Comprehensive evaluation method for performance of axially extruded pipe joint

Abstract

The invention discloses a comprehensive evaluation method for the performance of an axially extruded pipe joint, and the method comprises the steps: determining evaluation indexes which comprise the quality of the axially extruded pipe joint, the axial extrusion connection assembly load, the residual fatigue life of rotation fatigue, the machining and manufacturing cost and the axial compensation amount; and calculating a comprehensive evaluation value based on the dimensionless numerical value and the weight of the evaluation index, and evaluating the performance of the N types of axial extrusion pipe joints of the same guide pipe specification through the comprehensive evaluation value. And if the comprehensive evaluation value is lower than a set threshold value, optimization is carried out in the direction of increasing the compensation amount and the machining cost, and the residual fatigue life and the load index are weakened. According to the method, a test method, a simulation method, an expert group review method and a mathematical statistics method are combined, the performance of the axial extrusion pipe joint in the two aspects of dynamics and statics is considered, scientific, rapid and quantitative evaluation is conducted on the axial extrusion pipe joints in various forms through a comprehensive evaluation method, and good practicability is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of aviation pipeline performance testing, and in particular relates to a comprehensive evaluation method for the performance of an axially extruded pipe joint. Background Art

[0002] The axial extrusion pipe joint is a new type of mechanical joint connection technology for pipelines. It refers to a technology that connects or seals the same or multiple materials of the same type based on the basic principle that the materials produce elastic-plastic deformation under the action of interference fit at a temperature below the recrystallization temperature. This connection joint technology has the advantages of high pressure resistance, corrosion resistance, energy saving, safety, and quick installation. For example, the existing patent 202011079903.5 discloses an axial extrusion connection pipe joint assembly and a pipe joint composed thereof, which relates to the field of pipeline connection technology. The axial extrusion connection pipe joint assembly includes a joint part and an annular part, and a reliable connection is formed by radial mechanical cooperation between the joint part and the annular part. In addition, the groove structure designed on the outer surface of the joint part and the flange structure designed on the inner surface of the annular part cooperate with each other to form a structural self-locking, which further increases the reliability and strength of the connection.

[0003] Currently, all axially extruded pipe fittings developed by relevant research institutions using the axial extrusion principle have passed the so-called qualification test. However, within the same specification, pipe fittings can vary widely. For example, the number of grooves varies, with some featuring two, some three, and even some four grooves. Seal types vary, with some relying primarily on "point seals" and others on "sealing strips." Furthermore, various other aspects of pipe fittings vary, and a scientific evaluation method and standard are still lacking. Summary of the Invention

[0004] The purpose of the present invention is to provide a comprehensive evaluation method for the performance of an axially extruded pipe joint, aiming to solve the above-mentioned problems.

[0005] The present invention is mainly achieved through the following technical solutions: A comprehensive evaluation method for the performance of an axially extruded pipe joint comprises the following steps: Step S1: Determine the evaluation index, which includes the quality of the axial extrusion pipe joint m ij , axial extrusion connection assembly load F ij , Rotational fatigue residual fatigue life P ik , processing and manufacturing costs C ij and axial compensation L ik ; Step S2: obtaining original data of evaluation indicators of N types of axial extrusion pipe joints of the same pipe specification; Step S3: Perform dimensionless processing on the original cluster obtained in step S2 to obtain dimensionless values ​​of each indicator x iq ; Step S4: Determine the weight of each evaluation indicator w h ,in, ; m is the number of indicators, h=1,2,3,4,5…m; Step S5: adopting a comprehensive evaluation method to calculate a comprehensive evaluation value based on step S3 and step S4, wherein the comprehensive evaluation method is any one of a linear weighted method, a nonlinear weighted method, an approximate ideal point method, a fuzzy comprehensive evaluation method and a grey correlation method.

[0006] In order to better implement the present invention, further, in the step S2, the mass of the axial extruded pipe joint is obtained by weighing or measuring the digital model using CATIA software. m ij ; Obtain axial compression connection assembly load through simulation or testing F ij ; Determine the residual fatigue life of rotational fatigue by rotating bending test P ik ; The processing and manufacturing costs C ij Including the cost of machining accuracy, material consumption, heat treatment, cutting and labor; the distance between the inner ring flanges of the pipe joint is measured as the axial compensation amount L ik .

[0007] In order to better implement the present invention, further, in step S3, the dimensionless processing includes any one of the range change method, the vector normalization method, and the linear proportional transformation method.

[0008] In order to better realize the present invention, further, in step S3, the range change method is used for dimensionless transformation, wherein the positive index includes the remaining fatigue life of the axial extrusion pipe joint. P ik and axial compensation L ik , reverse indicators include the quality of axial extrusion pipe joints m ij , processing costs C ij and assembly loads F ij .

[0009] In order to better implement the present invention, further, in step S3, the remaining fatigue life P ik The dimensionless value of is: , , , The axial compensation amount L ik The dimensionless value of is: , , , The mass m ij The dimensionless value of is: , , , The processing cost C ij The dimensionless value of is: , , , The assembly load F ij The dimensionless value of is: , , , in: is the maximum value of the fatigue residual life of N axial pipe joints; is the minimum value of fatigue residual life among N axial pipe joints; is the maximum axial compensation value among N axial pipe joints; is the minimum value of axial compensation among N axial pipe joints; is the maximum mass among the N axial pipe joints; is the minimum mass among the N axial pipe joints; is the maximum processing cost among N axial pipe joints; is the minimum processing cost among N axial pipe joints; is the maximum value of the assembly load among N axial pipe joints; is the minimum value of the assembly load among N axial pipe joints; N is the type of axial extrusion pipe fittings of the same conduit specification, i=1, 2, 3, 4, 5...N.

[0010] In order to better implement the present invention, further, in step S5, a linear weighted function method is used to calculate the comprehensive evaluation value: .

[0011] In order to better implement the present invention, further, in step S5, the larger the comprehensive evaluation value, the better the comprehensive performance of the axial extruded pipe joint; if the comprehensive evaluation value is lower than the set threshold, it is recommended to optimize in the direction of increasing the compensation amount and processing cost, and weakening the remaining fatigue life and load indicators.

[0012] The beneficial effects of the present invention are as follows: (1) The present invention combines the test method, simulation method, expert group review and mathematical statistics method, considers the performance of axial extrusion pipe joints in both dynamics and statics, and uses a comprehensive evaluation method to conduct a scientific, rapid and quantitative evaluation of various forms of axial extrusion pipe joints.

[0013] (2) The method of the present invention enables a comprehensive evaluation of various types of axially extruded pipe joints on the market. It not only effectively distinguishes the performance advantages and disadvantages of different axially extruded pipe joints and their applicable conditions, but also provides a reference direction for the research and improvement of axially extruded pipe joints. The present invention is not only applicable to axially extruded pipe joints, but can also be used to evaluate rolled pipe joints, radially extruded pipe joints, and beam-type sealing joints. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 Flowchart of the comprehensive evaluation method for the performance of an axially extruded pipe joint according to the present invention; Figure 2 Schematic diagram determined for assembly loads; Figure 3 Schematic diagram of the rotational bending test; Figure 4 Schematic diagram of the structure determined for the circumferential compensation strategy.

[0015] Among them: 1-outer ring, 2-inner ring, 3-flange. DETAILED DESCRIPTION

[0016] Example 1: A comprehensive evaluation method for the performance of axially extruded pipe joints is proposed, which comprehensively evaluates the performance of axially extruded pipe joints based on weight, processing cost, assembly load, remaining fatigue life, axial compensation and other indicators. Figure 1 As shown, the specific steps include: The first step is to determine the evaluation indicators The quality of the axial extrusion pipe joint (including an inner ring 2 and two outer rings 1), the axial extrusion connection assembly load, the rotational fatigue residual fatigue life, the processing and manufacturing cost and the axial compensation amount are determined as comprehensive evaluation indicators.

[0017] The second step is to obtain the original data of the axial extrusion joint index of a certain specification 2.1 Quality indicators can be obtained by weighing or measuring the digital model using CATIA software to calculate the quality of the axial extrusion joint.

[0018] Assume that there are axial pipe joints of the same specification N The mass of various pipe joints can be calculated by weighing or converting three-dimensional models. The assembly includes an inner ring 2 and two outer rings 1, which are recorded as m ij , where i refers to different pipe joint types and j identifies the reverse index.

[0019] 2.2 Assembly load can be obtained through simulation and testing, such as Figure 2 As shown, (a) is a load-time curve obtained by the simulation method, and (b) is a schematic diagram of the experimental test. For example, an axial extrusion tool is used to continuously apply pressure and record the pressure gauge reading when the outer ring 1 and the inner ring 2 are tightly attached.

[0020] The assembly load of various pipe joints can be obtained by test measurement or placement to obtain the maximum axial load during the axial extrusion assembly connection process. There are two methods to obtain the assembly load of axial extrusion pipe joints. The maximum load is recorded as the assembly load as follows: F ij , where i refers to different pipe joint types and j identifies the reverse index.

[0021] 2.3 The remaining fatigue life is determined by the rotation bending test, and the axial extrusion connection combined conduit rotation bending test piece is manufactured, such as Figure 3 As shown, a rotational bending test is carried out on a rotational bending test machine until the combined catheter fails, and the number of rotational bending times is recorded.

[0022] The remaining fatigue life of various pipe joints is measured by a rotary bending test until the pipe breaks or leaks, and the number of rotary bending times R is recorded. i , the remaining fatigue life index is P ik =R i -1000, where i designates different pipe joint types and k designates positive indicators.

[0023] 2.4 Processing cost is obtained through accounting. The processing cost of various pipe joints needs to consider processing accuracy, material consumption, heat treatment and cutting processing and labor costs. The higher the processing accuracy, the greater the processing cost. The processing cost index is marked as C ij , where i refers to different pipe joint types and j identifies the reverse index.

[0024] 2.5 The axial extrusion compensation amount is obtained by measurement. The greater the distance between the two flanges 3 of the inner ring 2 of the axial extrusion joint, the greater the axial extrusion compensation amount.

[0025] like Figure 4 As shown, the axial compensation of various pipe joints can be measured by measuring the distance between the flange 3 of the inner ring 2 of the pipe joint as the compensation amount. L ik , where i designates different types of pipe joints and k designates positive indicators.

[0026] The third step is to use mathematical methods to non-dimensionalize each indicator. There are many methods for non-dimensionalizing indicators, including the range change method, vector normalization method, linear proportional transformation method, etc.

[0027] There are many methods for dimensionless processing. The present invention adopts the range change method for dimensionless processing, wherein the positive indicators include the remaining fatigue life and the axial compensation amount, and the negative indicators include the quality, assembly load, and processing cost.

[0028] For positive indicators, it involves the remaining fatigue life P ik and axial compensation L ik The dimensionless value of is: , , , , , , For the reverse indicator, it involves the quality m ij , processing cost C ij and assembly load F ij , the quality index is dimensionless and is recorded as; , , , , , , , , , Where N is the number of axial extrusion pipe fittings of the same conduit specification (i=1, 2, 3, 4, 5...N).

[0029] Step 4: Determine the weight of the indicators The weight of each indicator should be evaluated by a group of experts with relevant professional backgrounds, and the weight of each indicator should be given. Assume that the weight of each indicator is w h , m is the number of indicators (h=1,2,3,4,5...m), in this example the number of indicators is 5, , the current number of indicators is 5.

[0030] Step 5: Comprehensive evaluation calculation value Using linear weighting function method , as the comprehensive evaluation calculation value, where q is Pk, Lk, mj, Cj, Fj N is the type of axial extrusion pipe joint with the same pipe specification. i =1,2,3,4,5…… N ); 2.5 The comprehensive evaluation methods established include linear weighted comprehensive method, nonlinear weighted comprehensive method, ideal point approach method, fuzzy comprehensive evaluation method and grey correlation method, etc., which can be reasonably selected according to actual conditions.

[0031] Example 2: A comprehensive evaluation method for the performance of an axially extruded pipe joint comprises the following steps: Step 1: Assume that there are 6 types of axial extrusion pipe fittings of the same specification, then N=6.

[0032] Step 2: Assume there are five indicators, then m = 5, which are weight, processing cost, assembly load, remaining fatigue life, and axial compensation. As shown in Table 1, the raw data of different indicators of different types of axial extrusion joints are obtained using the above method.

[0033] Table 1 Step 3: Use the range change method to make the above indicators dimensionless.

[0034] For positive indicators, it involves the remaining fatigue life P ik and axial compensation L ik ; (1) , , , , , , , ; (2) , , , , , , , ; For the reverse indicator, it involves the quality m ij , processing cost C ij and assembly load F ij ; (3) , , , , , , ; (4) , , , , , , , ; (5) , , , , , , , .

[0035] Step 4: Determine the weight of indicators An expert group was organized to fully discuss the weight, processing cost, assembly load, remaining fatigue life, and axial compensation indicators, and the weight of each indicator was determined. w h Considering the large demand for weight reduction and compensation of aircraft, and the low demand for processing cost, assembly load and remaining fatigue life, the weights of each indicator are determined as follows: w 1 is 0.4, w 2 is 0.2, w 3 is 0.05, w 4 is 0.1, w 5 is 0.25.

[0036] Step 5 Comprehensive evaluation calculation value According to the weighting function ; The y1 of the first type of axial pipe joint is 0.469, y2 is 0.499, y3 is 0.436, y4 is 0.389, y5 is 0.649, and y6 is 0.450.

[0037] Step 6: Evaluation and optimization direction The y5 value is the largest, indicating that the comprehensive performance of the fifth type of axial extrusion pipe joint is better.

[0038] The y4 value is the smallest, indicating that the comprehensive performance of the fourth type of axial extrusion pipe joint is the worst, and it should be optimized in the direction of increasing the compensation amount and processing cost, while weakening the remaining fatigue life and load indicators.

[0039] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification or equivalent change made to the above embodiment based on the technical essence of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A comprehensive evaluation method for the performance of an axially extruded pipe joint, characterized in that: The following steps are involved: Step S1: Determine the evaluation index, which includes the quality of the axial extrusion pipe joint m ij , axial extrusion connection assembly load F ij , Rotational fatigue residual fatigue life P ik , processing and manufacturing costs C ij and axial compensation L ik ; Step S2: obtaining original data of evaluation indicators of N types of axial extrusion pipe joints of the same pipe specification; Step S3: Perform dimensionless processing on the original cluster obtained in step S2 to obtain dimensionless values ​​of each indicator x iq ; Step S4: Determine the weight of each evaluation indicator w h ,in, ; m is the number of indicators, h=1,2,3,4,5…m; Step S5: adopting a comprehensive evaluation method to calculate a comprehensive evaluation value based on step S3 and step S4, wherein the comprehensive evaluation method is any one of a linear weighted method, a nonlinear weighted method, an approximate ideal point method, a fuzzy comprehensive evaluation method and a grey correlation method.

2. A comprehensive evaluation method for the performance of an axially extruded pipe joint according to claim 1, characterized in that: In step S2, the mass of the axially extruded pipe joint is obtained by weighing or measuring the digital model using CATIA software. m ij ; Obtain axial compression connection assembly load through simulation or testing F ij ; Determine the residual fatigue life of rotational fatigue by rotating bending test P ik ; The processing and manufacturing costs C ij Including the cost of machining accuracy, material consumption, heat treatment, cutting and labor; the distance between the inner ring flanges of the pipe joint is measured as the axial compensation amount L ik .

3. A comprehensive evaluation method for the performance of an axially extruded pipe joint according to claim 1 or 2, characterized in that: In step S3, the dimensionless processing includes any one of a range change method, a vector normalization method, and a linear proportional transformation method.

4. A comprehensive evaluation method for the performance of an axially extruded pipe joint according to claim 3, characterized in that: In step S3, the dimensionless transformation is performed using the range change method, wherein the positive indicators include the remaining fatigue life of the axial extrusion pipe joint. P ik and axial compensation L ik , reverse indicators include the quality of axial extrusion pipe joints m ij , processing costs C ij and assembly loads F ij .

5. A comprehensive evaluation method for the performance of an axially extruded pipe joint according to claim 4, characterized in that: In step S3, the remaining fatigue life P ik The dimensionless value of is: ， ， ， The axial compensation amount L ik The dimensionless value of is: ， ， ， The quality m ij The dimensionless value of is: ， ， ， The processing cost C ij The dimensionless value of is: ， ， ， The assembly load F ij The dimensionless value of is: ， ， ， in: is the maximum value of the fatigue residual life of N axial pipe joints; is the minimum value of fatigue residual life among N axial pipe joints; is the maximum axial compensation value among N axial pipe joints; is the minimum value of axial compensation among N axial pipe joints; is the maximum mass among the N axial pipe joints; is the minimum mass among the N axial pipe joints; is the maximum processing cost among N axial pipe joints; is the minimum processing cost among N axial pipe joints; is the maximum value of the assembly load among N axial pipe joints; is the minimum value of the assembly load among N axial pipe joints; N is the type of axial extrusion pipe joints of the same conduit specification, i=1, 2, 3, 4, 5...N.

6. The comprehensive evaluation method for the performance of an axially extruded pipe joint according to claim 1, characterized in that: In step S5, a linear weighted function method is used to calculate the comprehensive evaluation value: 。 7. A comprehensive evaluation method for the performance of an axially extruded pipe joint according to claim 1 or 6, characterized in that: In step S5, the larger the comprehensive evaluation value, the better the comprehensive performance of the axial extrusion pipe joint; if the comprehensive evaluation value is lower than the set threshold, it is recommended to optimize in the direction of increasing the compensation amount and processing cost, and weakening the remaining fatigue life and load indicators.

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