CN101299034A - Acoustic emission system for monitoring construction collapse in fire and monitoring method thereof - Google Patents
Acoustic emission system for monitoring construction collapse in fire and monitoring method thereof Download PDFInfo
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- CN101299034A CN101299034A CNA2008100647622A CN200810064762A CN101299034A CN 101299034 A CN101299034 A CN 101299034A CN A2008100647622 A CNA2008100647622 A CN A2008100647622A CN 200810064762 A CN200810064762 A CN 200810064762A CN 101299034 A CN101299034 A CN 101299034A
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Abstract
The present invention provides a system for monitoring the emission of breakdown sound of the building structure in fire and a monitoring method thereof. The monitoring system is mainly composed of a sensing system, a signal amplification filtration system, a signal collecting system and a signal analysis and determination system which are connected in sequence through electric signal. The signal amplification filtration system is composed of a preamplifier, a signal filter and a main amplifier. The analysis judgment system is mainly composed of monitoring software and a display device. The invention determines whether the structure is in a safe state and instantly provides useful information for the fire fighter through analyzing the relationship between the acoustic emission parameter and the rupture and stability and the like of the structural element of building.
Description
(1) technical field
The invention belongs to the technical field of preventing and reducing natural disasters of buildings, be specifically related to construction collapse in fire acoustic emission monitoring technique.
(2) background technology
Acoustic emission, is promptly monitored and is estimated the whole destructive process of construction material in advance by acoustic emission all the time to be applied as purpose in the research in engineering field, thereby provides a kind of effective and dynamic monitoring method for the engineering field.
Past the and now research of acoustic emission is mainly concentrated on the generation of crackle in the base attribute, concrete of concrete material acoustic emission in the construction work and propagation law, concrete unstability pattern location technology, Kaiser effect mechanism and the aspects such as application in concrete material thereof with the relation between acoustic emission, crack defect.Along with development of science and technology, the research of concrete acoustic emission is also developed very fast, mainly show day by day deeply the research contents aspect of concrete acoustic emission, from the single shaft state to three Spindle Status, from the single factor analysis to the multiplicity etc.
But also do not have about building structure acoustic emission The Characteristic Study under the high temperature at present.
(3) summary of the invention
The object of the present invention is to provide a kind of acoustic emission system for monitoring construction collapse in fire and monitoring method thereof, the relation of the acoustic emission parameter when it passes through to analyze the building structure fire and building structural element fracture and stability etc. judges whether structure is in a safe condition.
Acoustic emission system for monitoring construction collapse in fire of the present invention is achieved in that it is mainly connected to form by sensor-based system, signal amplification filtering system, signal acquiring system and signal analysis judgement system electric signal successively, and signal amplifies filtering system and is made up of prime amplifier, signal filter and main amplifier; Analysis judgment system mainly is made up of monitoring software and display device.
Acoustic emission system for monitoring construction collapse in fire of the present invention also has some technical characterictics like this:
1, described sensor-based system is made up of waveguide rod and sensor.
Buildings issues out acoustic emission signal at high temperature action when fire, by sensor-based system signal is received, propagates, again by signal amplify filtering system to signal amplify, filtration and secondary amplify, then signal is handled, by analysis judgment system signal is analyzed and judged at last by signal acquiring processing system.Wherein, sensor-based system is made up of waveguide rod and sensor, to solve reception, the conducting problem of acoustic emission signal under the high temperature; Signal amplifies filtering system and is made up of prime amplifier, signal filter and main amplifier; Analysis judgment system mainly is made up of monitoring software and display device.
Building structure can produce the crack during fire under high temperature action, causes member structural instability destruction etc. to occur destroying and occurring.By setting up the relation between acoustic emission parameter and the configuration state, the state when utilizing acoustic emission monitoring system to the building structure fire is monitored, and whether the duty of understanding building structure safety, provides useful information for the fire fighter immediately.
The difficult problem that acoustic emission detection system was difficult to use when the use of the present invention by waveguide rod solved fire.On the basis of a large amount of experiments, by calculating the relation that burst and continuous signal and acoustic emission source position have been determined in simulation; Determined the relation of the structural outer variation that stored counts parameter (acoustie emission event sum, ring tale, gross energy, amplitude tale etc.) and inside configuration accumulated change are caused; Determined the relation of acoustic emission rate of change parameter (event count rate, Ring-down count rate, energy release rate etc.) with the structural cracks speed of development; And parameter attribute and the criterion of structure when approaching collapsing.
Monitoring method technical scheme of the present invention is:
(1), arranges calibrate AE sensor at the maximal bending moment place of buildings beam, plate, post and stress raiser (Gu Zhi Duan, steel construction connecting portion grade).Determine transducer spacing according to the wave propagation decay, determine structural elements measuring point quantity according to selected transducer spacing and member size.In time difference location, the pairing propagation attenuation of maximum sensor spacing should not and detect the poor of threshold value greater than predetermined minimum detection signal amplitude.In zone location, sensor array adopts planar delta.
(2) being connected of waveguide rod and probe, choose suitable steel screw rod, the steel screw rod is embedded in point position, spiral shell emits the top totally smooth with sand papering, contacts closely with probe, adopts the vacuum silicone grease as couplant.Because probe itself has very strong magnetic, waveguide rod is an iron, just in time can be coupled well.
(3) sensitivity of acoustic emission detection system is decided by sensitivity, transducer spacing and the setting of detection threshold of sensor.Wherein, threshold is set to its main may command factor.It is low more to detect threshold, and it is many more to record information, but is subject to interference of noise, therefore, detects threshold and done compromise selection between sensitivity and noise.The most detection is to carry out under threshold is the medium sensitivity of 35～55dB, and threshold value the most commonly used is 40dB.Acoustic emission detection system is provided with rational gain, and gain is the setting of instrument main amplifier to the acoustic emission waveform signal amplification factor, and it directly influences the measurement of energy and the energy counting of acoustic emission signal, and system of the present invention adopts gain to be the 40dB prime amplifier.Also will rationally be provided with the integrated circuit board parameter in addition, the integrated circuit board parameter comprises sample frequency, sampling length, parameter interval and locking time etc.The setting of sample frequency will be carried out different settings according to the difference of detected object, and centre frequency is promptly both greater than 10 times and to be less than 30 times sample frequency be the frequency band that we are concerned about most, and rule of thumb effect is best during 20 times of left and right sides.For example concrete acoustic emission frequency domain, integrated circuit board parameter of the present invention be set to sample frequency 625KHZ, sampling length 2048 (counting), parameter at interval and the locking time be 2000 μ s.
(4) during building structure fire of the present invention in the acoustic emission monitoring software (monitoring software of supervisory system), be provided with the locating module of acoustic emission source, determine the position of acoustic emission source by time-of-arrival loaction (, determining the position of wave source) and regional mapping method (localization method that processing speed is fast, easy and rough) analysis burst and continuous signal through, velocity of wave poor, the isoparametric measurement of probe spacing and complicated algorithm computing to each acoustic emission channel signal time of arrival; Be provided with the fire safety evaluating limit criterion of various structures (xoncrete structure, steel construction, masonry structure etc.), when the member of various structures can be made the early warning report when fire is issued to maximum safe limit; Set the relation that structural outer that stored counts parameter (acoustie emission event sum, ring tale, gross energy, amplitude tale etc.) and inside configuration accumulated change caused changes; Set the relation of acoustic emission rate of change parameter (event count rate, Ring-down count rate, energy release rate etc.) with the structural cracks speed of development; Be provided with the feature and the criterion of the acoustic emission signal of various structures when collapsing.
The present invention is just for solving the detection problem of building structure acoustic emission characteristic under the high temperature, structural collapse acoustic emission system for monitoring when a kind of fire that can be used for putting into practice is provided.
(1) position of monitoring point is set, is prone to the position (moment of flexure is a little bigger, stress concentration point etc.) in crack in structure.Reach the purpose that structural entity is monitored by monitoring to few unique point of trying one's best.
Acoustic emission signal when (2) gathering fire, and acoustic emission signal carried out denoising sound and filtration treatment.Threshold, gain, integrated circuit board parameter etc. are provided with, so that collected active and effective parameter such as event count, amplitude, energy counting etc.
(3) utilize construction collapse in fire acoustic emission monitor(ing) software that the acoustic emission parameter that collects is analyzed, make corresponding judgement, whether the duty that can understand building structure safety, provides useful information for the fire fighter immediately.
(4) description of drawings
Fig. 1 is the acoustic emission system for monitoring construction collapse in fire synoptic diagram;
Fig. 2-3 is that certain floor measuring point is arranged and acquisition system measuring point numbering figure;
Fig. 4 is waveguide rod and sensor connection layout;
Fig. 5-Fig. 7 is 1 point, 7 points, 13 event number synoptic diagram;
Fig. 8 is the program flow diagram of monitoring software.
(5) embodiment
Be described further below in conjunction with drawings and Examples:
In conjunction with Fig. 1, acoustic emission monitoring system mainly comprises during the building structure fire: sensor-based system 1, signal amplify the electric signal connection successively of filtering system, signal acquiring processing system and analysis judgment system.Wherein, sensor-based system is made up of waveguide rod and sensor, to solve reception, the conducting problem of acoustic emission signal under the high temperature; Signal amplifies, filtering system is made up of prime amplifier, signal filter and main amplifier; Analysis judgment system mainly is made up of monitoring software and display device.
(1) as shown in Figure 1 during the building structure fire key step of acoustic emission monitoring system be: a. wave source 3 produces wave propagations 2, and sensor receives acoustic emission signal; B. prime amplifier amplifies signal; C. wave filter filters out noise and the non-important parameter in the signal; D. main amplifier carries out the secondary amplification to the signal after filtering; E. monitoring of software is made judgement to signal analysis.
(2) as Fig. 2-selected characteristic node shown in Figure 3, the simply supported slab of certain floor is provided with measuring point in the centre position, is provided with 13 measuring points according to the size of plate and wave propagation decay.Waveguide rod is connected as shown in Figure 3 with sensor.
(3) because the voltage of sensor output signal is low to moderate the microvolt order of magnitude sometimes, faint like this signal, as if the transmission through long distance, signal to noise ratio (S/N ratio) must reduce.As shown in Figure 1, when the building structure fire in the acoustic emission monitoring system after the sensor signalization amplify filtering system.At first acoustic emission signal is amplified by prime amplifier; Secondly for reducing the electromagnetic interference (EMI) of environmental noise and electric equipment, wave filter is set after prime amplifier, acoustic emission signal is filtered; The last main amplifier that is provided with after wave filter carries out secondary master amplification to improve the dynamic range of system to acoustic emission signal.
(4) analysis judgment system of acoustic emission monitoring system is carried out analysis and judgement to the acoustic emission signal after amplifying through main amplifier and is shown during the building structure fire, as Fig. 51 point shown in Figure 7,7 points, 13 event number, monitoring of software is made judgement according to the breaking limit of plate in the middle of the relation of the event number of the xoncrete structure plate in the middle of the software and plate cracking and crack development and the software to event number analysis.The program flow diagram of monitoring of software as shown in Figure 8.Monitoring of software such as other parameter such as ring number, energy counting, amplitude are made corresponding judgement according to correlation parameter judgment criterion and safety criterion too.
Claims (9)
1, a kind of acoustic emission system for monitoring construction collapse in fire, it is characterized in that it is mainly connected to form by sensor-based system, signal amplification filtering system, signal acquiring system and signal analysis judgement system electric signal successively, signal amplifies filtering system and is made up of prime amplifier, signal filter and main amplifier; Analysis judgment system mainly is made up of monitoring software and display device.
2, acoustic emission system for monitoring construction collapse in fire according to claim 1 is characterized in that described sensor-based system is made up of waveguide rod and sensor.
3, a kind of construction collapse in fire acoustic emission monitor(ing) method according to claim 1 is characterized in that:
(1) position of monitoring point is set, is prone to the position in crack, comprise that moment of flexure is a little bigger, stress concentration point, reach purpose the structural entity monitoring by monitoring to few unique point of trying one's best in structure;
Acoustic emission signal when (2) gathering fire, and acoustic emission signal carried out denoising sound and filtration treatment; Threshold, gain, integrated circuit board parameter are provided with, comprised event count, amplitude, energy counting so that collect active and effective parameter;
(3) utilize construction collapse in fire acoustic emission monitor(ing) software that the acoustic emission parameter that collects is analyzed, make corresponding judgement, whether the duty that can understand building structure safety, provides useful information for the fire fighter immediately.
4, construction collapse in fire acoustic emission monitor(ing) method according to claim 3 is characterized in that:
(1) at the maximal bending moment place and the stress raiser of buildings beam, plate, post, promptly consolidates Zhi Duan, steel construction coupling part, arrange calibrate AE sensor; Determine transducer spacing according to the wave propagation decay, determine structural elements measuring point quantity according to selected transducer spacing and member size; In time difference location, the pairing propagation attenuation of maximum sensor spacing should not and detect the poor of threshold value greater than predetermined minimum detection signal amplitude, and in zone location, sensor array adopts planar delta;
(2) being connected of waveguide rod and probe, choose suitable steel screw rod, the steel screw rod is embedded in point position, spiral shell emits the top totally smooth with sand papering, contacts closely with probe, adopts the vacuum silicone grease as couplant;
(3) sensitivity of acoustic emission detection system is decided by sensitivity, transducer spacing and the setting of detection threshold of sensor, detect threshold and be under the medium sensitivity of 35～55dB and carry out, acoustic emission detection system is provided with gain and integrated circuit board parameter, the integrated circuit board parameter comprises sample frequency, sampling length, parameter at interval and the locking time, and sample frequency adopts centre frequency promptly both greater than 10 times and be less than 30 times sample frequency;
(4) during building structure fire of the present invention in the acoustic emission monitoring software, be provided with the locating module of acoustic emission source, analyze the position that burst and continuous signal are determined acoustic emission source by time-of-arrival loaction and regional mapping method; Be provided with various structures, comprise the fire safety evaluating limit criterion of xoncrete structure, steel construction and masonry structure, when the member of various structures can be made the early warning report when fire is issued to maximum safe limit; Set the relation that structural outer that stored counts parameter and inside configuration accumulated change caused changes; Set the relation of acoustic emission rate of change parameter and structural cracks speed of development; Be provided with the feature and the criterion of the acoustic emission signal of various structures when collapsing.
5, construction collapse in fire acoustic emission monitor(ing) method according to claim 4, it is characterized in that: the detection threshold value is 40dB.
6, construction collapse in fire acoustic emission monitor(ing) method according to claim 5 is characterized in that: sample frequency adopts 20 times of centre frequencies.
7, construction collapse in fire acoustic emission monitor(ing) method according to claim 6 is characterized in that: the integrated circuit board parameter be set to sample frequency 625KHZ, sampling length 2048 (counting), parameter at interval and the locking time be 2000 μ s.
8, construction collapse in fire acoustic emission monitor(ing) method according to claim 7, it is characterized in that: time-of-arrival loaction is determined the position of wave source for through, velocity of wave poor to each acoustic emission channel signal time of arrival, the isoparametric measurement of probe spacing and complicated algorithm computing.
9, construction collapse in fire acoustic emission monitor(ing) method according to claim 8, it is characterized in that: the stored counts parameter comprises acoustie emission event sum, ring tale, gross energy, amplitude tale, and acoustic emission rate of change parameter comprises event count rate, Ring-down count rate, energy release rate.
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103063808A (en) * | 2012-12-24 | 2013-04-24 | 上海交通大学 | Assessment method and system for building damage after fire |
| CN106959308A (en) * | 2017-03-20 | 2017-07-18 | 东南大学 | A kind of concrete structure influence of fire depth detection method |
| CN108426947A (en) * | 2018-03-13 | 2018-08-21 | 中国工程物理研究院化工材料研究所 | Plastic bonded explosives compression forming part moves back the acoustic emission monitor(ing) method of mould deformation process |
| CN109406279A (en) * | 2018-12-04 | 2019-03-01 | 华侨大学 | The experimental provision and experimental method of superstructure micromechanism of damage when a kind of research fire |
| CN110161116A (en) * | 2018-04-25 | 2019-08-23 | 北京机电工程研究所 | Displacement and sound emission integrated sensing device |
| CN113960176A (en) * | 2021-10-20 | 2022-01-21 | 应急管理部上海消防研究所 | Non-contact acoustic emission detection method for fire scene building structure safety state |
-
2008
- 2008-06-18 CN CN2008100647622A patent/CN101299034B/en not_active Expired - Fee Related
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103063808A (en) * | 2012-12-24 | 2013-04-24 | 上海交通大学 | Assessment method and system for building damage after fire |
| CN106959308A (en) * | 2017-03-20 | 2017-07-18 | 东南大学 | A kind of concrete structure influence of fire depth detection method |
| CN106959308B (en) * | 2017-03-20 | 2020-04-07 | 东南大学 | Method for detecting fire influence depth of concrete structure |
| CN108426947A (en) * | 2018-03-13 | 2018-08-21 | 中国工程物理研究院化工材料研究所 | Plastic bonded explosives compression forming part moves back the acoustic emission monitor(ing) method of mould deformation process |
| CN110161116A (en) * | 2018-04-25 | 2019-08-23 | 北京机电工程研究所 | Displacement and sound emission integrated sensing device |
| CN110161116B (en) * | 2018-04-25 | 2021-10-19 | 北京机电工程研究所 | Displacement and acoustic emission integrated sensing device |
| CN109406279A (en) * | 2018-12-04 | 2019-03-01 | 华侨大学 | The experimental provision and experimental method of superstructure micromechanism of damage when a kind of research fire |
| CN113960176A (en) * | 2021-10-20 | 2022-01-21 | 应急管理部上海消防研究所 | Non-contact acoustic emission detection method for fire scene building structure safety state |
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