Method, device and equipment for detecting yield strength of cable, medium and product

Abstract

The invention provides a cable yield strength detection method, device and equipment, a medium and a product, and the method comprises the steps: determining the size reduction of a to-be-detected cable according to the initial density of a mineral insulating material filled in the to-be-detected cable, and the initial size and target density of the to-be-detected cable; according to the size reduction, rolling the cable to be measured and obtaining rolling force in the rolling process; according to the rolling force and the horizontal projection area of the contact surface of the to-be-measured cable and the rolling machine in the rolling process, the average unit pressure of the to-be-measured cable is calculated, and then the yield strength of the to-be-measured cable is calculated. According to the scheme, the cable is rolled based on the target density, the yield strength is calculated according to the rolling force, the horizontal projection area, the average unit pressure and other physical parameters in the rolling process, more yield strength data of the cable in the rolling period can be obtained while destructive testing is avoided, and the yield strength of the cable is improved. Therefore, the calculation accuracy of the yield strength of the mineral insulated cable is improved.

Description

Technical Field

[0001] This application relates to the field of mineral-insulated cables, and more particularly to a method, apparatus, equipment, medium, and product for testing the yield strength of cables. Background Technology

[0002] Mineral-insulated cables are cables with high fire resistance and excellent mechanical properties, widely used in fields requiring high safety and reliability. They mainly consist of a metal sheath, a conductive core, and a mineral insulation layer. To ensure the reliability of mineral-insulated cables in practical applications, calculating the yield strength is particularly important. By accurately calculating the yield strength, the cable's performance under different load conditions can be evaluated, thereby optimizing design and material selection to ensure safe operation under various complex working conditions.

[0003] Current methods for calculating the yield strength of mineral-insulated cables typically involve sampling a section of the cable for destructive testing to obtain the yield strength parameter. However, this approach wastes resources through destructive testing, and the randomness inherent in sampling, which relies on the assumption of uniform material distribution within the cable, leads to inaccurate yield strength test results. Therefore, the current challenge is to improve the accuracy of yield strength calculations for mineral-insulated cables. Summary of the Invention

[0004] This application provides a method, apparatus, equipment, medium, and product for testing the yield strength of cables, in order to improve the accuracy of yield strength calculation for mineral-insulated cables.

[0005] On one hand, this application provides a method for testing the yield strength of a cable, wherein the cable is filled with mineral insulating material; the method includes: obtaining the initial density of the mineral insulating material in the cable under test based on the mass of the mineral insulating material and the initial size of the cable under test; determining the size reduction of the cable under test based on the initial density of the mineral insulating material, the initial size of the cable under test, and the target density; the size reduction of the cable under test is the change in the current size of the cable under test compared to the initial size when the density of the mineral insulating material in the cable under test is the target density; rolling the cable under test based on the size reduction and obtaining the rolling force during the rolling process; calculating the average unit pressure of the cable under test based on the rolling force and the horizontal projected area of ​​the contact surface between the cable under test and the rolling mill during the rolling process; and calculating the yield strength of the cable under test based on the average unit pressure of the cable under test.

[0006] In one possible implementation, the cable under test is rolled according to the dimensional reduction and the rolling force during the rolling process is obtained, including: determining the single diameter reduction amount and number of times according to the dimensional reduction; rolling the cable under test according to the diameter reduction amount and the number of diameter reduction times, and obtaining the rolling force during the most recent diameter reduction rolling process.

[0007] In one possible implementation, the yield strength of the cable under test is calculated based on the average unit pressure of the cable under test, including: obtaining the yield strength of the cable under test by weighted calculation based on the yield strength corresponding to the rolling force in each diameter reduction rolling process.

[0008] In one possible implementation, the yield strength of the cable under test is calculated based on the average unit pressure of the cable under test, including: calculating the yield strength of the cable under test based on the average unit pressure of the cable under test and the stress state coefficient of the cable under test.

[0009] In one possible implementation, the method further includes: detecting the cross-sectional shape of the cable under test before entering the rolling mill, and the roll pass of the rolling mill; if the cross-sectional shape of the cable under test is elliptical and the roll pass of the rolling mill is circular, then a first stress state coefficient is obtained based on the deformation zone shape factor, the ratio of the rolling mill roll diameter to the rolling mill roll diameter, and the friction between the cable under test and the rolling mill, and the first stress state coefficient is used as the stress state coefficient of the cable under test; if the cross-sectional shape of the cable under test is circular and the roll pass of the rolling mill is elliptical, then a second stress state coefficient is obtained based on the deformation zone shape factor, the roll pass axis ratio of the rolling mill, and the friction between the cable under test and the rolling mill, and the second stress state coefficient is used as the stress state coefficient of the cable under test.

[0010] In one possible implementation, the cable under test further includes a sheath and a core rod; after calculating the yield strength of the cable under test, the method further includes: calculating the yield strength of the mineral insulation material based on the yield strength of the cable under test, the yield strength of the sheath and the ratio of the cross-sectional area of ​​the sheath to the total cross-sectional area of ​​the cable under test, the yield strength of the core rod and the ratio of the cross-sectional area of ​​the core rod to the total cross-sectional area of ​​the cable under test, and the ratio of the cross-sectional area of ​​the mineral insulation material to the total cross-sectional area of ​​the cable under test.

[0011] On the other hand, this application provides a cable yield strength testing device, comprising: an acquisition module for obtaining the initial density of the mineral insulation material in the cable under test based on the mass of the mineral insulation material filling the cable under test and the initial size of the cable under test; a determination module for determining the size reduction of the cable under test based on the initial density of the mineral insulation material, the initial size of the cable under test, and the target density; the size reduction of the cable under test is the change in the current size of the cable under test compared to the initial size when the density of the mineral insulation material in the cable under test is the target density; and a calculation module for rolling the cable under test based on the size reduction and obtaining the rolling force during the rolling process; calculating the average unit pressure of the cable under test based on the rolling force and the horizontal projected area of ​​the contact surface between the cable under test and the rolling mill during the rolling process; and calculating the yield strength of the cable under test based on the average unit pressure of the cable under test.

[0012] On the other hand, this application provides an electronic device, including: a processor, and a memory communicatively connected to the processor; the memory stores computer-executable instructions; the processor executes the computer-executable instructions stored in the memory to implement the above method.

[0013] On the other hand, this application provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, are used to implement the above-described method.

[0014] On the other hand, this application provides a computer program product, including a computer program that, when executed by a processor, implements the method described above.

[0015] This application provides a method, apparatus, equipment, medium, and product for testing the yield strength of cables. The method includes determining the dimensional reduction of the cable under test based on the initial density of the mineral insulation material filling the cable, the initial size of the cable, and the target density; rolling the cable under test based on the dimensional reduction and obtaining the rolling force during the rolling process; calculating the average unit pressure of the cable under test based on the rolling force and the horizontal projected area of ​​the contact surface between the cable and the rolling mill during the rolling process, and then calculating the yield strength of the cable. This application's solution, by rolling the cable based on the target density and calculating the yield strength based on physical parameters such as the rolling force, horizontal projected area, and average unit pressure during the rolling process, avoids destructive testing while obtaining more yield strength data of the cable during rolling, thereby improving the accuracy of yield strength calculation for mineral-insulated cables. Attached Figure Description

[0016] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0017] Figure 1 The diagram above illustrates a flowchart of a method for testing the yield strength of a cable.

[0018] Figure 2 The diagram above illustrates a flowchart of a method for testing the yield strength of a cable.

[0019] Figure 3 The diagram above illustrates a flowchart of a method for testing the yield strength of a cable.

[0020] Figure 4 The diagram above illustrates a flowchart of a method for testing the yield strength of a cable.

[0021] Figure 5 The diagram above illustrates the structure of a cable yield strength testing device.

[0022] Figure 6 The diagram above illustrates the structure of an electronic device.

[0023] The accompanying drawings have illustrated specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to specific embodiments. Detailed Implementation

[0024] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0025] It should be noted that the brief descriptions of terms in this application are only for the convenience of understanding the embodiments described below, and are not intended to limit the embodiments of this application. Unless otherwise stated, these terms should be understood in their ordinary and common meaning. The terms "comprising" and "having," and any variations thereof, in the specification, claims, and accompanying drawings of this application are intended to be omnipresent but not exclusive. For example, a product or device that comprises a series of components is not necessarily limited to those components that are explicitly listed, but may include other components that are not explicitly listed or that are inherent to such products or devices. The term "module" as used in this application refers to any known or subsequently developed hardware, software, firmware, artificial intelligence, fuzzy logic, or combination of hardware and / or software code capable of performing the functions associated with that element.

[0026] Mineral-insulated cables are widely used in fields such as building fire protection systems, nuclear power plants, and petrochemical plants due to their high fire resistance, high temperature resistance, and high reliability. Their structure typically consists of a copper or nickel-copper alloy conductor, magnesium oxide insulation, and a seamless copper or stainless steel sheath. Due to the complexity of their structure, mineral-insulated cables possess high fire resistance, high temperature resistance, corrosion resistance, and high mechanical strength; however, calculating their yield strength is also quite difficult. One method for calculating the yield strength of mineral-insulated cables involves randomly or at fixed lengths cutting sections of the cable after manufacturing and performing stress-strain destructive testing to obtain the corresponding yield strength. However, because the insulation material in mineral-insulated cables is a powdery, amorphous mineral, using sampling to test the yield strength of cables hundreds or thousands of meters long can easily lead to uneven distribution of the filling material, resulting in yield strength data that does not accurately represent the actual yield strength. Furthermore, this cutting method can also lead to resource waste and lower stability of the connections at the cut sections.

[0027] The technical content provided in this application aims to solve the aforementioned technical problems in related technologies. This application discloses a method, apparatus, equipment, medium, and product for testing the yield strength of cables. The method includes determining the dimensional reduction of the cable under test based on the initial density of the mineral insulation material filling the cable, the initial size of the cable, and the target density; rolling the cable under test based on the dimensional reduction and obtaining the rolling force during the rolling process; calculating the average unit pressure of the cable under test based on the rolling force and the horizontal projected area of ​​the contact surface between the cable and the rolling mill during the rolling process, and then calculating the yield strength of the cable. The solution of this application, by rolling the cable based on the target density and calculating the yield strength based on physical parameters such as the rolling force, horizontal projected area, and average unit pressure during the rolling process, avoids destructive testing while obtaining more yield strength data of the cable during rolling, thereby improving the accuracy of yield strength calculation for mineral-insulated cables.

[0028] The technical solutions of this application will be described in detail below with reference to specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. In the description of this application, unless otherwise expressly specified and limited, the terms should be broadly understood within the art. The embodiments of this application will now be described with reference to the accompanying drawings.

[0029] Example 1

[0030] Figure 1The diagram illustrates a flowchart of a method for testing the yield strength of a cable. The executing entity in this example can be a cable yield strength testing device. The cable is filled with mineral insulation material; such as... Figure 1 As shown, the method includes:

[0031] Step 101: Based on the mass of the mineral insulation material filling the cable under test and the initial dimensions of the cable under test, obtain the initial density of the mineral insulation material in the cable under test;

[0032] Step 102: Determine the size reduction of the cable under test based on the initial density of the mineral insulation material, the initial size of the cable under test, and the target density. The size reduction of the cable under test is the change in the current size of the cable under test compared to its initial size when the density of the mineral insulation material in the cable under test is the target density.

[0033] Step 103: Based on the dimensional reduction, roll the cable to be tested and obtain the rolling force during the rolling process; calculate the average unit pressure of the cable to be tested based on the rolling force and the horizontal projected area of ​​the contact surface between the cable to be tested and the rolling mill during the rolling process; calculate the yield strength of the cable to be tested based on the average unit pressure of the cable to be tested.

[0034] In practical applications, the main body executing this method can be a cable yield strength testing device, which can be implemented in various ways. For example, it can be implemented through a computer program, such as application software; or it can be implemented as a medium storing the relevant computer program, such as a USB flash drive or cloud drive; or it can be implemented through a physical device that integrates or installs the relevant computer program, such as a chip.

[0035] In this example, the initial density of the mineral insulation material in the cable under test is obtained based on the mass of the mineral insulation material filling it and the initial dimensions of the cable. The mineral insulation material can be materials with good insulation and high-temperature resistance, such as magnesium oxide, aluminum oxide, or zirconium oxide. For example, the volume of the cable under test can be calculated using its initial dimensions (e.g., cable length) and the cross-sectional area of ​​the space filled with the mineral insulation material. The initial density is then calculated using the relationship between weight, density, and volume. It should be noted that the cable under test consists of a hollow cylindrical metal sheath, a conductive core rod, and a mineral insulation layer. During the initial manufacturing process, the core rod is passed through the sheath. One end is sealed with hot melt adhesive to fix the core rod in the central area of ​​the sheath, and a certain mass of mineral insulation material is filled into the gap between the core rod and the sheath from the other end. After the mineral insulation material is filled, it is compacted and the other end is sealed to complete the initial cable fabrication.

[0036] After obtaining the initial density of the cable under test, the dimensional reduction of the cable is determined based on the initial density of the mineral insulation material, the initial size of the cable, and the target density. The dimensional reduction is the change in the current size of the cable compared to its initial size when the density of the mineral insulation material in the cable reaches the target density. For example, based on the principle of mass conservation and the density formula, the target size of the cable can be determined according to the initial density of the mineral insulation material, the initial size of the cable, and the target density. The dimensional reduction is then the difference between the initial size and the target size. For example, based on the obtained dimensional reduction, and considering factors such as the rolling speed and temperature of the rolling mill, and the plasticity and ductility of the cable material, the total diameter reduction is calculated, and rolling is performed according to the total diameter reduction. During the rolling process, the rolling force is acquired. In practical applications, the rolling force can be acquired using a pressure sensor on the rolling mill. For example, only the rolling force corresponding to the last rolling process can be selected for yield strength calculation, or the rolling forces corresponding to the last few rolling processes can be selected for yield strength calculation. In this example, during the rolling process, the rolling force data corresponding to each segment of the cable under test can be obtained according to the rolling sequence. After calculating these rolling force data, the yield strength corresponding to each segment of the cable under test can be obtained.

[0037] In this example, the formula for calculating the average unit pressure of the cable under test, based on the rolling force and the horizontal projected area of ​​the contact surface between the cable under test and the rolling mill during the rolling process, is as follows:

[0038] P B =P / F B

[0039] Among them, P B Where P is the average unit pressure of the cable under test, and F is the rolling force. B This is the horizontal projected area of ​​the contact surface between the cable under test and the rolling mill.

[0040] As an example, the horizontal projected area F of the contact surface between the cable under test and the rolling mill. B The calculation formula is as follows:

[0041]

[0042] Where, d k1 The height of the cable to be tested after rolling (the diameter if the cross-section of the cable is circular, and the average of the sum of the major and minor axes if the cross-section of the cable is elliptical); ω is the reduction coefficient of the rolling mill; the formula for calculating A is as follows:

[0043]

[0044] Where D is the diameter of the rolling mill rolls, H is the diameter when the rolling mill pass is circular, and H is the axis length parallel to the rolling direction when the rolling mill pass is elliptical.

[0045] When the cross-section of the cable under test is circular, the formula for calculating ξ is as follows:

[0046]

[0047] When the cross-section of the cable under test is elliptical, the formula for calculating ξ is as follows:

[0048]

[0049] Among them, u k δ represents the roll pass axis ratio of the rolling mill (1 for a circular roll pass, and the axis length of the axis perpendicular to the rolling direction minus the axis length of the axis parallel to the rolling direction for an elliptical roll pass). i-1 δ represents the degree of filling of the test cable within the mill pass during the previous rolling process. i This represents the degree of filling of the test cable within the rolling mill pass during this rolling process.

[0050] The average unit pressure P of the cable under test is calculated using the above formula. B Subsequently, the yield strength of the cable under test corresponding to the average unit pressure can be obtained through computer simulation using structural analysis software such as finite element analysis software. Optionally, the yield strength of the cable under test corresponding to the average unit pressure can also be obtained through calculation using physical formulas. Among these methods, computer simulation can improve the accuracy of calculations in complex mechanical structures, while calculation using physical formulas can improve the efficiency of the calculation.

[0051] The cable yield strength testing method of this application includes: determining the dimensional reduction of the cable under test based on the initial density of the mineral insulation material filled in the cable, the initial size of the cable under test, and the target density; rolling the cable under test based on the dimensional reduction and obtaining the rolling force during the rolling process; calculating the average unit pressure of the cable under test based on the rolling force and the horizontal projected area of ​​the contact surface between the cable under test and the rolling mill during the rolling process, and then calculating the yield strength of the cable under test. This example scheme, by rolling the cable based on the target density and calculating the yield strength based on physical parameters such as the rolling force, horizontal projected area, and average unit pressure during the rolling process, avoids destructive testing while obtaining more yield strength data of the cable during rolling, thereby improving the accuracy of yield strength calculation for mineral-insulated cables.

[0052] As yet another example, Figure 2 The diagram illustrates a flowchart of a method for testing the yield strength of a cable. Figure 2As shown, in step 103, the cable to be tested is rolled according to the dimensional reduction, and the rolling force during the rolling process is obtained, including:

[0053] Step 201: Determine the diameter reduction amount and number of reductions per operation based on the dimensional reduction.

[0054] Step 202: Roll the cable to be tested according to the reduction amount and the number of reduction cycles, and obtain the rolling force in the most recent reduction rolling process.

[0055] In this example, the total reduction in diameter of the cable under test can be calculated based on the dimensional reduction, taking into account the plasticity and ductility of the sheath and mandrel. Further, the single reduction amount and number of reductions are determined based on the total reduction. In practical applications, due to the complexity of the cable's structure, to avoid damage caused by excessive deformation, the single reduction amount can be controlled below 10%. For example, when the total reduction is 20%, one rolling scheme is to perform rolling with multiple reductions gradually increasing in diameter, such as rolling with reductions of 1%, 2%, 3%, 4%, 5%, and 5%. This fully utilizes the ductility of the cable under test after each rolling to ensure its performance. Alternatively, multiple identical reduction amounts, such as five 4% reductions, can be used to improve rolling uniformity. In practical applications, adjustments can be made based on the material of the cable under test. For example, copper and aluminum have good ductility and can withstand larger reductions, while stainless steel and nickel alloys have poor ductility and are suitable for smaller reductions. The cable under test is rolled according to the reduction amount and the number of reduction cycles, and the rolling force during the most recent reduction rolling process is obtained. In practical applications, the yield strength corresponding to the rolling force is closer to the actual yield strength of the cable under test as the number of rolling cycles increases. Therefore, the last rolling force or the last few rolling forces can be used for yield strength calculation. The scheme in this example determines different single reduction amounts and corresponding cycles based on the dimensional reduction, which can make reasonable use of the ductility of the cable under test and improve the uniformity of rolling; by obtaining the rolling force during the rolling process at the number of reduction cycles for yield strength calculation, the accuracy of yield strength calculation can be improved.

[0056] As yet another example, the reduction in diameter ranges from 2% to 3%.

[0057] In practical applications, the reduction amount can be adjusted according to the ductility of the sheath and mandrel of the cable under test; for example, for materials with high ductility, the range can be set to 2% to 5%, and for materials with low ductility, the range can be set to 1% to 2%. The scheme in this example, by limiting the range of the reduction amount, ensures that the sheath thickness is reduced, minimizing earing during the rolling process, improving the uniformity of the cable under test, and thus improving the accuracy of the yield strength calculation.

[0058] As another example, step 103 calculates the yield strength of the cable under test based on the average unit pressure of the cable, including:

[0059] Based on the yield strength obtained from the rolling force during each diameter reduction rolling process, the yield strength of the cable under test is obtained through weighted calculation.

[0060] In practical applications, each segment of the cable under test undergoes multiple rolling processes. Based on the rolling time and the location of cable deformation, rolling in earlier stages where the deformation primarily affects the cable's sheath is called the tube rolling zone, while rolling in later stages affecting the entire cable is called the bar rolling zone. To obtain the overall stress of the cable under test, the yield strength is typically calculated using the rolling force corresponding to the bar rolling zone. After obtaining multiple yield strengths in the bar rolling zone, a weighted calculation is performed. If the weight values ​​are the same, the average of the multiple yield strengths is calculated. Optionally, by setting the weight values ​​to increase sequentially (i.e., the weight value is larger closer to the last rolling stage), the calculated result can be closer to the actual yield strength. The scheme in this example, by weighting the calculated yield strengths, avoids the error of calculating the yield strength using only the last rolling force, thus improving the accuracy of the yield strength calculation.

[0061] As another example, step 103 calculates the yield strength of the cable under test based on the average unit pressure of the cable, including:

[0062] The yield strength of the cable under test is calculated based on its average unit pressure and stress state coefficient. In this example, the formula for calculating the yield strength of the cable under test is:

[0063] P B =1.15σ*n σ

[0064] Among them, P B n represents the average unit pressure of the cable under test. σ Let σ be the stress state coefficient of the cable under test, and σ be the yield strength of the cable under test. The yield strength calculation formula provided in this example improves the accuracy of calculations compared to estimates made by engineers based on experience, and improves the efficiency of calculations compared to model simulations.

[0065] As yet another example, Figure 3 The diagram above illustrates a flowchart of a method for testing the yield strength of a cable.

[0066] like Figure 3 As shown, the method for testing the yield strength of mineral-insulated cables also includes:

[0067] Step 301: Detect the cross-sectional shape of the cable to be tested before it enters the rolling mill, as well as the roll pass of the rolling mill;

[0068] Step 302: If the cross-sectional shape of the cable to be tested is elliptical and the die of the rolling mill is circular, then the first stress state coefficient is obtained based on the deformation zone shape coefficient, the ratio of the rolling mill roll diameter to the rolling mill die diameter, and the friction between the cable to be tested and the rolling mill, and the first stress state coefficient is used as the stress state coefficient of the cable to be tested.

[0069] Step 303: If the cross-sectional shape of the cable to be tested is circular and the die of the rolling mill is elliptical, then the second stress state coefficient is obtained based on the deformation zone shape coefficient, the die axis ratio of the rolling mill, and the friction between the cable to be tested and the rolling mill, and the second stress state coefficient is used as the stress state coefficient of the cable to be tested.

[0070] It should be noted that the cross-sectional shape of the cable under test before entering the rolling mill is usually determined by the rolling mill in the previous rolling process. In practical applications, the rolling mill pass shape in the rolling process is usually arranged in alternating elliptical, circular, elliptical, and circular patterns. If the cross-sectional shape of the cable under test is elliptical and the rolling mill pass shape is circular, the corresponding formula for calculating the first stress state coefficient is:

[0071]

[0072] Where, n σ1 denoted as the first stress state coefficient, m as the deformation zone shape coefficient, a0 as the ratio of the rolling mill roll diameter to the rolling mill pass diameter, and φ as the frictional force between the cable under test and the rolling mill.

[0073] If the cross-sectional shape of the cable under test is circular and the die of the rolling mill is elliptical, the corresponding formula for calculating the second stress state coefficient is:

[0074]

[0075] Where, n σ2 U is the second stress state coefficient, m is the deformation zone shape coefficient, and u is the second stress state coefficient. k The roll pass ratio of the rolling mill (where the roll pass is elliptical, u) is the axial ratio of the rolling mill's pass. k φ is the length of the axis perpendicular to the rolling direction (the length of the axis parallel to the rolling direction), and φ is the frictional force between the cable under test and the rolling mill.

[0076] The formula for calculating the shape factor m of the deformation zone is as follows:

[0077] m = l / H

[0078] Where l is the horizontal projection of the contact arc length of the deformation zone of the cable under test, which can be approximated as equal to Where R is the radius of the rolling mill roll, Δh is the length of the cable pressed down along the rolling direction; when the rolling mill pass is circular, H is the diameter, and when the rolling mill pass is elliptical, H is the axis length parallel to the rolling direction.

[0079] The scheme in this example takes into account the cross-sectional shape of the cable under test before entering the rolling mill and the roll pass of the rolling mill. The formula for calculating the stress state coefficient is different under different conditions, which can improve the accuracy of the stress state coefficient and further improve the accuracy of the yield strength calculation.

[0080] As yet another example, Figure 4 The diagram illustrates a flowchart of a method for testing the yield strength of a cable. Figure 4 As shown, after calculating the yield strength of the cable under test based on the average unit pressure of the cable under test in step 103, the following steps are also included:

[0081] Step 401: Calculate the yield strength of the mineral insulation material based on the yield strength of the cable under test, the yield strength of the sheath, the ratio of the cross-sectional area of ​​the sheath to the total cross-sectional area of ​​the cable under test, the yield strength of the core rod, the ratio of the cross-sectional area of ​​the core rod to the total cross-sectional area of ​​the cable under test, and the ratio of the cross-sectional area of ​​the mineral insulation material to the total cross-sectional area of ​​the cable under test.

[0082] In practical applications, the components and proportions of the cable under test are fixed; that is, the area occupied by the sheath, core, and mineral insulation material in the cross-section of the cable is constant. In this example, the yield strength σ of the mineral insulation material can be calculated using the following formula. 矿 :

[0083]

[0084] Where, σ 总 S represents the yield strength of the cable under test. 总 σ is the total cross-sectional area of ​​the cable under test. 套 S represents the yield strength of the sheath. 套 σ is the cross-sectional area of ​​the sheath. 矿 S represents the yield strength of mineral insulating materials. 矿 σ is the cross-sectional area of ​​the mineral insulating material. 芯 S represents the yield strength of the mandrel. 芯 Let be the cross-sectional area of ​​the mandrel.

[0085] The scheme in this example calculates the yield strength of the mineral insulation material based on a formula, according to the components and proportions of the cable under test. Optionally, after obtaining the yield strength of the mineral insulation material, this value can be used for calculations of more refined stress data or stress models.

[0086] The cable yield strength testing method of this embodiment includes determining the dimensional reduction of the cable under test based on the initial density of the mineral insulation material filled in the cable, the initial size of the cable, and the target density; rolling the cable under test based on the dimensional reduction and obtaining the rolling force during the rolling process; calculating the average unit pressure of the cable under test based on the rolling force and the horizontal projected area of ​​the contact surface between the cable under test and the rolling mill during the rolling process, and then calculating the yield strength of the cable under test. This example scheme rolls the cable based on the target density and calculates the yield strength based on physical parameters such as the rolling force, horizontal projected area, and average unit pressure during the rolling process. This avoids destructive testing while obtaining more yield strength data of the cable during rolling, thereby improving the accuracy of yield strength calculation for mineral-insulated cables.

[0087] Example 2

[0088] Figure 5 The diagram above exemplarily illustrates the structure of the cable yield strength testing device provided in Embodiment 2 of this application. Figure 5 As shown, the device includes:

[0089] The module 51 is used to obtain the initial density of the mineral insulation material in the cable under test based on the mass of the mineral insulation material filling the cable under test and the initial dimensions of the cable under test.

[0090] The determination module 52 is used to determine the size reduction of the cable under test based on the initial density of the mineral insulation material, the initial size of the cable under test, and the target density; the size reduction of the cable under test is the change in the current size of the cable under test compared to the initial size when the density of the mineral insulation material in the cable under test is the target density.

[0091] The calculation module 53 is used to roll the cable under test according to the size reduction and obtain the rolling force during the rolling process; calculate the average unit pressure of the cable under test according to the rolling force and the horizontal projected area of ​​the contact surface between the cable under test and the rolling mill during the rolling process; and calculate the yield strength of the cable under test according to the average unit pressure of the cable under test.

[0092] In practical applications, there are various ways to implement a cable yield strength testing device. For example, it can be implemented through a computer program, such as application software; or it can be implemented as a medium storing the relevant computer program, such as a USB flash drive or cloud drive; or it can be implemented through a physical device that integrates or installs the relevant computer program, such as a chip.

[0093] In this example, the initial density of the mineral insulation material in the cable under test is obtained based on the mass of the mineral insulation material filling it and the initial dimensions of the cable. The mineral insulation material can be materials with good insulation and high-temperature resistance, such as magnesium oxide, aluminum oxide, or zirconium oxide. For example, the volume of the cable under test can be calculated using its initial dimensions (e.g., cable length) and the cross-sectional area of ​​the space filled with the mineral insulation material. The initial density is then calculated using the relationship between weight, density, and volume. It should be noted that the cable under test consists of a hollow cylindrical metal sheath, a conductive core rod, and a mineral insulation layer. During the initial manufacturing process, the core rod is passed through the sheath. One end is sealed with hot melt adhesive to fix the core rod in the central area of ​​the sheath, and a certain mass of mineral insulation material is filled into the gap between the core rod and the sheath from the other end. After the mineral insulation material is filled, it is compacted and the other end is sealed to complete the initial cable fabrication.

[0094] After obtaining the initial density of the cable under test, the dimensional reduction of the cable is determined based on the initial density of the mineral insulation material, the initial size of the cable, and the target density. The dimensional reduction is the change in the current size of the cable compared to its initial size when the density of the mineral insulation material in the cable reaches the target density. For example, based on the principle of mass conservation and the density formula, the target size of the cable can be determined according to the initial density of the mineral insulation material, the initial size of the cable, and the target density. The dimensional reduction is then the difference between the initial size and the target size. For example, based on the obtained dimensional reduction, and considering factors such as the rolling speed and temperature of the rolling mill, and the plasticity and ductility of the cable material, the total diameter reduction is calculated, and rolling is performed according to the total diameter reduction. During the rolling process, the rolling force is acquired. In practical applications, the rolling force can be acquired using a pressure sensor on the rolling mill. For example, only the rolling force corresponding to the last rolling process can be selected for yield strength calculation, or the rolling forces corresponding to the last few rolling processes can be selected for yield strength calculation. In this example, during the rolling process, the rolling force data corresponding to each segment of the cable under test can be obtained according to the rolling sequence. After calculating these rolling force data, the yield strength corresponding to each segment of the cable under test can be obtained.

[0095] In this example, the formula for calculating the average unit pressure of the cable under test, based on the rolling force and the horizontal projected area of ​​the contact surface between the cable under test and the rolling mill during the rolling process, is as follows:

[0096] P B =P / F B

[0097] Among them, P B Where P is the average unit pressure of the cable under test, and F is the rolling force.B This is the horizontal projected area of ​​the contact surface between the cable under test and the rolling mill.

[0098] As an example, the horizontal projected area F of the contact surface between the cable under test and the rolling mill. B The calculation formula is as follows:

[0099]

[0100] Where, d k1 The height of the cable to be tested after rolling (the diameter if the cross-section of the cable is circular, and the average of the sum of the major and minor axes if the cross-section of the cable is elliptical); ω is the reduction coefficient of the rolling mill; the formula for calculating A is as follows:

[0101]

[0102] Where D is the diameter of the rolling mill rolls, H is the diameter when the rolling mill pass is circular, and H is the axis length parallel to the rolling direction when the rolling mill pass is elliptical.

[0103] When the cross-section of the cable under test is circular, the formula for calculating ξ is as follows:

[0104]

[0105] When the cross-section of the cable under test is elliptical, the formula for calculating ξ is as follows:

[0106]

[0107] Among them, u k δ represents the roll pass axis ratio of the rolling mill (1 for a circular roll pass, and the axis length of the axis perpendicular to the rolling direction minus the axis length of the axis parallel to the rolling direction for an elliptical roll pass). i-1 δ represents the degree of filling of the test cable within the mill pass during the previous rolling process. i This represents the degree of filling of the test cable within the rolling mill pass during this rolling process.

[0108] The average unit pressure P of the cable under test is calculated using the above formula. B Subsequently, the yield strength of the cable under test corresponding to the average unit pressure can be obtained through computer simulation using structural analysis software such as finite element analysis software. Optionally, the yield strength of the cable under test corresponding to the average unit pressure can also be obtained through calculation using physical formulas. Among these methods, computer simulation can improve the accuracy of calculations in complex mechanical structures, while calculation using physical formulas can improve the efficiency of the calculation.

[0109] The yield strength testing device for mineral-insulated cables disclosed in this application includes: determining the dimensional reduction of the cable under test based on the initial density of the mineral insulation material filling the cable, the initial size of the cable, and the target density; rolling the cable under test based on the dimensional reduction and acquiring the rolling force during the rolling process; calculating the average unit pressure of the cable under test based on the rolling force and the horizontal projected area of ​​the contact surface between the cable and the rolling mill during the rolling process, and then calculating the yield strength of the cable under test. This example scheme, by rolling the cable based on the target density and calculating the yield strength based on physical parameters such as the rolling force, horizontal projected area, and average unit pressure during the rolling process, avoids destructive testing while obtaining more yield strength data of the cable during rolling, thereby improving the accuracy of the yield strength calculation for mineral-insulated cables.

[0110] In one example, calculation module 53 is specifically used for:

[0111] Based on the dimensional reduction, determine the amount and number of reductions per cycle;

[0112] The cable to be tested is rolled according to the reduction amount and the number of reduction cycles, and the rolling force of the most recent reduction rolling process is obtained.

[0113] In this example, the total reduction in diameter of the cable under test can be calculated based on the dimensional reduction, taking into account the plasticity and ductility of the sheath and mandrel. Further, the single reduction amount and number of reductions are determined based on the total reduction. In practical applications, due to the complexity of the cable's structure, to avoid damage caused by excessive deformation, the single reduction amount can be controlled below 10%. For example, when the total reduction is 20%, one rolling scheme is to perform rolling with multiple reductions gradually increasing in diameter, such as rolling with reductions of 1%, 2%, 3%, 4%, 5%, and 5%. This fully utilizes the ductility of the cable under test after each rolling to ensure its performance. Alternatively, multiple identical reduction amounts, such as five 4% reductions, can be used to improve rolling uniformity. In practical applications, adjustments can be made based on the material of the cable under test. For example, copper and aluminum have good ductility and can withstand larger reductions, while stainless steel and nickel alloys have poor ductility and are suitable for smaller reductions. The cable under test is rolled according to the reduction amount and the number of reduction cycles, and the rolling force during the most recent reduction rolling process is obtained. In practical applications, the yield strength corresponding to the rolling force is closer to the actual yield strength of the cable under test as the number of rolling cycles increases. Therefore, the last rolling force or the last few rolling forces can be used for yield strength calculation. The scheme in this example determines different single reduction amounts and corresponding cycles based on the dimensional reduction, which can make reasonable use of the ductility of the cable under test and improve the uniformity of rolling; by obtaining the rolling force during the rolling process at the number of reduction cycles for yield strength calculation, the accuracy of yield strength calculation can be improved.

[0114] In one example, the diameter reduction ranges from 2% to 3%.

[0115] In practical applications, the reduction amount can be adjusted according to the ductility of the sheath and mandrel of the cable under test; for example, for materials with high ductility, the range can be set to 2% to 5%, and for materials with low ductility, the range can be set to 1% to 2%. The scheme in this example, by limiting the range of the reduction amount, ensures that the sheath thickness is reduced, minimizing earing during the rolling process, improving the uniformity of the cable under test, and thus improving the accuracy of the yield strength calculation.

[0116] In one example, calculation module 53 is specifically used for:

[0117] Based on the yield strength obtained from the rolling force during each diameter reduction rolling process, the yield strength of the cable under test is obtained through weighted calculation.

[0118] In practical applications, each segment of the cable under test undergoes multiple rolling processes. Based on the rolling time and the location of cable deformation, rolling in earlier stages where the deformation primarily affects the cable's sheath is called the tube rolling zone, while rolling in later stages affecting the entire cable is called the bar rolling zone. To obtain the overall stress of the cable under test, the yield strength is typically calculated using the rolling force corresponding to the bar rolling zone. After obtaining multiple yield strengths in the bar rolling zone, a weighted calculation is performed. If the weight values ​​are the same, the average of the multiple yield strengths is calculated. Optionally, by setting the weight values ​​to increase sequentially (i.e., the weight value is larger closer to the last rolling stage), the calculated result can be closer to the actual yield strength. The scheme in this example, by weighting the calculated yield strengths, avoids the error of calculating the yield strength using only the last rolling force, thus improving the accuracy of the yield strength calculation.

[0119] In one example, calculation module 53 is specifically used for:

[0120] The yield strength of the cable under test is calculated based on its average unit pressure and stress state coefficient. In this example, the formula for calculating the yield strength of the cable under test is:

[0121] P B =1.15σ*n σ

[0122] Among them, P B n represents the average unit pressure of the cable under test. σLet σ be the stress state coefficient of the cable under test, and σ be the yield strength of the cable under test. The yield strength calculation formula provided in this example improves the accuracy of calculations compared to estimates made by engineers based on experience, and improves the efficiency of calculations compared to model simulations.

[0123] In one example, calculation module 53 is also used for:

[0124] The cross-sectional shape of the cable to be tested before entering the rolling mill, as well as the roll pass of the rolling mill, are detected.

[0125] If the cross-sectional shape of the cable under test is elliptical and the die of the rolling mill is circular, the first stress state coefficient is obtained based on the deformation zone shape coefficient, the ratio of the rolling mill roll diameter to the rolling mill die diameter, and the friction between the cable under test and the rolling mill. The first stress state coefficient is then used as the stress state coefficient of the cable under test.

[0126] If the cross-sectional shape of the cable under test is circular and the die of the rolling mill is elliptical, then the second stress state coefficient is obtained based on the deformation zone shape coefficient, the die axis ratio of the rolling mill, and the friction between the cable under test and the rolling mill, and the second stress state coefficient is used as the stress state coefficient of the cable under test.

[0127] It should be noted that the cross-sectional shape of the cable under test before entering the rolling mill is usually determined by the rolling mill in the previous rolling process. In practical applications, the rolling mill pass shape in the rolling process is usually arranged in alternating elliptical, circular, elliptical, and circular patterns. If the cross-sectional shape of the cable under test is elliptical and the rolling mill pass shape is circular, the corresponding formula for calculating the first stress state coefficient is:

[0128]

[0129] Where, n σ1 denoted as the first stress state coefficient, m as the deformation zone shape coefficient, a0 as the ratio of the rolling mill roll diameter to the rolling mill pass diameter, and φ as the frictional force between the cable under test and the rolling mill.

[0130] If the cross-sectional shape of the cable under test is circular and the die of the rolling mill is elliptical, the corresponding formula for calculating the second stress state coefficient is:

[0131]

[0132] Where, n σ2 U is the second stress state coefficient, m is the deformation zone shape coefficient, and u is the second stress state coefficient. k The roll pass ratio of the rolling mill (where the roll pass is elliptical, u) is the axial ratio of the rolling mill's pass. k φ is the length of the axis perpendicular to the rolling direction (the length of the axis parallel to the rolling direction), and φ is the frictional force between the cable under test and the rolling mill.

[0133] The formula for calculating the shape factor m of the deformation zone is as follows:

[0134] m = l / H

[0135] Where l is the horizontal projection of the contact arc length of the deformation zone of the cable under test, which can be approximated as equal to Where R is the radius of the rolling mill roll, Δh is the length of the cable pressed down along the rolling direction; when the rolling mill pass is circular, H is the diameter, and when the rolling mill pass is elliptical, H is the axis length parallel to the rolling direction.

[0136] The scheme in this example takes into account the cross-sectional shape of the cable under test before entering the rolling mill and the roll pass of the rolling mill. The formula for calculating the stress state coefficient is different under different conditions, which can improve the accuracy of the stress state coefficient and further improve the accuracy of the yield strength calculation.

[0137] In one example, calculation module 53 is also used for:

[0138] The yield strength of the mineral insulation material is calculated based on the yield strength of the cable under test, the yield strength of the sheath, the ratio of the cross-sectional area of ​​the sheath to the total cross-sectional area of ​​the cable under test, the yield strength of the core rod, the ratio of the cross-sectional area of ​​the core rod to the total cross-sectional area of ​​the cable under test, and the ratio of the cross-sectional area of ​​the mineral insulation material to the total cross-sectional area of ​​the cable under test.

[0139] In practical applications, the components and proportions of the cable under test are fixed; that is, the area occupied by the sheath, core, and mineral insulation material in the cross-section of the cable is constant. In this example, the yield strength σ of the mineral insulation material can be calculated using the following formula. 矿 :

[0140]

[0141] Where, σ 总 S represents the yield strength of the cable under test. 总 σ is the total cross-sectional area of ​​the cable under test. 套 S represents the yield strength of the sheath. 套 σ is the cross-sectional area of ​​the sheath. 矿 S represents the yield strength of mineral insulating materials. 矿 σ is the cross-sectional area of ​​the mineral insulating material. 芯 S represents the yield strength of the mandrel. 芯 Let be the cross-sectional area of ​​the mandrel.

[0142] The scheme in this example calculates the yield strength of the mineral insulation material based on a formula, according to the components and proportions of the cable under test. Optionally, after obtaining the yield strength of the mineral insulation material, this value can be used for calculations of more refined stress data or stress models.

[0143] The cable yield strength testing device of this embodiment includes: determining the dimensional reduction of the cable under test based on the initial density of the mineral insulation material filled in the cable, the initial size of the cable under test, and the target density; rolling the cable under test based on the dimensional reduction and acquiring the rolling force during the rolling process; calculating the average unit pressure of the cable under test based on the rolling force and the horizontal projected area of ​​the contact surface between the cable under test and the rolling mill during the rolling process, and then calculating the yield strength of the cable under test. This example scheme rolls the cable based on the target density and calculates the yield strength based on physical parameters such as the rolling force, horizontal projected area, and average unit pressure during the rolling process. This avoids destructive testing while obtaining more yield strength data of the cable during rolling, thereby improving the accuracy of yield strength calculation for mineral-insulated cables.

[0144] Example 3

[0145] Figure 6 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. The electronic device includes:

[0146] The electronic device includes a processor 291 and a memory 292; it may also include a communication interface 293 and a bus 294. The processor 291, memory 292, and communication interface 293 can communicate with each other via the bus 294. The communication interface 293 can be used for information transmission. The processor 291 can invoke logical instructions stored in the memory 292 to execute the methods described in the example above.

[0147] Furthermore, the logic instructions in the aforementioned memory 292 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium.

[0148] The memory 292, as a computer-readable storage medium, can be used to store software programs and computer-executable programs, such as program instructions / modules corresponding to the methods in the embodiments of this application. The processor 291 executes functional applications and data processing by running the software programs, instructions, and modules stored in the memory 292, that is, it implements the methods in the above method examples.

[0149] The memory 292 may include a program storage area and a data storage area. The program storage area may store the operating system and application programs required for at least one function; the data storage area may store data created based on the use of the terminal device. Furthermore, the memory 292 may include high-speed random access memory and may also include non-volatile memory.

[0150] This application also provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, are used to implement the method in any of the embodiments.

[0151] This application also provides a computer program product, including a computer program that, when executed by a processor, implements the method in any of the embodiments.

[0152] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this application are indicated by the following claims.

[0153] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. A method for testing the yield strength of a cable, characterized in that, The cable is filled with mineral insulating material; the method includes: The initial density of the mineral insulation material in the cable under test is obtained based on the mass of the mineral insulation material filling the cable under test and the initial dimensions of the cable under test. The dimensional reduction of the cable under test is determined based on the initial density of the mineral insulating material, the initial size of the cable under test, and the target density. The dimensional reduction of the cable under test is the change in the current size of the cable under test compared to the initial size when the density of the mineral insulating material in the cable under test is the target density. Based on the dimensional reduction, the cable under test is rolled and the rolling force during the rolling process is obtained; based on the rolling force and the horizontal projected area of ​​the contact surface between the cable under test and the rolling mill during the rolling process, the average unit pressure of the cable under test is calculated; based on the average unit pressure of the cable under test, the yield strength of the cable under test is calculated.

2. The method according to claim 1, characterized in that, The step of rolling the cable under test according to the dimensional reduction and obtaining the rolling force during the rolling process includes: Based on the stated dimensional reduction, determine the single diameter reduction amount and the number of reductions; The cable under test is rolled according to the reduction amount and the number of reduction cycles, and the rolling force during the most recent reduction rolling process is obtained.

3. The method according to claim 2, characterized in that, The step of calculating the yield strength of the cable under test based on the average unit pressure of the cable under test includes: Based on the yield strength obtained from the rolling force during each diameter reduction rolling process, the yield strength of the cable under test is obtained through weighted calculation.

4. The method according to claim 1, characterized in that, The step of calculating the yield strength of the cable under test based on the average unit pressure of the cable under test includes: The yield strength of the cable under test is calculated based on the average unit pressure and the stress state coefficient of the cable under test.

5. The method according to claim 4, characterized in that, The method further includes: The cross-sectional shape of the cable under test and the die shape of the rolling mill are detected before the cable enters the rolling mill. If the cross-sectional shape of the cable under test is elliptical and the die of the rolling mill is circular, then the first stress state coefficient is obtained based on the deformation zone shape coefficient, the ratio of the rolling mill roll diameter to the rolling mill die diameter, and the friction between the cable under test and the rolling mill, and the first stress state coefficient is used as the stress state coefficient of the cable under test. If the cross-sectional shape of the cable under test is circular and the die of the rolling mill is elliptical, then a second stress state coefficient is obtained based on the deformation zone shape coefficient, the die axis ratio of the rolling mill, and the friction between the cable under test and the rolling mill, and the second stress state coefficient is used as the stress state coefficient of the cable under test.

6. The method according to any one of claims 1 to 5, characterized in that, The cable under test further includes a sheath and a core rod; after calculating the yield strength of the cable under test, the method further includes: The yield strength of the mineral insulation material is calculated based on the yield strength of the cable under test, the yield strength of the sheath and the ratio of the cross-sectional area of ​​the sheath to the total cross-sectional area of ​​the cable under test, the yield strength of the core rod and the ratio of the cross-sectional area of ​​the core rod to the total cross-sectional area of ​​the cable under test, and the ratio of the cross-sectional area of ​​the mineral insulation material to the total cross-sectional area of ​​the cable under test.

7. A device for testing the yield strength of a cable, characterized in that, include: The module is used to obtain the initial density of the mineral insulation material in the cable under test based on the mass of the mineral insulation material filling the cable under test and the initial dimensions of the cable under test. The determining module is used to determine the size reduction of the cable under test based on the initial density of the mineral insulating material, the initial size of the cable under test, and the target density; the size reduction of the cable under test is the change in the current size of the cable under test compared to the initial size when the density of the mineral insulating material in the cable under test is the target density; The calculation module is used to roll the cable under test according to the size reduction and to obtain the rolling force during the rolling process; The average unit pressure of the cable under test is calculated based on the rolling force and the horizontal projected area of ​​the contact surface between the cable under test and the rolling mill during the rolling process. The yield strength of the cable under test is calculated based on the average unit pressure of the cable under test.

8. An electronic device, characterized in that, include: A processor, and a memory communicatively connected to the processor; The memory stores computer-executable instructions; the processor executes the computer-executable instructions stored in the memory to implement the method as described in any one of claims 1 to 6.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions, which, when executed by a processor, are used to implement the method as described in any one of claims 1 to 6.

10. A computer program product, characterized in that, It includes a computer program that, when executed by a processor, implements the method as described in any one of claims 1 to 6.

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