CN102798539A - Method for evaluating failure possibility in quantitative risk analysis of pressure-bearing equipment - Google Patents

Abstract

The invention discloses a method for evaluating failure possibility in quantitative risk analysis of pressure-bearing equipment. The method comprises the steps of: correcting failure possibility in RBI (Risk Based Inspection) of quantitative risk analysis by adopting misalignment angular distortion defect parameters, wherein the calculation method of the failure possibility F is that: F=FG*(FE+FD)*FM, wherein FG is an average failure probability of similar equipment, FD is a misalignment angular distortion defect correction parameter, FE is an equipment correction coefficient and FM is a management correction coefficient. As the misalignment angular distortion defect correction factor is introduced, the method for evaluating the failure possibility in the quantitative risk analysis of the pressure-bearing equipment, disclosed by the invention, has the advantages of avoiding the limitation that the misalignment and angular distortion defect are not considered in the API581 standard and enabling the calculation result of the pressure-bearing equipment with the misalignment and angular distortion defect in the risk analysis process to be more accurate. On the basis of the RBI, the method for evaluating the failure possibility in the quantitative risk analysis of the pressure-bearing equipment can obtain corresponding correction factors conveniently and rapidly by determining the size of the defect.

Description

Failure likelihood evaluation method in a kind of quantitative risk analysis of bearing device

Technical field

The present invention relates to the failure likelihood evaluation method in a kind of quantitative risk analysis of bearing device, particularly a kind of method that contains the quantitative risk analysis of misalignment and angular deformation defective bearing device.

Background technology

Bearing device is meant with pressure to be that basic load relates to life security, dangerous bigger pressure vessel, pressure pipeline, boiler, pressure-bearing annex etc.Along with progress of science and technology and industrial development; The usable range of bearing device is increasingly extensive; Bearing device is own through becoming chemical industry at present; Visual plant in each departments such as petroleum industry and petrochemical complex, coal, metallurgy, atomic energy, aerospace, oceanographic engineering, light industry, weaving, food, urban construction guarantees that it moves safely and reliably, to ensure people's safety of life and property, promoting national economic development has great importance.

Check (Risk based inspection is called for short RBI) based on risk is in the method for pursuing a kind of optimizing check strategy of setting up on the unified ideal basis of security of system and economy.The method is proposed and carries out the nineties in 20th century by American Petroleum Institute the earliest, introduces China afterwards, and is applied in the petrochemical equipment; Optimizing check efficient; Reduce or keep at least be equal to risk level in, prolong the operation of equipment time and the cycle of operation, reduce recondition expense.

In the API581 standard, always supposition equipment manufactures and designs completion according to strictness, does not have any original excessive defect.In the such developing country of China; Quite a few bearing device is owing to various reasons; Design, left over when making and much exceed the defective that manufactures and designs standard, the performance of domestic material is stable inadequately in addition, makes that the equipment breakdown that causes because of original excessive defect is of common occurrence.

Chinese patent " in the bearing device risk assessment be the failure probability evaluation method of characterization parameter with the residual life "; Application number CN200610039771.7; Introduce be exactly a kind of be the risk evaluating method of the bearing device of characterization parameter with the residual life alternate design life-span; For the venture analysis that contains the excessive defect bearing device, need to meet calculating to the several different methods of different problems, improve the accuracy of analyzing conclusion.

Bearing device owing to reasons such as pre-bending, assembling, welding are improper, is prone to produce misalignment and angular deformation defective in manufacture process.The existence of these defectives has caused the discontinuous of partial structurtes geometric configuratioies, and causes high additional bending stress at discontinuous place.If when quoting API581 these bearing devices that contain original excessive defect being carried out venture analysis, do not consider of the influence of these defectives, cause the value-at-risk and the actual conditions that calculate to have bigger difference to equipment operation.Therefore, with prior art the bearing device that contains misalignment and angular deformation defective is carried out venture analysis and have many irrationalities.

Summary of the invention

Goal of the invention: technical matters to be solved by this invention is the deficiency to prior art, and the failure likelihood evaluation method in a kind of quantitative risk analysis of bearing device is provided.

In order to solve the problems of the technologies described above, the invention discloses the failure likelihood evaluation method in a kind of quantitative risk analysis of bearing device, adopt the failure likelihood among misalignment and the angular deformation defect parameters correction quantitative risk analysis RBI;

The computing method of said failure likelihood F are:

F=F _G×(F _E+F _G)×F _M，

Wherein, F _GBe the average failure probability of same category of device, F _DBe misalignment and angular deformation defect correction coefficient, F _EBe equipment correction factor, F _MThe management correction factor.

Misalignment and angular deformation defect correction coefficient F _DDefinite method be:

(1) adopt macroscopic examination method in inside and outside to measure the height at the top of the horn peak of the unfitness of butt joint of misalignment defective in the bearing device, angular deformation defective;

(2) confirm that bearing device produces the stress of misalignment and angular deformation fault location;

The ratio R of the membrane stress that the bending stress of (3) confirming to confirm to bring out based on misalignment and angular deformation defective causes pressure load _b

The ratio R of the membrane stress that the bending stress of (4) confirming to confirm to bring out based on misalignment and angular deformation defective causes additional load _Bs

(5) confirm residual intensity coefficients R SF;

(6) set up the inefficacy equation of bearing device to be evaluated, adopt following formula:

Z=RSF-RSF _a，

RSF _aThe residual intensity coefficient that expression allows, RSF _aIn international standard " API579 " 2-7, check in.

(7) calculate the failure probability P that contains misalignment and angular deformation defective based on Monte Carlo method _f

(8) confirm to contain the correction factor F of misalignment and angular deformation defective _DValue.

Step (7) may further comprise the steps:

(a) adopt Monte Carlo method to calculate the failure likelihood of bearing device to be evaluated; The distribution pattern of confirming stray parameter is (in the bearing device Analysis on defects; The distribution form of mainly using has normal distribution, lognormal distribution, exponential distribution and Weibull distribution) and the simulation times N (Monte Carlo method is that a kind of computing machine that utilizes is asked the method for approximate solution through sampling test, and the precision of analog result is directly with to simulate number of times relevant.Facts have proved; For general engineering technology problem; The simulation times N is taken as 3000 ~ 5000 times and can satisfies requirement of engineering precision), parameter comprises the height at the top of the horn peak of unfitness of butt joint and angular deformation defective of internal diameter, wall thickness, interior pressure, permissible stress (parameter that can find according to the instructions of bearing device), the misalignment defective of bearing device;

(b) parameter in the employing step (a), double counting step successively (2) ~ (6) are up to N time according to each parameter distribution value (being generated the value of this parameter by computing machine according to the definite distribution pattern of this parameter), and simulation finishes;

(c) obtain losing efficacy equation value Z less than 0 inferior numerical value X, adopt following formula to calculate the failure probability P that contains misalignment and angular deformation defective _f:

P _f=X/N。

Adopt following formula to calculate the correction factor F that contains misalignment and angular deformation defective in the step (8) _D,

F _D=P _f/F _C

F wherein _CExpression accumulative total general failure possibility.F _CIn international standard " API 581 2008 ", check in.

Beneficial effect: the present invention is the failure likelihood evaluation method in a kind of quantitative risk analysis of bearing device; The misalignment and the angular deformation defect correction factor have been introduced; Avoided not considering in the API581 standard limitation of misalignment and angular deformation defective, made that the result of calculation of bearing device in the venture analysis process that contains misalignment and angular deformation defective is more accurate.This invention through to the confirming of flaw size, obtains corresponding with it modifying factor subnumber quickly and easily on the basis based on the check of risk.

Under the situation that has excessive defect at present, adopt this method that equipment is carried out venture analysis, value-at-risk that records and actual conditions similarity are higher, have reduced device security hidden danger, have reduced the accident generation.The present invention has considered the influence to bearing device of misalignment and angular deformation defective, the modifying factor F of introducing _D, make that the result of venture analysis is more accurate, optimized the check strategy, improved checkability, also more reasonable more targetedly to bearing device check maintenance the time, prolong the operation of equipment time and the cycle of operation, reduce recondition expense.

Description of drawings

Below in conjunction with accompanying drawing and embodiment the present invention is done specifying further, above-mentioned and/or otherwise advantage of the present invention will become apparent.

Fig. 1 is the schematic flow sheet of quantitative risk analysis of the present invention.

Fig. 2 is bearing device venture analysis weighting adjustment coefficient pie graph among the present invention.

Fig. 3 is the structural representation of misalignment defective among the present invention.

Fig. 4 is the structural representation of angular deformation defective among the present invention.

Embodiment

The invention discloses the failure likelihood evaluation method in a kind of quantitative risk analysis of bearing device, adopt the failure likelihood among misalignment and the angular deformation defect parameters correction quantitative risk analysis RBI;

The computing method of said failure likelihood F are:

F=F _G×(F _E+F _D)×F _M，

Wherein, F _GBe the average failure probability of same category of device, F _DBe misalignment and angular deformation defect correction coefficient, F _EBe equipment correction factor, F _MThe management correction factor.

Misalignment and angular deformation defect correction coefficient F _DDefinite method (is example with the spherical tank):

(1) adopts macroscopic examination method in inside and outside to measure misalignment and angular deformation flaw size take place in the bearing device; Described inside and outside macroscopic examination method (" special equipment solder technology " be data as a reference); With the naked eye or 5 ~ 10 accompany magnifier to detect and measure misalignment and angular deformation defective, the height δ at the top of the horn peak of the unfitness of butt joint e of misalignment defective and angular deformation defective with ruler or special measuring tool.

(2) confirm the stress of bearing device generation misalignment and angular deformation fault location, adopt following formula,

(2.1) confirm the membrane stress of bearing device generation misalignment and angular deformation fault location, adopt following formula,

obtains through consulting international standard " API579 " Table A-7

(2.2) if there is additional load, confirm the membrane stress of bearing device generation misalignment and angular deformation fault location and making a concerted effort of bending stress, adopt following formula,

obtains through consulting international standard " API579 " 8-7

Wherein, σ _mThe expression membrane stress, P representes the actual bearing load of bearing device, R representes the radius of bearing device cylindrical shell or spheroid; T representes the wall thickness of bearing device; E representes welding coefficient, and F representes the clean axial force of section, and A representes that metal cross section is long-pending; M representes the net section moment of flexure, and Z representes the modulus of section of cross section metal;

The ratio of the membrane stress that the bending stress of (3) confirming to bring out based on misalignment and angular deformation defective causes pressure load

(3.1) bending stress of confirming to bring out based on unfitness of butt joint adopts following formula with respect to the ratio of membrane stress,

${R_b}^{\mathrm{scjc}}=9.6291\left({10}^{-3}\right)+3.0791\left(\frac{e}{t-\mathrm{FCA}}\right)-0.24587{\left(\frac{e}{t-\mathrm{FCA}}\right)}^2+0.025734{\left(\frac{e}{t-\mathrm{FCA}}\right)}^3+$

$0.059281{\left(\frac{e}{t-\mathrm{FCA}}\right)}^4-6.1979\left({10}^{-3}\right)S_p+1.9252\left({10}^{-4}\right){S_p}^2+1.9815\left({10}^{-6}\right){S_p}^3-$

$1.8194\left({10}^{-7}\right){S_p}^4+2.0698\left({10}^{-9}\right){S_p}^5,$

In the formula;

obtains through consulting international standard " API579 " table 8.11

FCA representes the corrosion allowance of bearing device; E representes the unfitness of butt joint of misalignment defective, and t representes bearing device cylindrical shell or spheroid wall thickness (if the wall thickness of misalignment defective both sides is different, getting thin side thickness value); V representes Poisson ratio; P representes the actual bearing load of bearing device, and R representes the radius of bearing device cylindrical shell or spheroid, E _yThe expression Young modulus, S _pBe intermediate variable;

(3.2) bending stress of confirming to bring out based on the top of the horn peak heights adopts following formula with respect to the ratio of membrane stress,

${R_b}^{\mathrm{scja}}=\frac{C_1}{C_2},$

In the formula, C ₁=3.082+1.7207 (10 ^-3) S _p+ 1.3641 ψ+0.062407 ψ ²-0.033961 ψ ³,

C ₂=1.0+8.9503(10 ^-3)S _p-2.8724(10 ^-4)S _p+5.0797(10 ^-6)S _p ³-0.21717ψ，

obtains through consulting international standard " API579 " table 8.11

Wherein, δ representes the height at the top of the horn peak, S _pWith ψ be intermediate variable;

The ratio of the membrane stress that the bending stress of (3.3) confirming to bring out based on misalignment and angular deformation defective causes pressure load adopts following formula,

R _b=R _b ^Scjc+ R _b ^Scja, obtain through consulting international standard " API579 " 8-8,

The ratio of the membrane stress that the bending stress of (4) confirming to bring out based on misalignment and angular deformation defective causes additional load adopts following formula,

R _Bs=-1.0 (obtaining) through consulting international standard " API579 " 8-8

(5) confirm residual intensity coefficients R SF, adopt following formula,

$\mathrm{RSF}=\mathrm{Min}[\frac{H_f{S}_a}{{\mathrm{\σ}}_m(1+R_b)+{\mathrm{\σ}}_{\mathrm{Ms}}(1+R_{\mathrm{Bs}})},1.0],$ Obtain through consulting international standard " API579 " 8-8,

Wherein, RSF representes bearing device residual intensity coefficient, S _aExpression waits to evaluate the pairing permissible stress of bearing device;

H _fThe expression coefficient, when the stress that brings out when the formation of misalignment and angular deformation defective is primary stress, H _f=1.5, when misalignment and angular deformation defective form the stress that brings out and are secondary stress, H _f=3.0;

(6) set up the inefficacy equation of waiting to evaluate bearing device, adopt following formula,

Z=RSF-RSF _a，

Wherein, RSF _aThe residual intensity coefficient that expression allows;

With RSF value and RSF _aValue substitution inefficacy equation, judgement contains the safe condition of the bearing device of misalignment and angular deformation defective; If Z>0, judge that then it is safe containing this defective bearing device, bearing device can continue operation; Otherwise, i.e. Z<0, judge and contain this defective bearing device result for dangerous;

(7) calculate the failure probability that contains misalignment and angular deformation defective based on Monte Carlo method;

(8) confirm to contain the correction factor F of misalignment and angular deformation defective _DBe worth, and calculate the failure likelihood F of locking equipment to be evaluated.

Step (7) may further comprise the steps:

(a) adopt Monte Carlo method to calculate the failure likelihood of bearing device to be evaluated; Confirm the parameter distributions type; Comprise that normal distribution, lognormal distribution, logarithm distribute and Weibull distribution; And set the simulation times N, and the N span is a natural number, parameter comprises the height at the top of the horn peak of unfitness of butt joint and the angular deformation defective of internal diameter, the wall thickness of bearing device, interior pressure, permissible stress, misalignment defective;

For misalignment and angular deformation defective; Its distribution pattern that is suitable for mainly contains normal distribution, lognormal distribution and Weibull distribution; Normal distribution is the most conservative with respect to logarithm distribution and Weibull distribution, therefore in actual engineering, if be not sure of the distribution form of stochastic variable; The selection normal distribution that can guard, so normal distribution is adopted in the distribution of misalignment defective e and angular deformation defective δ.

Bearing device is in the process of design, and equipment wall thickness B satisfies certain regularity of distribution, assert that usually it satisfies normal distribution.Along with of the influence of factors such as the growth of duration of service and environment, make wall thickness B to reduce gradually to equipment.Consider above-mentioned these reasons, adopt the truncation normal distribution to come to reflect better the situation of actual wall thickness.Therefore, the truncation normal distribution is adopted in the distribution of the wall thickness B of bearing device.

The statistical distribution type of major parameter

Should be pointed out that the parameter distributions type is not a core of the present invention, those skilled in the art also know how to confirm concrete distribution pattern according to above various parameters.

(b) parameter in the employing step (a), up to N time, simulation finishes according to each parameter distribution value double counting step successively (2) ~ (6);

(c) obtain losing efficacy the equation value less than 0 inferior numerical value X, then contain the failure probability P of misalignment and angular deformation defective _fAdopt following formula to calculate:

P _f=X/N。

The correction factor F that contains misalignment and angular deformation defective described in the step (8) _DBe correction, adopt following formula bearing device failure likelihood F,

F _D=P _f/ F _C, consult " ORBIT Help " excessively and obtain,

F wherein _CExpression accumulative total general failure possibility.

Embodiment 1

Present embodiment discloses a kind of bearing device risk analysis method that contains misalignment and angular deformation defective, may further comprise the steps:

1, adopt macroscopic examination method in inside and outside to confirm position, the shape and size of misalignment and angular deformation defective in the bearing device.

2, confirm the membrane stress of locating of bearing device generation misalignment and angular deformation defective,

3, set up the Failure Assessment equation

The ratio R of the membrane stress that the bending stress of at first, confirming to bring out causes pressure load _b, adopt following formula,

R _b=R _b ^scjc+R _b ^scja；

The ratio R of the membrane stress that bending stress of then, confirming to bring out and extra-stress cause _Bs, adopt following formula,

R _bs=-1.0

Once more, confirm the residual intensity coefficient, adopt following formula,

$\mathrm{RSF}=\min [\frac{H_f{S}_a}{{\mathrm{\&sigma;}}_m(1+R_b)+{\mathrm{\&sigma;}}_{\mathrm{ms}}(1+R_{\mathrm{bs}})},1.0]$

Wherein, RSF representes bearing device residual intensity coefficient,

H _fThe expression coefficient, when the stress that brings out when the formation of misalignment and angular deformation defective is primary stress, H _f=1.5, when misalignment and angular deformation defective form the stress that brings out and are secondary stress, H _f=3.0;

At last, value and the RSF of the RSF that aforementioned calculation is obtained _aValue substitution inefficacy equation, adopt following formula,

Z=RSF-RSF _a

Wherein, RSF _aThe residual intensity coefficient that expression allows;

If Z>0, think that then this defects assessment is safe, bearing device can continue operation; Otherwise, promptly Z 0, think that this defects assessment result is for dangerous;

4, based on Monte Carlo method calculating failure probability, may further comprise the steps:

(1) confirm the distribution pattern and the simulation times N of a plurality of stray parameters related in the Monte Carlo method, parameter comprises the height at the top of the horn peak of unfitness of butt joint and the angular deformation defective of internal diameter, wall thickness, interior pressure, permissible stress, misalignment defective;

(2) confirm that the inefficacy equation adopts following formula,

Z=RSF-RSF _a；

(3) calculate R _bValue and R _BsValue;

(4) value and the RSF of calculating RSF _aValue;

(5) with value and the RSF of RSF _aValue substitution inefficacy equation Z=RSF-RSF _aCalculate;

(6) parameter in the employing step (1), up to N time, simulation finishes according to each parameter distribution value repeating step successively (3) ~ (5);

(7) the equation value that obtains losing efficacy is X time less than 0 number of times, and the failure probability that then contains misalignment and angular deformation defective adopts following formula,

P _f=X/N。

5, confirm misalignment and angular deformation defect correction coefficient F _D, calculate the bearing device failure likelihood

Misalignment and angular deformation defect correction coefficient F _D, adopt following formula,

F _D=P _f/ F _C, with the computing formula correction of venture analysis, adopt following formula,

F=F _G×(F _E+F _D)×F _M，

Obtain waiting to evaluate the bearing device failure likelihood;

Wherein, F representes bearing device failure likelihood, F _GRepresent the average failure probability of international same category of device, F _CExpression accumulative total general failure possibility, P _fExpression contains the failure probability of misalignment and angular deformation defective, F _DExpression contains the correction factor of misalignment and angular deformation defective, F _EThe indication equipment correction factor, F _MExpression management correction factor, F _G, F _C, F _E, F _MIn international standard " Risk based inspection 2008 ", check in.

Embodiment 2

Below case through a practical application specify the present technique scheme.

A certain lpg spherical tank came into operation in 1998, carried out complete examination first, and did not pinpoint the problems in 2002.Completely examined in 2012, and found that there was crackle at a jar end.The material of this spherical tank is 07MnCrMoVR, and internal diameter is 9200mm, and wall thickness is 38mm, and welding coefficient is 1, and corrosion allowance is 1mm.Working temperature is a normal temperature, and on-stream pressure is 2.94MPa.Find in the macroscopic examination of inside and outside that the spherical tank middle part exists angular deformation and misalignment defective.Testing result shows that this angular deformation amount is 10mm, and unfitness of butt joint is 4mm.

Utilize present embodiment that the misalignment and the angular deformation defective of this spherical tank are revised at present, calculate the failure likelihood of bearing device, its process is following:

1, utilizes the inside and outside macroscopic examination to confirm the position and the size of defective, comprise angular deformation amount δ and unfitness of butt joint e;

The inside and outside macroscopic examination finds that the spherical tank bottom exists misalignment and angular deformation defective.Testing result shows that this angular deformation amount is 10mm, and unfitness of butt joint is 4mm.

2, the mechanical property of material

The lpg spherical tank material is 07MnCrMoVR in the present embodiment, mechanical property such as table 1

The mechanical property of table 1 07MnCrMoVR

3, confirm the stress of bearing device generation misalignment and angular deformation fault location

In present case, misalignment and angular deformation defective appear in the spherical tank bottom, through consulting the membrane stress that international standard " API579 " appendix A obtains fault location;

${\mathrm{\&sigma;}}_m=\frac{P}{2E}(\frac{R}{t}+0.2)=183.1\mathrm{MPa}$

Wherein, σ _mThe expression membrane stress, P representes the actual bearing load of bearing device, and R representes the radius of bearing device cylindrical shell or spheroid, and t representes the wall thickness of bearing device, and E representes welding coefficient;

The ratio of the membrane stress that the bending stress of 4, confirming to confirm to bring out based on misalignment and angular deformation defective causes pressure load

(1) bending stress of confirming to bring out based on unfitness of butt joint adopts following formula with respect to the ratio of membrane stress,

${R_b}^{\mathrm{scjc}}=9.6291\left({10}^{-3}\right)+3.0791\left(\frac{e}{t-\mathrm{FCA}}\right)-0.24587{\left(\frac{e}{t-\mathrm{FCA}}\right)}^2+0.025734{\left(\frac{e}{t-\mathrm{FCA}}\right)}^3+$

$0.059281{\left(\frac{e}{t-\mathrm{FCA}}\right)}^4-6.1979\left({10}^{-3}\right)S_p+1.9252\left({10}^{-4}\right){S_p}^2+1.9815\left({10}^{-6}\right){S_p}^3-$

$1.8194\left({10}^{-7}\right){S_p}^4+2.0698\left({10}^{-9}\right){S_p}^5=0.2735$

In the formula, $S_p=\sqrt{\frac{12(1-v^2){\mathrm{PR}}^3}{E_y{(t-\mathrm{FCA})}^3}}=17.39,$

(2) bending stress of confirming to bring out based on the top of the horn peak heights adopts following formula with respect to the ratio of membrane stress,

${R_b}^{\mathrm{scja}}=\frac{C_1}{C_2}=1.481,$

In the formula, C ₁=3.082+1.7207 (10 ^-3) S _p+ 1.3641 ψ+0.062407 ψ ²-0.033961 ψ ³=1.922,

C ₂=1.0+8.9503(10 ^-3)S _p-2.8724(10 ^-4)S _p+5.0797(10 ^-6)S _p ³-0.21717ψ=1.298，

$\mathrm{\&psi;}=\ln \left(\frac{\mathrm{\&delta;}}{C_{\mathrm{ul}}}\right)=-0.932;$

The ratio of the membrane stress that the bending stress of (3) confirming to bring out based on misalignment and angular deformation defective causes pressure load adopts following formula,

R _b=R _b ^scjc+R _b ^scja=1.754

The ratio of the membrane stress that the bending stress of 5, confirming to confirm to bring out based on misalignment and angular deformation defective causes additional load adopts following formula,

R _Bs=-1.0 (obtaining) through consulting international standard " API579 " 8-8

6, confirm the residual intensity coefficient

The residual intensity coefficient is used to define the acceptability that a member is on active service continuously, when calculating the residual intensity coefficient, at first confirms the make a concerted effort ratio of sum of membrane stress that permissible stress and membrane stress and additional load cause and bending stress;

$\frac{H_f{S}_a}{{\mathrm{\&sigma;}}_m(1+R_b)+{\mathrm{\&sigma;}}_{\mathrm{ms}}(1+R_{\mathrm{bs}})}=1.208$

Secondly, whether judge the aforementioned calculation value less than 1, as if less than 1, residual intensity coefficient then

$\mathrm{RSF}=\frac{H_f{S}_a}{{\mathrm{\&sigma;}}_m(1+R_b)+{\mathrm{\&sigma;}}_{\mathrm{ms}}(1+R_{\mathrm{bs}})},$

Otherwise, RSF=1;

Draw residual intensity coefficient value RSF=1 in the present case at last;

Wherein, RSF representes bearing device residual intensity coefficient, H _fThe expression coefficient, the stress that the formation of misalignment and angular deformation defective is brought out in the present case is secondary stress, H _f=3.0;

7, set up the inefficacy equation

The inefficacy equation that the present invention adopted is following,

Z=RSF-RSF _a

The RSF substitution that aforementioned calculation is obtained wherein obtains Z=0.1;

The Z value that calculates thinks that greater than 0 this misalignment and angular deformation defective are to accept, and can guarantee that this bearing device normally moves.

7, based on Monte Carlo method calculating failure probability

This paper adopts Monte Carlo method to bearing device calculating failure possibility to be measured, carries out numerical simulation with matlab, and it is 5000 times that delivery is intended number of times.Stray parameter distributes and character such as table 2 in the model.

Table 2 stray parameter and distribution thereof

The parameter title	Symbol	The regularity of distribution	Average	Standard deviation	The upper bound
						Internal diameter/mm	D	Normal distribution	9200	46
Wall thickness/mm	t	The truncation normal distribution	38	1.9	38
						The top of the horn peak heights/mm	δ	Normal distribution	10	2
Unfitness of butt joint/mm	e	Normal distribution	4	0.8
						Interior pressure/MPa	P	Normal distribution	2.94	0.294
Permissible stress/MPa	S a	Normal distribution	203	40.6

According to each parameter distribution rule, can know that with the result of matlab process analysis bearing device can not safe operation, i.e. Z<0, contain the failure probability P of misalignment and angular deformation defective _fBe 0.0552.

8, confirm the correction factor F of misalignment and angular deformation defective _D, calculate the bearing device failure likelihood

According to formula F _D=P _f/ F _C, calculate the correction factor F of misalignment and angular deformation defective _D=354.2.

By formula F=F based on risk inspection _G* F _E* F _MCalculate its failure likelihood, according to formula, obtaining failure likelihood is 7.65*10 ^-4, the failure likelihood grade is 3 grades.

Press this patent method, introducing contains misalignment and angular deformation defect correction coefficient F _DThis bearing device is carried out failure likelihood calculate, according to formula, F=F _G* (F _E+ F _D) * F _M, obtaining failure likelihood is 1.159*10 ^-2, the failure likelihood grade is 5 grades.

The invention provides the thinking and the method for the failure likelihood evaluation method in a kind of quantitative risk analysis of bearing device; The method and the approach of concrete this technical scheme of realization are a lot, and the above only is a preferred implementation of the present invention, should be understood that; For those skilled in the art; Under the prerequisite that does not break away from the principle of the invention, can also make some improvement and retouching, these improvement and retouching also should be regarded as protection scope of the present invention.The all available prior art of each ingredient not clear and definite in the present embodiment realizes.

Claims (4)

1. the failure likelihood evaluation method in the quantitative risk analysis of a bearing device is characterized in that, adopts the failure likelihood among misalignment and the angular deformation defect parameters correction quantitative risk analysis RBI;

The computing method of said failure likelihood F are:

F=F _G×(F _E+F _D)×F _M，

Wherein, F _GBe the average failure probability of same category of device, F _DBe misalignment and angular deformation defect correction coefficient, F _EBe equipment correction factor, F _MThe management correction factor.

2. evaluation method according to claim 1 is characterized in that, misalignment and angular deformation defect correction coefficient F _DDefinite method be:

(1) height at the top of the horn peak of the unfitness of butt joint of misalignment defective, angular deformation defective in the measurement bearing device;

(2) confirm that bearing device produces the stress of misalignment and angular deformation fault location;

The ratio R of the membrane stress that the bending stress of (3) confirming to confirm to bring out based on misalignment and angular deformation defective causes pressure load _b

The ratio R of the membrane stress that the bending stress of (4) confirming to confirm to bring out based on misalignment and angular deformation defective causes additional load _Bs

(5) confirm residual intensity coefficients R SF;

(6) set up the inefficacy equation of bearing device to be evaluated, adopt following formula:

Z=RSF-RSF _a，

RSF _aThe residual intensity coefficient that expression allows;

(7) calculate the failure probability P that contains misalignment and angular deformation defective based on Monte Carlo method _f

(8) confirm to contain the correction factor F of misalignment and angular deformation defective _DValue.

3. evaluation method according to claim 2; It is characterized in that; Step (7) may further comprise the steps: (a) adopt Monte Carlo method to calculate the failure likelihood of bearing device to be evaluated; Confirm the parameter distributions type, comprise that normal distribution, lognormal distribution, logarithm distribute and Weibull distribution, and set the simulation times N; The N span is a natural number, and parameter comprises the height at the top of the horn peak of unfitness of butt joint and the angular deformation defective of internal diameter, the wall thickness of bearing device, interior pressure, permissible stress, misalignment defective;

(b) parameter in the employing step (a), according to each parameter distribution value, double counting step successively (2) ~ (6) are up to N time, and simulation finishes;

(c) obtain losing efficacy equation value Z less than 0 inferior numerical value X, adopt following formula to calculate the failure probability P that contains misalignment and angular deformation defective _f:

P _f=X/N。

4. evaluation method according to claim 3 is characterized in that, adopts following formula to calculate the correction factor F that contains misalignment and angular deformation defective in the step (8) _D,

F _D=P _f/F _C

Wherein FC representes accumulative total general failure possibility.

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