CN-121598716-B - Local reinforcing method for large-caliber tee pipe fitting

CN121598716BCN 121598716 BCN121598716 BCN 121598716BCN-121598716-B

Abstract

The invention relates to the technical field of pipe structural design and local reinforcement technology, and discloses a local reinforcement method of a large-caliber tee pipe, which comprises the steps of obtaining a boundary coordinate sequence of a stress concentration area of a standard pipe subjected to stress analysis, and generating an area characteristic description vector irrelevant to the scale; the method comprises the steps of calculating geometric scaling factors of a target specification and a reference specification, generating a boundary and a position index of a stress concentration candidate region of a target specification pipe fitting, calculating a predicted residual life cycle number by using a predicted damage evolution rate and a current damage amount of the target pipe fitting, generating a region residual life sequence, carrying out weighted fusion on a residual life reciprocal and a deformation energy density priority score, generating a comprehensive priority score, sequencing each stress concentration region of the target pipe fitting according to the comprehensive priority score, and outputting a strengthening priority sequence. The invention strengthens the priority ordering, can reflect the time-varying risk degree of each region, and provides dynamic basis for local reinforcement decision by stages.

Inventors

ZHOU ZHANHU
SUN TONG
ZHANG WEIQIANG
GAO ZHIYU
Geng Yaolei
SUN CHANGHONG
MA ZHONGTAO

Assignees

辽宁爱维尔金属成型科技股份有限公司

Dates

Publication Date: 20260508
Application Date: 20260129

Claims (10)

1. The local reinforcing method of the large-caliber tee pipe fitting is characterized by comprising the following steps of: acquiring a boundary coordinate sequence of a stress concentration region of a standard pipe fitting with the completed stress analysis, converting the boundary coordinate into a normalized parameter coordinate relative to an intersecting line topological skeleton by using a curve parameterization algorithm, and generating a region feature description vector irrelevant to the scale; Acquiring a historical stress amplitude sequence and a material S-N curve parameter of each stress concentration region of the standard pipe fitting, calculating the current damage accumulation amount of each region by using a Miner linear accumulation damage criterion, and generating a region damage accumulation value sequence; Calculating the ratio of the damage accumulation amount of each region to the service cycle number to obtain a damage evolution rate, dividing the damage evolution rate by the stress concentration coefficient of the corresponding region, and generating a damage evolution rate scale invariant of each region; obtaining geometric parameters of a target specification pipe fitting, calculating geometric scaling factors of the target specification and a reference specification, and performing inverse normalization mapping on the region feature description vector by using the geometric scaling factors to generate a stress concentration candidate region boundary and a position index of the target specification pipe fitting; Multiplying the damage evolution rate scale invariant by a stress concentration coefficient of a corresponding region of the target pipe fitting to obtain a predicted damage evolution rate, calculating a predicted residual life cycle number by using the predicted damage evolution rate and the current damage amount of the target pipe fitting, and generating a region residual life sequence; And carrying out weighted fusion on the reciprocal of the residual life and the deformation energy density priority score to generate a comprehensive priority score, sequencing each stress concentration area of the target pipe fitting according to the comprehensive priority score, and outputting a strengthening priority sequence.
2. The local strengthening method of the large-caliber tee pipe fitting according to claim 1 is characterized in that the calculation mode of the damage evolution rate scale invariant is that the current damage accumulation amount of a region is divided by the service cycle number to obtain the damage evolution rate, the damage evolution rate is divided by the normalized stress concentration coefficient of the region, and the damage evolution rate scale invariant represents the inherent damage evolution rate after the stress concentration degree difference is eliminated.
3. The method of claim 1, wherein the geometric scaling factors include a nominal diameter scaling factor, a wall thickness scaling factor, and a main pipe length scaling factor, and are determined based on a nominal diameter ratio, a wall thickness ratio, and a main pipe length ratio of the target specification to the reference specification, respectively.
4. The method for locally reinforcing a large-caliber tee pipe fitting according to claim 1, wherein the calculation mode of predicting the residual life cycle is that the residual damage capacity is divided by the predicted damage evolution rate, and the residual damage capacity is the difference between a critical damage value and the current damage amount.
5. The method for locally reinforcing a large-caliber tee fitting according to claim 1, wherein the deformation energy density priority score is obtained by integrating the deformation energy density of each stress concentration region in volume to obtain a region total deformation energy value, and normalizing the total deformation energy value to generate the deformation energy density priority score.
6. The method for locally reinforcing a large-caliber tee pipe fitting according to claim 1, further comprising obtaining a finite element stress analysis result of the target specification pipe fitting after generating a stress concentration candidate region boundary of the target specification pipe fitting, and performing boundary fine adjustment in a candidate region boundary neighborhood by using a local gradient search algorithm to generate an accurate stress concentration region boundary coordinate sequence.
7. The method of local reinforcement of a large-diameter three-way pipe fitting according to claim 6, further comprising calculating a ratio of an average value of the offset before and after trimming of the boundary to a threshold value of the allowable maximum offset, calculating a confidence index using the ratio, and outputting the confidence index together with the reinforcement priority sequence.
8. The method according to claim 1, wherein the intersecting line topological skeleton is a central skeleton of a space curve formed by intersecting a main pipe and a branch pipe of the three-way pipe, and the normalized parameter coordinates represent boundary points as dimensionless parameters relative to the intersecting line skeleton.
9. The method according to claim 1, wherein the sum of the weight coefficient of the reciprocal of the remaining life and the weight coefficient of the deformation energy density priority score in the weighted fusion of the comprehensive priority scores is 1.
10. A large-caliber tee fitting local reinforcement system for performing the large-caliber tee fitting local reinforcement method as set forth in any one of claims 1 to 9, comprising: The regional characteristic normalization module is used for acquiring a boundary coordinate sequence of a stress concentration region of the standard pipe fitting and generating a regional characteristic description vector irrelevant to the scale by using a curve parameterization algorithm; the damage accumulation calculation module is used for acquiring a historical stress amplitude sequence and material parameters and calculating a region damage accumulation value sequence by utilizing a Miner linear accumulation damage criterion; The scale invariant generation module is used for calculating the damage evolution rate and dividing the damage evolution rate by the stress concentration coefficient to generate a damage evolution rate scale invariant; the scale transformation mapping module is used for carrying out inverse normalization mapping on the region characteristic description vector according to the geometric scaling factor to generate a stress concentration candidate region boundary of the target pipe fitting; The residual life prediction module is used for calculating and predicting the residual life cycle number according to the damage evolution rate scale invariant and the target pipe fitting stress concentration coefficient; And the priority fusion output module is used for carrying out weighted fusion and arrangement on the residual life reciprocal and the deformation energy density priority score to output a reinforced priority sequence.

Description

Local reinforcing method for large-caliber tee pipe fitting Technical Field The invention relates to the technical field of pipe fitting structural design and local reinforcement technology, in particular to a local reinforcement method for a large-caliber tee pipe fitting. Background In the process of serializing design and operation and maintenance of large-caliber tee pipe fittings (such as DN800, DN1600, DN2400 and other nominal diameters), stress concentration is generated in the middle section of an intersecting line and in the area of a junction when the pipe fitting bears internal pressure, and the stress concentration area is a main dangerous position causing fatigue failure of the pipe fitting, and the stress concentration degree of the areas needs to be reduced through local reinforcing measures. According to the embodiment of the invention, the series of three-way pipe fittings with different nominal diameters have geometric similarity, and the relative positions of stress concentration areas and fatigue damage evolution rules of the series of three-way pipe fittings have scale correlation. The small-size pipe fitting (such as DN 800) accumulates complete stress concentration area identification result and fatigue damage data due to long service time and sufficient monitoring data, while the large-size pipe fitting (such as DN 2400) has short service time and insufficient damage data, so that the evolution trend of the strengthening priority of the large-size pipe fitting is difficult to be reliably predicted. The existing stress concentration area identification and priority ordering method independently executes a complete analysis flow for each pipe fitting with nominal diameter, and because a scale association mechanism of the position characteristics and the damage evolution rule of the stress concentration areas among the series of pipe fittings is not established, the evolution trend of the reinforcement priority of the large-specification pipe fitting cannot be reliably predicted under the condition of lacking long-term damage monitoring data, and the batch analysis time consumption of the series of pipe fittings linearly increases along with the number of specifications. Disclosure of Invention The invention provides a local reinforcing method for a large-caliber three-way pipe fitting, which solves the technical problems that the prior independent analysis method in the related art ignores the geometric similarity of a series of pipe fittings, the evolution of priority cannot be predicted due to the insufficient long-term damage data of a large-specification pipe fitting caused by short service time, and the prior static priority ordering method cannot reflect the evolution characteristics of fatigue damage along with time. The invention provides a local reinforcing method of a large-caliber tee pipe fitting, which comprises the following steps: acquiring a boundary coordinate sequence of a stress concentration region of a standard pipe fitting with the completed stress analysis, converting the boundary coordinate into a normalized parameter coordinate relative to an intersecting line topological skeleton by using a curve parameterization algorithm, and generating a region feature description vector irrelevant to the scale; Acquiring a historical stress amplitude sequence and a material S-N curve parameter of each stress concentration region of the standard pipe fitting, calculating the current damage accumulation amount of each region by using a Miner linear accumulation damage criterion, and generating a region damage accumulation value sequence; Calculating the ratio of the damage accumulation amount of each region to the service cycle number to obtain a damage evolution rate, dividing the damage evolution rate by the stress concentration coefficient of the corresponding region, and generating a damage evolution rate scale invariant of each region; obtaining geometric parameters of a target specification pipe fitting, calculating geometric scaling factors of the target specification and a reference specification, and performing inverse normalization mapping on the region feature description vector by using the geometric scaling factors to generate a stress concentration candidate region boundary and a position index of the target specification pipe fitting; Multiplying the damage evolution rate scale invariant by a stress concentration coefficient of a corresponding region of the target pipe fitting to obtain a predicted damage evolution rate, calculating a predicted residual life cycle number by using the predicted damage evolution rate and the current damage amount of the target pipe fitting, and generating a region residual life sequence; And carrying out weighted fusion on the reciprocal of the residual life and the deformation energy density priority score to generate a comprehensive priority score, sequencing each stress concentration area of the target pipe fitting according