Method and apparatus for determining the profile of a bent pipe based on cross-sectional deformation measurement

Abstract

This invention provides a method and apparatus for determining the profile of a bent pipe based on cross-sectional deformation measurement. The method includes: determining the relationship between stress and strain in the target bent pipe during the bending process; determining the outer profile curve of the cross-section of the target bent pipe based on beam deformation theory and measurement results of the transverse deformation section; and determining the deformation parameters of the target bent pipe based on the relationship and the outer profile curve. The method and apparatus for determining the profile of a bent pipe based on cross-sectional deformation measurement provided by this invention, through simple measurement, can reflect the influence of factors such as process parameters and bending angle, characterize the profile changes in the bent pipe cross-section, and assess technical indicators such as wall thickness and throughput. In production, it enables process evaluation and quality screening of pipe bending processes, and has significant theoretical and practical application value.

Description

Technical Field

[0001] This invention relates to the field of pipe plastic bending forming technology, specifically to a method and apparatus for determining the profile of a bent pipe based on cross-sectional deformation measurement. Background Technology

[0002] In existing technologies, metal pipes, as transmission components for liquids and high-pressure gases, offer advantages such as flexible design and good pressure resistance, and are widely used in shipbuilding, aerospace, automotive, rail transportation, and petrochemical industries. However, due to the hollow structure of the pipes, during plastic bending processes, defects such as elliptical distortion of the bending cross-section, thickening of the inner wall (even wrinkles), and thinning of the outer wall (even cracking) can easily occur, severely affecting the appearance quality, forming accuracy, and even the performance characteristics such as flow resistance and forming strength of the pipes.

[0003] To address phenomena such as cross-sectional distortion during pipe bending, the industry generally employs the following calculation method: based on the mechanical properties of the bending material and bending geometry parameters, including bending radius, pipe diameter, and wall thickness, a theoretical model is established. The location of the neutral layer is calculated through stress balance, thus yielding the wall thickness at each location. However, this method has the following problems in actual production and application: process parameters during pipe bending, such as bending die size, pipe feed rate, presence or absence of a mandrel, and the bending angle, all have a certain degree of influence on the cross-sectional deformation after bending. According to current calculation methods, pipe deformation and wall thickness changes are only related to material properties, pipe specifications, and bending radius, failing to reflect the differences in cross-sectional profiles between different individual pipes, especially those manufactured by different companies. Furthermore, current theoretical calculation methods often neglect the shrinkage of the pipe profile outside the bending center area, making it impossible to assess changes in the pipe's cross-sectional profile and diameter. This restricts further improvements in calculation accuracy and limits its application in actual production for judging pipe quality. Consequently, in actual production, pipe forming quality is usually mainly determined by dimensional inspection and ball-passing tests. There is a lack of accurate, convenient, and non-destructive inspection methods for local thinning of pipe wall thickness and changes in flow rate, resulting in a lack of quality control for bent pipes. Summary of the Invention

[0004] To address the problems in existing technologies, the present invention provides a method and apparatus for determining the profile of a bent pipe based on cross-sectional deformation measurement. This method, which uses simple measurement, can reflect the influence of factors such as process parameters and bending angle, and characterizes the profile changes in the cross-section of the bent pipe as well as technical indicators such as wall thickness and throughput. It enables process evaluation and quality screening of the pipe bending process in production, and has significant theoretical and practical application value.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0006] In a first aspect, the present invention provides a method for determining the profile of a bent pipe based on cross-sectional deformation measurement, comprising:

[0007] Determine the relationship between stress and strain during the bending process of the target pipe;

[0008] The outer contour curve of the cross section of the target bend is determined based on the deformation theory of beams and the measurement results of the transverse deformation section of the target bend.

[0009] The deformation parameters of the target bend are determined based on the relationship and the outer contour curve.

[0010] In one embodiment, determining the relationship between stress and strain during the bending process of the target bend includes:

[0011] A tensile test is performed on the target bend to obtain the relationship between stress and strain.

[0012] In one embodiment, determining the outer contour curve of the cross-section of the target bend based on beam deformation theory and measurement results of the transverse deformation section of the target bend includes:

[0013] Based on the deformation theory of the beam, a differential equation is established to characterize the displacement of the target bend element.

[0014] The differential equation is solved based on the characteristic parameters of the target bend cross-section to determine the outer contour curve of the target bend cross-section.

[0015] In one embodiment, determining the deformation parameters of the target bend based on the relationship and the outer contour curve includes:

[0016] The cross-sectional stress of the target pipe is determined based on the relationship between stress and strain and the outer contour curve.

[0017] The deformation parameters are determined based on the cross-sectional stress.

[0018] In one embodiment, determining the deformation parameters based on the cross-sectional stress includes:

[0019] The location of the neutral layer of the target bend is calculated based on the cross-sectional stress.

[0020] The deformation parameters are calculated based on the location of the neutral layer.

[0021] In one embodiment, the deformation parameters include: the minimum wall thickness, maximum wall thickness, throughput, and ball diameter of the target bend.

[0022] Secondly, the present invention also provides a device for determining the profile of a bent pipe based on cross-sectional deformation measurement, the device comprising:

[0023] The relationship determination module is used to determine the relationship between stress and strain in the target bend during the bending process;

[0024] The outer curve determination module is used to determine the outer contour curve of the cross section of the target bend based on the deformation theory of beams and the measurement results of the transverse deformation section of the target bend.

[0025] The deformation parameter determination module is used to determine the deformation parameters of the target bend based on the relationship and the outer contour curve.

[0026] In one embodiment, the relationship determination module includes:

[0027] The relationship determination unit is used to perform a tensile test on the target bend to obtain the relationship between stress and strain.

[0028] In one embodiment, the outer curve determination module includes:

[0029] The differential equation establishment unit is used to establish differential equations characterizing the displacement of the target bend pipe micro-element based on the deformation theory of the beam.

[0030] The outer curve determination unit is used to solve the differential equation based on the characteristic parameters of the target bend cross section to determine the outer contour curve of the target bend cross section.

[0031] In one embodiment, the deformation parameter determination module includes:

[0032] A cross-sectional stress determination unit is used to determine the cross-sectional stress of the target pipe based on the relationship between stress and strain and the outer contour curve.

[0033] The deformation parameter determination unit is used to determine the deformation parameters based on the cross-sectional stress.

[0034] In one embodiment, the deformation parameter determination unit includes:

[0035] A neutral layer position calculation unit is used to calculate the neutral layer position of the target bend based on the cross-sectional stress.

[0036] A contour-determining sub-unit is used to calculate the deformation parameters based on the location of the neutral layer.

[0037] In one embodiment, the deformation parameters include: the minimum wall thickness, maximum wall thickness, throughput, and ball diameter of the target bend.

[0038] Thirdly, the present invention provides a computer program product, including a computer program / instruction, which, when executed by a processor, implements the steps of a method for determining the profile of a bent pipe based on cross-sectional deformation measurement.

[0039] Fourthly, the present invention provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps of a method for determining the profile of a bent pipe based on cross-sectional deformation measurement.

[0040] Fifthly, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of a method for determining the profile of a bent pipe based on cross-sectional deformation measurement.

[0041] As described above, the method and apparatus for determining the profile of a bent pipe based on cross-sectional deformation measurement provided in this invention first determines the relationship between stress and strain in the target bent pipe during the bending process; then, based on beam deformation theory and the measurement results of the transverse deformation section of the target bent pipe, the outer profile curve of the cross-section of the target bent pipe is determined; finally, the deformation parameters of the target bent pipe are determined based on the relationship and the outer profile curve. This invention proposes a method for calculating the position of the neutral layer, wall thickness variation, and throughput of a bent pipe by measuring its cross-sectional dimensions. This method introduces the longitudinal and transverse outer diameters of the cross-section, which are closely related to process parameters and are easy to measure, thus solving the drawback of existing theoretical calculation methods that cannot reflect the influence of the process. Furthermore, this method can also evaluate non-destructive pipe wall thickness and throughput. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0043] Figure 1 This is a flowchart illustrating the method for determining the profile of a bent pipe based on cross-sectional deformation measurement in an embodiment of the present invention.

[0044] Figure 2 This is a flowchart illustrating step 100 in an embodiment of the present invention;

[0045] Figure 3 This is a flowchart illustrating step 200 in an embodiment of the present invention;

[0046] Figure 4 This is a schematic diagram of the cross-sectional deformation of the bend in an embodiment of the present invention. Figure 1 ;

[0047] Figure 5 This is a schematic diagram of the cross-sectional deformation of the bend in an embodiment of the present invention. Figure 2 ;

[0048] Figure 6 This is a schematic diagram showing the stress and deformation of the contour in an embodiment of the present invention;

[0049] Figure 7 This is a schematic diagram of the displacement of micro-elements in an embodiment of the present invention;

[0050] Figure 8 This is a flowchart illustrating step 300 in an embodiment of the present invention;

[0051] Figure 9 This is a flowchart illustrating step 302 in an embodiment of the present invention;

[0052] Figure 10 This is a general technical roadmap for the method of determining the profile of a bent pipe based on cross-sectional deformation measurement in a specific application example of the present invention;

[0053] Figure 11 The stress-strain curve of stainless steel material in a specific application example of the present invention;

[0054] Figure 12 The stress-strain curve of carbon steel material in a specific application example of the present invention;

[0055] Figure 13 The stress-strain curve of copper material in a specific application example of the present invention;

[0056] Figure 14 The stress-strain curve of the aluminum alloy material in a specific application example of the present invention;

[0057] Figure 15 This is a schematic diagram of the interface of the pipe bending deformation calculation system in a specific application example of the present invention. Figure 1 ;

[0058] Figure 16 This is a schematic diagram of the interface of the pipe bending deformation calculation system in a specific application example of the present invention. Figure 2 ;

[0059] Figure 17 This is a schematic diagram of the cross-sectional profile of a 12×1.5 pipe (bending angle of 60°) in a specific application example of the present invention.

[0060] Figure 18 This is a schematic diagram of the cross-sectional profile of a 12×1.5 pipe (bending angle of 90°) in a specific application example of the present invention.

[0061] Figure 19 This is a schematic diagram of the cross-sectional profile of a 12×1.5 pipe (bending angle of 120°) in a specific application example of the present invention.

[0062] Figure 20This is a structural block diagram of a pipe profile determination device based on cross-sectional deformation measurement in an embodiment of the present invention;

[0063] Figure 21 This is a structural block diagram of the relationship determination module 10 in an embodiment of the present invention;

[0064] Figure 22 This is a structural block diagram of the outer curve determination module 20 in an embodiment of the present invention;

[0065] Figure 23 This is a structural block diagram of the deformation parameter determination module 30 in an embodiment of the present invention;

[0066] Figure 24 This is a structural block diagram of the deformation parameter determination unit 302 in an embodiment of the present invention;

[0067] Figure 25 This is a schematic diagram of the structure of an electronic device in an embodiment of the present invention. Detailed Implementation

[0068] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0069] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0070] It should be noted that the terms "comprising" and "having" and any variations thereof in the specification, claims and accompanying drawings of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product or device.

[0071] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0072] An embodiment of the present invention provides a specific implementation of a method for determining the profile of a bent pipe based on cross-sectional deformation measurement. See [link to relevant documentation]. Figure 1 The method specifically includes the following:

[0073] Step 100: Determine the relationship between stress and strain in the target bend during the bending process.

[0074] Specifically, a tensile test is performed on the pipe sample corresponding to the target bend to obtain its stress-strain curve, thereby obtaining the stress on the material under a given strain.

[0075] Step 200: Determine the outer contour curve of the cross section of the target bend based on the deformation theory of beams and the measurement results of the transverse deformation section of the target bend;

[0076] It is understandable that when a pipe is bent and undergoes plastic deformation, the region inside the bending center experiences compressive deformation in the tangential direction (the bending direction of the pipe), resulting in increased wall thickness. In the radial direction (pointing towards the bending center), its profile is considered to align with the mold profile due to the rigid support of the mold. Conversely, the outer region undergoes tensile deformation in the tangential direction, resulting in decreased wall thickness and radial contraction, with an approximate elliptical profile. The region above the pipe centerline and outside the bending center is simplified as an arch structure. By analyzing the positional changes and stress state of the micro-element before and after deformation, a differential equation for the micro-element displacement is established. By measuring the characteristic parameters of the cross-section, including longitudinal contraction and lateral deformation as boundary conditions, solving the differential equation yields the profile curve of the pipe's outer diameter after deformation.

[0077] Step 300: Determine the deformation parameters of the target bend based on the relationship and the outer contour curve.

[0078] Specifically, parameters such as the neutral layer of the cross-section of the bent portion of the pipe and the wall thickness at various locations are calculated based on the plastic total amount theory to evaluate its deformation.

[0079] As described above, the pipe profile determination method based on cross-sectional deformation measurement provided by this invention first determines the relationship between stress and strain in the target pipe during the bending process; then, based on beam deformation theory and the measurement results of the transverse deformation section of the target pipe, the outer profile curve of the target pipe's cross-section is determined; finally, the deformation parameters of the target pipe are determined based on the relationship and the outer profile curve. This pipe profile determination method based on cross-sectional deformation measurement, provided by this invention, is a calculation method that reflects the influence of factors such as process parameters and bending angles through simple measurement. It characterizes the profile changes in the pipe cross-section and technical indicators such as wall thickness and throughput. In production, it enables process evaluation and quality screening of pipe bending processes, and has significant theoretical and practical application value.

[0080] In one embodiment, see Figure 2 Step 100 includes:

[0081] Step 101: Perform a tensile test on the target bend to obtain the relationship between stress and strain.

[0082] Specifically, a tensile test is performed on the pipe sample to obtain its stress-strain curve and equivalent stress. With equivalent strain The functional relationship is such that stress is positive when the material is under tension and negative when it is under compression:

[0083]

[0084] For materials with good isotropic properties, the equivalent stress when the material is in a compressed state With equivalent strain The relationship is as follows:

[0085]

[0086] In one embodiment, see Figure 3 Step 200 includes:

[0087] Step 201: Establish a differential equation to characterize the displacement of the target bend pipe element based on the deformation theory of the beam;

[0088] Step 202: Solve the differential equation based on the characteristic parameters of the target bend cross section to determine the outer contour curve of the target bend cross section.

[0089] In steps 201 and 202, the outer diameter of the compression zone increases during pipe deformation, but due to mold limitations, the final outer diameter dimension is consistent with the mold dimension, such as... Figure 4 as well as Figure 5 As shown, the tensile region is close to free deformation, deforming towards the bending center. Its compression can be measured. According to the Euler-Bernoulli beam theory, the part of the tube above the axis is simplified as a two-hinged arch, as shown below. Figure 6 As shown, Q is the radial resultant force acting on the infinitesimal element, and V... A V B H A H B These are the four support reactions in the vertical and horizontal directions, respectively. According to the resultant moment ∑M... A =0,∑M B =0, and the resultant forces ∑X=0, ∑Y=0 can be obtained:

[0090]

[0091] like Figure 7 As shown, at an angle of [angle] with the Y-axis angle The radial and tangential displacements of a infinitesimal element of length ds after deformation under stress are respectively... and The angle of the deformed micro-element radius of curvature angle Assuming the length of the infinitesimal element remains constant, then:

[0092]

[0093] Where r is the pipe radius.

[0094] according to Figure 4 In geometric relations, we have:

[0095]

[0096]

[0097] Based on the assumption that the rate of change of length of the infinitesimal element after deformation is 0, then:

[0098]

[0099] Combining (4), (5), (6), and (7), we get:

[0100]

[0101] The relationship between internal forces and deformations of a micro-element section:

[0102]

[0103] Where E' is the equivalent plastic modulus of the material, and I is the moment of inertia of the cross section. Let be the bending moment acting on the infinitesimal element. Then:

[0104] Substituting equations (8) and (10) into equation (9) yields:

[0105]

[0106] Solve the differential equation:

[0107]

[0108] A and B are constants.

[0109] Substituting equation (12) into equation (7) and integrating, we obtain:

[0110]

[0111] Where C is a constant. Substituting equations (12) and (13) into equation (5):

[0112]

[0113] Based on the boundary conditions:

[0114]

[0115] Where Δr1 is the longitudinal compression of the pipe cross-section, and Δr2 is the transverse extension of the pipe cross-section, such as... Figure 4 as well as Figure 5 and Figure 7 As shown, the constant is obtained:

[0116]

[0117] Therefore, the outer diameter of the tension zone above the centerline on the outer side of the bend satisfy:

[0118]

[0119] Due to mold limitations, the profiles of the pipe in the compression zone and between the central axis and the neutral layer are as follows:

[0120]

[0121] in The outer diameter of the compression zone inside the pipe. The outer diameter of the area between the central axis of the pipe and the neutral layer.

[0122] In one embodiment, see Figure 8 Step 300 includes:

[0123] Step 301: Determine the cross-sectional stress of the target pipe based on the relationship between stress and strain and the outer contour curve;

[0124] First, the strain of the micro-element on the cross section in the tangential, circumferential and thickness directions is analyzed. In the tangential strain analysis, the tangential strain at the neutral layer position is 0. The area from the neutral layer to the outermost side of the pipe is the tensile deformation area, and the area from the neutral layer to the innermost side of the pipe is the compressive deformation area.

[0125] Next, based on the total plasticity theory, the stress-strain relationship in each direction, as well as the equivalent stress and equivalent strain, are determined. Furthermore, the stress in the thickness direction is ignored, and the volume of the infinitesimal element is assumed to remain constant, to calculate the tangential stress and material wall thickness at various circumferential positions of the cross-section.

[0126] Furthermore, the angle between the pipe bending cross section and the Y-axis is taken as... Cross-section angle The infinitesimal element of the angle dθ of the bent surface, such as Figure 4 as well as Figure 5 As shown, the strain in each direction on the infinitesimal element is as follows:

[0127]

[0128] Where ε θ , ε t α represents the strain of the micro-element in the tangential, circumferential, and thickness directions, respectively; R is the bending radius; t is the original wall thickness of the pipe; and α is the neutral layer offset angle. The distance between the infinitesimal element and the X-axis. Let the outer diameter of the infinitesimal element be denoted as . The thickness is the micro-element thickness.

[0129] According to the total plasticity theory, the stress-strain relationship is as follows:

[0130]

[0131] Where σ θ , σ t These represent the stresses of the micro-element in the tangential, circumferential, and thickness directions, respectively.

[0132] Equivalent stress Equivalent variation for:

[0133]

[0134] Compared to tangential and circumferential stresses, thickness stresses are smaller. For ease of calculation, thickness stresses are neglected, i.e., σ t =0, from equations (20) and (21) we can obtain:

[0135]

[0136]

[0137] when At that time, from equations (1), (17), (19), and (23), the tangential stress σ of the infinitesimal element is... θo for:

[0138]

[0139] when At that time, from equations (1), (18), (19), and (23), the tangential stress σ of the infinitesimal element is... θo 'for

[0140]

[0141] when At that time, from equations (2), (18), (19), and (23), the tangential stress σ of the infinitesimal element is... θi for:

[0142]

[0143] Step 302: Determine the deformation parameters based on the cross-sectional stress.

[0144] In one embodiment, see Figure 9 Step 302 includes:

[0145] Step 3021: Calculate the neutral layer position of the target bend based on the cross-sectional stress;

[0146] Based on the assumption that the resultant tangential force on the pipe cross-section is zero, the location of the neutral layer is determined numerically. From equations (17), (18), (19), and (22), it is found that when... At that time, the wall thickness of the corresponding infinitesimal element and They are respectively:

[0147]

[0148] Since the net tangential force across the pipe cross-section is zero, we have:

[0149]

[0150] Based on equations (27) and (28), α is solved by numerical calculation.

[0151] Step 3022: Calculate the deformation parameters based on the location of the neutral layer.

[0152] After the neutral layer is determined, the wall thickness at each location of the bend is then determined, and subsequently, the internal profile at each location can be determined. Preferably, the deformation parameters include: the minimum wall thickness, maximum wall thickness, throughput, and ball diameter of the target bend.

[0153] Step 3022, when implemented, specifically involves: obtaining parameters such as wall thickness and diameter at various locations on the pipe cross-section based on equations (12), (17), (18), and (27), where the minimum wall thickness t is... min Maximum wall thickness t max Flux Ф, Pipe diameter The parameters used to assess the degree of deformation of the pipe cross-section are as follows:

[0154]

[0155] By comparing the diameters at various locations Minimum diameter That is, the diameter of the ball passing through that cross-section.

[0156] See Figure 10 To further illustrate this solution, the present invention also provides specific application examples of the method for determining the profile of a bent pipe based on cross-sectional deformation measurement.

[0157] Example 1:

[0158] In this embodiment, the pipe specifications are φ10×1.5, the bending radius is R20, the bending angle is 90°, and the materials are stainless steel 1Cr18Ni9, carbon steel Q235, copper T2 and aluminum alloy 6061, respectively. The forming process is CNC bending. There are 5 pipes of each specification. The maximum and minimum wall thickness of the pipe are calculated and compared with the measurement results after cutting.

[0159] Step 1: Obtain the stress-strain relationship of the material through tensile testing, and the results are as follows: Figures 11 to 14 As shown.

[0160] Step 2: Near the center of the bending angle, measure the maximum transverse diameter and the minimum longitudinal diameter perpendicular to the outer contour of the pipe interface, which is related to the pipe bending process and bending angle. Calculate the characteristic dimensions Δr1 and Δr2 of the pipe section. The calculation results for each pipe are shown in Table 1.

[0161] Table 1 Calculation results of cross-sectional characteristic dimensions

[0162]

[0163]

[0164] The outer diameter at each position of the cross section is calculated using equations (12), (15), (17), and (18). Where r = 5.

[0165] Step 3: Take the initial value of the neutral layer offset angle α as 0, and calculate the tangential stress σ at each position of the cross section using (24), (25), and (26). θo σ θo '、σ θi Where R = 20, the stress-strain function relationship is given in step one. The wall thickness at each location of the section is calculated using equation (27). and calculate:

[0166]

[0167] Each time α increases by π / 360, the calculation continues in equation (30). When f(α) is at its minimum, α is the neutral layer offset angle calculated numerically. Substituting α into equation (27) calculates the wall thickness at each location of the cross-section. and Substituting α into equation (29), the minimum and maximum wall thicknesses are calculated. The calculation results and the actual measurement results after sectioning are shown in Table 2. For pipes of different materials, the calculation and evaluation of wall thickness variation are basically controlled within 10%, as detailed in Table 2.

[0168] Table 2 Comparison of Calculated and Measured Wall Thickness Results

[0169]

[0170]

[0171] Example 2:

[0172] In this embodiment, the pipe specifications are φ12×1.5, the bending radius is R20, and the bending angles are 60°, 90° and 120° respectively. The material is stainless steel 1Cr18Ni9. Calculate the pipe cross-section profile, minimum wall thickness, maximum wall thickness, diameter and flow rate.

[0173] Step 1: Obtain the stress-strain relationship of the material through tensile testing, and the results are as follows: Figures 11 to 14 As shown.

[0174] Step 2: Near the center of the bending angle, measure the maximum transverse diameter and the minimum longitudinal diameter of the outer contour of the pipe interface, which are perpendicular to the pipe bending process and bending angle. Calculate the characteristic dimensions Δr1 and Δr2 of the pipe section, as shown in Table 3.

[0175] Step 3: Calculate the outer diameter at each position of the cross section using equations (12), (15), (17), and (18). According to equation (30), the neutral layer offset angle α is calculated by numerical method.

[0176] Step 4: Calculate according to equation (27) And calculated according to step three Draw the cross-sectional profile. Calculate the parameters of the cross-section according to equation (29).

[0177] Step 5: Visualize the above pipe deformation calculation algorithm using Python, such as... Figure 15 as well as Figure 16As shown, the system consists of three parts: a material fitting module, a parameter module, and a result display module. The material fitting module selects stress-strain spreadsheet data, chooses the required material data, and performs stress-strain curve fitting; here, the RBF fitting method is used. Further, in the parameter module, the inherent data of the bend to be inspected (bending radius, bend wall thickness, bend radius), measurement data (maximum measurement diameter, minimum measurement diameter), and inspection standards (qualified wall thickness coefficient) are input. Clicking the "Inspect" button completes the inspection. Finally, the result display module shows the judgment results, neutral layer offset angle, minimum bend wall thickness, maximum bend wall thickness, maximum ball diameter, and throughput. It also plots the cross-sectional profile of the bend before and after deformation. The application software displays the pipe profile as shown below. Figures 17 to 19 As shown in Table 3, the calculation results are as follows.

[0178] Table 3 Calculation results of cross-sectional characteristic dimensions

[0179]

[0180] As can be seen from the above description, the method and apparatus for determining the profile of a bent pipe based on cross-sectional deformation measurement provided in this embodiment of the invention first determines the relationship between stress and strain of the target bent pipe during the bending process; then, based on the deformation theory of beams and the measurement results of the transverse deformation section of the target bent pipe, the outer profile curve of the cross section of the target bent pipe is determined; finally, the deformation parameters of the target bent pipe are determined based on the relationship and the outer profile curve.

[0181] This invention combines beam deformation theory with plastic total quantity theory. Based on the measurement of characteristic dimensions of the bending section of the pipe, it achieves the evaluation of parameters such as the cross-sectional profile, wall thickness, and throughput of the pipe without damaging the pipe body. Specifically, this invention has the following technical effects:

[0182] (1) By introducing cross-sectional characteristic parameters related to the pipe bending forming process, under the same material, specifications and bending geometry parameters, the influence of process parameters on the deformation of pipe cross section can be effectively reflected.

[0183] (2) The area outside the relative bending center of the pipe and the area where tangential tensile deformation occurs is simplified into a two-hinged arch. The outer contour of this area is calculated through micro-element deformation geometric analysis.

[0184] (3) Based on the theory of total plasticity, calculate the neutral layer and wall thickness at each location of the cross section of the bent part of the pipe, and evaluate its deformation.

[0185] (4) In engineering, the outer diameter of any cross section can be measured, and parameters such as profile, wall thickness, bore diameter, and flow rate can be calculated to check whether the deformation quality of the pipe is qualified.

[0186] (5) The above-mentioned pipe deformation calculation algorithm is programmed in Python and the PySimpleGUI module is used for visual interface design. The inspectors select the material type, input the bending radius, the wall thickness of the bend, the bending wall thickness, the maximum and minimum measurement diameter of the cross section, and output the minimum and maximum wall thickness, the neutral layer offset angle, the maximum ball diameter, the throughput and other parameters according to the qualified wall thickness coefficient set according to the technical requirements. This can intuitively, clearly and conveniently guide the technical and inspection personnel to complete the inspection of the bend, which greatly improves the efficiency and quality of the inspection work.

[0187] Based on the same inventive concept, this application also provides a device for determining the profile of a bent pipe based on cross-sectional deformation measurement, which can be used to implement the method described in the above embodiments, as shown in the following embodiments. Since the principle of the device for determining the profile of a bent pipe based on cross-sectional deformation measurement is similar to that of the method for determining the profile of a bent pipe based on cross-sectional deformation measurement, the implementation of the device for determining the profile of a bent pipe based on cross-sectional deformation measurement can refer to the implementation of the method for determining the profile of a bent pipe based on cross-sectional deformation measurement, and repeated details will not be elaborated further. As used below, the terms "unit" or "module" can refer to a combination of software and / or hardware that performs a predetermined function. Although the system described in the following embodiments is preferably implemented in software, hardware implementation, or a combination of software and hardware, is also possible and contemplated.

[0188] The present invention provides a specific implementation of a device for determining the profile of a bent pipe based on cross-sectional deformation measurement, which enables a method for determining the profile of a bent pipe based on cross-sectional deformation measurement. See [link to relevant documentation]. Figure 20 The device for determining the profile of a bent pipe based on cross-sectional deformation measurement specifically includes the following components:

[0189] The relationship determination module 10 is used to determine the relationship between stress and strain of the target bend during the bending process;

[0190] The outer curve determination module 20 is used to determine the outer contour curve of the cross section of the target bend based on the deformation theory of the beam and the measurement results of the transverse deformation section of the target bend.

[0191] The deformation parameter determination module 30 is used to determine the deformation parameters of the target bend based on the relationship and the outer contour curve.

[0192] In one embodiment, see Figure 21 The relationship determination module 10 includes:

[0193] The relationship determination unit 101 is used to perform a tensile test on the target bend to obtain the relationship between stress and strain.

[0194] In one embodiment, see Figure 22 The outer curve determination module 20 includes:

[0195] Differential equation establishment unit 201 is used to establish differential equations characterizing the displacement of the target bent pipe micro-element based on the deformation theory of the beam;

[0196] The outer curve determination unit 202 is used to solve the differential equation based on the characteristic parameters of the target bend cross section to determine the outer contour curve of the target bend cross section.

[0197] In one embodiment, see Figure 23 The deformation parameter determination module 30 includes:

[0198] The cross-sectional stress determination unit 301 is used to determine the cross-sectional stress of the target pipe based on the relationship between stress and strain and the outer contour curve.

[0199] The deformation parameter determination unit 302 is used to determine the deformation parameters based on the cross-sectional stress.

[0200] In one embodiment, see Figure 24 The deformation parameter determination unit 302 includes:

[0201] Neutral layer position calculation unit 3021 is used to calculate the neutral layer position of the target bend based on the cross-sectional stress;

[0202] The contour determination subunit 3022 is used to calculate the deformation parameters based on the position of the neutral layer.

[0203] In one embodiment, the deformation parameters include: the minimum wall thickness, maximum wall thickness, throughput, and ball diameter of the target bend.

[0204] As can be seen from the above description, the method and apparatus for determining the profile of a bent pipe based on cross-sectional deformation measurement provided in this embodiment of the invention first determines the relationship between stress and strain of the target bent pipe during the bending process; then, based on the deformation theory of beams and the measurement results of the transverse deformation section of the target bent pipe, the outer profile curve of the cross section of the target bent pipe is determined; finally, the deformation parameters of the target bent pipe are determined based on the relationship and the outer profile curve.

[0205] The device for determining the profile of a bent pipe based on cross-sectional deformation measurement provided by this invention is a calculation method that can reflect the influence of factors such as process parameters and bending angle through simple measurement. It can characterize the profile change in the cross-section of the bent pipe as well as technical indicators such as wall thickness and throughput. It can realize process evaluation and quality screening of the pipe bending process in production, and has important theoretical and practical application significance.

[0206] The apparatus, module, or unit described in the above embodiments may be implemented by a computer chip or entity, or by a product having a certain function. A typical implementation device is an electronic device, specifically, such as a personal computer, laptop computer, cellular phone, camera phone, smartphone, personal digital assistant, media player, navigation device, email device, game console, tablet computer, wearable device, or any combination of these devices.

[0207] In a typical example, the electronic device specifically includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, it implements the steps of the aforementioned method for determining the profile of a bent pipe based on cross-sectional deformation measurement. These steps include:

[0208] Step 100: Determine the relationship between stress and strain during the bending process of the target bend;

[0209] Step 200: Determine the outer contour curve of the cross section of the target bend based on the deformation theory of beams and the measurement results of the transverse deformation section of the target bend;

[0210] Step 300: Determine the deformation parameters of the target bend based on the relationship and the outer contour curve.

[0211] The following is for reference. Figure 25 It shows a schematic diagram of the structure of an electronic device 600 suitable for implementing the embodiments of this application.

[0212] like Figure 25 As shown, the electronic device 600 includes a central processing unit (CPU) 601, which can perform various appropriate tasks and processes according to a program stored in a read-only memory (ROM) 602 or a program loaded from a storage section 608 into a random access memory (RAM) 603. The RAM 603 also stores various programs and data required for the operation of the system 600. The CPU 601, ROM 602, and RAM 603 are interconnected via a bus 604. An input / output (I / O) interface 605 is also connected to the bus 604.

[0213] The following components are connected to I / O interface 605: an input section 606 including a keyboard, mouse, etc.; an output section 607 including a cathode ray tube (CRT), liquid crystal display (LCD), etc., and speakers, etc.; a storage section 608 including a hard disk, etc.; and a communication section 609 including a network interface card such as a LAN card, modem, etc. The communication section 609 performs communication processing via a network such as the Internet. A drive 610 is also connected to I / O interface 605 as needed. A removable medium 611, such as a disk, optical disk, magneto-optical disk, semiconductor memory, etc., is installed on drive 610 as needed so that computer programs read from it can be installed in storage section 608 as needed.

[0214] In particular, according to embodiments of the present invention, the processes described above with reference to the flowchart can be implemented as computer software programs. For example, embodiments of the present invention include a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the above-described method for determining the profile of a bent pipe based on cross-sectional deformation measurement, the steps including:

[0215] Step 100: Determine the relationship between stress and strain during the bending process of the target bend;

[0216] Step 200: Determine the outer contour curve of the cross section of the target bend based on the deformation theory of beams and the measurement results of the transverse deformation section of the target bend;

[0217] Step 300: Determine the deformation parameters of the target bend based on the relationship and the outer contour curve.

[0218] In such an embodiment, the computer program can be downloaded and installed from a network via the communication section 609, and / or installed from the removable medium 611.

[0219] Computer-readable media includes both permanent and non-permanent, removable and non-removable media that can store information using any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic magnetic disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.

[0220] For ease of description, the above devices are described separately by function as various units. Of course, in implementing this application, the functions of each unit can be implemented in one or more software and / or hardware.

[0221] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0222] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0223] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0224] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0225] This application can be described in the general context of computer-executable instructions, such as program modules, that are executed by a computer. Generally, program modules include routines, programs, objects, components, data structures, etc., that perform a specific task or implement a specific abstract data type. This application can also be practiced in distributed computing environments where tasks are performed by remote processing devices connected via a communication network. In distributed computing environments, program modules can reside in local and remote computer storage media, including storage devices.

[0226] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0227] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A method for determining the profile of a bent pipe based on cross-sectional deformation measurement, characterized in that, include: Determine the relationship between stress and strain during the bending process of the target pipe; The outer contour curve of the cross section of the target bend is determined based on the deformation theory of beams and the measurement results of the transverse deformation section of the target bend. The deformation parameters of the target bend are determined based on the relationship and the outer contour curve. The step of determining the deformation parameters of the target bend based on the relationship and the outer contour curve includes: The cross-sectional stress of the target pipe is determined based on the relationship between stress and strain and the outer contour curve. The deformation parameters are determined based on the cross-sectional stress. Determining the deformation parameters based on the cross-sectional stress includes: The location of the neutral layer of the target bend is calculated based on the cross-sectional stress. The deformation parameters are calculated based on the location of the neutral layer.

2. The method for determining the profile of a bent pipe as described in claim 1, characterized in that, Determining the relationship between stress and strain during the bending process of the target bend includes: A tensile test is performed on the target bend to obtain the relationship between stress and strain.

3. The method for determining the profile of a bent pipe as described in claim 1, characterized in that, The determination of the outer contour curve of the cross-section of the target bend based on beam deformation theory and measurement results of the transverse deformation section of the target bend includes: Based on the deformation theory of the beam, a differential equation is established to characterize the displacement of the target bend element. The differential equation is solved based on the characteristic parameters of the target bend cross-section to determine the outer contour curve of the target bend cross-section.

4. The method for determining the profile of a bent pipe as described in claim 3, characterized in that, The deformation parameters include: the minimum wall thickness, maximum wall thickness, flow rate, and ball diameter of the target bend.

5. A device for determining the profile of a bent pipe based on cross-sectional deformation measurement, characterized in that, include: The relationship determination module is used to determine the relationship between stress and strain in the target bend during the bending process; The outer curve determination module is used to determine the outer contour curve of the cross section of the target bend based on the deformation theory of beams and the measurement results of the transverse deformation section of the target bend. The deformation parameter determination module is used to determine the deformation parameters of the target bend based on the relationship and the outer contour curve. The deformation parameter determination module includes: A cross-sectional stress determination unit is used to determine the cross-sectional stress of the target pipe based on the relationship between stress and strain and the outer contour curve. A deformation parameter determination unit is used to determine the deformation parameters based on the cross-sectional stress. The deformation parameter determination unit includes: A neutral layer position calculation unit is used to calculate the neutral layer position of the target bend based on the cross-sectional stress. A contour-determining sub-unit is used to calculate the deformation parameters based on the location of the neutral layer.

6. The pipe profile determining device as described in claim 5, characterized in that, The relationship determination module includes: The relationship determination unit is used to perform a tensile test on the target bend to obtain the relationship between stress and strain.

7. The pipe profile determining device as described in claim 5, characterized in that, The outer curve determination module includes: The differential equation establishment unit is used to establish differential equations characterizing the displacement of the target bend pipe micro-element based on the deformation theory of the beam. The outer curve determination unit is used to solve the differential equation based on the characteristic parameters of the target bend cross section to determine the outer contour curve of the target bend cross section.

8. The pipe profile determining device as described in claim 7, characterized in that, The deformation parameters include: the minimum wall thickness, maximum wall thickness, flow rate, and ball diameter of the target bend.

9. A computer program product comprising a computer program / instructions, characterized in that, When the computer program / instruction is executed by the processor, it implements the steps of the method for determining the profile of a bent pipe based on cross-sectional deformation measurement as described in any one of claims 1 to 4.

10. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the steps of the method for determining the profile of a bent pipe based on cross-sectional deformation measurement as described in any one of claims 1 to 4.

11. A computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the computer program implements the steps of the method for determining the profile of a bent pipe based on cross-sectional deformation measurement as described in any one of claims 1 to 4.

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