JPS6079274A - Measurement for kinetic energy of impact object - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a method for measuring the kinetic energy of an object when the object collides with a structure, and particularly relates to a method for measuring the kinetic energy of an object when it collides with a structure, and in particular, when a foreign metal object collides with the inner wall of a nuclear reactor pressure vessel. This invention relates to a method for measuring the 2% energy of

[Background of the invention]

Conventionally, the kinetic energy E of an object that collides with a structure is detected by acoustic detectors (
An acceleration detector using a piezoelectric element, etc.) is attached, and the amplitude value a of its output signal and the distance r from the 11i+1 bump position to the detector position (using r, E-k, a 2 ,
r 2- J , , , , , It is derived from the equation (1). Here, k is a constant determined by the detector sensitivity, etc., and J is an attenuation constant due to the acoustic band. However, when the shape of the structure becomes complex, the attenuation constant J varies depending on the propagation path of the impact sound, so assuming a constant J, (
1) Subtracting the ] sign from equation will result in a large error. In addition, in a cylindrical structure like the reactor pressure vessel E, the sound waves rotating clockwise and counterclockwise on the side wall of the vessel interfere with each other, making it difficult to obtain accurate wave height values. This is a major cause of measurement error in energy E.

[Purpose of the invention]

The purpose of the present invention is to determine the detector to be used for energy estimation for each region of the target structure, and to calculate the peak value of the detector signal six times when a shock of known energy is applied to each region. This provides a method for accurately determining the motion energy of a foreign object when it collides with a structure.

[Summary of the invention]

In the present invention, when an impact is applied to a structure with a constant kinetic energy, even if the distance from the impact point to the detector is constant, if the positional relationship between the impact point and the detection point changes, the peak value of the detection signal will change. It was experimentally confirmed that the main cause of this change is due to the interference of sound waves, and that there is a risk of an error of more than one digit when determining the energy using equation (1). In order to eliminate errors due to interference, the energy of the unknown impact is determined by referring to the detector output peak value when an impact of known energy is applied to a structure in advance.

[Embodiments of the invention]

Below, the detection signal peak value when impact sound on a structure is detected by an acoustic detector and the positional relationship between the sound source and the detector will be explained based on experimental data, and furthermore, the impact energy ~6 (1j Explain the fixed law.

FIG. 1 shows a developed view of the side wall of a cylindrical tank used for impact sound detection. This cylindrical tank has a height of 5
m, diameter is 2m, so the cylinder is about 6m. As shown in Figure 1, nine detectors were attached to the side wall of this cylindrical tank to detect impact sounds. In addition, as shown in Figure 1, each part of the side wall of the cylindrical tank was equipped with a steel ball pendulum.

The kinetic energy of the steel ball pendulum during impact is always 3.51 nJ
It is intended to be.

FIG. 2 shows the relationship between the peak value of the impact sound signal and the distance from the sound source position to the detector position, that is, the propagation distance of the sound wave. In FIG. 2, data from all the detectors in FIG. 1 are plotted. 1. There are many impact sound sources not only in the area circled in FIG. 1, but also over the entire side wall of the tank. These data are obtained by plotting the average value of the wave height when three impacts were applied to the same sound source position (71c).

The reproducibility of the wave height value when impact is applied to the same point with the same energy is within ±10%. As is clear from FIG. 2, even if the OA impact energy is the same and the propagation distance is the same, the wave height values vary over about one order of magnitude. This fluctuation is much larger than the variation (within ±10 inches) in peak values when impact sounds at the same point are detected by the same detector. From this fact, (1)
Calculating the energy E from the peak value based on the equation will result in a variation of about two orders of magnitude, and the energy estimation will include an extremely large error.

There are several reasons why the wave height value varies greatly even if the impact energy is constant and the propagation distance is the same, but the main cause in the case of the cylindrical tank 7 is considered to be the interference of sound waves. That is, whether the sound waves from the sound source travel clockwise around the tank and reach the detector, or the sound waves travel counterclockwise and reach the detector, they will cause interference with each other.

The X wave height value changes greatly due to a slight difference in phase between the clockwise sound wave and the counterclockwise sound wave. Therefore, in order to avoid variations in wave height values, it is necessary to measure the wave basin with a detector located at a position that does not cause interference as much as possible. FIG. 3 shows the relationship between the signal peak value detected by the detector 2 and the propagation distance when a constant energy impact is applied to the area surrounded by a circle in FIG. 1. 4 shows the peak value of the signal from the detector 5, and FIG. 5 shows the peak value of the signal from the detector 7, and the data are similarly plotted. child! If we consider Figures 3 to 5 of L et al., we will find the following.

In Fig. 3, based on the positional relationship between the sound source area and the detector 2 in Fig. 1, the sound waves propagate to the left and reach the detector), and propagate to the right, go around the side wall of the tank, and reach the detector. The sound waves that reach 2 are considerably attenuated, so there is almost no interference. Therefore, the variation in wave height is small. Also, since the propagation distance is about twice as large as that of a small propagation distance,
The shorter the propagation distance, the greater the wave height, and the data has the entire slope of the right F. In the case of FIG. 4, the sound wave reaches the detector 5 while rotating the side wall of the tank Vi in the right direction in FIG. In this case as well, the light must go around the cylinder almost once to reach the detector 5, so interference with the direct wave is considered to be small, and data variations are small. Since the maximum and minimum propagation distances are only about 1.4 times different, there is no noticeable dependence on distance. The variation in peak value in the case of Figures 3 and 4 is ±1
It can be seen that it is within 5 inches. In the case of FIG. 5, the maximum and minimum data variations are about 5 times. Figure 5 shows the first
As is clear from the positional relationship between the hemorrhoid source area and the detector 7 in the figure, the sound waves circulate in the right direction and reach the detector 7, and in other cases the sound waves circulate in the left direction and reach the detector 7. There is almost no difference in the propagation resistance between the two, and it is therefore thought that the right-handed and left-handed sound waves interfere with each other. This wave height value varies by about five times. The following conclusions can be drawn from the above experimental results. First, even if the cylinder j energy is the same and the sound wave propagation path μIli is the same, the detected signal peak values vary by about one order of magnitude. Second, by limiting the impact sound source position to a certain area and the detection position to a specific position, variations in wave height values can be reduced.
It can be within ±15%. Based on the above knowledge, it is possible to reduce the error in impact energy measurement by the following method.

(1) Placing multiple 8-sound detectors in a structure (j'f, zui).

(2) Divide the structure into appropriate regions and apply an impulse gA with known energy to each region. This combination applies shocks to several points within the same area at intervals of about 1/2 the wavelength of the sound wave.

(3) Each area! In contrast, the peak value al of the signal detected by the calyx (each detector when the total is applied) with kinetic energy EO
, record the data.

(4) Select a detector with the least variation in wave height data for a plurality of impact sounds in each region i.

In this case, if there are two or more detectors whose data variation falls within the permissible range, those detectors are selected in advance.

(5) When an unknown impact sound is detected, the sound source position is first located and it is determined to which region 1 the sound source belongs.

(6) Once region 1 is determined, the peak value Act for the unknown sound of a predetermined detector J, which is useful for measuring impact energy in that region, is determined.

(7) Determine the impact energy Ek using the following equation.

Based on the above, the impact energy E can be determined, but as shown in the graph in Figure 3, the peak value may change depending on the distance between the sound source and the detector even within the same area. . In such a case, the attenuation constant J for ship separation is determined in advance from the data, and the impact energy E is determined using the following formula.

However, RI: ° distance from unknown sound source to detector j t rot: distance from 91 constant position of area i to detector J (a17) O: impact of known energy E is applied to a specific position of area 1 / Wave height value of Kotoki's detector J Now, in order to measure the impact energy exerted on a structure, it is necessary to know the distance roj from the detector to the impact point or the area i to which the impact point belongs, that is, @ The premise is to locate the source of the sound. There are various methods for locating the impact sound source position, and for structures with complex shapes, a method applying slam recognition R is effective.

Hereinafter, the method of ``pressure d'' impact energy i1+11
' An example applied to an Al device will be described in detail.

Preferred examples are shown in FIGS. 6 and 7.

As shown in FIG. 6, the pressure vessel 1 includes J detectors S1. Ss...4S has been detected, and the signals detected by them are from the pressure vessel? 1lij impact energy measuring device 100. This pressure vessel impact energy measuring device is constructed as shown in FIG. In FIG. 7, detectors S+, 82...SJ
The signals are input to the signal waveform storage device 120 via amplifiers 111°...IIJ. The signal waveform storage device is capable of storing signal waveforms of each detector for a period of approximately several IQIllS before and after the impact sound occurs. The stored waveform is analyzed by a sound source position location and energy energy estimation computer 130 to extract all information necessary for position location and energy estimation. The Sugi Teru and I-O station take-write series d-pi memory device 140 is equipped with the sound No. 11 output from the valley detector when each part of the pressure vessel is hit with a hammer or the like. The time difference wave height value is recorded in correspondence with the zero hit position, that is, the known product source position, along with the standard baton data. ~In addition, information on kinetic energy at the time of batting is also recorded. The peak value aIIs of the output signal of the first detector S, which divides the pressure vessel into one region and corresponds to the sound source position of the representative point i of each region, the signal arrival time difference τl, and the movement at the time of impact. Energy EI
is recorded.

Furthermore, the detector number jo used for energy measurement in the i region is also recorded.

In addition, in the total X device 130, a signal from an unknown sound source is input to the signal waveform storage device 120, and from the waveform of this unknown sound source, the peak value A of each detector and the signal arrival time difference τj are extracted. do. Information AI of these unknown sound sources, τ
j (J""1 + 2+...J) and the reference button data alltτ in the reference sound source data library storage device ff 140, (1=1,2.-1゜j=i,2
．． . . . From J), first, to which region the hill source belongs, the phonetic position + ti is determined using the following equation.

I)+=(V'--(τ14-τj))2...(5
) DF=(1-α) D': +αD7 0. (6) In these equations, V, , (Xj) is the dispersion fr of Xj: Hail. D↑ is the distance between the wave height information A of the unknown sound source and the reference wave information all of the reference point The smaller the value of j), D';, the closer the reference sound source and unknown sound source are. DH is the bang distance similarly defined for the signal arrival time difference. Dl is the baton distance that is a combination of D↑ and Dl, and the constant α when subtracting Dl from equation (6) is 0 to
It is set to an appropriate value between 1 and 1. In the above manner, the slam distance D7 is determined by each '(""1 + 2 +...
1) and determine i with the minimum value of Dε from among them. The unknown sound source will fall within one area determined in this way. Once i is determined here, the reference wave height data allo corresponding to area i and the estimated kinetic energy when hitting reference point i are read out from the reference data library, and based on equation (2), The energy E of the unknown sound source is determined using equation (7).

JO2 E = E I・(−,−,−)・・・・・・(7)1
10 The area i to which the sound source belongs and the impact energy E calculated in this way are calculated using the keyboard+j(i ILT15
By displaying 0, it can be seen what kind of energy impact has occurred at that part in the pressure vessel.

The above methods can be summarized in the form of a flowchart (see Figure 8).

〔Effect of the invention〕

As described above, according to the present invention, the energy of the impact sound in the conventional power trash machine, which had an error of more than 1 digit, can be measured with an error of 130%, and the error can be reduced. It has the effect of dramatically reducing the amount of water.

[Brief explanation of the drawing]

Figure 1 is a developed view of the side wall of a cylindrical tank that was used in an experiment that revealed the secret of the present invention, and Figures 2 to 5 show the side wall of a cylindrical tank used when a certain amount of impact energy was applied to the side wall of the tank. ,,Including the taste,
A diagram showing the relationship between the detected sound (wave height value of the Q signal and the sound propagation distance 11), FIG. 6 and FIG. 7 are diagrams showing an embodiment of the present invention, and FIG. 7 is a flowchart illustrating the entire operation of the embodiment shown in FIG. 7. 1... Pressure vessel, 100... Pressure vessel valence impact energy measuring device, 120... Signal waveform storage device, 130...
... Sound source location and impact energy d(()
jtl-machine, 140...Storage device for reference sound source data library, 150...Cit'r0 with keyboard
Figure 71〈−−−−11−−=−−−−−4/7(−111−□
□－－－〉￥2 Figure 4 Scooping Madness (Engineer) ￥30 April Ship Loss (Pile) ￥qH Den 1 General Angle 1

Claims (1)

[Claims] 1. Install multiple detectors that detect sound on a structure at appropriate locations, extract the impact sound generated when an object collides with the structure in the form of an electrical signal, and process the signal. In particular, in a method of measuring the kinetic energy of an object when it collides with the object, the structure is divided into regions as appropriate, and the collision of each detector when an object collides with each region with a known kinetic energy is used. The peak value of the three-tone signal was recorded along with the area number and detector number, and the detector number used for energy measurement was determined in advance for each area, so that an impact sound with unknown energy was detected. In this case, first determine a similar area where the impact sound occurs, and then calculate the ratio of the signal wave height value for the impact sound with known kinetic energy to the signal wave height value for the impact sound with unknown energy of the detector used for energy measurement in that area. Based on the method of measuring the kinetic energy of an impacting object.