Stress calculation method for composite material reinforcing defective pipeline and calculation system thereof

Abstract

The application discloses a stress calculation system and method for a composite material reinforced defective pipeline. Relevant parameters are measured; the hoop stress of a pipeline matrix defect area, the hoop stress of a filling material, the hoop stress of a composite material, the axial stress of the pipeline matrix defect area and the axial stress of the composite material in an elastic stage of the composite material reinforced defective pipeline are calculated; the pressure when the pipeline matrix yields is calculated; the hoop stress of the pipeline matrix defect area, the hoop stress of the filling material, the hoop stress of the composite material, the axial stress of the pipeline matrix defect area and the axial stress of the composite material after yielding are calculated; and the burst pressure is calculated. The method considers the elastic-plastic constitutive relationship before and after the pipeline matrix yields, and can accurately calculate the hoop stress and the axial stress of the pipeline matrix, the filling material and the composite material in the whole process from no load to pipeline burst. The method is simple, and has high operability, and the accuracy of the calculation of the ultimate internal pressure bearing capacity is improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of reinforcement construction design of pressure vessels, and particularly relates to a stress calculation method for composite material reinforced defective pipelines and a calculation system thereof. BACKGROUND

[0002] Different forms of defects may occur in a pressure vessel during service. For defects such as wall thinning, composite material reinforcement is a room temperature reinforcement method with simple construction and wide application. The stress state reflects the stress state of the pressure vessel, the filling material and the composite material, and accurate calculation of the stress of the composite material reinforced pressure vessel plays an important role in evaluating the reinforcement effect of the composite material and the strength of the pressure vessel after reinforcement. The current calculation method for the stress of the composite material reinforced pressure vessel only considers the hoop stress and ignores the influence of the axial stress, and also ignores the strain hardening effect of the pressure vessel after yielding. For the composite material reinforced pressure vessel with defects, the axial stress and the hoop stress jointly act to determine the stress state of the pressure vessel. Ignoring the strain hardening reduces the accuracy of the stress. SUMMARY

[0003] The application provides a stress calculation method for composite material reinforced defective pipelines, which corrects the deviation caused by the above-mentioned assumptions, improves the accuracy of the calculation of the ultimate internal pressure bearing capacity, and is simple and easy to operate.

[0004] The application is implemented by the following technical solutions:

[0005] A stress calculation method for composite material reinforced defective pipelines, the stress calculation method comprising the following steps:

[0006] Step 1: measuring the related parameters of the defective pipeline and the related parameters of the filling material;

[0007] Step 2: based on the parameters in step 1, calculating the hoop stress of the defective area of the pipeline matrix, the hoop stress of the filling material, the hoop stress of the composite material, the axial stress of the defective area of the pipeline matrix and the axial stress of the composite material in the elastic stage of the composite material reinforced defective pipeline;

[0008] Step 3: based on the hoop stress and the axial stress of the defective area of the pipeline matrix in the elastic stage of the composite material reinforced defective pipeline in step 2, calculating the pressure when the defective pipeline matrix yields;

[0009] Step 4: based on the pressure when the defective pipeline matrix yields in step 3, calculating the hoop stress of the defective area of the pipeline matrix, the hoop stress of the filling material, the hoop stress of the composite material, the axial stress of the defective area of the pipeline matrix and the axial stress of the composite material after yielding;

[0010] Step 5: based on the hoop stress of the composite material after yielding in step 4, calculating the burst pressure.

[0011] A stress calculation method for a composite material reinforced defective pipeline, wherein step 1 defective pipeline related parameters include defective pipeline elastic modulus E s , yield strength σ y , initial outer diameter r c , initial inner diameter r i , defective area defective pipeline outer diameter r p , and residual wall thickness t s ; measured elastic modulus E p of the filling material; and composite material related parameters including hoop elastic modulus E c , axial elastic modulus E ca , tensile strength σ c , and the distance r e from the outer surface of the composite material to the center of the defective pipeline.

[0012] A stress calculation method for a composite material reinforced defective pipeline, wherein step 2 calculates the filling material thickness of the composite material reinforced defective pipeline to be equal to the defect depth.

[0013] A stress calculation method for a composite material reinforced defective pipeline, wherein step 2 calculates the hoop stress σ θse of the defective area of the pipeline matrix in the elastic stage of the composite material reinforced defective pipeline by the following formula, wherein r p is the distance from the outer surface of the filling material to the center of the pipeline:

[0014]

[0015] The hoop stress σ θpe of the filling material in the elastic stage of the composite material reinforced defective pipeline is calculated by the following formula:

[0016]

[0017] The hoop stress σ θce of the composite material in the elastic stage of the composite material reinforced defective pipeline is calculated by the following formula:

[0018]

[0019] The axial stress σ ase of the defective area of the pipeline matrix in the elastic stage of the composite material reinforced defective pipeline is calculated by the following formula:

[0020]

[0021] The axial stress σ ace of the composite material in the elastic stage of the composite material reinforced defective pipeline is calculated by the following formula:

[0022]

[0023] A stress calculation method for a composite material reinforced defective pipeline, wherein step 3 calculates the pressure P at which the base material of the defective pipeline yields y The following formula is calculated by substituting formula (7)-(8) into (6):

[0024]

[0025]

[0026]

[0027] A stress calculation method for a composite material reinforced defective pipeline, wherein step 4 calculates the hoop stress σ of the defective pipeline base material defect area after the composite material reinforced defective pipeline yields θs The following formula is calculated:

[0028]

[0029] The hoop stress σ of the filling material after the composite material reinforced defective pipeline yields θp The following formula is calculated:

[0030]

[0031] The hoop stress σ of the composite material after the composite material reinforced defective pipeline yields θc The following formula is calculated:

[0032]

[0033] The axial stress σ of the defective pipeline base material defect area in the elastic stage of the composite material reinforced defective pipeline as The following formula is calculated:

[0034]

[0035] The axial stress σ of the composite material after the composite material reinforced defective pipeline yields ac The following formula is calculated:

[0036]

[0037] A stress calculation method for a composite material reinforced defective pipeline, wherein step 5 calculates the burst pressure P b The following formula is calculated:

[0038]

[0039] A stress calculation method for reinforcing defective pipes with composite materials, based on the equality of radial displacement of the defective pipe, filling material, and composite material, and the relationship between radial displacement and circumferential strain, the circumferential strain of the defective pipe, filling material, and composite material satisfies the following equation:

[0040] ε θs r i =ε θp (r p )=ε θc r c (15);

[0041] ε in equation (15) θs ε θp and ε θc These are defective pipes, filling materials, and composite materials, respectively. θc Circumferential strain;

[0042] When the defective conduit is in the elastic stage, the circumferential stress of the defective conduit, the filling material, and the composite material is: σ θs =E s ε θc r c / r i ;σ θp =E p ε θc r c / r p ;σ θc =E c ε θc (16);

[0043] Based on the equilibrium condition of reinforced composite materials for defective pipes under internal pressure, the relationship between the defective pipe, the filling material, and the circumferential stress of the composite material is as follows:

[0044] PD = 2(σ θs t r +σ θf t f +σ θc t c (17);

[0045] Substituting formula (16) into (17), we obtain formulas (1), (2) and (3);

[0046] When the defective conduit is in the elastic stage, the axial stress of the defective conduit, the filling material, and the composite material is: σ as =E s ε a ;σ ap =0; σ ac =E ca ε a(18);

[0047] According to the equilibrium condition of the composite reinforced defective pipeline under internal pressure, the relationship among the defective pipeline, the filling material and the axial stress of the composite material is:

[0048]

[0049] The formula (18) is brought into (19) to obtain the formula (4) and (5);

[0050] The yield pressure is calculated according to the von-Mises yield criterion;

[0051] The pressure P in the formula (1), (2), (3), (4) and (5) is replaced by the pressure increment P-P y after yielding to obtain the stress increment caused by the defective pipeline under the pressure increment P-P y , and the sum of the stress under the pressure P and the stress increment is the stress under the pressure P.

[0052] A stress calculation method for a composite material reinforced defective pipeline, before the defective pipeline yields, E s =E se , wherein E se is the elastic modulus of the defective pipeline;

[0053] The Von-Mises yield criterion is used to determine whether the defective pipeline yields;

[0054] After the defective pipeline yields, E s =[1 / E se +(na / b)(σ / b) n-1 ] -1 ,

[0055] wherein E se is the elastic modulus of the defective pipeline, and a, b and n are material constants, which are obtained by fitting the real stress-strain curve of the defective pipeline.

[0056] A stress calculation method for a composite material reinforced defective pipeline, the stress calculation system comprises a measurement unit and a calculation unit;

[0057] The measurement unit is used to measure the related parameters of the defective pipeline and the related parameters of the filling material;

[0058] The data processing unit is used for calculating hoop stress of the defect area of the pipeline base body in the elastic stage of the composite material reinforced defect pipeline, hoop stress of the filling material in the elastic stage of the composite material reinforced defect pipeline, hoop stress of the composite material in the elastic stage of the composite material reinforced defect pipeline, axial stress of the defect area of the pipeline base body in the elastic stage of the composite material reinforced defect pipeline and axial stress of the composite material in the elastic stage of the composite material reinforced defect pipeline, calculating the pressure when the defect pipeline base body yields, calculating hoop stress of the defect area of the pipeline base body after the composite material reinforced defect pipeline yields, hoop stress of the filling material after the composite material reinforced defect pipeline yields, hoop stress of the composite material after the composite material reinforced defect pipeline yields, axial stress of the defect area of the pipeline base body after the composite material reinforced defect pipeline yields and axial stress of the composite material after the composite material reinforced defect pipeline yields, calculating the burst pressure and outputting the result.

[0059] The present application has the following advantages:

[0060] The present application can calculate the stress of the pipeline base body, the filling material and the composite material in the composite material reinforced defect pipeline, and can guide the selection of the filling material and the composite material and the reinforcement design of the defect pipeline.

[0061] The present application adopts the Ranbery-Osgood model to simulate the elastic-plastic behavior of the pipeline base body, and the fitting degree is more accurate and convenient to apply.

[0062] The present application considers the elastic-plastic constitutive relation before and after the pipeline base body yields, and can accurately calculate the hoop stress and the axial stress of the pipeline base body, the filling material and the composite material from the no-load to the pipeline burst. BRIEF DESCRIPTION OF DRAWINGS

[0063] Figure 1 is a schematic diagram A of the composite material reinforced pressure vessel under pressure of the present application.

[0064] Figure 2 is a schematic diagram B of the composite material reinforced pressure vessel under pressure of the present application.

[0065] Figure 3 is a structural schematic diagram of the present application.

[0066] Figure 4 is a method flowchart of the present application.

[0067] Figure 5 is a comparison diagram of the present application and the test and stress. DETAILED DESCRIPTION

[0068] Clearly, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present application.

[0069] A stress calculation method for a composite material reinforced defective pipeline, the stress calculation method comprising the following steps:

[0070] Step 1: measuring pressure vessel related parameters and filling material related parameters;

[0071] Step 2: based on the parameters in step 1, calculating the hoop stress of the defective area of the container base body in the elastic stage of the composite material reinforced pressure vessel, the hoop stress of the defective area of the filling material in the elastic stage of the composite material reinforced defective pipeline, the hoop stress in the elastic stage of the composite material reinforced defective pipeline, the axial stress of the defective area of the container base body in the elastic stage of the composite material reinforced pressure vessel, and the axial stress in the elastic stage of the composite material reinforced defective pipeline;

[0072] Step 3: based on the hoop stress of the defective area of the container base body in the elastic stage of the reinforced pressure vessel in step 2, calculating the pressure when the pressure vessel base body yields;

[0073] Step 4: based on the pressure when the pressure vessel base body yields in step 3, calculating the hoop stress of the defective area of the pressure vessel base body after the composite material reinforced defective pipeline yields, the hoop stress of the defective area of the filling material in the elastic stage of the composite material reinforced defective pipeline, the hoop stress in the elastic stage of the composite material reinforced defective pipeline, the axial stress of the defective area of the container base body in the elastic stage of the composite material reinforced pressure vessel, and the hoop stress in the elastic stage of the composite material reinforced defective pipeline;

[0074] Step 5: based on the hoop stress of the defective area of the pressure vessel base body after the reinforced defective pipeline yields in step 4, calculating the burst pressure.

[0075] A stress calculation method for a composite material reinforced defective pipeline, the step 1 defective pipeline related parameters comprising the elastic modulus E s of the defective pipeline, the yield strength σ y , the initial outer diameter r c , the initial inner diameter r i , the outer diameter r p of the defective area of the defective pipeline, and the residual wall thickness t s ; the elastic modulus E p of the filling material is measured; the composite material related parameters comprising the hoop elastic modulus E c , the axial elastic modulus E ca , the tensile strength σ cand the distance r of the outer surface of the composite material to the center of the defective pipe e .

[0076] A stress calculation method for a composite material reinforced defective pipe, wherein the thickness of the filling material of the composite material reinforced defective pipe is calculated in step 2 to be equal to the defect depth.

[0077] A stress calculation method for a composite material reinforced defective pipe, wherein the hoop stress σ of the defective area of the pipe matrix in the elastic stage of the composite material reinforced defective pipe is calculated in step 2. θse calculated by the following formula, wherein r p is the distance from the outer surface of the filling material to the center of the pipe:

[0078]

[0079] The hoop stress σ of the defective area of the filling material in the elastic stage of the composite material reinforced defective pipe θpe calculated by the following formula:

[0080]

[0081] The hoop stress σ in the elastic stage of the composite material reinforced defective pipe θce calculated by the following formula:

[0082]

[0083] The axial stress σ of the defective area of the pipe matrix in the elastic stage of the composite material reinforced pressure vessel ase calculated by the following formula:

[0084]

[0085] The axial stress σ in the elastic stage of the composite material reinforced defective pipe ace calculated by the following formula:

[0086]

[0087] A stress calculation method for a composite material reinforced defective pipe, wherein the pressure P when the pipe matrix of the defective pipe yields in step 3 y calculated by substituting formulas (7)-(8) into (6) as follows:

[0088]

[0089]

[0090]

[0091] A stress calculation method of a composite material reinforced defective pipeline, wherein the hoop stress σ of the defective pipeline matrix defect area after the composite material reinforced defective pipeline yields in step 4 is calculated θs The hoop stress σ of the composite material reinforced defective pipeline after yielding is calculated by the following formula:

[0092]

[0093] The hoop stress σ of the composite material reinforced defective pipeline after yielding is calculated by the following formula: θp The hoop stress σ of the composite material reinforced defective pipeline after yielding is calculated by the following formula:

[0094]

[0095] The hoop stress σ of the composite material reinforced defective pipeline after yielding is calculated by the following formula: θc The hoop stress σ of the composite material reinforced defective pipeline after yielding is calculated by the following formula:

[0096]

[0097] The axial stress σ of the defective pipeline matrix defect area in the elastic stage of the composite material reinforced defective pipeline is calculated by the following formula: as The axial stress σ of the defective pipeline matrix defect area in the elastic stage of the composite material reinforced defective pipeline is calculated by the following formula:

[0098]

[0099] The axial stress σ of the composite material reinforced defective pipeline after yielding is calculated by the following formula: ac The axial stress σ of the composite material reinforced defective pipeline after yielding is calculated by the following formula:

[0100]

[0101] A stress calculation method of a composite material reinforced defective pipeline, wherein the burst pressure P in step 5 is calculated b The burst pressure P in step 5 is calculated by the following formula:

[0102]

[0103] A stress calculation method of a composite material reinforced defective pipeline, according to the equal radial displacement of the defective pipeline, the filling material and the composite material and the relationship between the radial displacement and the hoop strain, the hoop strain of the defective pipeline, the filling material and the composite material satisfies the equation:

[0104] ε θs r i = ε θp (r p ) = ε θc r c (15);

[0105] ε θs , ε θp and ε θcThese are defective pipes, filling materials, and composite materials, respectively. θc circumferential strain;

[0106] When the defective conduit is in the elastic stage, the circumferential stress of the defective conduit, the filling material, and the composite material is: σ θs =E s ε θc r c / r i ;σ θp =E p ε θc r c / r p ;σ θc =E c ε θc (16);

[0107] Based on the equilibrium condition of reinforced composite materials for defective pipes under internal pressure, the relationship between the defective pipe, the filling material, and the circumferential stress of the composite material is as follows:

[0108] PD = 2(σ θs t r +σ θf t f +σ θc t c (17);

[0109] Substituting formula (16) into (17), we obtain formulas (1), (2) and (3);

[0110] When the defective conduit is in the elastic stage, the axial stress of the defective conduit, the filling material, and the composite material is: σ as =E s ε a ;σ ap =0; σ ac =E ca ε a (18);

[0111] Based on the equilibrium condition of reinforced composite material pipes under internal pressure, the relationship between the axial stress of the defective pipe, the filling material, and the composite material is as follows:

[0112]

[0113] Substituting formula (18) into (19), we obtain formulas (4) and (5);

[0114] Calculate the yield pressure according to the von-Mises yield criterion;

[0115] Substitute the pressure P in the formula (1), (2), (3), (4) and formula (5) with the pressure increment P-P y after yielding of the defective pipeline, obtain the stress increment caused by the pressure increment P-P y after yielding of the defective pipeline under the action of the pressure P (P>P y ), which is the sum of the stress under the pressure P (P>P

[0116] A stress calculation method for composite material reinforced defective pipeline, which ignores the influence of radial stress, is suitable for thin-walled pipeline with a diameter-thickness ratio greater than or equal to 20;

[0117] The thickness of the filling material is equal to the defect depth;

[0118] It is assumed that the bonding length of the composite material in the axial direction of the pressure vessel is greater than or equal to twice the effective bonding length, that is, the filling material can transmit deformation to the composite material, so that the axial strain of the pipeline matrix and the composite material is equal;

[0119] Before the defective pipeline yields, E s = E se , wherein E se is the elastic modulus of the defective pipeline;

[0120] The Von-Mises yield criterion is used to determine whether the defective pipeline yields;

[0121] After the defective pipeline yields, E s = [1 / E se +(na / b)(σ / b) n-1 ] -1 ,

[0122] wherein E se is the elastic modulus of the defective pipeline, and a, b and n are material constants, which are obtained by fitting the real stress-strain curve of the defective pipeline.

[0123] A stress calculation system for composite material reinforced pressure vessel, the stress calculation system comprises a measurement unit and a calculation unit;

[0124] The measurement unit is used to measure the pressure vessel related parameters and the filling material related parameters;

[0125] The data processing unit is used for calculating hoop stress of a defect area of a pipe base body in an elastic stage of the composite material reinforced defect pipe, hoop stress of the filling material in the elastic stage of the composite material reinforced defect pipe, hoop stress of the composite material in the elastic stage of the composite material reinforced defect pipe, axial stress of the defect area of the pipe base body in the elastic stage of the composite material reinforced defect pipe and axial stress of the composite material in the elastic stage of the composite material reinforced defect pipe, calculating the pressure when the defect pipe base body yields, calculating hoop stress of the defect area of the pipe base body after the composite material reinforced defect pipe yields, hoop stress of the filling material after the composite material reinforced defect pipe yields, hoop stress of the composite material after the composite material reinforced defect pipe yields, axial stress of the defect area of the pipe base body after the composite material reinforced defect pipe yields and axial stress of the composite material after the composite material reinforced defect pipe yields, calculating the burst pressure and outputting the result.

[0126] A stress calculation device of a composite material reinforced pressure vessel, the stress calculation system comprising a measurement module and a calculation module;

[0127] The measurement module is used for measuring pressure vessel related parameters and filling material related parameters.

[0128] The data processing module is used for calculating hoop stress of a defect area of a vessel base body in an elastic stage of the composite material reinforced pressure vessel, hoop stress of a defect area of the filling material in the elastic stage of the composite material reinforced defect pipe, hoop stress in the elastic stage of the composite material reinforced defect pipe, axial stress of the defect area of the vessel base body in the elastic stage of the composite material reinforced pressure vessel and axial stress in the elastic stage of the composite material reinforced defect pipe, calculating the pressure when the pressure vessel base body yields, calculating hoop stress of the defect area of the pressure vessel base body after the composite material reinforced defect pipe yields, hoop stress of the defect area of the filling material in the elastic stage of the composite material reinforced defect pipe, hoop stress in the elastic stage of the composite material reinforced defect pipe, axial stress of the defect area of the vessel base body in the elastic stage of the composite material reinforced pressure vessel and hoop stress in the elastic stage of the composite material reinforced defect pipe, calculating the burst pressure and outputting the result.

[0129] The present application obtains a stress calculation method of the composite material reinforced pressure vessel according to the von-Mises yield criterion, the Rambery-Osgood elastic-plastic model and the hoop and axial balance conditions of the composite material reinforced pressure vessel. Therefore, the present application provides a more accurate and actual stress calculation method of the composite material reinforced pressure vessel, effectively improves the calculation precision and has strong operability. Thus, the stress, yield pressure and burst pressure of the composite material reinforced pressure vessel are calculated, so as to evaluate and verify the composite material reinforced pressure vessel with defects.

Claims

1. A method for stress calculation of composite material-reinforced defective pipes, characterized in that, The stress calculation method includes the following steps: Step 1: Measure the relevant parameters of the defective pipe and the relevant parameters of the filling material; Step 2: Based on the parameters in Step 1, calculate the circumferential stress in the defective region of the pipe matrix, the circumferential stress of the filler material, the circumferential stress of the composite material, the axial stress in the defective region of the pipe matrix, and the axial stress of the composite material in the elastic stage of the composite reinforced defective pipe. Step 3: Based on the circumferential and axial stresses in the defective region of the pipeline matrix during the elastic stage of the reinforced defective pipeline in Step 2, calculate the pressure at which the defective pipeline matrix yields. Step 4: Based on the pressure at which the defective pipe matrix yields in Step 3, calculate the circumferential stress in the defective region of the defective pipe matrix, the circumferential stress of the filling material, the circumferential stress of the composite material, the axial stress in the defective region of the pipe matrix, and the axial stress of the composite material after yielding. Step 5: Calculate the burst pressure based on the circumferential stress of the composite material after yielding in Step 4; Before the defective pipeline yields, E s = E se ,in E se The elastic modulus of the defective pipe; The Von-Mises yield criterion is used to determine whether a defective pipe has yielded. After the defective pipe yields, E s =[1 / E se +(na / b)( σ / b) n-1 ] -1 , in E se Let be the elastic modulus of the defective pipe, and a, b, and n be material constants, obtained by fitting the actual stress-strain curve of the defective pipe.

2. The stress calculation method for composite material reinforcement of defective pipelines according to claim 1, characterized in that, The parameters related to the defective pipeline in step 1 include the elastic modulus of the defective pipeline. E s Yield strength σ y Initial outer diameter r c Initial inner diameter r i Defective area, outer diameter of the defective pipe r p and residual wall thickness t s The elastic modulus of the filling material was measured. E p The measured parameters of the composite material include the circumferential elastic modulus. E c axial elastic modulus E ca ,tensile strength σ c and the distance from the outer surface of the composite material to the center of the defective pipe r e .

3. The stress calculation method for composite material reinforcement of defective pipelines according to claim 1, characterized in that, In step 2, the thickness of the filling material in the composite material reinforced defective pipe is calculated to be equal to the defect depth.

4. The stress calculation method for composite material reinforcement of defective pipelines according to claim 1, characterized in that, In step 2, the circumferential stress in the defect region of the pipe matrix during the elastic stage of the composite material-reinforced defect pipe is calculated. σ θse Calculated using the following formula, where r p The distance from the outer surface of the filler material to the center of the pipe: （1）； The composite material used to reinforce the defective pipeline in the elastic stage filler material circumferential stress σ θpe Calculated using the following formula: （2）； The composite material reinforces the defective pipeline during the elastic stage of the composite material circumferential stress. σ θce Calculated using the following formula: （3）； The composite material reinforces the defective pipe during the elastic stage, causing axial stress in the defective region of the pipe matrix. σ ase Calculated using the following formula: （4）； The composite material reinforces the defective pipe during the elastic stage of the composite material axial stress. σ ace Calculated using the following formula: （5）。 5. The stress calculation method for composite material reinforcement of defective pipelines according to claim 1, characterized in that, The pressure at which the defective pipe matrix yields in step 3 P y The following formula is calculated by substituting formulas (7)-(8) into formula (6): （6） （7） （8）。 6. The stress calculation method for reinforcing defective pipelines with composite materials according to claim 1, characterized in that, In step 4, the circumferential stress in the defect region of the defective pipe matrix after yielding is calculated. σ θs Calculated using the following formula: （9）； The circumferential stress of the filler material after yielding σ θp Calculated using the following formula: （10）； The circumferential stress of the composite material after yielding σ θc Calculated using the following formula: （11）； The axial stress in the defect region of the pipe matrix after yielding σ as Calculated using the following formula: （12）； The axial stress of the composite material after yielding σ ac Calculated using the following formula: （13）。 7. The stress calculation method for composite material reinforcement of defective pipelines according to claim 1, characterized in that, Step 5 calculates the burst pressure. P b Calculated using the following formula: （14）。 8. The stress calculation method for reinforcing defective pipelines with composite materials according to claim 1, characterized in that, Based on the equality of radial displacement in the defective pipe, filling material, and composite material, and the relationship between radial displacement and circumferential strain, the circumferential strain in the defective pipe, filling material, and composite material satisfies the following equation: （15）； In equation (15) ε θs , ε θp as well as ε θc These are defective pipes, filling materials, and composite materials. ε θc circumferential strain; When the defective conduit is in the elastic stage, the circumferential stress of the defective conduit, the filler material, and the composite material is: ; ; (16); Based on the equilibrium condition of reinforced composite materials for defective pipes under internal pressure, the relationship between the defective pipe, the filling material, and the circumferential stress of the composite material is as follows: （17）； Substituting formula (16) into (17), we get formulas (1), (2) and (3); When the defective pipe is in the elastic stage, the axial stress of the defective pipe, the filling material, and the composite material is: ; ; (18); Based on the equilibrium condition of reinforced composite material pipes under internal pressure, the relationship between the axial stress of the defective pipe, the filling material, and the composite material is as follows: （19） Substituting formula (18) into (19), we obtain formulas (4) and (5); Calculate the yield pressure according to the von-Mises yield criterion; The pressure in formulas (1), (2), (3), (4) and (5) P Replace with pressure increment after yielding P - P y After the defective pipeline yields, the pressure increment P - P y The stress increment caused by the action, summed with the stress at the yield pressure, equals the pressure. P Stress under action.

9. A stress calculation system for reinforcing defective pipelines with composite materials, characterized in that, The stress calculation system uses the stress calculation method for reinforcing defective pipes with composite materials as described in claim 1, and the stress calculation system includes a measurement unit and a calculation unit; The measuring unit is used to measure parameters related to the defective pipe and parameters related to the filling material; The calculation unit is used to calculate the circumferential stress in the defective region of the pipe matrix during the elastic stage of the composite material reinforced defective pipe, the circumferential stress of the filling material during the elastic stage of the composite material reinforced defective pipe, the circumferential stress of the composite material during the elastic stage of the composite material reinforced defective pipe, the axial stress in the defective region of the pipe matrix during the elastic stage of the composite material reinforced defective pipe, and the axial stress of the composite material during the elastic stage of the composite material reinforced defective pipe. Calculate the pressure at which the defective pipe matrix yields; calculate the circumferential stress in the defective region of the defective pipe matrix after yielding, the circumferential stress of the filler material after yielding, the circumferential stress of the composite material after yielding, the axial stress in the defective region of the pipe matrix after yielding, and the axial stress of the composite material after yielding; calculate the burst pressure and output the results.

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