CN104374556A - Jacket monitoring method - Google Patents
Jacket monitoring method Download PDFInfo
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- CN104374556A CN104374556A CN201410628997.5A CN201410628997A CN104374556A CN 104374556 A CN104374556 A CN 104374556A CN 201410628997 A CN201410628997 A CN 201410628997A CN 104374556 A CN104374556 A CN 104374556A
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Abstract
The invention provides a jacket monitoring method. The method includes the following steps that firstly, a finite element model of a jacket is established, the largest stress point of the jacket is calculated, and therefore the installation position of a sensor is determined; secondly, the sensor is installed in the installation position and connected to a monitoring computer; thirdly, under the calm and tranquil sea condition, the structural stress of the sensor is calculated, the value of the sensor is set to be zero according to the structural stress, and temperature compensation is conducted on temperature stress of the sensor through a temperature compensation sensor; fourthly, the monitoring computer acquires detection data of the sensor in real time and analyzes the detection data. In the fourth step, the detection data are analyzed through sensitivity analysis or horizontal comparison. By the adoption of the method, the structural damage of the jacket can be monitored and located in real time.
Description
Technical field
The present invention relates to structural health monitoring technology field and oceanographic engineering field, particularly, relate to a kind of jacket monitoring method.
Background technology
Approach on offshore jacket platforms is a class ocean engineering structure, and it provides the place of offshore operation and life for development and utilization ocean resources.Ocean platform and jacket structure long service are in severe marine environment, bear from marine environment various load, as wind load, seaway load, ice load etc. and the reciprocation of the own load such as upper chunk and drilling-production equipment, sometimes also to be subjected to the destruction of earthquake, typhoon, tsunami, boats and ships etc. in addition.The intensity and life-span and kinetic characteristic that directly affect platform and jacket structure are understood in the bearing capacity that these load produces and vibration, and even cause collapsing and toppling of platform, consequence is very serious.
Current approach on offshore jacket platforms mainly takes two aspect measures to understand platform situation, first periodic detection, its two be calculate assessment.Two kinds of measures be combined with each other and reflect platform structure situation to a certain extent, but also exist significantly not enough.Periodic detection (detecting especially under water) the large cost of difficulty is high, and period distances is longer, limited coverage area, and the detection method adopted is mainly with being visually main, is aided with part Dynamic Non-Destruction Measurement; Calculating assessment is adopt computer software to carry out modeling computing, is a kind of partially theoretical method, and adopts the authenticity of data and rationality (being often the most difficult clear and definite) directly impact evaluation result in modeling.Two kinds of measures are had nothing in common with each other, and be combined with each other and can only reflect platform structure situation to a certain extent.
Carry out real-time online to jacket platform health status to assess accurately, the security of structure, integrality are carried out to real-time monitoring, thus positioned early impaired rod member and repair, the incidence of offshore oil and gas accident can be reduced, reduce economic loss.But, rely on manual detection or ROV detections, supercritical ultrasonics technology, radioactive method to detect, can only be monitor " afterwards ", the on-line real time monitoring of structural intergrity and security can not be realized under severe sea condition.In contrast to this, adopting the vibratory response data of structure, comprise structural natural frequencies, intrinsic formation, modal strain energy etc., identify the damage with deagnostic structure, is a kind ofly study more and that cost is low lossless detection method.But this method has certain limitation, there is interference to modal idenlification in the coloured noise of irregular water wave and test noise, very large on diagnostic result impact.
Summary of the invention
For defect of the prior art, the object of this invention is to provide a kind of jacket monitoring method.
The present invention proposes the damage ONLINE RECOGNITION method of two kinds of in-service jacket platforms, i.e. lateral comparison method between sensitivity analysis method and rod member.Its principle of sensitivity analysis method is when a certain important support rod member on jacket platform lost efficacy, and the stress of itself and certain some specific rod member around can be different from time harmless.This change of each rod member stress is counted by result of calculation, find that responsive rod member combination when different rod member lost efficacy is different, namely each rod member STRESS VARIATION caused that lost efficacy is unique, by detecting the response condition of these more responsive rod members in real time, finally real-time diagnosis is carried out to the security of jacket platform, and the degree of impairment of jacket platform can be judged further according to the stress intensity collected.Rod member lateral comparison method is that sensitivity analysis take time as self comparing of precedence relationship relative to the longitudinal comparison method of sensitivity analysis, lateral comparison be with space be relation same time different rod member between lateral comparison.As a certain rod member damages, stress then between rod member all can change in the mutual relationship of size, amplitude and frequency, and this change has singularity and uniqueness, by more this mutual relationship of monitoring rate, determine the position of generation and the damage damaged.
According to jacket monitoring method provided by the invention, comprise the steps:
Step 1: the finite element model setting up jacket, calculates the stressed maximum point of jacket, thus determines the installation site of sensor;
Step 2: sensor to be arranged on described installation site and sensor is accessed monitoring computer;
Step 3: when choosing right up and down sea situation, calculates the structural stress of installation site, to return to zero and adopt temperature compensation sensor to carry out temperature compensation to the temperature stress of sensor according to described structural stress to sensor;
Step 4: the detection data of monitoring computer Real-time Obtaining sensor to detection data analysis.
Preferably, adopt sensitivity analysis and/or lateral comparison to detection data analysis in described step 4.
Preferably, described temperature compensation act is specially and adopts the thermal expansivity of jacket material and the temperature-sensitivity coefficient of sensor to carry out calculation of temperature stresses, in the output valve of sensor, compensate or adopt the output valve of the reference sensor on the unloaded reference substance being attached to same jacket same material, the measured value of sensor is compensated.
Preferably, described step 2 specifically comprises the steps:
Step 2.1: on the welding pedestal be installed on by sensor, and apply corresponding prestress;
Step 2.2: the welding pedestal of multiple sensor is welded on the rod member of described jacket;
Step 2.3: spool is walked in welding, walks spool access demodulated equipment described in being passed through by the optical fiber of connecting sensor, and then access detection computations machine.
Preferably, described sensor adopts optical fiber FBG sensor.
Preferably, walking spool and described welding pedestal described in adopts sacrificial anode protection to carry out anticorrosion.
Preferably, described installation site is specially the rod end of the diagonal brace rod member of jacket or the rod end of horizontal brace rod member.
Preferably, also comprise the steps:
-calculate the stress data of each installation site under jacket health condition under different wind, wave, stream environment.
Compared with prior art, the present invention has following beneficial effect:
1, the present invention can the structural damage that occurs of Real-Time Monitoring positioning catheter frame;
2, the present invention is comparatively simple, and cost is low and limitation is little;
3, the present invention adopts sensitivity analysis and lateral comparison to detection data analysis, and providing can accuracy of detection.
Accompanying drawing explanation
By reading the detailed description done non-limiting example with reference to the following drawings, other features, objects and advantages of the present invention will become more obvious:
Fig. 1 is principle flow chart of the present invention;
Fig. 2 is flow chart of steps of the present invention.
Embodiment
Below in conjunction with specific embodiment, the present invention is described in detail.Following examples will contribute to those skilled in the art and understand the present invention further, but not limit the present invention in any form.It should be pointed out that to those skilled in the art, without departing from the inventive concept of the premise, some distortion and improvement can also be made.These all belong to protection scope of the present invention.
The present invention for the detection of structural health based on sensitivity analysis and lateral comparison two kinds of modes.The lateral comparison i.e. stress relation of more symmetrical two rod members, its stress of two rod members that structure is in distribution symmetrically is all in similar state in size, frequency and amplitude, if there is structural damage to destroy structural symmetry, its stress can produce relatively big difference, and this do not coexist apply different directions external applied load time all very similar.Namely sensitivity analysis compares the relation of the existing stress of rod member and health status stress, rod member is measured the healthy stress that stress and FEM (finite element) calculation and historical data determines jointly to compare, as structure is damaged, can there is larger change in rod member itself and its peripheral rod part stress that damage occurs compared with healthy stress.
Two kinds of results of mainly carrying out time-domain analysis and frequency-domain analysis based on counter stress signal.Time-domain analysis analyzes stress mean value, stress amplitude mainly through statistical analysis technique, and frequency-domain analysis analyzes the stress spectra peak cycle mainly through Fourier transform, stress has adopted wave height.
In the present embodiment, jacket monitoring method provided by the invention comprises the steps:
Step 1: the finite element model setting up jacket, calculates the stressed maximum point of jacket, thus determines the installation site of sensor;
Step 2: sensor to be arranged on described installation site and sensor is accessed monitoring computer;
Step 3: when choosing right up and down sea situation, utilizes ANSYS to calculate the structural stress of installation site, to return to zero and adopt temperature compensation sensor to carry out temperature compensation to the temperature stress of sensor according to described structural stress to sensor;
Step 4: the detection data of monitoring computer Real-time Obtaining sensor to detection data analysis.Right up and down sea situation is that wind scale is less than 3 grades, unrestrained higher primary school is in 0.6m.
Adopt sensitivity analysis and lateral comparison to detection data analysis in described step 4.Described sensor adopts optical fiber FBG sensor.Monitoring computer, according to the monitoring facilities of design, monitors the health status of rod member.Adopt two kinds of monitoring modes to carry out Real-Time Monitoring, if wherein a kind of monitoring mode monitoring is gone wrong, then system alarm, and the position of orienting damage, for monitoring on the spot.Computer Analysis process real time data, carry out Real-Time Monitoring while, by historical data stored in database, with help monitoring damage.Simultaneously for forecasting the tired serviceable life of jacket.
Sensor needs to carry out temperature compensation, to eliminate the composition of temperature stress, extract the composition of structural stress, described temperature compensation act is specially and adopts the thermal expansivity of jacket material and the temperature-sensitivity coefficient of sensor to carry out calculation of temperature stresses, in the output valve of sensor, compensate or adopt the output valve of the reference sensor be attached on the unloaded reference substance of same jacket same material, the measured value of sensor is compensated.
Described step 2 specifically comprises the steps:
Step 2.1: packaged optical fiber FBG sensor has been installed on the water surface with spelter welding pedestal on, and by nut, corresponding prestress is applied to optical fiber FBG sensor;
Step 2.2: frogman clears up the attachment of installing optical fibres FBG sensing station on jacket, by banded ring set in measurement cross section, is welded on the monitoring point on the rod member of described jacket by Underwater Welding by the welding pedestal of three sensors;
Step 2.3: weld away spool everywhere at jacket, walks spool access demodulated equipment described in being passed through by the optical fiber of connecting sensor, and then access detection computations machine.
The material used due to the erecting device of optical fiber and jacket material different, walk spool and described welding pedestal therefore and adopt sacrificial anode protection to carry out anticorrosion.
For the consideration of controlling cost, only choose several important rod members, at its rod end sensor installation.Concrete installation member is that stress is large and main diagonal brace, the horizontal brace rod member of damage easily occur.
-calculate the stress data of each installation site under jacket health condition under different wind, wave, stream environment.
When measuring the rod member stress of jacket of having gone into operation, when sensor is installed, rod member has strain, therefore needs to correct sensor initial strain.Correct by without under the side crops industry of stormy waves, with the stress of ANSYS FEM (finite element) calculation for true stress, optical fiber FBG sensor is returned to zero.
The wiring of optical fiber adopts spool, to reduce the impact of hydrodynamic force on cable, improves the serviceable life of optical fiber.
Three sensors are installed better to measure the stress state of bar cross section in the monitoring cross section of a monitoring point, rod member stress is divided into tension and compression stress and bending stress two parts, the strain data that the sensor fixed by three angles obtains, calculate cross section tension and moment of flexure, and calculating cross section maximum stress, the erecting device that three sensors pass through is located and is installed.
Described step 1 is specially: the finite element model setting up jacket, the stressed maximum point of computing platform, i.e. dangerous point, sets up sensitivity analysis database; According to practical structures feature and result of finite element, determine the installation site of sensor; Calculate the stress data of each monitoring point under platform health condition under different wind, wave, stream environment.
Above specific embodiments of the invention are described.It is to be appreciated that the present invention is not limited to above-mentioned particular implementation, those skilled in the art can make various distortion or amendment within the scope of the claims, and this does not affect flesh and blood of the present invention.
Claims (8)
1. a jacket monitoring method, is characterized in that, comprises the steps:
Step 1: the finite element model setting up jacket, calculates the stressed maximum point of jacket, thus determines the installation site of sensor;
Step 2: sensor to be arranged on described installation site and sensor is accessed monitoring computer;
Step 3: when choosing right up and down sea situation, calculates the structural stress of installation site, to return to zero and adopt temperature compensation sensor to carry out temperature compensation to the temperature stress of sensor according to described structural stress to sensor;
Step 4: the detection data of monitoring computer Real-time Obtaining sensor to detection data analysis.
2. jacket monitoring method according to claim 1, is characterized in that, adopts sensitivity analysis and/or lateral comparison to detection data analysis in described step 4.
3. jacket monitoring method according to claim 1, it is characterized in that, described temperature compensation act is specially and adopts the thermal expansivity of jacket material and the temperature-sensitivity coefficient of sensor to carry out calculation of temperature stresses, in the output valve of sensor, compensate or adopt the output valve of the reference sensor on the unloaded reference substance being attached to same jacket same material, the measured value of sensor is compensated.
4. jacket monitoring method according to claim 1, is characterized in that, described step 2 specifically comprises the steps:
Step 2.1: on the welding pedestal be installed on by sensor, and apply corresponding prestress;
Step 2.2: the welding pedestal of multiple sensor is welded on the rod member of described jacket;
Step 2.3: spool is walked in welding, walks spool access demodulated equipment described in being passed through by the optical fiber of connecting sensor, and then access detection computations machine.
5. jacket monitoring method according to claim 1, is characterized in that, described sensor adopts optical fiber FBG sensor.
6. jacket monitoring method according to claim 4, is characterized in that, described in walk spool and described welding pedestal and adopt sacrificial anode protection to carry out anticorrosion.
7. jacket monitoring method according to claim 1, is characterized in that, described installation site is specially the rod end of the diagonal brace rod member of jacket or the rod end of horizontal brace rod member.
8. jacket monitoring method according to claim 1, is characterized in that, also comprise the steps:
-calculate the stress data of each installation site under jacket health condition under different wind, wave, stream environment.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410628997.5A CN104374556A (en) | 2014-11-10 | 2014-11-10 | Jacket monitoring method |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410628997.5A CN104374556A (en) | 2014-11-10 | 2014-11-10 | Jacket monitoring method |
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| CN104374556A true CN104374556A (en) | 2015-02-25 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106017906A (en) * | 2016-07-26 | 2016-10-12 | 南京航空航天大学 | Cooling tower modal testing method |
Citations (4)
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|---|---|---|---|---|
| US6813592B1 (en) * | 1999-06-20 | 2004-11-02 | Mtu Aero Engines Gmbh | Method for crack propagation simulation |
| CN102901560A (en) * | 2012-10-24 | 2013-01-30 | 天津亿利科能源科技发展股份有限公司 | Safe comprehensive monitoring system for structure of offshore jacket platform |
| CN102944581A (en) * | 2012-12-07 | 2013-02-27 | 大连理工大学 | Method for monitoring structural damage of conduit offshore platform |
| CN103398860A (en) * | 2013-07-26 | 2013-11-20 | 天津亿利科能源科技发展股份有限公司 | Method for monitoring safety of ocean platform on basis of displacement sensors |
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2014
- 2014-11-10 CN CN201410628997.5A patent/CN104374556A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6813592B1 (en) * | 1999-06-20 | 2004-11-02 | Mtu Aero Engines Gmbh | Method for crack propagation simulation |
| CN102901560A (en) * | 2012-10-24 | 2013-01-30 | 天津亿利科能源科技发展股份有限公司 | Safe comprehensive monitoring system for structure of offshore jacket platform |
| CN102944581A (en) * | 2012-12-07 | 2013-02-27 | 大连理工大学 | Method for monitoring structural damage of conduit offshore platform |
| CN103398860A (en) * | 2013-07-26 | 2013-11-20 | 天津亿利科能源科技发展股份有限公司 | Method for monitoring safety of ocean platform on basis of displacement sensors |
Non-Patent Citations (1)
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| 王启广 等: "《测试技术与实验方法》", 31 December 2009 * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106017906A (en) * | 2016-07-26 | 2016-10-12 | 南京航空航天大学 | Cooling tower modal testing method |
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Application publication date: 20150225 |