CN108363859A - A kind of overall evaluation method to the atmospheric storage tank containing defect - Google Patents
A kind of overall evaluation method to the atmospheric storage tank containing defect Download PDFInfo
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Abstract
The invention discloses a kind of overall evaluation methods to the atmospheric storage tank containing defect, which is characterized in that includes the following steps：Measure property, size and the position of defect on storage tank；According to tank structure and defective locations, size, property, the storage tank model of defect is established in Ansys softwares；Using Ansys softwares, load real load calculates tank structure intensity and storage tank stress intensity factor, and load specific loading carries out stable calculation；The tank structure intensity, storage tank stress intensity factor and stability result that are calculated are evaluated, the safe condition of storage tank is fully assessed.The present invention solves the deficiency and missing in terms of current state's inner storage tank Safety Assessment Standard, the method that finite element soft Ansys calculate is combined by non-destructive testing detection early period, the safe condition of storage tank is had evaluated from multi-angles such as structural mechanics, fracture mechanicses, result of calculation has higher reliability.
Description
Technical field
The present invention relates to petrochemical equipment technical fields, and in particular to a kind of entirety to the atmospheric storage tank containing defect is commented
Valence method.
Background technology
It is later that the storage tank in China examines work to carry out, and not yet forms the storage tank test stone of complete set at present.China exists
Large quantities of Petroleum Storage Tanks are built up the 80s and 90s, due to the missing of statutory standard at that time, the construction quality of many storage tanks is all
Ideal not to the utmost, internal usually all there is more defects.Currently, the domestic safety evaluation side for not being exclusively used in storage tank defect
Method, if carrying out qualitative, quantitative to the defect of storage tank, can generally use RT (ray) flaw detections and PT (magnetic powder) flaw detections or
The method that MT (infiltration) flaw detections combine, fault grading is with reference to NB/T47013《Bearing device non-destructive testing》, but this method has
It is following insufficient：
NB/T47013《Bearing device non-destructive testing》The method and technique for only discussing defect detection means, not to defect
Local pressure situation is calculated, but defect is defined the level according to flaw size, even but RT detects IV grade of defect
Or II grade of defect of PT, MT, it also not necessarily influences storage tank and uses.NB/T47013 simultaneously《Bearing device non-destructive testing》
The object of fault grading is bearing device, is not fully suitable for storage tank.Storage tank is according to the difference of construction quality, more or less all
There can be the defect at several places or tens, in this case, if all defect all to be regarded as to unqualified, mechanic
Making can be troublesome, greatly influences the production of enterprise, meanwhile, it, then may be due to once defects count is more in mending course
Welding procedure, welder be horizontal, welding residual stress such as interacts at a variety of causes between the defect of many places, and storage tank is caused to repair aftereffect
Fruit is often not fully up to expectations.
Invention content
In view of the defects and deficiencies of the prior art, the present invention intends to provide a kind of based on finite element modelling to containing
The overall evaluation method of the atmospheric storage tank of defect, to solve the problems, such as proposed in background technology.
To achieve the above object, the technical solution adopted by the present invention is：A kind of entirety to the atmospheric storage tank containing defect is commented
Valence method, which is characterized in that property, size and the position of defect on detection storage tank；According to tank structure and defective locations, ruler
Very little, property establishes the storage tank model of defect in Ansys softwares；Using Ansys softwares, load real load calculates storage tank knot
Structure intensity and storage tank stress intensity factor, load specific loading carry out stable calculation；To be calculated tank structure intensity,
Storage tank stress intensity factor and stability result are evaluated, and the safe condition of storage tank is fully assessed.
Further, a kind of overall evaluation method to the atmospheric storage tank containing defect, specifically includes following steps：
S1. the property of defect, size and position on storage tank are detected using nondestructive means；
S2. finite element analysis Ansys softwares are used, in Ansys, according to the position of the structure of storage tank and defect, size, property
Matter, according to 1:1 equal proportion establishes the storage tank model containing defect；
S3. Ansys softwares are used, real load is loaded, calculate tank structure intensity, the real load is according to storage tank itself
Situation and storage tank local environment calculate, and the calculating of the tank structure intensity includes maximum primary stress, maximum secondary stress, most
Big primary plus secondary stress, maximum total stress calculating, and by the maximum primary stress, most in calculated tank structure intensity
Big secondary stress, maximum primary plus secondary stress, maximum total stress and national standard《JB/T4732-2005 steel pressure vessel-
Analyze design standard》Compared one by one, if there are one not being inconsistent standardization requirement above, need to take integral reinforcing storage tank or
Person repairs the defect of stress higher position；
S4. when containing crackle or incomplete fusion in defect type, Ansys softwares need to be used to calculate storage tank crackle under real load
Or the point stresses intensity factor of incomplete fusion, by the point stresses intensity factor of crackle in storage tank or incomplete fusion and the storage tank institute
It is compared using the fracture toughness of material；If the stress intensity factor of storage tank is less than fracture toughness, crackle and incomplete fusion exist
It can't be extended under current working；If it is greater than or equal to fracture toughness, then crackle and incomplete fusion have generation under current working
The possibility of extension need to repair in time, eliminate extension hidden danger；
S5. Ansys softwares, load specific loading is used to carry out stable calculation, the spy of tank material buckling analysis is calculated
Unstability does not occur and can bear maximum load for value indicative, that is, storage tank；If the load that characteristic value is more than gained in Strength Calculation is practical
Maximum total stress under load modes, then unstability does not occur for storage tank, if characteristic value is less than the load of gained in Strength Calculation
Maximum total stress under real load pattern, then storage tank unstability has occurred, then need eliminate unstable position all defect or
Integral reinforcing is carried out to storage tank；
S6. when the result being calculated in step S3, S4 and S5 can be met the requirements, then show under the storage tank current working
It need not place under repair, Daily Round Check can be reinforced, regular non-destructive testing ensures the safety of storage tank by shortening round of visits
Property；If more than one result of calculation is unsatisfactory for requiring, need according to the corresponding place of result of calculation selection for being unsatisfactory for requiring
Reason measure simultaneously calculates storage tank after processing again, with verification processing effect.
Wherein, the material of the storage tank uses linear elastic materials.
Wherein, nondestructive means in the step S1 select radiographic inspection to be combined with magnetic powder inspection, radiographic inspection and
One kind in penetrant inspection combination.
Wherein, real load is loaded in the step S3 and calculate tank structure intensity, specifically include following steps：A. basis
Medium, material, structure and the max reassembly amount of storage tank apply maximum level load and from heavy load to storage tank；B. inquiry is local
Highest wind velocity and it is on the books since highest earthquake intensity, load maximum wind velocity load and maximum seismic (seismal；C. it is walked by loading
Maximum level load in rapid a and step b, from heavy load, maximum wind velocity load and maximum seismic (seismal, calculate the storage tank
In the stress distribution suffered by local most extreme environment, the stress distribution includes maximum primary stress, maximum secondary stress, most
It is big once to add secondary stress and maximum total stress.
Wherein, in the step S4 load real load calculate storage tank in the point stresses intensity of crackle or incomplete fusion because
Son specifically includes following steps：According to linear elastic fracture mechanics theory, in Ansys softwares, stress-strain field is established；It uses
Ansys software calculating stress strength factors；When establishing stress-strain field, first, for the crackle or incomplete fusion on storage tank, draw
The line of the open bottom of crackle or incomplete fusion；Secondly, the office at description crackle or incomplete fusion tip is defined first using KACLC orders
Portion's coordinate system；Again, definition is along the path of crack surface；Finally, it is strong that defect or the point stresses of incomplete fusion position in storage tank are calculated
Spend the factor；Wherein, in Ansys software calculating stress strength factors, it is plane stress or plane to need manual designated analysis type
One kind in strain, the calculating for storage tank stress intensity factor select plane stress.
Wherein, in the step S5, load specific loading carries out stable calculation, according to Plate Theory, linear elasticity shell
Section very little between the balance and unstability of component, when linear elasticity hin shell member balances, material is in elastic deformation；When
When linear elasticity hin shell member unstability, material enters surrender；Storage tank load specific loading stable calculation needs bending based on material
Clothes are calculated；Stable calculation specifically includes following steps：(1) the face regional location one with actual loading is loaded on storage tank
The specific loading of cause, while applying identical constraints；(2) in Ansys softwares, the eigenvalue buckling in software point is used
Characteristic value is calculated in analysis；(3) characteristic value being calculated is multiplied by the specific loading of application, when obtaining storage tank unstability not occurring
The maximum load that can bear, since loaded load is unit load, obtained characteristic value is storage tank in step (2)
The maximum load that can bear when unstability does not occur；(4) it can bear when unstability not being occurred for the storage tank obtained in step (3)
Characteristic value in maximum load, that is, step (2) and obtained load real load mould in Strength Calculation in the S1 steps
Maximum total stress under formula is compared analysis；If characteristic value is more than the maximum total stress obtained in Strength Calculation, store up
Unstability does not occur for tank；Conversely, storage tank unstability.
With the above structure, the present invention has the beneficial effect that：The present invention has filled up the storage tank flaw evaluation side of the current country
The blank of method, it is proposed that a kind of storage tank flaw evaluation system based on finite element modelling is calculated by finite element soft Ansys and stored up
The structural strength and stability of tank analyze the point stresses intensity factor of crackle and incomplete fusion, prevent crack propagation；Meanwhile
The two kinds of failure modes of strength failure and unstability for considering storage tank, can more all-sidedly and accurately evaluate the safe condition of storage tank.This hair
Deficiency in terms of the bright current state's inner storage tank Safety Assessment Standard of solution and missing, by non-destructive testing detection early period in conjunction with software meter
The method of calculation, the safe condition of storage tank is had evaluated from multi-angles such as structural mechanics, fracture mechanicses, and result of calculation has higher reliable
Property.
Description of the drawings
Fig. 1 is the flow chart of the overall evaluation method of the present invention；
Fig. 2 is the stress result figure after the storage tank Ansys simulations of embodiment one in the present invention；
Fig. 3 is the stress result figure after the storage tank Ansys simulations of embodiment two in the present invention；
Fig. 4 is the stress result figure after the storage tank Ansys simulations of embodiment three in the present invention；
Fig. 5 is the stress result figure after the storage tank Ansys simulations of example IV in the present invention；
Fig. 6 is the stress result figure after the storage tank Ansys simulations of embodiment five in the present invention；
Fig. 7 is the stress result figure after the storage tank Ansys simulations of embodiment six in the present invention；
Fig. 8 is the stress result figure after the storage tank Ansys simulations of embodiment seven in the present invention；
Fig. 9 is the stress result figure after the storage tank Ansys simulations of embodiment eight in the present invention；
Specific implementation mode
The present invention will be further described below with reference to the drawings.
In order to make the purpose , technical scheme and advantage of the present invention be clearer, below in conjunction with attached drawing and specific implementation
Mode, the present invention will be described in further detail.It should be appreciated that the specific embodiments described herein are only explaining this
Invention, is not intended to limit the present invention.
As shown in Figure 1, a kind of overall evaluation method to the atmospheric storage tank containing defect, wherein the material of the storage tank is adopted
Use linear elastic materials；Specifically include following steps：
S1. the property of defect, size and position on storage tank are detected using nondestructive means；Wherein, the nondestructive inspection side
Method selects one kind during radiographic inspection is combined with magnetic powder inspection, radiographic inspection is combined with penetrant inspection.
S2. finite element analysis Ansys softwares are used, in Ansys, according to the position of tank structure and defect, size, property
Matter, according to 1:1 equal proportion establishes the storage tank model containing defect.
S3. Ansys softwares, load real load is used to calculate tank structure intensity, the calculating of the tank structure intensity
Including maximum primary stress, maximum secondary stress, maximum primary plus secondary stress, maximum total stress calculating, and will calculate
Tank structure intensity in maximum primary stress, maximum secondary stress, it is maximum once plus secondary stress, maximum total stress and state
Family's standard《JB/T4732-2005 steel pressure vessel-analysis design standard》Compared one by one, if there are one do not meet above
Requirements of the national standard then needs to take integral reinforcing storage tank or repairs the defect of stress higher position；Wherein, the load is practical
LOAD FOR tank structure intensity, specifically includes following steps：A. according to the medium of storage tank, material, structure and maximum filling weight,
Maximum level load is applied to storage tank and from heavy load；B. inquire local highest wind velocity and it is on the books since highest earthquake intensity,
Load maximum wind velocity load and maximum seismic (seismal；C. pass through the maximum level load in load step a and step b, heavy duty certainly
Lotus, maximum wind velocity load and maximum seismic (seismal calculate stress distribution of the storage tank suffered by local most extreme environment,
The stress distribution includes maximum primary stress, maximum secondary stress, maximum primary plus secondary stress and maximum total stress.Due to
Country, which there is no, at present formulates professional standard about storage tank, and storage tank and pressure vessel in structure and in use condition in the presence of compared with
More similitudes, therefore this programme reference《Steel pressure vessel-analysis design standard》
S4. use Ansys softwares, load real load calculate storage tank in the point stresses intensity of crackle or incomplete fusion position because
Son will lack the fracture toughness of crackle or the point stresses intensity factor and the used material of the storage tank of incomplete fusion position in storage tank
It is compared；If the stress intensity factor of storage tank is less than the defect of fracture toughness, crackle and incomplete fusion under current working simultaneously
It will not extend；If it is greater than or equal to fracture toughness, then crackle and incomplete fusion have the possibility extended under current working,
It need to repair in time, eliminate the defect of extension hidden danger；Wherein, the load real load calculates the point of crackle or incomplete fusion in storage tank
Stress intensity factor is held, following steps are specifically included：According to linear elastic fracture mechanics theory, in Ansys softwares, stress is established
Strain field；Use Ansys software calculating stress strength factors；When establishing stress-strain field, first, on storage tank crackle or
Incomplete fusion draws the line of the open bottom of crackle or incomplete fusion, secondly, is defined first using KACLC orders and describes crackle or not
The local coordinate system at tip is fused, again, is defined along the path of crack surface；Finally, defect or incomplete fusion position in storage tank are calculated
Point stresses intensity factor；Wherein, in Ansys software calculating stress strength factors, it is flat to need manual designated analysis type
One kind in face stress or plane strain, the calculating for storage tank stress intensity factor select plane stress.
S5. Ansys softwares, load specific loading is used to carry out stable calculation, tank material buckling analysis is calculated
Characteristic value, that is, storage tank unstability do not occur can bear maximum load；If characteristic value is more than the load of gained in Strength Calculation
Maximum total stress under real load pattern, then unstability does not occur for storage tank, if characteristic value is less than gained in Strength Calculation
The maximum total stress under real load pattern is loaded, then unstability has occurred for storage tank, then needs all defect for eliminating unstable position
Or integral reinforcing is carried out to storage tank；Wherein, load specific loading carries out stable calculation, and according to Plate Theory, linear elasticity is thin
Section very little between the balance and unstability of mould component, when linear elasticity hin shell member balances, material is in elastic deformation；
When linear elasticity hin shell member unstability, material enters surrender；Storage tank load specific loading stable calculation is needed based on material
Surrender is calculated；Stable calculation specifically includes following steps：(1) the face regional location with actual loading is loaded on storage tank
Consistent specific loading, while applying identical constraints；(2) in Ansys softwares, the eigenvalue buckling in software is used
Characteristic value is calculated in analysis；(3) characteristic value being calculated is multiplied by the specific loading of application, storage tank is obtained and unstability does not occur
When the maximum load that can bear, since loaded load is unit load, obtained characteristic value is storage in step (2)
The maximum load that can bear when unstability does not occur for tank；(4) it can bear when unstability not being occurred for the storage tank obtained in step (3)
Maximum load, that is, step (2) in characteristic value and the S1 steps in obtained load real load in Strength Calculation
Maximum total stress under pattern is compared analysis；If characteristic value is more than the maximum total stress obtained in Strength Calculation,
Unstability does not occur for storage tank；Conversely, storage tank has unstability risk.
S6. when the result being calculated in step S3, S4 and S5 can be met the requirements, then show the current work of the storage tank
It need not place under repair under condition, Daily Round Check can be reinforced, regular non-destructive testing ensures the peace of storage tank by shortening round of visits
Quan Xing；If more than one result of calculation is unsatisfactory for requiring, need corresponding according to the result of calculation selection for being unsatisfactory for requiring
Treatment measures simultaneously calculate storage tank after processing again, have verified that treatment effect.
The computational methods of wind load suffered by storage tank, include the following steps：It for 12 grades of typhoons of 36m/s is basic wind to use wind speed
Speed analyzes the wind load that storage tank is subject to according to the pertinent regulations of wind load.
Following formula is that the wind load standard value acted perpendicularly on tall and slender structure surface unit area calculates：
wk=βzμsμzw0
In formula, βzWind pulse at-height z；
mμs- structural shape factor of wind load；
mμz- height variation coefficient of wind pressure；
w0- fundamental wind pressure (KN/m2)
Wherein βz=1+ ξ ε1ε2
X ξ-fluctuation amplifying coefficient in formula；
ε1- wind pressure pulsation and wind pressure height change etc. influence coefficient；
ε2- the vibration shape, construction profile influence coefficient.
The relationship of wind speed and wind pressure can be obtained according to the Bernoulli equation in hydrodynamics.What the wind speed of free stream generated
Wind pressure w on unit area0(KN/m2) be：
In formula
w0--- the wind pressure (KN/m on unit area2)；
R ρ --- atmospheric density (t/m3)；n
v0--- wind speed (m/s).
The atmospheric conditions in different geographical locations are different, so atmospheric density also differs.Atmospheric density be air pressure,
The function of temperature and humidity can determine as the following formula：
In formula
T --- air themperature (DEG C)；
P --- air pressure (Pa)；
pvap--- vapour pressure (Pa).
Atmospheric density can also be according to the height above sea level z (m) of location approximate estimation as the following formula：
ρ=0.00125e-0.0001z(t/m3)r
When height above sea level is 0m, atmospheric density ρ=1.25kg/m3, then fundamental wind pressure w is understood0(KN/m2)：
Remaining parameter is not only related with the build of storage tank and size, also related with ambient enviroment and surface roughness.According to wind load
The specification handbook of calculating divides since the relevant parameter of height difference wind load is just different so carrying out different height to storage tank
Piecewise analysis.
The wind load that storage tank is subject to is divided into two to calculate according to height, is the upper storage that average height is 9.375m respectively
Tank load F1, it is highly the lower storage tank F2, specific result of calculation such as following table 2-1 and table 2-2 of 2.818m：
Wind load relevant parameter when table 2-1 wind speed is 36m/s
| Component | Highly (m) | Fluctuation amplifying coefficient ξ | Influence coefficient ε1 | Influence coefficient ε2 | Wind pulse β3 |
| Upper oil storage tank | 9.375 | 2.16 | 0.72 | 0.30 | 1.467 |
| Lower oil storage tank | 2.818 | 2.16 | 0.72 | 0.08 | 1.124 |
Wind load relevant parameter when table 2-2 wind speed is 36m/s
It is as follows to load real load calculating tank structure strength analysis method：According to storage tank real work situation, storage tank is by certainly
Body gravity, internal hydrostatic pressure and effect (the wherein hydrostatic pressure consideration for considering the wind load under inclement weather conditions
The case where water is filled in storage tank).The load condition being subject to according to storage tank passes through finite element analysis software to storage tank model
ANSYSWorkbench carries out finite element static structure calculating, specifically includes following steps：Storage tank model is imported into
In ANSYSWorkbench, since tank roof is reduced to lumped mass.Mesh generation is carried out to storage tank model.It is added for model
Constraint, the bottom surface that storage tank is arranged are fixed constraint.According to storage tank stressing conditions, apply load for storage tank model, including storage tank by
The wind load being subject under the action of force 12 wind by the static pressure of internal liquid, storage tank to its own gravity load, storage tank.It asks
Solution, obtains the stress distribution cloud atlas of storage tank.
Embodiment used in the present invention is the crude oil storage tank that a use surpasses 20 years, which selects 5000 cubes
Rice vertical cylinder steel (interior floating plate) welds storage tank, and the threedimensional model of storage tank is established according to storage tank two dimensional model figure, utilizes three
Dimension modeling software solidworks establish internal diameter r be 11440mm, thickness be 6mm height be 6400mm, thickness is that 8mm height is
3000mm, thickness 10mm, highly it is 1500mm and thickness is each one piece of annulus that 12mm height is 1600mm, is assembled
Storage tank three-dimensional model diagram, tank material select Q235 steel.It is required tank roof being reduced to lumped mass according to analysis, size is
22.16t.Storage tank three-dimensional simplified is imported in finite element analysis software ANSYS Workbench softwares, definition material is
Q235, storage tank select Meshing Method to be divided for mapping surface grids.
To ensure safety in production, radiographic inspection is carried out to it and lossless detection method that magnetic powder inspection is combined, as a result shown
Show exist inside the storage tank welding seam a large amount of lack of penetration.Therefore using the overall evaluation method of the atmospheric storage tank of the present invention to storage
The overall performance of tank evaluate as follows：When oil storage tank presence is a large amount of lack of penetration, the intensity of weld seam will reduce, when weld seam
When intensity deficiency, it will weld seam is caused to destroy, it is therefore desirable to analyze weld seam there are it is lack of penetration constantly, the intensity of oil storage tank weld seam is big
It is small.
Selection highest first weld seam of lower part stress is studied, when the lack of penetration place's thickness of weld seam is reduced to wall thickness thickness
1/2 when, analyze oil storage tank weld seam intensity；Model is imported in ANSYS Workbench, lumped mass is added, divides net
Lattice, and apply load and constraint for model；Solution obtains oil storage tank Stress Map and maximum stress partial enlarged view：It can by analysis
See, when weld seam is steel plate thickness 1/2, limit stress of the maximum stress of weld seam already close to Q235 steel under limiting condition.
Oil storage tank is during long-time service, however not excluded that therefore the weld seam of some positions can lead to Cracking Failure.
Embodiment one
Oil storage pot bottom second layer weld seam have 1/3 it is lack of penetration when stability analysis, concrete analysis it is as follows：Model is imported
In ANSYSWorkbench, when the oil storage pot bottom second layer has 1/3 weld cracking, by the contact between the Oil Storage Tank Model second layer
It is set as 2/3 contact surface binding, and fixed constraint is added in oil storage pot bottom；Apply gravity for Oil Storage Tank Model；For oil storage
Tank model applies wind load；It solves, obtains the stress result after oil storage tank linear buckling, as shown in Fig. 2, by solving the line obtained
Property buckling stress result obtain, graph area show the buckling load factor be only 0.49413.Therefore when the oil storage pot bottom second layer welds
Be sewed with 1/3 it is lack of penetration when, unstability will occur for oil storage tank under the action of wind load and gravity.
Embodiment two
Stability analysis when oil storage pot bottom second layer weld seam has 1/3 lack of penetration (crack is discontinuous), concrete analysis are as follows：Weld seam
(assuming that there are two positions to crack for weld seam, and 1/6) weld cracking is all when cracking 1/3 and discontinuous cracking；Model is imported
In ANSYS Workbench, when the oil storage pot bottom second layer has 1/3 weld cracking and discontinuous weld cracking, by oil storage tank mould
Contact between the second layer of type bottom is set as 2/3 binding, adds fixed constraint to Oil Storage Tank Model and applies load；It solves,
Obtain the stress result after oil storage tank linear buckling, as shown in figure 3, obtained by solving the linear buckling stress result obtained,
Graph area shows that the buckling load factor is 1.5563.Therefore oil storage pot bottom second layer weld seam have that 1/3 is lack of penetration but crack not
Consecutive hours, oil storage tank can keep stable under the action of wind load and gravity.
Embodiment three
Oil storage pot bottom second layer weld seam have 1/2 it is lack of penetration when stability analysis, concrete analysis it is as follows：Model is imported
In ANSYSWorkbench, when the oil storage pot bottom second layer has 1/2 weld cracking, by the contact between the Oil Storage Tank Model second layer
It is set as 1/2 contact surface binding, and fixed constraint is added in oil storage pot bottom；Apply gravity for Oil Storage Tank Model；For oil storage
Tank model applies wind load；It solves, obtains the stress result after oil storage tank linear buckling, as shown in Figure 4；By solving the line obtained
Property buckling stress result obtain, graph area show the buckling load factor be 0.1391.Therefore work as oil storage pot bottom second layer weld seam
Have 1/2 it is lack of penetration when, unstability will occur for oil storage tank under the action of wind load and gravity.
Example IV
Stability analysis when oil storage pot bottom second layer weld seam has 1/2 lack of penetration (crack is discontinuous), concrete analysis are as follows：By mould
Type imports in ANSYS Workbench, when the oil storage pot bottom second layer has 1/2 weld cracking and discontinuous weld cracking, will store up
Contact between the oil tank model bottom second layer is set as 1/2 binding, adds fixed constraint to Oil Storage Tank Model and applies load；
It solves, obtains the stress result after oil storage tank linear buckling, as shown in Figure 5；By solving the linear buckling stress result obtained
It obtains, graph area shows that the buckling load factor is 0.92749.Therefore oil storage pot bottom second layer weld seam have 1/2 it is lack of penetration still
When crack is discontinuous, unstability will occur under the action of wind load and gravity for oil storage tank.
Tightness improvement is carried out to above-mentioned 20 years crude oil storage tank structures, selects the channel steel of four 36#C, length 12m,
Uniform welding is in storage tank surrounding, after being reinforced.
Contain that part weld seam is lack of penetration in tank body, for not carrying out analysis of stability containing saturating tank body containing commissure
Analysis, it is as a result as follows：
Embodiment five
The tank bottom second layer have 1/3 it is lack of penetration when stability, include the following steps：
Model is imported in ANSYS Workbench, the tank bottom second layer have 1/3 weld seam it is lack of penetration when, by storage tank model the
Contact between two layers is set as 2/3 contact surface binding, and adds fixed constraint in tank bottom；Storage tank model applies weight
Power；Apply wind load for storage tank model；It solves, obtains the stress result after storage tank linear buckling after reinforcing, as shown in Figure 6；Pass through
It solves and show that the linear buckling stress result after reinforcing obtains, graph area shows that the buckling load factor is only 2.4565, and storage tank adds
After Gu tank bottom second layer weld seam have 1/3 it is lack of penetration when, under the action of wind and gravity will not unstability, reinforcement measure improve
The stability of oil storage tank.
Embodiment six
Tank bottom second layer weld seam has 1/3 lack of penetration and stability analysis when crack is discontinuous, includes the following steps：
Weld seam is lack of penetration 1/3 and it is discontinuous lack of penetration when, it is assumed that weld seam is there are two position is lack of penetration, and it is all 1/ that weld seam is lack of penetration
6；Model is imported in ANSYS Workbench, the tank bottom second layer has 1/3 weld seam lack of penetration, and when weld seam is discontinuous, will
Contact between the storage tank model bottom second layer is set as 2/3 binding, adds fixed constraint to storage tank model and applies load；It asks
Solution obtains storage tank linear buckling stress result after reinforcing, as shown in Figure 7；Linear buckling is answered after obtaining storage tank reinforcing by solution
Power result show that graph area shows that the buckling load factor is 2.119.Therefore tank bottom second layer weld seam have 1/3 it is lack of penetration but
When being that crack is discontinuous, after storage tank reinforcing under the action of wind load and gravity, unstability, reinforcement measure do not improve oil storage tank to storage tank
Stability.
Embodiment seven
Tank bottom second layer weld seam have 1/2 it is lack of penetration when stability analysis, specifically include following steps：Model is imported
In ANSYSWorkbench, the tank bottom second layer have 1/2 weld seam it is lack of penetration when, the contact between the storage tank model second layer is set
It is set to 1/2 contact surface binding.And add fixed constraint in tank bottom；Apply gravity for storage tank model；It is applied for storage tank model
Add wind load；It solves, obtains storage tank linear buckling stress result after reinforcing, as shown in Figure 8；It is linear after the reinforcing obtained by solution
Buckling stress result show that graph area shows that the buckling load factor is 3.555.Therefore when tank bottom second layer weld seam has 1/2
When lack of penetration, unstability will not occur for storage tank after being reinforced under the action of wind load and gravity, and reinforcement measure improves oil storage tank
Stability.
Embodiment eight
Tank bottom second layer weld seam has 1/2 lack of penetration, and stability analysis when crack is discontinuous, specifically includes following steps：
Model is imported in ANSYS Workbench, the tank bottom second layer has 1/2 weld seam lack of penetration and when weld seam is discontinuous, will store up
Contact between the tank model bottom second layer is set as 1/2 binding, adds fixed constraint to storage tank model and applies load, asks
Solution, obtains the stress result after storage tank linear buckling, as shown in Figure 9；By solve obtain storage tank reinforce after linear buckling stress
As a result it obtains, graph area shows that the buckling load factor is 3.6378.Therefore tank bottom second layer weld seam has 1/2 not weld after reinforcing
It is saturating but it is discontinuous when, unstability will not occur under the action of wind load and gravity for storage tank, and reinforcement measure improves oil storage tank
Stability.
By the above embodiments one to embodiment eight it is found that the present invention has filled up the storage tank flaw evaluation method of the current country
Blank, it is proposed that a kind of storage tank flaw evaluation system based on finite element modelling calculates storage tank by finite element soft Ansys
Structural strength and stability, in the presence of crackle and incomplete fusion, analyze crackle and incomplete fusion point stresses intensity
The factor prevents crackle and incomplete fusion tip extension；Simultaneously, it is contemplated that two kinds of failure modes of strength failure and unstability of storage tank, energy
More all-sidedly and accurately evaluate the safe condition of storage tank.The present invention solve deficiency in terms of current state's inner storage tank Safety Assessment Standard with
Missing combines the method that software calculates by non-destructive testing detection early period, is had evaluated from multi-angles such as structural mechanics, fracture mechanicses
The safe condition of storage tank, result of calculation have higher reliability.
The above is merely illustrative of the technical solution of the present invention and unrestricted, and those of ordinary skill in the art are to this hair
The other modifications or equivalent replacement that bright technical solution is made, as long as it does not depart from the spirit and scope of the technical scheme of the present invention,
It is intended to be within the scope of the claims of the invention.
Claims (7)
1. a kind of overall evaluation method to the atmospheric storage tank containing defect, which is characterized in that include the following steps：It detects on storage tank
Property, size and the position of defect；According to tank structure and defective locations, size, property, defect is established in Ansys softwares
Storage tank model；Using Ansys softwares, load real load calculates tank structure intensity and storage tank stress intensity factor, load
Specific loading carries out stable calculation；To the tank structure intensity, storage tank stress intensity factor and stability result being calculated
It is evaluated, fully assesses the safe condition of storage tank.
2. a kind of overall evaluation method to the atmospheric storage tank containing defect according to claim 1, which is characterized in that specific
Include the following steps：
S1. the property of defect, size and position on storage tank are detected using nondestructive means；
S2. finite element analysis Ansys softwares are used, in Ansys, according to the position of the structure of storage tank and defect, size, property
Matter, according to 1:1 equal proportion establishes the storage tank model containing defect；
S3. Ansys softwares are used, real load is loaded, calculate tank structure intensity, the real load is according to storage tank itself
Situation and storage tank local environment calculate, and the calculating of the tank structure intensity includes maximum primary stress, maximum secondary stress, most
Big primary plus secondary stress, maximum total stress calculating, and by the maximum primary stress, most in calculated tank structure intensity
Big secondary stress, maximum primary plus secondary stress, maximum total stress and national standard《JB/T4732-2005 steel pressure vessel-
Analyze design standard》Compared one by one, if there are one not being inconsistent standardization requirement above, need to take integral reinforcing storage tank or
Person repairs the defect of stress higher position；
S4. when containing crackle or incomplete fusion in defect type, Ansys softwares need to be used to calculate storage tank crackle under real load
Or the point stresses intensity factor of incomplete fusion, by the point stresses intensity factor of crackle in storage tank or incomplete fusion and the storage tank institute
It is compared using the fracture toughness of material；If the stress intensity factor of storage tank is less than fracture toughness, crackle and incomplete fusion exist
It can't be extended under current working；If it is greater than or equal to fracture toughness, then crackle and incomplete fusion have generation under current working
The possibility of extension need to repair in time, eliminate extension hidden danger；
S5. Ansys softwares, load specific loading is used to carry out stable calculation, the spy of tank material buckling analysis is calculated
Unstability does not occur and can bear maximum load for value indicative, that is, storage tank；If the load that characteristic value is more than gained in Strength Calculation is practical
Maximum total stress under load modes, then unstability does not occur for storage tank, if characteristic value is less than the load of gained in Strength Calculation
Maximum total stress under real load pattern, then storage tank unstability has occurred, then need eliminate unstable position all defect or
Integral reinforcing is carried out to storage tank；
S6. when the result being calculated in step S3, S4 and S5 can be met the requirements, then show under the storage tank current working
It need not place under repair, Daily Round Check can be reinforced, regular non-destructive testing ensures the safety of storage tank by shortening round of visits
Property；If more than one result of calculation is unsatisfactory for requiring, need according to the corresponding place of result of calculation selection for being unsatisfactory for requiring
Reason measure simultaneously calculates storage tank after processing again, with verification processing effect.
3. a kind of overall evaluation method to the atmospheric storage tank containing defect according to claim 1 or 2, which is characterized in that
The material of the storage tank uses linear elastic materials.
4. a kind of overall evaluation method to the atmospheric storage tank containing defect according to claim 2, which is characterized in that described
Nondestructive means in step S1 selects one during radiographic inspection is combined with magnetic powder inspection, radiographic inspection is combined with penetrant inspection
Kind.
5. a kind of overall evaluation method to the atmospheric storage tank containing defect according to claim 2, which is characterized in that described
Real load is loaded in step S3 and calculates tank structure intensity, specifically includes following steps：A. according to the medium of storage tank, material,
Structure and max reassembly amount apply maximum level load and from heavy load to storage tank；B. local highest wind velocity and on the books is inquired
Since highest earthquake intensity, load maximum wind velocity load and maximum seismic (seismal；C. by load step a and step b most
Big liquid level load, from heavy load, maximum wind velocity load and maximum seismic (seismal, calculate the storage tank in local most extreme environment
Stress distribution suffered by lower, the stress distribution once add secondary stress including maximum primary stress, maximum secondary stress, maximum
And maximum total stress.
6. a kind of overall evaluation method to the atmospheric storage tank containing defect according to claim 2, which is characterized in that described
Real load is loaded in step S4 and calculates the point stresses intensity factor of crackle or incomplete fusion in storage tank, specifically includes following step
Suddenly：According to linear elastic fracture mechanics theory, in Ansys softwares, stress-strain field is established；Stress is calculated using Ansys softwares
Intensity factor；When establishing stress-strain field, first, for the crackle or incomplete fusion on storage tank, opening for crackle or incomplete fusion is drawn
The line of mouth bottom；Secondly, description crackle or the local coordinate system at incomplete fusion tip are defined first using KACLC orders；Again, fixed
Justice is along the path of crack surface；Finally, the point stresses intensity factor of defect or incomplete fusion position in storage tank is calculated；Wherein, exist
When Ansys software calculating stress strength factors, it is one kind in plane stress or plane strain, needle to need manual designated analysis type
Plane stress is selected to the calculating of storage tank stress intensity factor.
7. a kind of overall evaluation method to the atmospheric storage tank containing defect according to claim 2, which is characterized in that described
In step S5, load specific loading carries out stable calculation, according to Plate Theory, the balance and unstability of linear elasticity hin shell member it
Between section very little, when linear elasticity hin shell member balances, material is in elastic deformation；When linear elasticity hin shell member unstability
When, material enters surrender；Storage tank load specific loading stable calculation needs the surrender based on material to be calculated；Stability meter
Calculator body includes the following steps：（1）The specific loading consistent with the face regional location of actual loading is loaded on storage tank, is applied simultaneously
Add identical constraints；（2）In Ansys softwares, characteristic value is calculated using the Eigenvalue Buckling Analysis in software；
（3）The characteristic value being calculated is multiplied by the specific loading of application, obtains the maximum load that storage tank does not occur to can bear when unstability
Lotus, since loaded load is unit load, step（2）In obtained characteristic value unstability when institute energy does not occur for storage tank
The maximum load born；（4）By step（3）In obtained storage tank the maximum load that can bear when unstability i.e. step does not occur
（2）In characteristic value in Strength Calculation in the S1 steps it is obtained load real load pattern under maximum always answer
Power is compared analysis；If characteristic value is more than the maximum total stress obtained in Strength Calculation, unstability does not occur for storage tank；Instead
It, storage tank unstability.
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