CN102721457A - Ultrasonic speckle underwater steady-state vibration measuring method and measuring device - Google Patents
Ultrasonic speckle underwater steady-state vibration measuring method and measuring device Download PDFInfo
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Abstract
The invention discloses an ultrasonic speckle underwater steady-state vibration measuring method and device and belongs to the vibration measuring technology. The measuring method comprises the steps of: repeatedly emitting ultrasonic pulse trains focused on the current measuring point on the surface of an underwater vibrating object to be measured, and determining the object vibrating frequency according to the stable condition of received object surface speckle signals; performing time delay processing on the emitted focused ultrasonic pulse trains, and determining the amplitude of the current measuring point on the surface of the vibrating object according to the difference of the shortest time and the longest time of synchronously receiving the speckle signals; focusing the ultrasonic pulse trains on an adjacent measuring point, performing time delay processing on the repeatedly emitted focused ultrasonic pulse trains, and determining the phase difference of the two measuring points according to the time delay difference of the time delay processing of the two measuring points, namely, the phase of the adjacent measuring points; and repeatedly and sequentially determining the phases and amplitudes of different measuring points on the surface of the underwater vibrating object. The measuring method provided by the invention is suitable for performing real-time, stable, non-contact and full-field scanning type measurement on the steady-state vibration frequency, amplitude and phase of an underwater rough object.
Description
Technical field
The invention belongs to vibration measurement technique, be specifically related to the method and apparatus that the using ultrasound speckle is measured vibration frequency, amplitude and the phase place of steady-state vibration object under water.
Background technology
Vibration survey under water has special demand in engineering construction, for example need carry out not timing detection or real time and on line monitoring to submerged structures such as bridge pier, dock, submarine vibration frequency and amplitude under steady stimulation; In addition; Vibration survey under water has demand equally in scientific research; For example, in structural design, need the vibration-mode analysis that experimentizes of model under water, this just requires the vibration frequency, amplitude and the phase place that receive to compel each node in the steady-state vibration model or key aspect are measured.
Traditional vibration measurement technique has several different methods such as the strainometer of use, capacitive transducer, piezoelectric sensor, Fibre Optical Sensor and eddy current sensor.Wherein strainometer is owing to simply accurately and the earliest be applied in the vibration-testing, and it can be used for the measurement of vibration frequency and phase place, but it is confined to the contact type measurement of single-point type, and the amplitude of measuring vibrations object effectively; Capacitance type sensor also can be used for vibration survey, and it has, and measurement range is big, simple in structure, cost is low, the sensitivity advantages of higher, but it is subject to the interference of stray capacitance, and output characteristics is non-linear, particularly is difficult to use under water; Novel piezoelectric transducer precision is high, dynamic range is big, frequency response is wide, but it equally only is applicable to the contact type measurement of single-point type; And the fiber optic sensor system that development in recent years is got up; Through fiber coupler and single-mode fiber structure optical interference circuit, form the variation of laser interference state according to the reverberation surface vibration, carry out amplitude, frequency; The measurement of speed etc.; But its measurement receives the disturbing influence of water bigger, job insecurity in the water, and be difficult to coarse object plane is measured; The measurement that eddy current sensor can be used for vibrating under water, but owing to the non-linear of it and the bigger defective that exists of sensitive face end face, and it can only be measured the vibration of metal object plane; At present; Maximum laser triangulation law technologies is used in vibration survey in the engineering, and its advantage is a non-cpntact measurement, and range is big and resolution is high; But because the photoelectric response unevenness of its line array CCD (Charge Coupled Device) pixel and non-linear; And degree of accuracy is subject to the inclination at tested interface and the disturbing influence of water, and it is difficult to vibration object is under water measured, and particularly it can't be measured coarse vibration object plane.Ultrasound speckle of the present invention is vibration measurement method and device under water; Can overcome the existing difficulty of above-mentioned various measuring method; Frequency, amplitude and the phase place of thing steady-state vibration under water implemented the real-time measurement of high precision, noncontact, scan-type, and receive object material and surfaceness, current and influence of temperature variation seldom.
Summary of the invention
The object of the present invention is to provide a kind of ultrasound speckle steady-state vibration measuring method under water and measurement mechanism, the present invention be suitable for to the frequency of rough object steady-state vibration under water, amplitude and phase place carry out in real time, stablize, noncontact, whole audience scan-type measure.
A kind of ultrasound speckle provided by the invention steady-state vibration measuring method under water is characterized in that this method comprises the steps:
The 1st step focused on the ultrasonic pulse string on the current measuring point to vibrating object to be measured surface repeat its transmission under water;
The 2nd step was confirmed the object vibration frequency according to the stable case of the object plane speckle signals of the vibrating object to be measured that receives;
The 3rd step was further carried out delay process to the focus supersonic train of impulses of emission, and the shortest and maximum duration was poor according to synchronous reception speckle signals spends, confirmed the amplitude of the surperficial current measuring point of vibration object;
The 4th step, to its surperficial current measuring point repeat its transmission focus supersonic train of impulses, the line delay of going forward side by side was handled, and was the shortest up to synchronous reception speckle signals spended time according to the vibration frequency of vibrating object to be measured under water; Again ultrasonic probe is focused on the adjacent measuring point of the current measuring point in vibrating object to be measured surface under water, also adjacent measuring point repeat its transmission focus supersonic train of impulses is carried out delay process, make synchronous reception speckle signals spended time the shortest; The difference of the amount of delay when carrying out delay process according to two measuring points is confirmed the phase differential of the current relatively measuring point of adjacent measuring point, the i.e. phase place of adjacent measuring point;
The 5th goes on foot with this adjacent measuring point as current measuring point;
The 6th step constantly repeated for the 3rd to the 5th step, confirmed the phase place and the amplitude of vibration object surface different measuring points under water successively.
A kind of ultrasound speckle provided by the invention is the steady-state vibration measurement mechanism under water, it is characterized in that, this device comprises pulse signal generator; Chronotron, power amplifier, focus ultrasonic probe; Voltage amplifier, digital storage oscilloscope, microcomputer and three-dimensional electronic control translation stage; Pulse signal generator is connected with cable with the interface of focus ultrasonic probe through chronotron, power amplifier successively; The interface of focus ultrasonic probe is implemented the speckle signals data transmission through voltage amplifier, digital storage oscilloscope with microcomputer successively again and is connected; Pulse signal generator is implemented control linkage with microcomputer and digital storage oscilloscope respectively again; The focus ultrasonic probe is connected on the three-dimensional electronic control translation stage, implements the translation control linkage with microcomputer again.
Use method and apparatus of the present invention when vibrating object is measured under water, require in testee is positioned under water 30 meters, measured object surface each point curvature is less than 1, and water velocity is less than 1 meter per second on the tested object plane, and water temperature is lower than 60 degrees centigrade, and current do not have bubble.Use method and apparatus of the present invention stream time when vibrating object is measured under water and do not limit, the range of frequency measurement can reach 0.5 hertz to 2000 hertz, and measuring error can reach ± and 0.01 hertz; The range of amplitude measurement can reach 0.1 millimeter to 10 millimeters, and measuring error can reach ± and 0.02 millimeter; The range of phase measurement can reach-720 degree to 720 degree, and measuring error can reach ± 0.01 degree.
Description of drawings
Fig. 1 is that the focus ultrasonic probe transmits and receives hyperacoustic form;
Fig. 2 is the speckle signals that the interior electronic horizon deflection scanning frequency of electric pulse repetition frequency and the oscillograph display screen of excitation ultrasonic probe shows on the display screen when asynchronous;
The speckle signals that shows on the display screen when Fig. 3 is the interior electronic horizon deflection scanning Frequency Synchronization of electric pulse repetition frequency and the oscillograph display screen of excitation ultrasonic probe;
Fig. 4 be the present invention when measuring immersed body steady-state vibration frequency in order to judge that the speckle signals that shown is whether stable and to measure the software flow pattern of frequency;
Fig. 5 is that the vibration object plane moves to positive-displacement steady display speckle signals on ultra-Left side position on oscillograph display screen time shaft when maximum;
Fig. 6 is that the vibration object plane moves to the reverse displacement speckle signals of steady display on ultra-Right side position on oscillograph display screen time shaft when maximum;
Fig. 7 be the present invention control when measuring immersed body steady-state vibration amplitude speckle signals between the position of ultra-Left side and ultra-Right side on the oscillograph display screen time shaft variation and calculate the software flow pattern of amplitude;
Fig. 8 is the present invention's software flow pattern that process is controlled and calculated when measuring immersed body steady-state vibration phase place;
Fig. 9 is a ultrasound speckle of the present invention steady-state vibration measurement mechanism synoptic diagram under water.
Embodiment
The basic thought and the principle of ultrasound speckle of the present invention steady-state vibration measuring method under water are:
When inciding the medium rough interfaces, its scattering wave can be interfered in dielectric space each other, forms the speckle field of amplitude and phase place stochastic distribution when ultrasonic.Most engineering detect with medical imaging technology in, ultrasound speckle is regarded as noise and quilt is avoided and suppressed, but ultrasound speckle is followed the scattering interface and made the state of regular motion and comprised the displacement at scattering interface and the information of distortion.In addition, ultrasonic and speckle has the advantage of a lot of uniquenesses, not only can in air, propagate such as ultrasonic, can also in water, propagate with solid interior; The general disturbance of water and temperature variation are very little to transonic and speckle influence; Ultrasonic have a penetrability, and ultrasound speckle can produce to coarse object plane by the remote emission of focus ultrasonic probe is ultrasonic, also can be received non-contactly by same probe simultaneously; In water general ultrasonic wavelength submillimeter and centimetre between, the magnitude of this and common engineering malformation matches; More than these have established physical basis for the foundation of ultrasound speckle of the present invention steady-state vibration measuring method under water.
It is as shown in Figure 1 that the focus ultrasonic probe transmits and receives hyperacoustic form.In the electric pulse excitation that takes place with a certain repetition frequency down, ultrasonic probe produces a series of ultrasonic pulse string, after they are transmitted under water on the rough object surface, the ultrasound speckle that scattering wave produced by same focus ultrasonic pop one's head in receive.During the immersed body vibration, each point is done corresponding to-and-fro movement on the also corresponding rough object of the ultrasound speckle surface everywhere.Ultrasound wave is formed with the burnt post of certain diameter and length in focusing range; When ultrasonic probe focuses on the vibration object plane; The ultrasound speckle of in burnt post scope, moving is focused and directly converts electric signal into after ultrasonic probe receives, and after amplifying, can on oscillograph, show.If the electric pulse repetition frequency of excitation ultrasonic probe is not equal to 1/n (n=1,2,3 of object plane vibration frequency ...), the speckle signals that at this moment shows on the display screen is chaotic unclear, as shown in Figure 2; Otherwise, speckle signals can steady display on certain position on the display screen time shaft, as shown in Figure 3.Here it is uses the principle that the present invention measures immersed body steady-state vibration frequency approach.
If the electric pulse repetition frequency of excitation ultrasonic probe is not only identical with the object vibration frequency; And ultrasonic probe is just in time triggered by electric pulse when the vibration object plane moves to the positive-displacement maximum; At this moment focus ultrasonic probe from emission ultrasonic pulse string to receiving time of being spent during the speckle signals on the tested object plane for the shortest; Ultrasound speckle signal on the measuring point of corresponding is digital storage oscilloscope institute synchronous recording resides on the display screen time shaft on the ultra-Left side position; As shown in Figure 5, this can realize through the triggering of appropriate time-delay electric pulse to focusing probe constantly; Under the kindred circumstances; When the vibration object plane move to reverse displacement when maximum ultrasonic probe just in time triggered by electric pulse; At this moment focus ultrasonic probe from emission ultrasonic pulse string to receiving time of being spent during the speckle signals on the tested object plane for the longest; Ultrasound speckle signal on the measuring point of corresponding is digital storage oscilloscope institute synchronous recording resides on the display screen time shaft on the ultra-Right side position, and is as shown in Figure 6.Below can realize constantly through of the triggering of time-delay electric pulse equally focusing probe; And according to receiving the poor of the shortest and maximum duration that speckle signals spent respectively under above-mentioned two kinds of situation; The mistiming of the electric pulse time-delay of being regulated when just making speckle signals be stabilized on the oscillograph display screen time shaft on the ultra-Left side and ultra-Right side position respectively; According to the speed of ultrasound wave at water transmission, microcomputer just can calculate the amplitude on the vibrating object measuring point again.Focus ultrasonic probe from emission ultrasonic pulse string to receiving the definite of the shortest and maximum duration that spent during the speckle signals on the tested object plane; That is the ultrasound speckle signal on the measuring point of corresponding digital storage oscilloscope institute synchronous recording resides in confirming of ultra-Left side position and ultra-Right side position on the display screen time shaft, and magnitude determinations is accomplished by the computer software of process flow diagram shown in Figure 7.
After the speckle signals on the current measuring point of vibration object plane is focused the probe reception, stablize when residing on the ultra-Left position on the display screen time shaft; With the focusing probe translation under still in running order and focus on the contiguous adjacent measuring point; If the phase differential of these two measuring point vibrations equals zero; Also be that speckle signals on the adjacent measuring point also is that measuring point is received by probe when being vibrated to the forward maximum displacement, at this moment, this speckle signals also will reside on the ultra-Left side position on the display screen time shaft.Because two measuring points are contiguous each other, phase differential can not be 2 π between them.Certainly, the amplitude of current generally speaking measuring point and adjacent measuring point is inequality, and the position of the ultra-Left side of their correspondences on display screen is also inequality.If the phase differential of current measuring point and the vibration of adjacent measuring point is not equal to zero; Also be that speckle signals on the adjacent measuring point is not to be received by probe when moving to the forward maximum displacement; At this moment received speckle signals will not reside on the ultra-Left side position on the display screen time shaft; Just not when adjacent measuring point is vibrated to the forward maximum displacement on the pairing screen position; At this moment the triggering of regulating time-delay excitation ultrasonic probe electric pulse constantly, reside on the display screen speckle signals will about move around.Gradually this speckle signals is moved on the leftmost position on the display screen time shaft, trigger amount of delay and vibration frequency constantly, can calculate the trail of adjacent measuring point with respect to contiguous current measuring point vibration phase according to electric pulse.Above phase measurement process is accomplished by the computer software of process flow diagram shown in Figure 8 with calculating.
In a word, instance of the present invention provide ultrasound speckle steady-state vibration measuring method under water may further comprise the steps:
The 1st step focused on the ultrasonic pulse string on the measuring point to vibrating object to be measured surface repeat its transmission under water;
The 2nd step handled the object plane speckle signals of the vibrating object to be measured that receives, according to the signal stabilization situation, confirmed the object vibration frequency.
Whether stable the speckle signals that shows and object vibration frequency measurement judged by computer software and accomplish that the designed software flow process is as shown in Figure 4, and its processing procedure is following:
(2.1) the repetition frequency F of the electric pulse of some triggering focus ultrasonics probe is set, F should be lower than the estimated frequency of object vibration; If be unable to estimate the object vibration frequency, then the F value is got one smaller or equal to 0.5 hertz value;
(2.2) N that successively focus ultrasonic probe continuous synchronization is repeated to receive
1Individual speckle signals is sampled, and its sampling period is T
S, T
SConfirm T according to error requirements
SSpan is 0.005 microsecond to 0.1 microsecond; N
1For more than or equal to 5 positive integer, this instance is got N
1=5;
(2.3) calculate the centre of gravity place G of square value on time domain of these speckle signals waveforms respectively
i, subscript i representes the sequence number of speckle signals, i=1,2 ... N
1;
(2.4) the maximal value max|G of the difference of any 2 centre of gravity places in the above-mentioned speckle signals of judgement
m-G
n| (m=1,2 ... .N
1; N=1,2 ... N
1; M ≠ n) whether less than N
2Sampling period T doubly
SIf,, expression signal is resident stable, then gets into next process (2.5); If not, expression signal is unstable, then gets into process (2.7); Subscript m, n representes the sequence number of centre of gravity place, N
2Be positive integer, its span is 5 to 20, this instance N
2=10;
(2.5) write down this repetition frequency F value and be F
j, get into process (2.6) simultaneously; The sequence number of the repetition frequency of getting when subscript j expression signal is stablized, its initial value are 1;
(2.6) stepping increases repetition frequency F value; Value according to error requirements is got step-length
gets into process (2.2) once more; The span of
is 0.01 hertz to 0.1 hertz;
(2.7) stepping increases repetition frequency F value; After this value according to error requirements is got step-length
will get into process (2.8); The span of
is 0.01 hertz to 0.1 hertz;
Whether the frequency values after (2.8) judgement increases progressively is greater than F
The upper limitIf,, get into step (2.9); If not, then get into process (2.2); Value F
The upper limitFor the maximum estimated value of object vibration frequency is set in advance; F
The upper limitValue can confirm that its scope is 10 hertz to 2000 hertz according to the form and the material of submerged structure.After passing through process (2.6) and (2.8) respectively, get into process (2.2), (2.3), (2.4) once more, and (2.5) or (2.7), in constantly repeating, obtain a series of F from small to large
jValue back entering process (2.9);
(2.9) constantly get F
jMaximal value and output, the repetition frequency value F after increasing progressively is greater than F
The upper limitAnd the software running stops, then F
jMaximal value be the object vibration frequency values.
The 3rd step was further carried out delay process to the focus supersonic train of impulses of emission, and the shortest and maximum duration was poor according to synchronous reception speckle signals spends, confirmed the amplitude of the surperficial measuring point of vibration object;
As shown in Figure 7, employed software processes process is following:
(3.1) the triggering time-delay τ of increase chronotron, τ=k Δ τ; Δ τ is required to confirm that its span is 0.005 microsecond to 0.1 microsecond by measuring error for time-delay step-length, its size; K is the time-delay number of times that progressively increases, and k is continuous positive integer, its initial value k=1;
(3.2) the speckle signals waveform after will delaying time carries out square operation, and calculates its center-of-gravity value G on time domain
k, its subscript k represent to delay time sequence number of back waveform, it is consistent with time-delay number of times k value in the step (3.1), G
kTo change along with the increase of time-delay number of times k;
(3.3) make k=k+1, repeating step (3.1) and (3.2); Constantly increase the k value, repeating step (3.1) and (3.2) are up to definite G
kObtain minimum value, get into step (3.4) then;
(3.4) record G
kWaveform sequence number k value during for minimum value, k=K
1;
(3.5) increase the triggering time-delay τ of chronotron again, τ=k Δ τ; Δ τ still is the time-delay step-length, and k still is the time-delay number of times that progressively increases, and k is continuous positive integer, its initial value k=K
1+ 1;
(3.6) the speckle signals waveform after will delaying time carries out square operation, calculates its center-of-gravity value G on time domain
k, G
kTo become big along with the increase of time-delay number of times k;
(3.7) make k=k+1, repeating step (3.5) and (3.6); Constantly increase the k value, repeating step (3.5) and (3.6) are up to definite G
kObtain maximal value, get into step (3.8) then;
(3.8) record G
kWaveform sequence number k value during for maximal value, k=K
2;
(3.9) according to K
1And K
2Value can be calculated the measuring point amplitude A, A=V (K
2-K
1) Δ τ, V is ultrasonic velocity of propagation in water.
The 4th step, to its surperficial current measuring point emission focus supersonic train of impulses, the line delay of going forward side by side was handled, and made synchronous reception speckle signals spended time the shortest according to the vibration frequency of vibrating object to be measured under water; Again ultrasonic probe is focused on the adjacent measuring point in vibrating object to be measured surface under water, also its repeat its transmission focus supersonic train of impulses is carried out delay process, make synchronous reception speckle signals spended time the shortest.The difference of the amount of delay when carrying out delay process according to current measuring point and adjacent measuring point can be confirmed the phase differential of the current relatively measuring point of adjacent measuring point, the just phase place of adjacent measuring point.
As shown in Figure 8, employed software processes process is following:
(4.1) the focus ultrasonic probe is focused on the current measuring point in the surface of object under test under water as benchmark; Regulate trigger repetition rate, make it identical with the object vibration frequency, it is consistent that its process and the object vibration frequency of Fig. 4 are confirmed shown in the software, on this basis, and entering process (4.2);
(4.2) the triggering time-delay τ of increase chronotron, τ=k Δ τ; Δ τ is required to confirm that its span is 0.005 microsecond to 0.1 microsecond by measuring error for time-delay step-length, its size; K is the time-delay number of times that progressively increases, and k is continuous positive integer, its initial value k=1;
(4.3) the speckle signals waveform after will delaying time carries out square operation; And calculate subscript k in its center-of-gravity value
on time domain represent the to delay time sequence number of back waveform, it is consistent with the number of times k value of delaying time; The current measuring point of subscript 1 expression in
.
will change along with the increase of time-delay number of times k;
(4.4) progressively increase the k value; Whether judge
is minimum value; If not, then enter into process (4.2) again; If, entering process (4.5);
(4.5) record
K value during for minimum value, k=k
1;
(4.6) translation ultrasonic probe, make it to focus on the adjoining adjacent measuring point of current measuring point on;
(4.7) progressively increase the triggering time-delay τ of chronotron; The time-delay step-length is Δ τ; Speckle waveform after the time-delay is carried out square operation; And the subscript of calculating in its center-of-gravity value
on time domain representes adjacent measuring point,
will change along with the increase of time-delay number of times k;
Whether (4.8) judge
is minimum value; If not, then enter into process (4.7) again; If, entering process (4.9);
(4.9) record
K value during for minimum value, k=K
2
(4.10) according to K
1And K
2Value can be calculated the poor of adjacent measuring point and current measuring point vibration phase
Wherein f is the vibration frequency of current measuring point.
The 5th step repetition the 3rd goes on foot, and confirms the amplitude of the another measuring point of the contiguous adjacent measuring point in vibration object surface;
The 6th step constantly repeated for the 4th and the 5th step, confirmed the phase place and the amplitude of vibration object surface different measuring points under water successively.
As shown in Figure 9, ultrasound speckle of the present invention steady-state vibration measurement mechanism under water comprises pulse signal generator 1, chronotron 2; Power amplifier 3, focus ultrasonic probe 4, vibrating object 5 under water; Voltage amplifier 6, digital storage oscilloscope 7, microcomputer 8 and three-dimensional electronic control translation stage 9.Interconnect between them as follows: pulse signal generator 1 is connected with cable with the interface of focus ultrasonic probe 4 through chronotron 2, power amplifier 3 successively; The interface of focus ultrasonic probe 4 is implemented the speckle signals data transmission through voltage amplifier 6, digital storage oscilloscope 7 with microcomputer 8 successively again and is connected; Pulse signal generator 1 is implemented control linkage with microcomputer 8 and digital storage oscilloscope 7 respectively again; Focus ultrasonic probe 4 is connected on the three-dimensional electronic control translation stage 9, implements the translation control linkage with microcomputer 8 again.
The action function of each instrument and parts is following in the measurement mechanism: pulse signal generator 1 produces tens of nanoseconds of a series of pulsewidths; The hundreds of microvolts of amplitude; Repetition frequency is adjustable needle pattern electric pulse in several hertz to thousands of hertz, and the adjusting of its repetition frequency receives microcomputer 8 controls.The electric pulse that is produced inputs to chronotron 2 and digital storage oscilloscope 7 respectively, comes to accept respectively to trigger delay process constantly and the scan-synchronized control of implementing digital storage oscilloscope 7.It is to make by oneself in 0.005 microsecond to 0.1 microsecond that step-length is regulated in the time-delay of chronotron 2, and its time-delay is regulated and received microcomputer 8 controls.After the electric pulse that chronotron 2 is exported inputs to power amplifier 3, export focus ultrasonic probe 4 again to.Focus ultrasonic probe 4 is encouraged by the electric pulse after the power amplification; Launch the ultrasonic pulse string of length for the number microsecond; The centre frequency of ultrasonic pulse string and nominal probe frequency are consistent; The electric pulse repetition frequency that its repetition frequency and pulse signal generator produce is consistent, and it takes place constantly consistent with the electric pulse triggering of chronotron 2 adjustings constantly.After the focus ultrasonic that focus ultrasonic probe 4 is launched was incident on the rough surface of vibrating object 5 in the water, it was 4 receptions of same focus ultrasonic probe that its lip-deep scattering wave is interfered formed ultrasound speckle each other, inputs to voltage amplifier 6 then.Speckle signals inputs to after voltage amplifier 6 amplifies carries out Signal Pretreatment, sampling and quantification in the digital storage oscilloscope 7, input to then in the microcomputer 8 store, computing and output result.In addition; Microcomputer 8 sends and controls signal to three-dimensional electronic control translation stage 9; Make its focus ultrasonic that connects probe 4 along making step motion on two quadrature sides that are parallel to vibrating object 5 surfaces under water and the direction perpendicular to vibrating object 5 surfaces under water; To carry out location and scanning, its step-length is to make by oneself in 0.01 millimeter to 1 millimeter.
The steady-state vibration measurement mechanism is following to the operating process of steady-state vibration thing vibration frequency, amplitude and phase measurement under water under water to use ultrasound speckle of the present invention:
(I) testee under water remains static; Perpendicular to placing focus ultrasonic probe 4 on the vibrating object surface direction under water; Regulate three-dimensional electronic control translation stage 9 through microcomputer 8 focus ultrasonic probe 4 is scanned in water, the surface profile height when traditional pulse echo method confirms that tested vibration object is static in the using ultrasound Non-Destructive Testing.
The three-dimensional electronic control translation stage 9 of (II) adjusting makes the focus ultrasonic of focus ultrasonic probe 4 emissions on the current measuring point on vibration object 5 surfaces.Through microcomputer 8 from small to large the repetition frequency of stepping regulating impulse signal generator 1 pulse of exporting to certain maximal value; The frequency measurement software judgement as shown in Figure 4 when flow process in the microcomputer 8 remained unchanged by the center of gravity on its time domain of ultrasound speckle signal of digital storage oscilloscope 7 synchronous recordings; Ultrasound speckle waveform on the promptly corresponding display screen is resident when motionless; The maximal value of the repetition frequency of the pulse of exporting this moment is exactly the vibration frequency of the body surface of surveying, and microcomputer 8 is noted this frequency values automatically.
(III) regulated the triggering moment that chronotron 2 outputs to the pulse excitation signal of focus ultrasonic probe through microcomputer 8; Judge focus ultrasonic probe 4 when the amplitude measurement software as shown in Figure 7 of flow process in the microcomputer 8 and be respectively the shortest and the longest from the time that emission ultrasonic pulse string is experienced during receive speckle signals; Be that the ultrasound speckle signal of 7 synchronous recordings of digital storage oscilloscope resides on the oscillograph 7 display screen time shafts on the ultra-Left side and ultra-Right side position; According to the two mistiming, microcomputer 8 calculates the amplitude of measuring point vibration.
(IV) keep focus ultrasonic probe 4 from emission ultrasonic pulse string to receiving time of being experienced during the speckle signals on the current measuring point of tested object plane for the shortest, promptly the ultrasound speckle signal of 7 synchronous recordings of digital storage oscilloscope resides on the oscillograph 7 display screen time shafts on the ultra-Left side position.Control three-dimensional electronic control translation stage 9 through microcomputer 8, focusing probe 4 is focused on the adjacent measuring point on vibration object 5 surfaces.Carry out delay operation through 8 pairs of chronotrons of microcomputer 2; When the phase measurement software as shown in Figure 8 of flow process in the microcomputer 8 judge focus ultrasonic probe 4 from emission ultrasonic pulse string to receiving time of being experienced during the speckle signals on the adjacent measuring point of tested object plane for the shortest, promptly the ultrasound speckle signal on the adjacent measuring point of 7 synchronous recordings of digital storage oscilloscope resides on the oscillograph 7 display screen time shafts on the ultra-Left side position.The mistiming that chronotron 2 is regulated in microcomputer 8 these processes of record, calculate the vibration phase difference of adjacent measuring point with respect to current measuring point.
(V) repeating step (III) is measured the amplitude of adjacent measuring point.
(VI) repeating step (IV) and (V) measure the three, four successively ... The phase place of each measuring point and amplitude, the vibration frequency of each measuring point is identical.
Those skilled in the art will readily understand; The above is merely preferred embodiment of the present invention; Not in order to restriction the present invention, all any modifications of within spirit of the present invention and principle, being done, be equal to and replace and improvement etc., all should be included within protection scope of the present invention.
Claims (6)
1. ultrasound speckle steady-state vibration measuring method under water is characterized in that, this method comprises the steps:
The 1st step focused on the ultrasonic pulse string on the current measuring point to vibrating object to be measured surface repeat its transmission under water;
The 2nd step was confirmed the object vibration frequency according to the stable case of the object plane speckle signals of the vibrating object to be measured that receives;
The 3rd step was further carried out delay process to the focus supersonic train of impulses of emission, and the shortest and maximum duration was poor according to synchronous reception speckle signals spends, confirmed the amplitude of the surperficial current measuring point of vibration object;
The 4th step, to its surperficial current measuring point repeat its transmission focus supersonic train of impulses, the line delay of going forward side by side was handled, and was the shortest up to synchronous reception speckle signals spended time according to the vibration frequency of vibrating object to be measured under water; Again ultrasonic probe is focused on the adjacent measuring point that vibrating object to be measured surface is adjacent to current measuring point under water, also adjacent measuring point repeat its transmission focus supersonic train of impulses is carried out delay process, make synchronous reception speckle signals spended time the shortest; The difference of the amount of delay when carrying out delay process according to two measuring points is confirmed the phase differential of the current relatively measuring point of adjacent measuring point, the i.e. phase place of adjacent measuring point;
The 5th goes on foot with this adjacent measuring point as current measuring point;
The 6th step constantly repeated for the 3rd to the 5th step, confirmed the phase place and the amplitude of vibration object surface different measuring points under water successively.
2. ultrasound speckle according to claim 1 steady-state vibration measuring method under water is characterized in that, in the 2nd step, according to following process judgment whether signal stabilization and computing object vibration frequency:
(2.1) the repetition frequency F of the electric pulse of some triggering focus ultrasonics probe is set, F is lower than the estimated frequency of object vibration, or gets one smaller or equal to 0.5 hertz value;
(2.2) N that successively focus ultrasonic probe continuous synchronization is repeated to receive
1Individual speckle signals is sampled, and its sampling period is T
S
(2.3) calculate N respectively
1The centre of gravity place G of the square value of individual speckle signals waveform on time domain
i, i representes the sequence number of speckle signals, i=1, and 2 ..., N
1
(2.4) the maximal value max|G of the difference of any 2 centre of gravity places in the above-mentioned speckle signals of judgement
m-G
n| (m=1,2 ... .N
1; N=1,2 ... N
1; M ≠ n) whether less than N
2Sampling period T doubly
SIf,, expression signal is stable, then gets into next process (2.5); If not, expression signal is unstable, then gets into process (2.7); M, n represent the sequence number of two different centre of gravity places, N
2Be positive integer;
(2.5) write down this repetition frequency F value and be F
j, get into process (2.6) simultaneously; The sequence number of the repetition frequency of getting when the j expression signal is stablized, its initial value are 1;
(2.6) stepping increases repetition frequency F value, gets step-length according to error requirements and gets into process (2.2) once more for
;
(2.7) stepping increases repetition frequency F value, gets step-length according to error requirements and after this will get into process (2.8) for certain value
;
(2.8) the maximum estimated value F of object vibration frequency is set
The upper limit, whether the frequency value F after judgement increases progressively is greater than F
The upper limitIf,, get into step (2.9); If not, then get into process (2.2);
(2.9) with F
jMaximal value as the object vibration frequency values.
3. ultrasound speckle according to claim 1 and 2 steady-state vibration measuring method under water is characterized in that, in the 3rd step, its processing procedure is following:
(3.1) the triggering time-delay τ of increase chronotron, τ=k Δ τ, the time-delay step-length is Δ τ, and k is the time-delay number of times that progressively increases, and its initial value is k=1;
(3.2) the speckle signals waveform after will delaying time carries out square operation, and calculates its center-of-gravity value G on time domain
k
(3.3) make k=k+1, repeating step (3.1) and (3.2) are up to definite G
kObtain minimum value, get into step (3.4) then;
(3.4) record G
kWaveform sequence number k value during for minimum value, k=K
1
(3.5) increase the triggering time-delay τ of chronotron again, τ=k Δ τ; Make k=K
1+ 1;
(3.6) the speckle signals waveform after will delaying time carries out square operation,, calculate its center-of-gravity value G on time domain
k, G
kTo become big along with the increase of time-delay;
(3.7) make k=k+1, repeating step (3.5) and (3.6) are up to definite G
kObtain maximal value, get into step (3.8) then;
(3.8) record G
kWaveform sequence number k value during for maximal value, k=K
2;
(3.9) according to K
1And K
2Value is calculated the measuring point amplitude A, A=V (K
2-K
1) Δ τ, V is ultrasonic velocity of propagation in water.
4. ultrasound speckle according to claim 5 steady-state vibration measuring method under water is characterized in that, in the 4th step, its processing procedure is following:
(4.1) the focus ultrasonic probe is focused on the current measuring point in the surface of object under test under water as benchmark; Regulate trigger repetition rate, make it identical with the object vibration frequency;
(4.2) the triggering time-delay τ of increase chronotron, τ=k Δ τ; Δ τ is the time-delay number of times that progressively increases for time-delay step-length, k, the initial value k=1 of k;
(4.3) the speckle signals waveform after will delaying time carries out square operation, and calculates its center-of-gravity value
on time domain
(4.4) progressively increase the k value; Whether judge
is minimum value; If not, then enter into process (4.2) again; If, entering process (4.5);
(4.5) record
K value during for minimum value, k=K
1;
(4.6) translation ultrasonic probe makes it to focus on the adjacent measuring point of contiguous body surface;
(4.7) progressively increase the triggering time-delay τ of chronotron; The time-delay step-length is Δ τ; Speckle waveform after the time-delay is carried out square operation, and calculate its center-of-gravity value
on time domain
Whether (4.8) judge
is minimum value; If not, then enter into process (4.7) again; If, entering process (4.9);
(4.9) record
K value during for minimum value, k=K
2
(4.10) according to K
1, and K
2Value is calculated the poor of two measuring point vibration phases
Wherein f is the vibration frequency of current measuring point.
5. ultrasound speckle according to claim 4 steady-state vibration measuring method under water is characterized in that, in the 2nd step,
Span be 0.01 hertz to 0.1 hertz, F
The upper limitSpan be 10 hertz to 2000 hertz.
6. ultrasound speckle steady-state vibration measurement mechanism under water is characterized in that this device comprises pulse signal generator, chronotron, power amplifier, focus ultrasonic probe, voltage amplifier, digital storage oscilloscope, microcomputer and three-dimensional electronic control translation stage; Pulse signal generator is connected with cable with the interface of focus ultrasonic probe through chronotron, power amplifier successively; The interface of focus ultrasonic probe is implemented the speckle signals data transmission through voltage amplifier, digital storage oscilloscope with microcomputer successively again and is connected; Pulse signal generator is implemented control linkage with microcomputer and digital storage oscilloscope respectively again; The focus ultrasonic probe is connected on the three-dimensional electronic control translation stage, implements translation with microcomputer again and is connected with positioning control.
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2012
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