CN105388469A - Figure-based ultrasonic detection pulse echo signal analysis method - Google Patents

Abstract

The present invention relates to a figure-based ultrasonic detection pulse echo signal analysis method. For automatic-sending and sutomatic-receiving mode ultrasonic detection, according to the physical law that a probe piezoelectric element emits pulse ultrasonic waves under the excitation of pulse voltage and the ultrasonic wave is transmitted in coupling medium and a detected object and is reflected by an interface to generate echo, the invention provides a two-dimensional expression figure which is described in detail in a specification and comprises an ultrasonic pulse transmission time and space relation and echo waveform information and the ultrasonic detection pulse echo signal analysis method based on the figure, and by using the method, the echo times and the reflection surface of each echo signal can be rapidly identified.

Description

A kind of Ultrasonic Detection pulse echo signal analytical approach of graphic based

One, technical field

The present invention proposes a kind of Ultrasonic Detection pulse echo signal analytical approach of graphic based.The method detects for internal loopback mode ultrasound, the two dimension proposing a kind of time and space relation and echo waveform information that describe ultrasonic pulse travels expresses figure and the Ultrasonic Detection pulse echo signal analytical approach based on this figure, can recognize the echo that each echoed signal is which time of which reflecting surface fast.

Two, background technology

When analyzing the pulse echo signal adopting piezoelectric type ultrasonic transducer internal loopback detecting pattern, multiple reflections is produced because acoustic signals runs into multiple reflecting body, receive MUT to time domain echoed signal present complicated rule, directly more difficult with the concrete source of each echoed signal of time-domain waveform analysis of echoed signal, if there is mistake to the source analysis of echoed signal, just may to the testing result made mistake and conclusion.

Adopt transonic rule that the piezoelectric ultrasonic of single band lens is popped one's head in when carrying out Non-Destructive Testing in internal loopback mode as shown in Figure 1.Suppose that the length of lens is L ₁, the velocity of sound is c ₁, the length of coupled water journey is L ₂, the velocity of sound is c ₂.2. the ultrasound wave that 1. piezoelectric element produces under the excitation of electric pulse imports lens into by interface A, produces transmittance and reflectance when reaching its other end at interface B.If it was 0 moment that pressure electric device produces hyperacoustic moment, then reflection echo turns back to the time that piezoelectric element converts electric signal to and is after lens are propagated transmitted wave water transmission arrive emitter 4. time, interface C produce reflection, the travel-time of this reflection echo between B and C of interface is the researchist of Non-Destructive Testing frequently by by the time as horizontal ordinate, reflected impulse amplitude, as the curve of ordinate, is called that A sweeps curve, analyzes the detection signal of internal loopback mode, as shown in Figure 2.

Sweep curve as can be seen from A, each interface pulse echo returns the moment of piezoelectric element, but directly can not find out each pulse is from which reflecting interface.

When the present invention proposes a kind of analysis list probe internal loopback Ultrasonic Detection, express the X-Y scheme analytical approach of ultrasonic pulse travels path and the information in travel-time simultaneously.

Three, summary of the invention:

As shown in Figure 3, coupled interface between piezoelectric element and lens is A, the coupled interface of lens and water is B, the coupled interface of water and tested reflecting body is C, three interfaces represent with parallel lines, space representation lens medium between A, B interface, space representation coupled water medium between B, C interface, oblique line in order to the incidence of θ angle represents the travel path of ultrasonic pulse in each medium, the length of oblique line represents the length of ultrasound wave in each Propagation path, supposes that the two-way propagation T.T. of ultrasound wave in lens is t ₁, the two-way propagation T.T. in water journey is t ₂, then

$\begin{array}{cc}{l}_1=c_1\frac{t_1}{2},& l_2=c_2\frac{t_2}{2}\end{array}$

L ₁＝l ₁cosθ∝l ₁，L ₂＝l ₂cosθ∝l ₂

$\begin{array}{cc}{l}_{t1}=l_{1}sin\mathrm{\θ}=c_1\frac{t_1}{2}sin\mathrm{\θ}\∝t_1,& l_{t2}=l_{2}sin\mathrm{\θ}=c_2\frac{t_2}{2}sin\mathrm{\θ}\∝t_2\end{array}$

In the point of intersection of travel path oblique line and interface A (piezoelectric element and lens surface of contact), represent boundary reflection echo with vertical line, the length of vertical line represents the intensity of echo.

With above-mentioned relational expression for constraint, draw by Fig. 3 mode, scale factor scale is considered to transverse and longitudinal coordinate simultaneously, then the horizontal ordinate of Fig. 3 represents the ultrasonic pulse travels time, ordinate direction comprises dielectric thickness information, add and represent the ordinate of echo strength, the Time and place information of pulse propagation when Fig. 3 clearly have expressed internal loopback ultrasonic inspection.Consider each interface multiple reflections, echoed signal analysis as shown in Figure 4, intuitively can be recognized rapidly in detection signal waveform and appear at the echo that not echoed signal is in the same time which time from which reflecting surface from figure.

The present invention relates to a kind of echoed signal analytical approach of pulse excitation sound wave of figure based on comprising room and time information.This method can recognize the echo that each echoed signal is which time from which reflecting surface fast.

The condition possessed of the inventive method is such, gives and visits first pulse excitation signal, adopts internal loopback pattern to carry out Ultrasonic Detection, analyzes the reflecting surface that in detection signal, each echo-pulse is corresponding.

Four, accompanying drawing illustrates:

Ultrasonic propagation principle schematic when Fig. 1 internal loopback mode ultrasound detects

Description of reference numerals is as follows: L ₁for the length of lens, c ₁for the velocity of sound in lens, L ₂for the length of coupled water journey, c ₂for the velocity of sound in water, being 1. piezoelectric element, is 2. lens, is 3. couplant water, is 4. tested reflecting body.A interface is the surface of contact of piezoelectric element and lens, and B interface is the surface of contact of another surface of lens and couplant water, and C interface is the upper surface of reflecting body in couplant water.

Fig. 2 internal loopback mode ultrasound detects the time and magnitude relation waveform schematic diagram that receive echoed signal

Description of reference numerals is as follows: S ₀for transponder pulse; S ₁for the echoed signal after interface B reflects, i.e. an echoed signal of interface B; S ₁₁for the echoed signal after interface C reflection, i.e. an echoed signal of interface C.

The time and space relation of ultrasonic propagation and echo waveform bivariate table diagram when Fig. 3 internal loopback mode ultrasound detects

Description of reference numerals is as follows: l ₁for the one way propagation path of sound wave in lens; l ₂for the one way propagation path of sound wave in couplant water.L _t1for the horizontal component in the one way propagation path of sound wave in lens; l _t2for the horizontal component in the one way propagation path of sound wave in couplant water.

The time and space relation of ultrasonic propagation and echo waveform bivariate table diagram when Fig. 4 considers interface multiple reflections

Description of reference numerals is as follows: S ₀for transponder pulse; S ₁, S ₂, S ₃, S ₄for interface B reflect after echoed signal, namely interface B once, secondary, three times, four times echoed signals, and S ₁, S ₂, S ₃, S ₄the adjacent signals time interval is equal is Δ t ₁=t ₁; S _i1, S _i2, S _i3(i=1,2,3,4) are interface B once, secondary, three times, four secondary reflections (transmission) signal interface C produce once, secondary, three echoed signals, and S _i1, S _i2, S _i3the adjacent signals time interval is equal is Δ t ₂=t ₂.

Five, embodiment:

Below the specific embodiment of the present invention is described in detail:

For the band lens probe internal loopback detecting pattern shown in Fig. 1, after probe sends sound wave, propagate in lens, in couplant water and in testee, at lens and water termination and water and testee boundary reflection, reflection echo signal, as Fig. 2, can obtain travel-time t between interface ₁and t ₂.

Setting represents the oblique line incidence angle θ in acoustic propagation path when drawing, calculate the length L representing lens ₁with the L representing coupled water dielectric thickness ₂value

$\begin{array}{cc}{L}_1=\frac{l_{1}cos\mathrm{\θ}}{2}=\frac{c_1{t}_{1}cos\mathrm{\θ}}{2},& L_2=\frac{l_{2}cos\mathrm{\θ}}{2}=\frac{c_2{t}_{2}cos\mathrm{\θ}}{2}\end{array}$

Get suitable scale-up factor, consider multiple reflections, according to the spatial relation of probe, couplant and testee, draw the bivariate table diagram of ultrasound propagation time and spatial relationship and echoed signal u (t)-t, as Fig. 4.

From Fig. 4, reflecting interface is found along acoustic propagation oblique line in the position that each echo occurs interface A, intuitively can analyze fast in detection signal waveform and appear at the echo that not echoed signal is in the same time which time from which reflecting surface.

Claims (4)

1. a Ultrasonic Detection pulse echo signal analytical approach for graphic based, is characterized in that: Graphics Application represents the due in of echo-pulse and corresponding reflecting interface, can recognize the echo that each echoed signal is which time of which reflecting surface fast.

2. method according to claim 1, ultrasonic wave propagation path is represented with oblique line, and utilize the velocity of sound, physical relation between sound path and travel-time makes travel-time and dielectric thickness can concentrate expression in 2 d plane picture, have expressed time and space relation and the echoed signal shape information of ultrasonic pulse travels simultaneously.

3. method according to claim 1, consider that scale factor carries out scale to transverse and longitudinal coordinate, the horizontal ordinate length of figure represents the travel-time, ordinate comprises dielectric thickness information and echo signal amplitude information, and the travel-time therefore between pulse echo directly can read by coordinate from figure.And time interval between adjacent the echoed signal at each interface is equal.

4. method according to claim 1, represents echo in the echo point of piezoelectric element and lens interface with vertical line, and vertical line length represents echo signal intensity, consistent with the signal waveform that oscillograph in reality is observed, and meets engineer applied custom.