CN103149383B - Structure impact zone image alarm method based on number sequence and time reversal - Google Patents
Structure impact zone image alarm method based on number sequence and time reversal Download PDFInfo
- Publication number
- CN103149383B CN103149383B CN201310048298.9A CN201310048298A CN103149383B CN 103149383 B CN103149383 B CN 103149383B CN 201310048298 A CN201310048298 A CN 201310048298A CN 103149383 B CN103149383 B CN 103149383B
- Authority
- CN
- China
- Prior art keywords
- signal
- array
- serial
- impact
- impulse response
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000000034 method Methods 0.000 title claims abstract description 57
- 230000004044 response Effects 0.000 claims abstract description 91
- 238000012544 monitoring process Methods 0.000 claims abstract description 46
- 238000003384 imaging method Methods 0.000 claims abstract description 15
- 230000035939 shock Effects 0.000 claims description 54
- 230000000630 rising effect Effects 0.000 claims description 25
- 238000005259 measurement Methods 0.000 claims description 15
- 239000011159 matrix material Substances 0.000 claims description 13
- 239000000203 mixture Substances 0.000 claims description 6
- 238000005070 sampling Methods 0.000 claims description 6
- 230000015572 biosynthetic process Effects 0.000 claims description 5
- 230000008569 process Effects 0.000 claims description 5
- 230000036541 health Effects 0.000 abstract description 6
- 238000003786 synthesis reaction Methods 0.000 abstract description 3
- 230000008901 benefit Effects 0.000 abstract description 2
- 238000005516 engineering process Methods 0.000 abstract description 2
- 238000003491 array Methods 0.000 abstract 5
- 238000010226 confocal imaging Methods 0.000 abstract 2
- 239000002131 composite material Substances 0.000 description 8
- 238000010586 diagram Methods 0.000 description 7
- 238000012423 maintenance Methods 0.000 description 5
- 238000012360 testing method Methods 0.000 description 3
- 230000003750 conditioning effect Effects 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000009466 transformation Effects 0.000 description 2
- NAWXUBYGYWOOIX-SFHVURJKSA-N (2s)-2-[[4-[2-(2,4-diaminoquinazolin-6-yl)ethyl]benzoyl]amino]-4-methylidenepentanedioic acid Chemical compound C1=CC2=NC(N)=NC(N)=C2C=C1CCC1=CC=C(C(=O)N[C@@H](CC(=C)C(O)=O)C(O)=O)C=C1 NAWXUBYGYWOOIX-SFHVURJKSA-N 0.000 description 1
- 206010061245 Internal injury Diseases 0.000 description 1
- 239000011157 advanced composite material Substances 0.000 description 1
- 230000003321 amplification Effects 0.000 description 1
- 230000002929 anti-fatigue Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 230000004807 localization Effects 0.000 description 1
- 208000020442 loss of weight Diseases 0.000 description 1
- 238000005272 metallurgy Methods 0.000 description 1
- 238000009659 non-destructive testing Methods 0.000 description 1
- 238000003199 nucleic acid amplification method Methods 0.000 description 1
- 230000001902 propagating effect Effects 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 230000001360 synchronised effect Effects 0.000 description 1
Landscapes
- Emergency Alarm Devices (AREA)
Abstract
The invention discloses a structure impact zone image alarm method based on number sequences and time reversal, belonging to the field of aerospace structure health monitoring technologies. The method comprises the following steps of: estimating the frequency bandwidth of impact response signal arrays according to number sequence arrays obtained by an impact monitoring system; constructing impact response characteristic signal arrays corresponding to the number sequence arrays by adopting sinusoidal-modulated narrowband signals; searching and imaging impact event occurring positions by adopting a phase-synthesis time-reversal confocal imaging method based on the constructed impact response characteristic signal arrays; and judging impact event occurring regions based on an error ellipse method according to the obtained images. The method has the advantages that the problem that the phase-synthesis time-reversal confocal imaging cannot be realized by relying on the number sequences is solved, and the application range of time-reversal-based impact monitoring methods is enlarged.
Description
Technical field
The present invention relates to a kind of based on Serial No. and the structural impact area image alarm method of time reversal, belong to aeronautic structure health monitoring technique field.
Background technology
Composite structure is widely used at each industrial circles such as Aero-Space, ground rail traffic, petrochemical industry metallurgy, has especially started to use advanced composite structure to reach the object of loss of weight and antifatigue more and more on military-civil aircraft.But, compound substance inevitably will bear the impact of various foreign body under arms in process, as bird hit, airport rubble etc., very easily cause the internal injury of composite structure and cause its mechanical property degradation, load-bearing capacity reduces, and even causes the entirety of structure destroy and lost efficacy.Therefore composite structure is carried out to on-line monitoring and the location of impact event, ensure safety of structure and reduce structural maintenance expense that there is urgent application demand.
Passive structure health monitor method can realize online Impact monitoring, the information such as Real-time Obtaining shock zone, position, and then utilize Non-Destructive Testing to detect further the shock zone obtained by passive structure monitoring method, greatly can shorten detection time, reduce maintenance cost.But for the Impact monitoring of large aerospace structure, to adopt No. 64 piezoelectric sensor monitoring impact signals, traditionally high-speed data acquisition test mode carries out monitor signal collection, system hardware adopts the signal of 64 commercial passage independent synchronization High Speed Analog data collecting cards and 64 passages to amplify conditioning device, additional this band needed for quantity hardware integrated unifies processor and the cabinet of control core, cause the height of test environment complexity and test macro debugging difficulty, system bulk and the problem such as weight is huge.But, for airborne equipment, require that the interpolation of this equipment can not cause excessive load-carrying burden to aircraft, and the area of the required monitoring of aircraft body structure is very large, the large-sized civil passenger plane C919 of development stage is particularly in as China, the passive monitoring system supporting No. 64 piezoelectric sensors is far from being enough, needs large-scale piezoelectric sensor array to meet the demands, but further increases again the volume and weight of monitoring system like this.So existing conventional passive structure health monitoring systems can not meet the requirement of Impact monitoring airborne equipment.
For the problems referred to above, over the past two years, a kind of large-scale sensor array impact monitoring system (hereinafter referred impact monitoring system) being applicable to airborne miniature digital formula was suggested and was progressively applied.This system is in order to meet the requirement of miniaturization and low-power consumption, outside piezoelectric sensor array is directly connected with intrasystem comparator array, the impulse response signal that piezoelectric sensor array exports is converted to Serial No. after comparator array, realize the warning of shock zone according to the feature of Serial No., thus eliminate the data acquisition of conventional passive structure health monitoring systems and the hardware of signal amplification conditioning.Therefore, this system possessed that volume is little, lightweight, low-power consumption, easy to install and use, monitored area large, can real-time response impact event effectively can store Serial No. corresponding to impulse response signal and impact multiple features such as alarming result.
Impact monitoring system, after obtaining Serial No., needs to be equipped with the function that shock zone alarm method accurately and effectively really could realize its monitoring impact event.For the orientation problem that composite structure impacts, the Impact monitoring method based on time reversal improves Signal-to-Noise because it has, the advantage such as frequency dispersion effect of automatic compensating signal obtains and studies widely.But the transport function that the method needs acquisition impact signal structurally to propagate, limits the application of the method.So, in recent years, a kind of impact imaging localization method based on phase measurements time-reversal focusing is suggested, the impulse response signal array of the piezoelectric sensor array that the method is obtained by passive structure health monitoring systems, the narrow band signal frequency content in impact signal velocity of propagation impact response signal is in the structure relied on to carry out synthetic focusing time reversal, the imaging of impact event can be realized and locate accurately, solving the problem of the Impact monitoring method dependence transport function based on time reversal.But the method needs could implement when obtaining impulse response signal at present, the simple digital sequence array relying on impact monitoring system to obtain cannot apply the method.Because impulse response signal is after being converted to Serial No., the information dropout of the signal frequency composition needed for phase measurements time-reversal focusing method.
Summary of the invention
It is a kind of based on Serial No. and the structural impact area image alarm method of time reversal that the present invention proposes, impulse response signal array cannot obtained, when can only obtain digital sequence array, imaging and Zone Alerts are carried out to impact event, for impact monitoring system provides one shock zone alarm method accurately and effectively.Play when the posterior maintenance of structure, the region that instruction impact event occurs, reduce and adopt lossless detection method to need the structural area of examinations, shortening maintenance time and reduce the object of maintenance cost.
The present invention adopts following technical scheme for solving its technical matters:
Based on Serial No. and the structural impact area image alarm method of time reversal, comprise the steps:
(1) obtain digital sequence array according to impact monitoring system, estimate the frequency bandwidth of impulse response signal array;
(2) the shock response characteristic signal array that Sine Modulated narrow band signal structure digital sequence array is corresponding is adopted;
(3) based on the shock response characteristic signal array of structure, phase measurements time-reversal focusing formation method is adopted to carry out search imaging to the position that impact event occurs;
(4) according to the image obtained, differentiate based on error ellipse method the region that impact event occurs.
In described step (1), the method for estimation of the frequency bandwidth of impulse response signal array, comprises the steps:
if by
the Serial No. composition digital sequence array of individual passage, calculates the signal frequency corresponding to each rising edge in the Serial No. of single passage
, expression formula is as follows, wherein
represent the
in the Serial No. of individual passage
the duration of individual rising edge:
；
get the Frequency Estimation result of the impulse response signal that the minimum value in the signal frequency corresponding to rising edge is answered as single passage numeral sequence pair, expression formula is as follows, wherein
represent the
the rising edge number contained in the Serial No. of individual passage:
；
get
minimum value in the frequency of the impulse response signal that the Serial No. of individual passage is corresponding, as the frequency bandwidth lower limit estimated result of impulse response signal array, is got
mean value in the frequency of the impulse response signal that the Serial No. of individual passage is corresponding is as the frequency bandwidth upper limit estimated result of impulse response signal array, and expression formula is as follows:
，
；
finally obtain impulse response signal array frequency bandwidth estimated result [
,
], described in
for being greater than the natural number of zero.
Described step (2) is for constructing the centre frequency of the Sine Modulated narrow band signal of shock response characteristic signal array corresponding to digital sequence array
, periodicity
, the time
tspan:
extremely
, the time interval is
, wherein
f s for gathering the sampling rate of Serial No..
In the phase measurements time-reversal focusing imaging process of described step (3), searching position (x, the y) place of shock response characteristic signal array in monitored area time reversal phase measurements signal calculation expression as follows:
Wherein,
represent the
the energy envelope of the shock response characteristic signal that the Serial No. of individual passage is corresponding,
represent the velocity of propagation of impact signal,
represent the time span that signal is sampled,
represent signal propagation distance.
Based on error ellipse method, described step (4) differentiates that the method in the region that impact event occurs is as follows:
first find in the pixel matrix of shock zone image, coordinate corresponding to pixel value maximum of points be (
,
), and set threshold value
.
next is found out pixel value in pixel matrix and is more than or equal to setting threshold value
coordinate corresponding to pixel value point (
,
), amount to
individual coordinate points,
the pixel value being more than or equal to setting threshold value for pixel value is always counted;
then this is calculated
individual coordinate points and coordinate (
,
) the mean square deviation of transverse and longitudinal coordinate, expression formula is as follows:
，
；
finally with coordinate (
,
) centered by, transverse axis long 2
, the longitudinal axis long 2
draw error ellipse, using the region that this error ellipse is encircled a city as final impact event alarm region.
Beneficial effect of the present invention is as follows:
(1) the present invention is that the large-scale sensor array impact monitoring system being applicable to airborne miniature digital formula provides a kind of shock zone method of discrimination.
(2) accuracy rate that the shock zone that the present invention realizes is reported to the police is high, can realize the generation area warning of impact event with the accuracy being greater than 95%.
(3) the invention solves the problem relying on Serial No. cannot realize the imaging of phase measurements time-reversal focusing, extend the range of application of the Impact monitoring method based on time reversal.
Accompanying drawing explanation
Fig. 1 is the flow chart of steps based on Serial No. and the structural impact area image alarm method of time reversal.
Fig. 2 (a) is real impulse response signal array schematic diagram; The digital sequence array schematic diagram that Fig. 2 (b) obtains for impact monitoring system.
The digital sequence array schematic diagram that Fig. 3 (a) obtains for impact monitoring system; Fig. 3 (b) is the shock response characteristic signal array schematic diagram of structure.
Fig. 4 is shock response characteristic signal array energy envelope schematic diagram.
Fig. 5 is signal time inverted phase synthesis schematic diagram.
Fig. 6 is shock zone imaging results and impact event alarm region schematic diagram.
Embodiment
Below in conjunction with accompanying drawing, the invention is described in further details.
The present invention is a kind of based on Serial No. and the structural impact area image alarm method of time reversal.The basic thought of the method is: first according to the digital sequence array that impact monitoring system obtains, and estimates the frequency bandwidth of impulse response signal array; Secondly, the shock response characteristic signal array that Sine Modulated narrow band signal structure digital sequence array is corresponding is adopted; Then, based on the shock response characteristic signal array of structure, adopt phase measurements time-reversal focusing formation method to carry out search imaging to the position that impact event occurs; Finally, according to the image obtained, differentiate based on error ellipse method the region that impact event occurs, thus realize the warning of shock zone.The implementation step of method is as follows:
(1) impact monitoring system is utilized to obtain digital sequence array
When composite structure be subject to external object impact time, this impact event cause impact signal in the structure and with impacts generation position for propagating to surrounding source position.Be arranged in structural piezoelectric sensor array to experience impact signal by direct piezo electric effect and export impulse response signal array later.Impulse response signal array directly transfers to the comparator array of impact monitoring system inside by the signal-transmitting cable of piezoelectric sensor array, and is converted into corresponding digital sequence array.If structurally arrange
the piezoelectric sensor array of individual piezoelectric sensor composition Impact monitoring, each piezoelectric sensor and impact monitoring system inside have
a comparer of the comparator array of individual comparer connects, and is formed
individual Impact monitoring passage, then impact monitoring system can obtain by
the digital sequence array of the Serial No. composition of individual passage.If the sampling rate that impact monitoring system gathers Serial No. is
f s , the sampling length of Serial No. is
r, then the size of digital sequence array is
n×
r.
(2) frequency bandwidth of impulse response signal array is estimated
based on the Serial No. of each passage in digital sequence array, estimate the frequency bandwidth of the impulse response signal that single port number word sequence pair is answered
, wherein
represent the
individual passage, method is as follows:
First, if
in the Serial No. of individual passage, the number of rising edge (an effective rising edge comprises a rising edge and a negative edge) is
, calculate the signal frequency corresponding to each rising edge
, wherein
represent the
individual rising edge, expression formula is as follows:
（1）
Wherein,
represent the
in the Serial No. of individual passage
the duration of individual rising edge.
Then, this is got
minimum value in signal frequency corresponding to individual rising edge is as
the Frequency Estimation result of the impulse response signal that individual passage numeral sequence pair is answered, expression formula is as follows:
（2）
get
minimum value in the frequency of the impulse response signal that the Serial No. of individual passage is corresponding, as the frequency bandwidth lower limit estimated result of impulse response signal array, is got
mean value in the frequency of the impulse response signal that the Serial No. of individual passage is corresponding is as the frequency bandwidth upper limit estimated result of impulse response signal array, and expression formula is as follows:
（3）
（4）
Finally obtain impulse response signal array frequency bandwidth estimated result [
,
], described in
for being greater than the natural number of zero.
(3) shock response characteristic signal array is constructed
calculate the moment that first rising edge of the Serial No. of each passage in digital sequence array is corresponding
.
according to the frequency bandwidth estimated result of impulse response signal array, utilize Sine Modulated narrow band signal, structure shock response characteristic signal, the calculation expression of Sine Modulated narrow band signal is as follows:
（5）
Wherein,
represent the centre frequency of Sine Modulated narrow band signal,
represent the periodicity of the sine wave that Sine Modulated narrow band signal comprises.
with
calculation expression as follows:
（6）
（7）
The span of the time t in expression formula (5) is:
extremely
, the time interval is
(8)
if the moment that the maximal value of the absolute value of the voltage of the Sine Modulated narrow band signal of above-mentioned structure is corresponding is
, the moment corresponding according to first rising edge of the Serial No. of each passage
, the time span constructing the Serial No. of each passage corresponding is
r/
f s shock response characteristic signal
, expression formula is as follows:
（9）
Finally, the shock response characteristic signal that the Serial No. of each passage of structure is corresponding constitutes shock response characteristic signal array corresponding to digital sequence array
.
(4) phase measurements time-reversal focusing imaging
obtain signal energy envelope:
Impact response characteristic signal array
carry out continuous Complex Wavelet Transform, and to transformation results delivery value, obtain the energy envelope of shock response characteristic signal array
.
signal time inverted phase is synthesized:
First, suppose the position that in monitored area, (x, y) occurs for impact event, calculate it and be respectively relative to the distance of each piezoelectric sensor
,
,
,
, substitute into phase measurements signal time reversal that expression formula (10) calculates this position shock response characteristic signal array, expression formula is as follows:
（10）
Wherein,
represent the
the energy envelope of the shock response characteristic signal that the Serial No. of individual passage is corresponding,
represent the velocity of propagation of impact signal,
represent the time span that signal is sampled,
represent signal propagation distance.
The energy value of the composite signal calculated is as the pixel value of this position, and expression formula is as follows:
（11）
Then, transverse and longitudinal coordinate changes with Δ x and Δ y respectively, travels through whole monitored area.Obtain each pixel value being traversed position according to said process, form pixel matrix
h.
computer image genration:
After obtaining being traversed in monitored area the pixel matrix of position, be normalized it, expression formula is as follows:
（12）
By normalized pixel matrix
, the imaging results just obtaining shock zone is shown according to the mode of image.
(5) shock zone is differentiated based on error ellipse
if in pixel matrix, coordinate corresponding to pixel value maximum of points be (
,
), and set threshold value
.
find out pixel value in pixel matrix to be more than or equal to
coordinate corresponding to pixel value point (
,
), if amount to
individual coordinate points,
the pixel value being more than or equal to setting threshold value for pixel value is always counted.
calculate this
individual coordinate points and coordinate (
,
) the mean square deviation of transverse and longitudinal coordinate, expression formula is as follows:
，
（13）
with coordinate (
,
) centered by, transverse axis long 2
, the longitudinal axis long 2
draw error ellipse, using the region that this error ellipse is encircled a city as final impact event alarm region, thus realize the image alarm of shock zone.
Based on Serial No. and the structural impact area image alarm method steps flow chart of time reversal as shown in Figure 1.The method, first according to the digital sequence array that impact monitoring system obtains, estimates the frequency bandwidth of impulse response signal array; Secondly, the shock response characteristic signal array that Sine Modulated narrow band signal structure digital sequence array is corresponding is adopted; Then, based on the shock response characteristic signal array of structure, adopt phase measurements time-reversal focusing formation method carry out search to the position that impact event occurs and represent in the form of images; Finally, according to the image obtained, differentiate based on error ellipse method and realize the warning of shock zone with image mode in the region that impact event occurs.
(1) impact monitoring system is utilized to obtain digital sequence array
Structurally arrange the piezoelectric sensor array of 4 piezoelectric sensor composition Impact monitorings, the area of monitored area is 1300mm × 1300mm.When impact event occurs, piezoelectric sensor exports impulse response signal array, impulse response signal array directly transfers to the comparator array of impact monitoring system inside by the signal-transmitting cable of piezoelectric sensor array, and is converted into corresponding digital sequence array, as shown in Figure 2.The sampling rate that impact monitoring system gathers Serial No. is
f s =1MHz, the sampling length of Serial No. is
r=5000 data points.In actual applications, impact monitoring system cannot obtain impulse response signal as shown in Figure 2 (a) shows, can only get the Serial No. shown in Fig. 2 (b).Present embodiment is in order to the impulse response signal array of vivider explanation piezoelectric sensor is converted to digital sequence array by impact monitoring system, provides so the impulse response signal array shown in Fig. 2 (a) is the synchronous acquisition using oscillograph to carry out.
(2) frequency bandwidth of impulse response signal array is estimated
After obtaining digital sequence array, the signal frequency that each rising edge calculated in the Serial No. of each passage according to expression formula (1) is corresponding, then gets the Frequency Estimation result of the impulse response signal that the minimum value in the signal frequency corresponding to rising edge is answered as single passage numeral sequence pair.For the Serial No. of piezoelectric sensor 1 to 4 correspondence, 14 rising edges are had in this Serial No., calculate the signal frequency that each rising edge is corresponding, the Frequency Estimation result of the impulse response signal that the minimum value of getting these 14 frequency values is answered as this passage numeral sequence pair is 3816Hz.The Frequency Estimation result of impulse response signal corresponding to the Serial No. of piezoelectric sensor 1 to 4 correspondence can be obtained according to this method, be respectively
=2890Hz,
=3311Hz,
=4716Hz,
=3816Hz.Getting minimum value is
=2890Hz, average into
=3683Hz.Finally obtain frequency bandwidth estimated result [2890, the 3683] Hz of impulse response signal array.
(3) shock response characteristic signal array is constructed
First the moment that first rising edge of the Serial No. of each passage in digital sequence array is corresponding is calculated, in the digital sequence array that the impact monitoring system as shown in Fig. 3 (a) obtains
extremely
; Then expression formula (5) is adopted to construct Sine Modulated narrow band signal, wherein
=3287Hz,
n=8; Secondly the time span that constructs the Serial No. of each passage corresponding is 5 × 10 moment corresponding according to first rising edge of the Serial No. of each passage
-3the shock response characteristic signal of s
; The shock response characteristic signal that the Serial No. of each passage constructed the most at last is corresponding forms shock response characteristic signal array corresponding to digital sequence array
, shown in the shock response characteristic signal array of structure as shown in Figure 3 (b).
(4) phase measurements time-reversal focusing imaging
To shock response characteristic signal array as shown in Figure 3 (b)
carry out continuous Complex Wavelet Transform, and to transformation results delivery value, obtain the energy envelope of shock response characteristic signal array
, as shown in Figure 4.
As shown in Figure 5, the area according to monitored area is 1300mm × 1300mm, sets the traversal scope as-650 to 650, Δ x=20 of X-direction, sets the traversal scope as-650 to 650, Δ y=20 of Y direction.
Suppose the position that in monitored area, (x, y) occurs for impact event, calculate (x, y) and be respectively relative to the distance of each piezoelectric sensor
,
,
,
, substitute into phase measurements expression formula time reversal (10) and calculate this position shock response characteristic signal array time inverted phase composite signal.The energy value of composite signal adopting expression formula (11) to calculate is as the pixel value of this position.Then, transverse and longitudinal coordinate changes with Δ x and Δ y respectively, travels through whole monitored area, obtains each pixel value being traversed position according to said process, forms pixel matrix
h, then adopt expression formula (12) to be normalized it.By normalized pixel matrix
, show the imaging results just obtaining shock zone according to the mode of image, as shown in Figure 6.
(5) shock zone is differentiated based on error ellipse method
In pixel matrix, coordinate corresponding to pixel value maximum of points is (450 ,-170), and sets threshold value
tH=0.5.Find out pixel value in pixel matrix be more than or equal to 0.5 coordinate corresponding to pixel value point (
,
), amount to
k=1782 coordinate points.Expression formula (13) is adopted to calculate this
kthe mean square deviation of the transverse and longitudinal coordinate of individual coordinate points and coordinate (325 ,-325), is respectively
=209,
=241.
Centered by coordinate (450 ,-170), transverse axis long 418, the longitudinal axis long 482 draws error ellipse, as shown in Figure 6.Using the region that this error ellipse is encircled a city as final impact event alarm region, thus realize the image alarm of shock zone.
Claims (1)
1., based on Serial No. and the structural impact area image alarm method of time reversal, it is characterized in that, comprise the steps:
(1) obtain digital sequence array according to impact monitoring system, estimate the frequency bandwidth of impulse response signal array;
(2) according to the frequency bandwidth estimated result of impulse response signal array, the shock response characteristic signal array that Sine Modulated narrow band signal structure digital sequence array is corresponding is adopted;
(3) based on the shock response characteristic signal array of structure, phase measurements time-reversal focusing formation method is adopted to carry out search imaging to the position that impact event occurs;
(4) according to the image obtained, differentiate based on error ellipse method the region that impact event occurs;
In described step (1), the method for estimation of the frequency bandwidth of impulse response signal array, comprises the steps:
if by
the Serial No. composition digital sequence array of individual passage, calculates the signal frequency corresponding to each rising edge in the Serial No. of single passage
, expression formula is as follows, wherein
represent the
in the Serial No. of individual passage
the duration of individual rising edge:
；
get the Frequency Estimation result of the impulse response signal that the minimum value in the signal frequency corresponding to rising edge is answered as single passage numeral sequence pair, expression formula is as follows, wherein
represent the
the rising edge number contained in the Serial No. of individual passage:
；
get
minimum value in the frequency of the impulse response signal that the Serial No. of individual passage is corresponding, as the frequency bandwidth lower limit estimated result of impulse response signal array, is got
mean value in the frequency of the impulse response signal that the Serial No. of individual passage is corresponding is as the frequency bandwidth upper limit estimated result of impulse response signal array, and expression formula is as follows:
，
；
finally obtain impulse response signal array frequency bandwidth estimated result [
,
], described in
for being greater than the natural number of zero;
The building method of the shock response characteristic signal array of described step (2), comprises the steps:
calculate the moment that first rising edge of the Serial No. of each passage in digital sequence array is corresponding
;
according to the frequency bandwidth estimated result of impulse response signal array, utilize Sine Modulated narrow band signal, structure shock response characteristic signal, the calculation expression of Sine Modulated narrow band signal is as follows:
Wherein,
represent the centre frequency of Sine Modulated narrow band signal,
represent the periodicity of the sine wave that Sine Modulated narrow band signal comprises;
According to the frequency bandwidth estimated result of impulse response signal array [
,
],
with
calculation expression as follows:
Time in the calculation expression of Sine Modulated narrow band signal
tspan be:
extremely
, the time interval is
Wherein
f s for gathering the sampling rate of Serial No.;
if the moment that the maximal value of the absolute value of the voltage of the Sine Modulated narrow band signal of above-mentioned structure is corresponding is
, the moment corresponding according to first rising edge of the Serial No. of each passage
, the time span constructing the Serial No. of each passage corresponding is
r/
f s shock response characteristic signal
, expression formula is as follows:
Finally, the shock response characteristic signal that the Serial No. of each passage of structure is corresponding constitutes shock response characteristic signal array corresponding to digital sequence array
;
In the phase measurements time-reversal focusing imaging process of described step (3), searching position (x, the y) place of shock response characteristic signal array in monitored area time reversal phase measurements signal calculation expression as follows:
Wherein,
represent the
the energy envelope of the shock response characteristic signal that the Serial No. of individual passage is corresponding,
represent the velocity of propagation of impact signal,
represent the time span that signal is sampled,
represent signal propagation distance;
Based on error ellipse method, described step (4) differentiates that the method in the region that impact event occurs is as follows:
first find in the pixel matrix of shock zone image, coordinate corresponding to pixel value maximum of points be (
,
), and set threshold value
;
next is found out pixel value in pixel matrix and is more than or equal to setting threshold value
coordinate corresponding to pixel value point (
,
), amount to
individual coordinate points,
the pixel value being more than or equal to setting threshold value for pixel value is always counted;
then this is calculated
individual coordinate points and coordinate (
,
) the mean square deviation of transverse and longitudinal coordinate, expression formula is as follows:
，
；
finally with coordinate (
,
) centered by, transverse axis long 2
, the longitudinal axis long 2
draw error ellipse, using the region that this error ellipse is encircled a city as final impact event alarm region.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310048298.9A CN103149383B (en) | 2013-02-07 | 2013-02-07 | Structure impact zone image alarm method based on number sequence and time reversal |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310048298.9A CN103149383B (en) | 2013-02-07 | 2013-02-07 | Structure impact zone image alarm method based on number sequence and time reversal |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN103149383A CN103149383A (en) | 2013-06-12 |
| CN103149383B true CN103149383B (en) | 2015-07-01 |
Family
ID=48547582
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201310048298.9A Active CN103149383B (en) | 2013-02-07 | 2013-02-07 | Structure impact zone image alarm method based on number sequence and time reversal |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN103149383B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103473441B (en) * | 2013-08-26 | 2016-06-29 | 南京航空航天大学 | Impact energy levels method of discrimination based on digital sequence array two dimensional character |
| CN112945442B (en) * | 2021-01-29 | 2022-07-22 | 南京航空航天大学 | Large-area structure impact imaging method based on piezoelectric-guided wave array |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101000325A (en) * | 2006-12-31 | 2007-07-18 | 南京航空航天大学 | Method for investigating failure connection of engineering structure by signal focus |
| CN102288346A (en) * | 2011-07-11 | 2011-12-21 | 南京航空航天大学 | Miniaturized digital large-scale sensor array impact monitoring system |
-
2013
- 2013-02-07 CN CN201310048298.9A patent/CN103149383B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101000325A (en) * | 2006-12-31 | 2007-07-18 | 南京航空航天大学 | Method for investigating failure connection of engineering structure by signal focus |
| CN102288346A (en) * | 2011-07-11 | 2011-12-21 | 南京航空航天大学 | Miniaturized digital large-scale sensor array impact monitoring system |
Non-Patent Citations (2)
| Title |
|---|
| A miniaturized composite impact monitor and its evaluation research;YUAN Shengfan et al.;《Sensors and actuators A》;20121231;第182-192页 * |
| A phase synthesis based time reversal focusing method for impact and damage imaging of complex composite structures;QIU Lei et al.;《4th international sympostium on NDTin aerospace- Ww.2.A.4》;20121231;第1-9页 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN103149383A (en) | 2013-06-12 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN101509949B (en) | Double-end asynchronous and parameter self-adapting fault distance measuring time-domain method for direct current transmission line | |
| CN106499957B (en) | A kind of pressure wave signal generator and in-pipeline detector real-time tracking localization method | |
| CN102680860B (en) | Automatic fault-point locating method for traveling-wave based fault location of high-voltage electric power lines | |
| CN106198924B (en) | Precarious rock mass monitoring system and its methods of risk assessment based on adaptive frequency acquisition | |
| CN102539107A (en) | Method for accurately synchronizing test signals of wind tunnel | |
| CN112525201B (en) | Underwater target tracking method based on electromagnetic field characteristic multi-information fusion | |
| CN108037410B (en) | Partial discharge ultrasonic positioning method and device based on controllable response power | |
| CN103487786B (en) | Structural impact wave-velocity-free positioning method based on two-dimensional linear arrays and spatial filters | |
| CN110570520A (en) | substation maintenance safety distance monitoring method based on SLAM | |
| CN108520227A (en) | A kind of Bridge Structural Damage localization method of the transfer entropy based on dual sensor information | |
| CN105702305A (en) | Multi-target three-dimensional dynamic tracking method of loose parts of nuclear power plant | |
| CN103149383B (en) | Structure impact zone image alarm method based on number sequence and time reversal | |
| CN105627978B (en) | A kind of rainy season Slip moinitoring method and system | |
| CN110608716A (en) | Substation maintenance safety distance monitoring method based on SLAM | |
| CN107179473B (en) | A kind of power transmission line fault locating method | |
| CN103076399B (en) | Knock scan-type damage detection for bridges positioning system | |
| CN104462803A (en) | Autonomous underwater robot fault identification method based on wavelet approximate entropy | |
| CN112363017A (en) | Line fault positioning method based on wavelet transformation | |
| CN102889896B (en) | Two-stage noise reduction method for impact monitoring digital sequence of composite structure | |
| CN108181313A (en) | A kind of device and method suitable for the detection of contact net running environment safe condition | |
| CN202770552U (en) | Continuous temperature-measuring device for aluminum electrolytic cell based on acoustic technique | |
| CN113687192B (en) | Method for collecting and positioning discharge signal of power transmission line | |
| CN103064067B (en) | Maneuvering weak target detecting and tracking integral variable rate sampling fast method | |
| CN205880942U (en) | High accuracy developments are from network deployment vehicle traveling data recorder | |
| CN114065487A (en) | Structure impact positioning method based on error function |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant |