CN107179250A - A kind of detection method of submarine pipeline bend fatigue crack initiation process - Google Patents
A kind of detection method of submarine pipeline bend fatigue crack initiation process Download PDFInfo
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- CN107179250A CN107179250A CN201710376829.5A CN201710376829A CN107179250A CN 107179250 A CN107179250 A CN 107179250A CN 201710376829 A CN201710376829 A CN 201710376829A CN 107179250 A CN107179250 A CN 107179250A
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- test part
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/24—Investigating strength properties of solid materials by application of mechanical stress by applying steady shearing forces
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0058—Kind of property studied
- G01N2203/006—Crack, flaws, fracture or rupture
- G01N2203/0062—Crack or flaws
Abstract
The invention discloses a kind of detection method and detection means of submarine pipeline bend fatigue crack initiation process, wherein detection method is：Duct test part centre position is provided with foil gauge；Duct test part is placed on tired pressure exerting arrangement platform, the two ends of duct test part are hanging as the strong point, centre；Downward cyclic load is applied by tired pressure exerting arrangement two positions symmetrical to duct test part middle part；Whether fatigue crack is germinated in the strain difference detection pipe road measured by the stress section being located on duct test part, the extension length of crackle is can determine that according to differently strained strain value measured of ring, the relation between duct test part circulating load number of times and fatigue crack length can be further learnt.The beneficial effects of the invention are as follows：The present invention can predict the crack initiation situation of submarine pipeline by the detection to duct test part, and detection method is simple and accurate, can judge whether it meets seabed service demand as the detection to not installing submarine pipeline.
Description
Technical field
The present invention relates to submarine pipeline by curved detection technique field, more particularly to a kind of submarine pipeline bend fatigue crackle is sprouted
The detection method and detection means of raw process.
Background technology
Submarine pipeline belongs to one kind of pressure pipeline, but is with the difference of usual pressure pipeline, and submarine pipeline will be born
Tide, wave, ocean current, sea ice, ocean fall the shock of thing, and seawater the effect, these load such as erosion, the friction of fishing net
Effect make it that the probability of the more universal Failure Criterion of Pressure Piping of submarine pipeline is higher, it is easier to occur accident.Inducing pipeline thing
Therefore various defect types in, the ratio shared by rift defect that pipeline is produced is maximum.Accordingly, it would be desirable to be sentenced by detection and experiment
Determine the Crack Damage and structural strength of structure.
The content of the invention
Situations such as crack initiation process and active time in order to predict submarine pipeline, the invention provides one kind
The detection method and detection means of submarine pipeline bend fatigue crack initiation process, can be applied to the submarine pipeline of various diameters
Detection.
In order to realize foregoing invention purpose, the invention provides a kind of inspection of submarine pipeline bend fatigue crack initiation process
Survey method, it is characterised in that the detection method is：
Take an oil pipeline part as duct test part, the centre position of duct test part lower surface is axially disposed to be had
Several columns are into axisymmetric foil gauge, and foil gauge described in each column is radially arranged in rows；Each foil gauge is along duct test
Part it is axially arranged, for detecting axial stretching strain of the pipeline testpieces under Moment；
The duct test part for having set foil gauge is placed on tired pressure exerting arrangement platform, the two ends conduct of duct test part
The strong point, middle part are hanging；
Downward cyclic load is applied by tired pressure exerting arrangement two positions symmetrical to duct test part middle part,
So that pure bending power is born in duct test part middle part；
It can detect whether pipeline germinates fatigue crack by the strain difference measured to foil gauge, it is differently strained according to ring
The strain value that piece is measured can determine that the extension length of crackle, can further learn circulating load number of times and oil pipeline span centre fatigue
Numerical relation between crack length.
In the non-crack initiation of duct test part, because pure bending, each foil gauge are born in duct test part middle part
It is identical in the contingency theory measured, the strain value for obtaining foil gauge can be calculated according to formula (1), formula is as follows：
Wherein, E is pipeline material modulus of elasticity, and D and T are respectively the external diameter and thickness of pipeline, M by pipeline bear it is curved
Square, θiCentral angle for i-th of foil gauge relative to vertical direction；
When some position of duct test part starts crack initiation, turn into the scope of freedom at two crack surfaces, not tension masterpiece
With so pipe surface strain levels off to zero where crackle.Now, it can be shown according to two foil gauges where the position both sides
Reading detection crackle whether germinate；The distance between assumed strain field piece and crackle are respectively r1And r2, the strain difference measured
For ε1And ε2, then can estimate that the strain value at the place of crack initiation position is according to formula (2)：
As ε → 0, that is, show that the measuring point generates fatigue crack, you can learn the length value of crack initiation, and can obtain
Know the vertical relation now between circulating load number of times and crack length value.
In order to more clearly tell about the detection method of submarine pipeline bend fatigue crack initiation process, below to detection side
Method is described in further detail, and is specially：
Take 3-5m oil pipelines as duct test part, duct test part is handled, be specially：In duct test part
On be symmetrical arranged two vertical load plates for carrying central through hole, the distance between two vertical load plates are 2-4m；In pipeline
Two support end plates are fixed at testpieces two ends, and the height of vertical load plate and support end plate is all higher than the diameter of duct test part；
The treated duct test part is placed on testing stand, only connect two support end plates with testing stand
Touch, duct test part middle part is hanging, two vertical load plate upper surfaces are placed directly over a level board, level board
The tired pressure exerting arrangement of the level board can be applied pressure to by being provided with；
The centre position of duct test part lower surface is provided with radially and axisymmetricly several columns foil gauge.
In order to realize above-mentioned detection method, present invention also offers a kind of inspection of submarine pipeline bend fatigue crack initiation process
Survey device, including base frame, two be symmetricly set on the base frame upper support frame and the tired pressing machine being arranged on the base frame
Structure；Duct test part is provided with support frame as described above, the duct test part two ends are fixedly connected with a support end plate, the pipe
Road testpieces middle part is symmetrically arranged with two vertical load plates, and the duct test part is passed through in the middle of the vertical load plate
Position, two vertical load plate upper surfaces set a level board；The support end plate lower surface is placed on support frame as described above
Upper surface；The drift lower surface of the tired pressure exerting arrangement can be contacted with the level board upper surface；
The duct test part lower surface centre position is axially disposed to have several columns into axisymmetric foil gauge, each column institute
State foil gauge radially arranged in rows；Each foil gauge is along the axially arranged of duct test part, for detecting duct test
Axial stretching strain of the part under Moment.
The level board upper surface is provided with locating dowel, the drift lower surface of the tired pressure exerting arrangement be provided with it is described
The positioning hole that locating dowel is used cooperatively.
The vertical load plate upper surface is provided with bar shaped locating slot, and the level board lower surface is provided with and the bar shaped
The bar shaped positioning convex that locating slot is used cooperatively.
Support frame as described above upper surface is provided with limiting plate, and the limiting plate includes bottom plate and is arranged on determining on the bottom plate
Position frame, the locating rack is included between the fixed dam of two side plate sides of two side plates and connection, two side plates
Distance be equal or slightly larger than it is described support end plate thickness.
The locating rack also includes sideboard, perpendicular away from being provided with described two side plates in fixed dam side
To locating slot, the sideboard both sides are inserted into two vertical locating slots.
In order to preferably realize foregoing invention purpose, present invention also offers a kind of duct test part welding positioning dress
Put, including platform and the locomotive that is movably arranged on the platform, be provided with the platform on intermediate plate, the locomotive
Two circular arc support frames are symmetrically arranged with, being symmetrically arranged with two on the platform on the outside of the curved support frame carries
The strap of arc notch, two are symmetrically arranged with the platform on the outside of the strap and carries arc notch
Ambulatory splint, is symmetrically arranged with two movable positioning plates on the platform on the outside of the ambulatory splint；The circular arc branch
Axle is axisymmetricly centered on the intermediate plate for support, the strap, the ambulatory splint and the movable positioning plate；
The platform lower surface is provided with the synchronous drive mechanism used cooperatively with the movable positioning plate；
The synchronous drive mechanism includes the drive gear for being arranged on the platform lower surface and two and the sliding tooth
Take turns engagement driven gear, two driven gears be internally provided with screw thread cooperation leading screw, two leading screws from
One end is fixedly connected with the movable positioning plate；The duct test part is placed on the circular arc support frame.
Retaining mechanism is provided between the ambulatory splint and the strap.
The movable positioning plate lower surface and ambulatory splint lower surface both sides are provided with roller, the platform upper end
Face is provided with the track used cooperatively with the roller.
The movable positioning plate and the ambulatory splint two sides are provided with fixed ear, the platform and are provided through
The guide rod of the fixed ear.
The platform upper surface is additionally provided with the lazy-tongs used cooperatively with the ambulatory splint；The lazy-tongs bag
The rack being fixedly connected with ambulatory splint side lower end is included, described rack one end is fixed on the ambulatory splint side, two
The other end of the individual rack is oppositely arranged, and the fixed gear engaged with the rack is provided with the platform；The fixation
Gear is fixedly connected with one handle.Preferably, the fixed gear is located on the central axis of the intermediate plate.
The locomotive includes being provided with the track used cooperatively with the wheel, institute on sweep and wheel, the platform
State and the elevating mechanism that driving circular arc support frame moves up and down is provided with sweep；The elevating mechanism can be hydraulic cylinder,
The leading screw and nut that can coordinate for screw thread, the nut is fixed on the sweep by bearing, the nut by axle with
Motor connection, motor drive nut rotation, nut rotation drives leading screw to move up and down, described flat between the two row wheels
The rectangular through holes for being easy to elevating mechanism activity are provided with platform.
The beneficial effects of the invention are as follows：The present invention is by the way that duct test part two ends are supported, using tired pressure exerting arrangement pair
Two positions in the middle of duct test part carry out circulating load, by the several columns for being symmetricly set on duct test part centre position
Whether the strain difference detection pipe road that stress section is measured germinates fatigue crack, can according to differently strained strain value measured of ring
The extension length of crackle is determined, the pass between duct test part circulating load number of times and fatigue crack length can be further learnt
System；By the detection to duct test part, the crack initiation situation of submarine pipeline can be predicted, can be as to not installing Submarine Pipeline
The detection in road judges whether it meets seabed service demand；This detection method can be examined according to the full-size(d) of submarine pipeline
Survey, can more accurately learn the fatigue crack situation of submarine pipeline.In addition, present invention also offers one kind and detection method phase
The detection means of adaptation, this detection means can be good at the external force that wave simulated etc. is caused to submarine pipeline, make duct test
Part bears pure bending effect, and passes through the length value of the accurate fatigue crack of stress section calculating located at duct test part bottom；
The submarine pipeline of various sizes can be applied to, the full size little progress row detection to submarine pipeline is particular enable to, can be more accurate
The fatigue crack situation for reflecting submarine pipeline.In addition, present invention also offers one kind and detection method and detection means phase
The positioning device for welding of the duct test part of cooperation, using this positioner, without by manual measurement or using traditional
Weld jig, positioner platform is directly placed at by welded pipe line, can vertically be added two by simple drive mechanism
Support plate is positioned at on the center line of duct test part position axisymmetricly, easy to use and accurate positioning so that Submarine Pipeline
The detection method of road bend fatigue crack initiation process or the measurement structure of detection means are more accurate.
Brief description of the drawings
Fig. 1 is schematic diagram in the embodiment of the present invention 1.
Fig. 2 is the foil gauge of the embodiment of the present invention 1 relative to vertical direction central angle θiSchematic diagram.
Fig. 3 is duct test part mechanical model figure in the embodiment of the present invention 1.
Fig. 4 is duct test part mechanics Q figures in the embodiment of the present invention 1.
Fig. 5 is duct test part mechanics M figures in the embodiment of the present invention 1.
Fig. 6 is the structural representation of the embodiment of the present invention 2.
Fig. 7 is the structural representation A of the embodiment of the present invention 3.
Fig. 8 is the structural representation B of the embodiment of the present invention 3.
Fig. 9 is the structural scheme of mechanism of synchronous drive mechanism in the embodiment of the present invention 3.
Figure 10 is the structural representation of platform in the embodiment of the present invention 3.
Wherein, reference is：
1st, platform；2nd, support；3rd, guide rod；4th, movable positioning plate；5th, end plate is supported；6th, vertical load plate；7th, pipeline is tried
Test part；8th, strap；9th, ambulatory splint；10th, fixed ear；11st, reducing motor；12nd, handle；13rd, elevating mechanism；14th, it is synchronous
Mechanism；15th, leading screw；16th, circular arc support frame；17th, screwed hole；18th, rack；19th, driven gear；20th, drive gear；21st, from
Moving gear；22nd, leading screw；23rd, rectangular through holes；24th, strip v notch v；25th, intermediate plate；26th, wheel rail；27th, roller track；
28th, locomotive；
31st, base frame；32nd, support frame；33rd, bottom plate；34th, locating rack；35th, end plate is supported；36th, duct test part；37th, position
Post；38th, tired pressure exerting arrangement；39th, drift；40th, level board；41st, vertical load plate.
Embodiment
The present invention is by applying fatigue load to duct test part so that the effect of pipeline lower tension power, and then is passed through
The stress difference of pipeline middle part is understood located at the stress section of pipeline bottom, so as to reflect the germinating process of pipeline crack
Or the extended length of crackle, it can be derived that the seabed military service situation of duct test part with reference to the number of times of fatigue load.By this hair
Bright detection method and detection means, can clearly predict or understand material of the same race submarine pipeline fatigue crack initiation mistake
Journey.
For the technical characterstic for illustrating this programme can be understood, below by embodiment, this programme is illustrated.
The detection method of embodiment 1
The embodiments of the invention provide a kind of detection method of submarine pipeline bend fatigue crack initiation process, detection method
For：
Take an oil pipeline part as duct test part, have if duct test part lower surface centre position is axially disposed
Dry to arrange into axisymmetric foil gauge, foil gauge described in each column is (referring to Fig. 1) radially arranged in rows, each foil gauge edge pipe
Road testpieces it is axially arranged, for detecting axial stretching strain of the pipeline testpieces under Moment；In Fig. 1, A is crack, B
For duct test part bottom, C is foil gauge.
The duct test part for having set foil gauge is placed on tired pressure exerting arrangement platform, the two ends conduct of duct test part
The strong point, middle part are hanging；
Downward cyclic load is applied by tired pressure exerting arrangement two positions symmetrical to duct test part middle part,
So that pure bending power is born in duct test part middle part；
It can detect whether pipeline germinates fatigue crack by the strain difference measured to foil gauge, it is differently strained according to ring
The strain value that piece is measured can determine that the extension length of crackle, can further learn circulating load number of times and oil pipeline span centre fatigue
Numerical relation between crack length.
Referring to Fig. 2, specific computational methods are as follows：
In the non-crack initiation of duct test part, because pure bending, each foil gauge are born in duct test part middle part
It is identical in the contingency theory measured, the strain value for obtaining foil gauge can be calculated according to formula (1), formula is as follows：
Wherein, E is pipeline material modulus of elasticity, and D and T are respectively the external diameter and thickness of pipeline, M by pipeline bear it is curved
Square, θiCentral angle for i-th of foil gauge relative to vertical direction；
When some position of duct test part starts crack initiation, turn into the scope of freedom at two crack surfaces, not tension masterpiece
With so pipe surface strain levels off to zero where crackle.Now, it can be shown according to two foil gauges where the position both sides
Reading detection crackle whether germinate；The distance between assumed strain field piece and crackle are respectively r1And r2, the strain difference measured
For ε1And ε2, then can estimate that the strain value at the place of crack initiation position is according to formula (2)：
As ε → 0, that is, show that the measuring point generates fatigue crack, you can learn the length value of crack initiation, and can obtain
Know the vertical relation now between circulating load number of times and crack length value.
In order to the above method more clearly embodied, detection method is described in detail below, reference can be made to Fig. 4,
Detection method is specially：
Take 4m oil pipelines as duct test part, duct test part is handled, be specially：On duct test part
It is symmetrical arranged two vertical load plates for carrying central through hole, the distance between two vertical load plates are 3m；In duct test
Two support end plates are fixed at part two ends, and the height of vertical load plate and support end plate is all higher than the diameter of duct test part；
Treated duct test part is placed on testing stand, only two support end plates are contacted with testing stand, managed
Road testpieces middle part is hanging, and a level board is placed in two vertical load plate upper surfaces, and level board is arranged above energy
Enough apply pressure to the tired pressure exerting arrangement of level board；
The centre position of duct test part lower surface is provided with radially and axisymmetricly several columns foil gauge.
Above-mentioned detection method is that duct test part is applied into four_point bending beam, and its mechanical model is as shown in Figure 3.Two pieces with holes
Vertical load plate 41 supports 2 points of A and B in the simulation drawing 3 of end plate 35 equivalent to C the and D positions in Fig. 3.2 points of C and D collection
Middle power is delivered to two pieces of vertical load plates 41 by level board 40.It was found from Fig. 4 and Fig. 5 internal force diagram：CD sections (i.e. two pieces vertical
Pipeline between load plate 41) bear pure bending effect.
The detection means of embodiment 2
Referring to Fig. 6, the embodiments of the invention provide a kind of submarine pipeline that can realize detection method in embodiment 1 by curved
Fatigue crack initiation process detection means, including base frame 31, two be symmetricly set on the upper support frame 32 of base frame 31 and be arranged on bottom
Tired pressure exerting arrangement 38 on platform 31；Duct test part 36 is provided with support frame 32, the two ends of duct test part 36 are fixed to be connected
A support end plate 35 is connect, the middle part of duct test part 36 is symmetrically arranged with two vertical load plates 41, and duct test part 41 is worn
The vertical middle part of load plate 41 is crossed, two vertical upper surfaces of load plate 41 set a level board 40；Support the lower surface of end plate 35
It is placed on the upper surface of support frame 32；The lower surface of drift 39 of tired pressure exerting arrangement 38 can be contacted with the upper surface of level board 40；
Referring to Fig. 2, the lower surface of duct test part 36 is axially disposed to have several columns into axisymmetric foil gauge, described in each column
Foil gauge is radially arranged in rows；Each foil gauge is along the axially arranged of duct test part, for detecting pipeline testpieces
Axial stretching strain under Moment.
The upper surface of level 40 is provided with locating dowel 37, and the lower surface of drift 39 of tired pressure exerting arrangement 38 is provided with and locating dowel
37 positioning holes used cooperatively.
The vertical upper surface of load plate 41 is provided with bar shaped locating slot, and the lower surface of level board 40 is provided with matches somebody with somebody with bar shaped locating slot
Close the bar shaped positioning convex used.
The upper surface of support frame 32 is provided with limiting plate, and limiting plate includes bottom plate 33 and the locating rack being arranged on bottom plate 33
34, locating rack 34 includes the fixed dam of two side plate sides of two side plates and connection, the distance between two side plates be equal to or
Slightly larger than the thickness of support end plate.
Locating rack 34 also includes being provided with vertical locating slot on sideboard, remote fixed dam side two side plate,
Sideboard both sides are inserted into two vertical locating slots.
Wherein, tired pressure exerting arrangement 38 is fatigue tester, and fatigue tester can simulate the pressure pair of seabed wave
Duct test part applies cyclic load, belongs to prior art, in this not go into detail.Foil gauge and how with duct test
Part connection belongs to prior art, and in this not go into detail.
The positioning device for welding of embodiment 3
In order to obtain accurate testing result, the embodiments of the invention provide a kind of duct test part welding positioning
Device, referring to Fig. 7-Figure 10, positioner includes setting on platform 1 and the locomotive 28 being movably arranged on platform 1, platform 1
Have and two circular arc support frames 16 are symmetrically arranged with intermediate plate 25, locomotive 28, on the outside platform 1 of curved support frame 16
Two straps 8 for carrying arc notch are symmetrically arranged with, two are symmetrically arranged with the outside platform 1 of strap 8
Ambulatory splint 9 with arc notch, two movable positioning plates 4 are symmetrically arranged with the outside platform 1 of ambulatory splint 9；Circle
Axle is axisymmetricly centered on intermediate plate 25 for curved support frame 16, strap 8, ambulatory splint 9 and movable positioning plate 4；
The lower surface of platform 1 is provided with the synchronous drive mechanism used cooperatively with movable positioning plate 4；
Synchronous drive mechanism includes the drive gear 20 for being arranged on the lower surface of platform 1 and two are engaged with drive gear 20
Driven gear (19 and 21), two driven gears (19 and 21) are internally provided with the leading screw (22 and 15) of screw thread cooperation, two silks
Thick stick (22 and 15) from one end be fixedly connected with movable positioning plate 4；The lower end of movable positioning plate 4 is provided with connecting plate, connecting plate
The strip v notch v 24 for being passed down through platform 1 is connected with leading screw (22 and 15).
Retaining mechanism is provided between ambulatory splint 9 and strap 8；Retaining mechanism can be in clamping screw, in work
Dynamic clamping plate 9 and the opposite position of strap 8 offer screwed hole 17, and ambulatory splint 9 and strap 8 are by through screwed hole
17 clamping screw is fastenedly connected.
The lower surface of movable positioning plate 4 and the lower surface both sides of ambulatory splint 9 are provided with roller, and the upper surface of platform 1 is provided with
The roller track 27 used cooperatively with roller.
Movable positioning plate 4 and the two sides of ambulatory splint 9 are provided with fixed ear 10, platform 1 and are provided with support 2, support 2
On be provided through fixing the guide rod 3 of ear 10.
The upper surface of platform 1 is additionally provided with the lazy-tongs used cooperatively with ambulatory splint 9；Lazy-tongs 14 include and activity
The rack 18 that the side lower end of clamping plate 9 is fixedly connected, one end of rack 18 is fixed on the side of ambulatory splint 9, two racks 18 it is another
End is oppositely arranged, and the fixed gear engaged with rack 18 is provided with platform 1；Fixed gear is fixedly connected with one handle 12.It is excellent
Selection of land, fixed gear is located on the central axis of intermediate plate 25.
Locomotive 28 includes being provided with the wheel rail 26 used cooperatively with wheel, sweep on sweep and wheel, platform 1
It is provided with the elevating mechanism that driving circular arc support frame 16 moves up and down；Elevating mechanism can be hydraulic cylinder, or screw thread
The leading screw and nut of cooperation, nut are fixed on sweep by bearing, and nut passes through axle and motor connection, the rotation of motor drive nut
Turn, nut rotation drives leading screw to move up and down, and is provided with the length for being easy to elevating mechanism activity on platform between two Train Wheels
Square through hole 23.Locomotive 28 is additionally provided with detent mechanism, ensure that locomotive 28 is fixed, and detent mechanism can be to set
The brake component on roller, or the alignment pin being arranged between sweep and platform are put, detent mechanism is prior art,
This is no longer described in detail.
In use, in advance two vertical load plates 6 are socketed on duct test part 7, and duct test part 7 is placed on
On circular arc support frame 16 so that vertical load plate 6 is located between two straps 8, by adjusting locomotive 28 and activity
The position of clamping plate 9 so that strap 8 and ambulatory splint 9 are by the end for supporting end plate 5 to abut against duct test part 7, by pipeline
End plate 5 is supported in the two ends welding of testpieces 7；Then, duct test part 7 is lifted by elevating mechanism 13, will be mobile vertical
Load plate 6 is located between strap 8 and ambulatory splint 9, and mobile movable positioning plate 4 is located at the outside of support end plate 5；
Then duct test part 7 is fallen, starts reducing motor 11 so that two movable positioning plates 4 are moved towards, promote locomotive 28
On duct test part 7, movable positioning plate 4 synchronous drive mechanism effect under, synchronously move towards so that duct test part 7
Center line be located at intermediate plate center line be located at same vertical plane on, then again inwardly promote side ambulatory splint 9, it is another
The ambulatory splint 9 of side also moves inward in the presence of lazy-tongs, after ambulatory splint 9 is contacted with vertical load plate 6 and pushes away
It is moved in the lump to move inward, will be living by retaining mechanism after ambulatory splint 9 and strap 8 clamp vertical load plate 6
Dynamic clamping plate 9 and strap 8 are locked, and then weld vertical load plate 6 and duct test part 7, can in welding process
First duct test part 7 is again lifted by elevating mechanism 13 in welding upper surface welds lower surface again., can by this positioner
Position that is convenient and more accurately orienting vertical load plate 6.
The foregoing is only presently preferred embodiments of the present invention, be not intended to limit the invention, it is all the present invention spirit and
Within principle, any modification, equivalent substitution and improvements made etc. should be included in the scope of the protection.
Claims (9)
1. a kind of detection method of submarine pipeline bend fatigue crack initiation process, it is characterised in that the detection method is：
Take an oil pipeline part as duct test part, the centre position of duct test part lower surface is axially disposed some
Axisymmetric foil gauge is arranged into, foil gauge described in each column is radially arranged in rows；Each foil gauge is along duct test part
It is axially arranged, for detecting axial stretching strain of the pipeline testpieces under Moment；
The duct test part for having set foil gauge is placed on tired pressure exerting arrangement platform, the two ends of duct test part are used as support
Point, middle part are hanging；
Downward cyclic load is applied by tired pressure exerting arrangement two positions symmetrical to duct test part middle part so that
Bear pure bending power in duct test part middle part；
It can detect whether pipeline germinates fatigue crack by the strain difference measured to foil gauge, according to differently strained survey of ring
The strain value obtained can determine that the extension length of crackle, can further learn circulating load number of times and oil pipeline span centre fatigue crack
Numerical relation between length.
2. the detection method of submarine pipeline bend fatigue crack initiation process according to claim 1, it is characterised in that
During the non-crack initiation of duct test part, because pure bending, the strain that each foil gauge is measured are born in duct test part middle part
Theoretically identical, can calculate the strain value for obtaining foil gauge according to formula (1), and formula is as follows：
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<mi>&epsiv;</mi>
<mi>i</mi>
</msub>
<mo>=</mo>
<mfrac>
<mi>M</mi>
<mrow>
<mi>E</mi>
<mo>&CenterDot;</mo>
<mfrac>
<mrow>
<mi>&pi;</mi>
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<mo>&lsqb;</mo>
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<mi>D</mi>
<mn>4</mn>
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<mn>64</mn>
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<mo>&CenterDot;</mo>
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<mi>D</mi>
<mn>2</mn>
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<msub>
<mi>cos&theta;</mi>
<mi>i</mi>
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Wherein, E is pipeline material modulus of elasticity, and D and T are respectively the external diameter and thickness of pipeline, the moment of flexure that M is born by pipeline, θi
Central angle for i-th of foil gauge relative to vertical direction；
When some position of duct test part starts crack initiation, turn into the scope of freedom, not by pulling force effect, institute at two crack surfaces
Zero is leveled off to pipe surface strain where crackle.Now, the reading that can be shown according to two foil gauges where the position both sides
Whether number detection crackle germinates；The distance between assumed strain field piece and crackle are respectively r1And r2, the strain measured respectively ε1
And ε2, then can estimate that the strain value at the place of crack initiation position is according to formula (2)：
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<mo>-</mo>
<mrow>
<mo>(</mo>
<mn>2</mn>
<mo>)</mo>
</mrow>
</mrow>
As ε → 0, that is, show that the measuring point generates fatigue crack, you can learn the length value of crack initiation, and this can be learnt
When circulating load number of times and crack length value between vertical relation.
3. the detection method of submarine pipeline bend fatigue crack initiation process according to claim 1 or 2, its feature exists
In the detection method is specially：
Take 3-5m oil pipelines as duct test part, duct test part is handled, be specially：It is right on duct test part
Claim to set two vertical load plates for carrying central through hole, the distance between two vertical load plates are 2-4m；In duct test
Two support end plates are fixed at part two ends, and the height of vertical load plate and support end plate is all higher than the diameter of duct test part；
The treated duct test part is placed on testing stand, only two support end plates are contacted with testing stand, managed
Road testpieces middle part is hanging, and a level board is placed in two vertical load plate upper surfaces, and level board is arranged above
The tired pressure exerting arrangement of the level board can be applied pressure to by having；
The centre position of the duct test part lower surface radially and be axisymmetricly provided with several columns be used for foil gauge.
4. a kind of submarine pipeline bend fatigue crack initiation process detection means, it is characterised in that symmetrically set including base frame, two
Put in the base frame upper support frame and the tired pressure exerting arrangement being arranged on the base frame；Pipeline examination is provided with support frame as described above
Part is tested, the duct test part two ends are fixedly connected with a support end plate, and the duct test part middle part is symmetrically arranged with
Two vertical load plates, the duct test part is passed through in the vertical load plate middle part, two vertical load plates
End face sets a level board；The support end plate lower surface is placed on support frame as described above upper surface；The tired pressure exerting arrangement
Drift lower surface can be contacted with the level board upper surface；
The centre position of the duct test part lower surface is axially disposed to have several columns into axisymmetric foil gauge, described in each column
Foil gauge is radially arranged in rows；Each foil gauge is along the axially arranged of duct test part, for detecting pipeline testpieces
Stretching strain under Moment.
5. submarine pipeline bend fatigue crack initiation process detection means according to claim 4, it is characterised in that described
Level board upper surface is provided with locating dowel, and the drift lower surface of the tired pressure exerting arrangement, which is provided with to coordinate with the locating dowel, to be made
Positioning hole.
6. the submarine pipeline bend fatigue crack initiation process detection means according to claim 4 or 5, it is characterised in that
The vertical load plate upper surface is provided with bar shaped locating slot, and the level board lower surface is provided with matches somebody with somebody with the bar shaped locating slot
Close the bar shaped positioning convex used.
7. the submarine pipeline bend fatigue crack initiation process detection means according to claim any one of 4-6, its feature
It is, support frame as described above upper surface is provided with limiting plate, the limiting plate includes bottom plate and the positioning being arranged on the bottom plate
Frame, the locating rack is included between the fixed dam of two side plate sides of two side plates and connection, two side plates
The thickness of the equal or slightly larger than described support end plate of distance.
8. the submarine pipeline bend fatigue crack initiation process detection means according to claim any one of 4-7, its feature
It is, the locating rack also includes sideboard, it is vertical away from being provided with described two side plates in fixed dam side
Locating slot, the sideboard both sides are inserted into two vertical locating slots.
9. the submarine pipeline bend fatigue crack initiation process detection means according to claim any one of 4-8, its feature
It is, in addition to for welding the positioning device for welding of the duct test part, including platform and is movably arranged on described flat
It is provided with locomotive on platform, the platform on intermediate plate, the locomotive and is symmetrically arranged with two circular arc support frames, position
In being symmetrically arranged with two straps for carrying arc notch on the outside of the curved support frame on the platform, positioned at described solid
Two ambulatory splints for carrying arc notch are symmetrically arranged with the outside of clamp plate on the platform, on the outside of the ambulatory splint
Two movable positioning plates are symmetrically arranged with the platform；The circular arc support frame, the strap, the ambulatory splint
Axle is axisymmetricly centered on the intermediate plate with the movable positioning plate；
The platform lower surface is provided with the synchronous drive mechanism used cooperatively with the movable positioning plate；
The synchronous drive mechanism includes the drive gear for being arranged on the platform lower surface and two are nibbled with the drive gear
The driven gear of conjunction, two driven gears be internally provided with screw thread cooperation leading screw, two leading screws from one end
It is fixedly connected with the movable positioning plate；The duct test part is placed on the circular arc support frame.
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| CN108020654A (en) * | 2017-11-09 | 2018-05-11 | 广西交通科学研究院有限公司 | A kind of fracture width changed measurement method for testing based on foil gauge |
| CN110174314A (en) * | 2019-04-30 | 2019-08-27 | 上海市特种设备监督检验技术研究院 | High-pressure heater tube side inner wall plastic strain appraisal procedure |
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| CN115267123A (en) * | 2022-09-30 | 2022-11-01 | 华南理工大学 | Detection method for surface crack initiation and propagation of steel structure |
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| CN112254940A (en) * | 2019-07-05 | 2021-01-22 | 中车长春轨道客车股份有限公司 | Testing device and testing method for axle fatigue test |
| CN113375883A (en) * | 2021-04-28 | 2021-09-10 | 天津钢管制造有限公司 | Tracking and judging method for full-size resonance fatigue failure of deep-sea pipeline pipe |
| CN115267123A (en) * | 2022-09-30 | 2022-11-01 | 华南理工大学 | Detection method for surface crack initiation and propagation of steel structure |
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