JPS61254850A - Method for nondestructive inspection of bonded part - Google Patents

Abstract

PURPOSE:To inspect a bonded part by making acoustic waves to be made incident on one of bonded two materials from the surface and, at the same time, detecting the reflecting waves of the acoustic waves, and then, preparing frequency spectra by Fourier-transforming the detected reflecting wave signals and discriminating the pattern. CONSTITUTION:A plastic delay 5 for providing intervals between each reflecting wave component is joined to the surface of a steel plate 1 and the acoustic waves of 10MHz are made incident on the plastic delay 5 from the steel plate 1 side. For this purpose, acoustic waves A(t) are made incident by using an ultrasonic flaw detector 6 and wide-band probe 7 and, at the same time, multiple reflecting waves from internal interfaces are received and monitored by means of an oscilloscope 8. Moreover, the multiple reflecting waves are electrically fetched and inputted in a spectrum analyzer 9. Then the reflecting waves are subjected to Fourier transformation process in such a way that only the 1st reflecting wave I1(t) from the joined interface is first fetched and Fourier-transformed. The Fourier-transformed reflecting wave is displayed on a screen in dB display and, simultaneously, stored in the analyzer 9 as a memory A. Then a totally reflecting wave R(t) is Fourier-transformed and used as a memory B and the joined condition is discriminated by finding (B-A).

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method for non-destructive testing of bonded parts by injecting sound waves into bonded materials and inspecting the bond based on detected reflected waves.

[Prior art]

Bonding members (bonding members) in which two materials S are bonded together, such as metal and rubber, metal and glass, and glass and rubber, are widely used in various fields.

In these O-joining members, an adhesive layer is formed inside the O-joining member, and the functional quality of the joining member O is greatly influenced by the quality of the adhesive aO.

Therefore, for those who manufacture these 0-joint members,
There is a strong demand for technology for non-destructively inspecting tangential lines from zero points for quality assurance.

Therefore, a method using ultrasonic waves has been conventionally adopted as the D inspection method.

One example is the ultrasonic reflection method.

This method involves injecting ultrasonic waves from the surface of the material and detecting reflected waves from the adhesive interface (internal interface) on the same surface as the incident waves, and changing the intensity or phase of the reflected waves at the bonded part θ. This is a method of trying to judge the state.

By the way, in the conventional O ultrasonic reflection method, the acoustic impeder/
If the radiation is incident from the surface of the material Q, which has a higher
In principle, sound waves are generated at the adhesive interface! It is completely reflected, and the tangential store becomes unclear.

On the other hand, in the case of joining members like ○ mentioned above, the 0 material is the structure O
In many cases, the inside has a structure with 4 layers of Kakuza n Ikekata O material. For this reason, the conventional ultra-d wave reflection method cannot be applied to θ bonded members with a structure in which the damaged side is exposed on the surface, and the range of application is limited. was there.

Another testing method that uses ultrasound is the ultra-hepatic resonance method.

This method involves injecting ultrasonic waves at an appropriate frequency into the inspection area and slightly sweeping the frequency to create a resonant state. Determining the down payment is also ■.

However, this θ testing method has a problem in that it is difficult to find an appropriate frequency t for resonant head-cutting, which is difficult in terms of operational technology. In addition, as in the case of the conventional ultrasonic reflection method Q described above, the applicable range is limited by θ, which becomes impossible to inspect if incident from the high acoustic impedance side.
There is also the problem of being exposed.

〔the purpose〕

The purpose of the present invention is to solve the problem of the conventional WiQ, to be able to inspect even if the sound a is incident from either side of the contact layer n or two O material Q, and to be easy to operate. Non-destructive testing method for contact 4 parts? It is to provide.

〔composition〕

The present invention is a method for non-destructively inspecting a bonded layer between two D materials and a contact layer, in which a sound wave is incident from the surface of one θ material and the reflected wave is detected, and the detected reflected wave signal is 7
The purpose described above can be achieved by determining the bonding part O from the mother turn of the θ frequency S (the vector is II, the spectrum O).

The zero frequency of the sound wave to be used may be within a range of 11 in which negative or multiple reflected waves, that is, one or more O reflected waves can be detected, and can be freely set within a wide range of, for example, 0.1 to 10 QOMHz θ.

Further, as the two Q materials to be brought into contact with each other, metal, rubber, glass, or any other suitable combination of materials can be used.

The non-destructive inspection method of the contact layer according to the present invention is
As a result, the frequency spectrum intensity obtained by 7-RIE conversion of the acoustic wave O detection reflected wave signal varies depending on the adhesion state, that is, the presence or absence of voids (usually missing).
The method was completed by discovering the phenomenon that when the adhesion is good, the spectral intensity is high, and when the adhesion is poor, the spectrum intensity is low.The method of the present invention can also be proven theoretically.

The detected sound wave O detection reflected wave signal is detected 0 times each (n=1.2
...) can be expressed as a superposition of 0 reflected wave components, and each n@reflected wave component O has the coefficients related to material properties (attenuation coefficient, reflection coefficient and Transmission coefficient, etc.) can be expressed as a function that is multiplied by 1 and subjected to phase correction based on the number of reflections.If the detected reflected wave signal is expressed mathematically and subjected to 7-Lier transformation, the frequency that includes the coefficient (or physical property value) related to the physical properties of the material can be expressed. A spectrum is obtained.

For example, as shown in FIG.
When a waveform function A (t) o sound wave is input from the surface,
Each n1g1 reflected wave component can be expressed as follows.

Shell t) = (klRyo, Niko) A(t)2J.

Inot) = klR engineering, klR engineering. (klR, ni□
) A(t--) where k is the attenuation coefficient, R is the reflection coefficient at the interface -, T is the zero transmission coefficient at the interface, and C is the speed of sound. are the propagation distances, and the suffixes 0, 1, 2.3 represent the probe, material 1, material 2, and o1 for the opposite dlD interface material (eg, air), respectively.

Furthermore, there is a lack of relationship between each of the above coefficients, the physical property value of the material, and 0.

k1=e″″a1x α,: Material IC) Absorption coefficient ■Sound speed T12 = 2 P IC/ (PIC1+/'2C
2) C work = / a work / ρ, E work: Material 10 elastic modulus The total reflected wave R(t) is expressed by the superposition of each reflected wave component 0.

bile) = I, (tl + l2(tl+...+J
Engineering (t) + J,! tl+...7-If the Rie transformation is represented by F[], the relationship shown by the arrow holds true.

FCh(t)), f''h(t)e -' ``td is 3h(#) Then, the total reflected wave R(tl) is subjected to 7-Lier transform.

F(fat)]=FCI,(tl)+F(: l2(
t)] +−−−−−+・・・・・・・・・・ In the 7-lier transform, the following equation generally holds true.

F(h(t-to))=e−'(′”h(m) Therefore, we define the following c*Jlst.

S = 20 log l F CR(t))/F C1
1(t) month S obtained in this way is k + Rt T z
Ce 1st grade ■Consists of material constant O, and frequency -
It is an O periodic function and can be calculated theoretically. Therefore, by observing the quantity St, information on material properties and interfaces (adhesion parts, etc.) can be obtained.

In addition, as will be described later, if the impedances of the two materials are significantly different, an appropriate approximation method should be used (the function St- can be simplified, and the material 1.
It can be proven that the function SO spectrum/turn shows a significant difference between the two 0 contact areas (forming an interface) when the adhesion condition is good and when the adhesion condition is 0. Available for

Roughly speaking, in the function S, the influence of the strong incident wave A (t) is canceled, and at Q, the incident wave is mostly reflected at the adhesive part (interface) and transmitted through the adhesive part to the opposite surface (interface). Even if the sound waves reflected from the sensor are weak, information from these sound waves can be reliably detected. In other words, the incident side ■
Even if the material 1 has high acoustic impedance θ, such as metal, the adhesion state can be reliably determined by the function S'Os (Q, which changes the vector strength) depending on the state of the contact layer.

Furthermore, since the function S does not include the incident waveform function A (tl), there is an advantage that a statistical value from which the influence of the measurement system O is removed can be obtained.

Hereinafter, μ examples in which tests were actually performed using the method of the present invention will be described.

Example I: Steel plate and Rinjun blended natural comb were made into Chemlock 205/2.
20 (cI-do Co., Ltd. III) was used to inspect the bonded part of the joint member O bonded by vulcanization. Figure 2 shows the member to be inspected, and
The thickness is f 2 am sbo-2Q thickness f3rnm,
The size was 50 am x 50 mm. In addition, an Of Terrace delay (acrylic delay) 5 was bonded to the surface of the steel plate 10 to provide an interval (time) t between each reflected wave component, and a 10 MHz C) sound wave was incident from the steel plate 1 side through this.

Figure 3 shows a measurement system in which an ultrasonic flaw detector 615 and a broadband probe 7 are used to inject a sound wave A (t) and receive multiple reflected waves from the internal interface, which are monitored by an Osimiskog 8. did. Furthermore, one multiple reflected wave was electrically extracted and inputted to the spectrum analyzer 9, where it was subjected to 7-RIE conversion processing.

Note that 1) the flaw detection device 6 was O model 5052UA manufactured by Manametrics Co., Ltd. of Japan; the probe 7 was a model V115 (12) manufactured by Nametrics Co., Ltd. of Japan; and the oscilloscope 8 was a model 111740A manufactured by Ni-Rett Packard Co., Ltd. A Spectrum Analyzer 2 ID 9 TOSHITEHURET/GUTSUKARD Co., Ltd. 113585AI was used.

First, the first reflected wave I, (t) O was taken out from the adhesive interface and subjected to 7-lier transformation, which was displayed on the screen in t-dB and also stored in the spectrum analyzer 9 as memory ■. . A long time ago, the total reflected wave R(t)' was taken out, subjected to 7-lier transform, displayed on the screen in dB, and stored in memory (2).

Then, the -@■ operation was performed using Spectrum Analyzer 2 and ID 9 to obtain the spectrum corresponding to the O function S described above.

Hereinafter, the θ function SO spectrum and the O correspondence will be explained separately for cases where the adhesion is good and cases where the adhesion is poor.

I) In the case of good adhesion O: If the adhesive line is good, the reflected wave will be as shown in Figure 4 and Figure 4 (B) [IK1kl incident wave A (t)
Then, each n-times reflected wave component is expressed as 0 below.

5'r5
2'xTxs'! (-)CI Jit) = to 5T51kIT12 to 2R23 to 2T21
kIR15kIR12kIT155 Therefore, K(
:, e The total reflection wave R(t) between K1 and K1 can be expressed as follows.

i*t) =KOft) +I, (t)+ Ijt)+
... + JJit (t) + JJit + ... Perform 7-lier transformation to obtain function s = 2.

Δ3α”5fxs; 3+21x512”L23(α5)
, 2-β512)cosc"!')2m1.20m1
2 +2α5. ．． 2α123 COS (+)CI
C2 ”5122kl Cr51Tl 5R12/R51)
α12. ): "z (", T2.ru23/R12)
β5123<R15R12 The following approximation is clf function when the acoustic I/P/S is greatly different between gold j11 and rubber 2.

kl ”=-1-dVe (dyyo〉0)k2ζ1-d
y2 (dy2)o) R”q −1+ dz 5 □(a z 51 > o
) Rx zζ1- d 112 (d Z 12>
O) R23”'-1-d Z 23 (d Z 23
> 0) Using this Q approximation, S is simplified as follows. In other words,
) + Q3)+Q(+) ) 2dz5□+dz, +
2dy Kozo W and d Z r, □3dz: 3
Estimating the next minute amount, that is, the above 0 lack 17)
01og (Q(0) )2 Since the O attenuation is sufficiently small in metals, dy1 □kuku1, ”=-2010flO=-■ If the adhesive field is good like this, the spectrum with high intensity will be Uneura will be done.

The O solid line in Fig. 5 (4) shows the SO theoretical spectra measured by the above O coupling, and Fig. 5 (8) shows the nine observed spectra obtained with the O system in Fig. 3. Figure 5 (All
The medium chain line shows the measured value. It was confirmed from these 0 figures that the two agree well.

11) If the adhesion failure is 0, if the adhesion failure is O, the reflected wave will be
), and if the incident wave is t A (t), each n-times reflected wave component is expressed as O below.

Ko(t) = k 5R5,k , A(t)'1 Therefore, the total reflection wave R(t) between 0 and 0 at Ko is rKO
It is expressed as follows.

desired t)=, 0(tl+I, (t)=I, (t) +I,
(tJ+...This is converted to 7-IJ to obtain the function S.

Here, α513 three ￥ (T51T15R13/R51) β51
32kl R15R-13 Gold jll and rubber 2 have very different acoustic i/pigs/s, and an approximation of 0 and missing is possible.

k knee 1-dyyo (dy engineering) 0) R# -1+ dz5. (dz5.>O)R-1-
dz (dz, , > 0) Leaving this approximation, the function S is simplified to lack O.

Saki □ ~ nπ (n = 1 + 2 e...) ■ When b - 20 log (1 + d z 5 □) Try to find the torque strength.

dy1 □(ku1 is 0, and if the tangent head is defective like this, a spectrum with low intensity will be observed.

Figure 7 (AJ middle Q practical) shows the SO theoretical spectrum calculated using the O formula above, and Figure 7 (B) shows the l1lfs spectrum obtained with the Figure 3 O system.
4) The middle O skin line shows the actual measured value. From these figures, the two agree well, and in the case of good adhesion, Q Figures 5 (A) and (B
) It was confirmed that it was clearly different from OX-'ctor. Below, in i) and il), approximations were used to improve the visibility of 1-theory O, but of course, the same conclusion can be reached even if the equations ■ and ■ before the approximation are directly calculated numerically on a computer/computer. I can do it.

Example ri: A sound wave was applied to the same joining member as in Example I (FIG. 2) from the comb 2 side, and the frequency spectrum was determined. The measurement system is the same as in FIG.

In this Q case, the Q reflected wave will be in the state shown in Figure 8 (A) and Figure 8 CB), and if the incident wave is A (t), each n reflected wave component can be expressed as missing O. .

Inot) = k, 'rwork, 2R23, 2R2, 2
R23 is 2T2, kA (-μm) Therefore, the total reflected wave R(t) is expressed as the following Q.

R(t) = Ko(t)+, (tl+-...-+
I, (t) + I, (tl +-----This is two IJ
Then, calculate the function S.

Here, α1233'% (Tx2'r21B-23/'”1
2) β. , 7 R engineering on 23rd. R-engineer.

β1233μm2R23 The first term of the above function SQ is the Q contribution from rubber l, and the second term is the Q contribution from gold j12. The spectrum can be calculated by directly numerically calculating the formula 0, but for better visibility, the following
Since the acoustic impedance of the rubber 1 and the metal 2 for which the approximation is performed is greatly different, the following approximation is possible.

k2ζ1 dy2 (dy2> 0) kl ζ1-dy (dy>0) R12" l + dZ12 (d Z 12> O
)R23""-dz23(dz23") R1() "" 1 + dZ x .(d Z
x o > 0) Using the 0 approximation, S is simplified to 0. If the first term (O contribution from rubber) is t-8r, then S = S r + 2OA! og (1+ dZx2)
Main S=Sr+20Jog[QfO)+Q(1)+Q(
2)+Q(3)) With 2, dz12+dz23” 2dy2 壬W e dz,,,
==+ dz as 2ω! , cos (-) Figure 9 (solid solid line in At) So second top portion (■ contribution from metal) O theoretical spectrum calculated in this way.

9 (Bl indicates the spectrum measured by that person).

Moreover, the cDA mark in FIG. 9(A) shows the actually measured value.

These ■spectrum zJ? When examining the turn, all resonance conditions are met.

On the other hand, the size Q at the Q bond between comb 1 and metal 2
If a gap exists, O wavelength components smaller than the size of this gap will not be able to enter the metal 2 from MfiJ (, com l. Therefore, the Inari condition mentioned above is violated and the corresponding wave component θ in the spectrum The peak is lost.

Therefore, spectrum! By measuring the turn, it is possible to determine the condition of the bonded portion (interface), that is, the presence or absence of a chip. If there is a chip, the size of the chip can be inspected.

Figure 10 (A) shows O observation scale (cuttle) when the contact layer is good.
Figure 10 (81 is an example of a contact failure 0 contact O observed squictor. In Figure 10 (B), the peak is about to disappear at the arrow It is determined that there is a chip of similar size O.The same result was obtained when the sample was destroyed and examined.

Example: Plasted metal (JIS standard 550C) K
For the joining member partially vulcanized and bonded with Rinjun blended nitrile rubber using W layer agent (Metalloc F'C/Chemloc 220) T-, a delay material (acrylic gas layer) was applied from the metal side.
A 5MHzO sound wave was applied through the bonded area and the non-bonded area D.
J# wavenumber spectrum fta was determined. The test was conducted in the same manner as in Example IO.

FIG. 11(4) shows the 0-view 1 spectrum of the contacting part, and FIG. 11(B) shows the O observation spectrum of the non-contacting part.

Although periodic sharp peaks appeared in the bonded part, these did not appear in the non-contacted part, and it was confirmed that the two could be clearly distinguished from this spectrum.

Example: When fv nibbutyl yarn vibration isolating rubber and shot-blasted metal were vulcanized and bonded using a bonding agent (Chem-A-Tsuku 205/220), on the other hand, the O sample was vulcanized and bonded using a hot press; Laminated by injection molding.

This ■211! For the type 0 joint member, inject a sound wave from the j゛m side in the same manner as in the gun example
- Rie f Isashi Ura ripple spectrum (corresponding to function SK)
was measured.

FIG. 12(A) shows the O observed spectrum of the product bonded by hot press, and FIG. 12(B) shows the O■ observed spectrum of the product obtained by injection molding.

In the case of heat breath pressure shoulders, peaks appear up to high frequencies,
In injection molding, 2.768 MH2 (λ = 0.29rn
m ) and 2.64 MHz (λ = 0.3 mm) C) peaks have disappeared, indicating that approximately 0.
It was determined that there was a blank value of approximately 3 mm.

Example V: For a sample in which vulcanized natural rubber and 6 Nylon were partially adhered, a 5 MHz sound wave was applied from the 6 Nylon side, and the frequency squictre of the bonded part and the non-contacted part was measured.

Figure 13 (A) shows the contact layer OI! Inciting the Spectrum, Part 13
Figure (B) shows the non-adhesive part.

In this case, the peak value itself is small because the difference in acoustic impedance O between the two materials is relatively small, but the spectral patterns are clearly different between the bonded portion and the non-contact layer portion.

It was confirmed that the O spectral tree / in this Q case also coincides with ■, which is predicted from the previous equation approximated in the O theory.

〔effect〕

As is clear from the above description, the present invention provides a non-destructive testing method that can easily and accurately inspect the condition of the bond between two θ materials (such as missing parts, etc.).

[Brief explanation of drawings]

Fig. 1 (8) and Fig. 1 (B) are explanatory colors illustrating a sonic wave 0 incident wave and a reflected wave Q shape 1 m in the bonded member, and Fig. 2 is a perspective view of the inspected bonded member O in which metal and rubber are bonded. ,
FIG. 3 is a block diagram illustrating a suitable measurement system for carrying out the method of the invention, FIG. 4(4) and FIG.
) is an explanatory diagram illustrating the O state of the O reflected wave when the contact layer is good with high acoustic I/Begun input side incidence, Fig. 5 (A) and Fig. 5 @
) is a graph showing the theoretical θ spectrum and observed spectrum when the adhesion is good with incidence on the high acoustic impedance side, and Figure 6 (
A) and Figure 6 (@ is an explanatory diagram illustrating the O-shaped reflected wave O-shaped ta1 at the time of poor adhesion when the incidence is on the high acoustic impedance side, and Fig. 7
Color range and Figure 7 (Decoy is a graph showing the O theoretical spectrum and l! error spectrum when adhesion is poor with high sound 4 impedance side incidence, Figure 8 (A) and Figure 8 (B) are graphs showing low sound I/Pedance side incidence. An explanatory diagram illustrating the reflected wave O state when a sound wave is incident from A) and Figure 10 + 8) are diagrams showing the observed spectra in Figure 8 when the bond is good and when the bond is poor, Figure 11) and Figure 11 (B) are the bonded and non-bonded areas. Figure 12 (A) and Figure 12 (81 = Heat press vulcanization bonding and rubber injection molding bonded material ■ Q shows the observed spectrum when incident on the rubber side. figure,
13th Color Circle and Figure 10+8) H is a diagram showing the bonded part and non-bonded part O@warm spectrum in the Futo Derastechuku Q bonded member. 1.2...Touched material, A(t)...Incident wave waveform function, ■Yo(t),
I 2 (t) ~ J engineering (t) e, y2it) ~...
...Reflected wave component O waveform function. Agent Patent Attorney Yasutake Oto Figure 3 Figure 4 ≦ Figure 7 (B) Figure 8 (B) Figure 9 (A) (IS Figure 10 (A) (B) Figure 11 (A) ) (B) fo 3fo 6f. Fig. 12 (A) fn(MHz) (B) fn(M)-12)

Claims (1)

[Claims] (1) In a non-destructive inspection method for a bond between two bonded materials, a sound wave is incident on the surface of one material, the reflected wave is detected, and the detected reflected wave signal is Fourier-transformed to obtain its frequency spectrum. An inspection method characterized in that the state of the bonded portion is determined from the spectral pattern.