle; a phase information measurement means for starting measurement of phase information of the repeated stress in response to detection of the reference position; and a phase information measurement means for detecting an AE wave within the inspected member. a sensor that outputs an AE multiplied signal; a phase information reading means that is connected to the sensor and the phase information measuring means and reads a measured value of the phase information measuring means at the rising edge of the AE multiplied signal; and a phase information reading means that reads a stress value from the stress signal. The apparatus includes a stress reading means and a determining means for determining in which region of the cycle divided into at least four phase regions the phase information is included.

In the present invention, the detection means detects the reference position of each cycle of the stress signal, and in response to the detection, the phase information measurement 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 multiplied signal, and the stress reading means reads the stress value at the rising edge of the AE multiplied signal. Furthermore, it is determined in which region of the stress cycle divided into at least four phase regions the measured phase information is included.

F. Embodiment FIG. 1 shows an embodiment of the present invention, in which a stress signal is input to one terminal of a comparator l. A stress signal is a signal with a voltage level corresponding to the amplitude and frequency of repeated stress applied to a member to be inspected. For example, as shown in FIG. 2(a), maximum stress σmax, minimum stress σm
This is a voltage signal whose amplitude corresponds to in and which repeats in cycles corresponding to one cycle of repeated stress. A threshold voltage signal TH is input to the other terminal of the comparator 1. The comparator 1 is followed by a one-shot multivibrator 3, the output of which is connected to the reset terminal of the counter 5. The output of an oscillator 7 which outputs a pulse signal of a reference frequency is connected to the counter 5, and a latch 9 follows the counter 5. The latch 9 is connected to the output of an AE sensor 11 that detects the AE wave and outputs an AE multiplied signal, and in response to the input of the AE multiplied signal in response to the AE wave from the AE sensor 11, It is configured to latch the input signal of the latch 9 and output it. Here, the oscillator 7 and the counter 5 correspond to phase information measuring means.

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

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

When the stress signal shown in FIG. 2(a) 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 greater than the threshold TH. The multivibrator 3 is triggered by the rising edge of the high-level signal of the conoparator 1, and one-shot pulses are obtained at times t1 and t2. As shown in FIG. 2(d), the counter 5 is reset by the one-shot pulse and its contents become "0". Then, in response to the pulse from the 1 oscillator 7, the
As shown in d), the counter 5 increments by "+1". Second
When the AE multiplied 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 its rise (see FIG. 2(d)). Therefore, the count value of the counter 5 latched by the latch 9 itself indicates the phase information of the repeated stress at the time when the AE wave is generated. For example, if the frequency of the repeated stress is IHz and the frequency of the output pulse of the oscillator 7 is set as l KHz, the count value of the force counter 5 is 25 when the maximum stress σmax
0, and 750 when the minimum mental force is σmin.

Based on the program shown in FIG. 3, the microprocessor 15 outputs the phase and stress value at the time of AE wave generation from the signal indicating the stress value. That is, when the program shown in FIG. 3 is activated by a predetermined interwoven signal, the frequency TS of the repetitive stress and the reference frequency TR of the output pulse of the oscillator are read in step Sl. These values can be set manually by the operator. In step S2, the stress value in response to the rise of the AE multiplied signal, that is, the digital signal from the A/D converter 13 is read. Next, the process proceeds to step S3, and it is determined whether TR/TS is 4 or more. If it is less than 4, the process jumps to step S12 and an error signal is output. If it is 4 or more, the 0 phase region for determining in which phase region of each cycle of repeated stress the count value from the latch 9 is included in each step of steps 54 to S7 is, for example, as shown in FIG. It is divided into four phase regions 1 to 4 every 90 degrees. If an affirmative determination is made in any of steps 54 to S7, steps S8 to Sl
The contents of the corresponding step in step I are executed and the program ends. The phase region and stress value data 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 used as the reference position, but the reference position is not limited to the starting point of each cycle, and it is of course possible to use an intermediate point as the reference position.

G8 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 can be determined based on the phase information at the time the AE wave is generated. In addition to determining whether the stress is being applied, the value of the -repetitive stress at that point is output. Therefore, <
AE in which phase region of repeated stress in repeated tests
It is possible to measure whether a wave is generated and the stress value at that time.In addition, according to this embodiment, the frequency of repeated stress becomes larger than the reference frequency of one oscillator output pulse, and the resolution as a count value decreases. Also, since it is possible to measure at least where in the four phase regions of the stress cycle the AE wave is generated and the stress value at that time, accurate measurement is possible even when the frequency of repetitive stress is relatively high.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention, and FIG. 2 (
a) to (d) are waveform diagrams showing output waveforms of each part, FIG. 3 is a flowchart showing an example of a program for calculating a phase region and stress value, and FIG. 4 is an explanatory diagram of the phase region. 1: Comparator 3: One-shot multivibrator 5: Counter 7 Two oscillators 9: Latch 11: Sensor 13: A/D converter 15: Microprocessor 17: Data recorder

Claims (1)

[Claims] a detection means for detecting a reference position of each cycle of a signal corresponding to repeated stress applied to a member to be inspected; a phase information measurement means for starting measurement of phase information of the repeated stress in response to detection of the reference position; a sensor that detects an AE wave in the inspected member and outputs an AE signal; and a phase information that is connected to the sensor and phase information measuring means and reads a measured value of the phase information measuring means at the rising edge of the AE signal. The method further comprises a reading means, a stress reading means for reading a stress value from the stress signal, and a determining means for determining in which region of the cycle divided into at least four phase regions the phase information is included. AE characterized by
Measuring device.