Silicone rubber rough contact interface ultrasonic detection simulation method and device and storage medium

Abstract

The invention relates to an ultrasonic detection simulation method and device for a rough contact interface of silicone rubber and a storage medium. The method comprises the following steps: acquiring the surface roughness of semi-conductive silicone rubber of a stress cone; performing curve fitting on data obtained by the tensile experiment to obtain hyperelastic material parameters required by the material in simulation; establishing an ultrasonic simulation model of the two-dimensional rough contact interface according to the surface roughness; inputting the parameters into an ultrasonic simulation model of the two-dimensional rough contact interface for ultrasonic simulation calculation; by means of the arrangement, the mapping relation between the interface pressure and the ultrasonic nonlinear coefficient can be established, and reference is provided for engineering application feasibility of the ultrasonic nonlinear detection method on high-voltage cable terminal interface pressure detection.

Description

Technical Field

[0001] The present invention relates to the technical field of ultrasonic detection of high-voltage cable accessories, and in particular to a simulation method, device and storage medium for ultrasonic detection of a rough contact interface of silicone rubber. Background Art

[0002] In recent years, cable accessories have accounted for over 50% of high-voltage cable line failures. Prefabricated high-voltage cable terminals are a common type of terminal used in 110kV and above lines. Research has shown that the pressure at the interface between the internal stress cone and the cable itself is a significant factor affecting the insulation strength of the terminal.

[0003] There is an urgent need to conduct in-depth research on the nonlinear response characteristics of the rough contact interface of high-voltage cable terminals under different interface pressures, and to analyze the related factors affecting the ultrasonic nonlinear response characteristics, so that the interaction between ultrasound and the contact interface at the macro level can be explained at the micro level, thereby providing a basis for the application of nonlinear ultrasonic detection methods in high-voltage cable terminal interface pressure detection. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a simulation method, device and storage medium for ultrasonic detection of the rough contact interface of silicone rubber. Its advantage is that it can establish a mapping relationship between the interface pressure and the ultrasonic nonlinear coefficient, and provide a reference for the feasibility of engineering application of ultrasonic nonlinear detection method in the interface pressure detection of high-voltage cable terminals.

[0005] The above-mentioned object of the present invention is achieved through the following technical solutions: On the one hand, the present invention provides a simulation method for ultrasonic detection of a rough contact interface of silicone rubber, comprising the following steps:

[0006] Obtain the surface roughness of stress cone semi-conductive silicone rubber;

[0007] The data obtained from the tensile test are curve fitted to obtain the hyperelastic material parameters required for the material in the simulation;

[0008] Establishing an ultrasonic simulation model of a two-dimensional rough contact interface according to the surface roughness;

[0009] Parameters are input into the ultrasonic simulation model of the two-dimensional rough contact interface to perform ultrasonic simulation calculations, wherein the parameters include material parameters, excitation signals, boundary conditions, and simulation model grids.

[0010] Preferably, the ultrasonic detection simulation method for the rough contact interface of silicone rubber provided by the present invention, wherein the surface roughness of the stress cone semi-conductive silicone rubber is obtained, comprises:

[0011] The prefabricated silicone rubber stress cone was planed along the axial direction, and the inner surface of the semi-conductive silicone rubber of the stress cone was measured using a white light interferometer to obtain the three-dimensional morphology.

[0012] Based on the three-dimensional topography, the white light interferometer obtains the surface roughness.

[0013] Preferably, the ultrasonic detection simulation method for the rough contact interface of silicone rubber provided by the present invention, wherein the curve fitting of the data obtained from the tensile test to obtain the hyperelastic material parameters required for the material in the simulation, comprises:

[0014] Use a high-temperature vulcanizer to stamp out silicone rubber samples;

[0015] Performing a tensile test on the silicone rubber sample to obtain uniaxial tensile data;

[0016] Through curve analysis and fitting, the uniaxial tensile stress-strain fitting curve of the semi-conductive silicone rubber is obtained to obtain the hyperelastic material parameters required for the material in the simulation.

[0017] Preferably, the ultrasonic detection simulation method for the rough contact interface of silicone rubber provided by the present invention, wherein the ultrasonic simulation model of the two-dimensional rough contact interface is established according to the surface roughness, comprises:

[0018] The equivalent roughness σ of the contact surface is calculated;

[0019] Acquire three-dimensional modeling data of simulated rough surface;

[0020] The simulation model adopts a two-dimensional model. The corresponding y and z column data are randomly intercepted along a certain x column in the generated three-dimensional modeling data. The "polygon" command is selected in the geometry command of the COMSOL software, and the generation object is selected as "open curve". The three-dimensional modeling data is imported to generate the rough interface contour. By generating line segments, the solid modeling steps are converted to generate an ultrasonic simulation model of the two-dimensional rough contact interface.

[0021] Preferably, in the ultrasonic detection simulation method for the rough contact interface of silicone rubber provided by the present invention, the calculation formula of the equivalent roughness σ of the contact surface is:

[0022]

[0023] Wherein, in formula (1), σ1 is the surface roughness; σ2 is the surface roughness of the cable insulation outer shielding layer.

[0024] Preferably, in the ultrasonic detection simulation method for the rough contact interface of silicone rubber provided by the present invention, the calculation formula of the power spectrum density function C(q) of the surface profile height is:

[0025]

[0026] Where, in formula (2), B(q) is the wave vector amplitude function; q is the total wave vector including the component 2π / L; A represents the sampling cross-sectional area. Since the sampling lengths in the x-direction and the y-direction are the same, A = L 2 .

[0027] Preferably, the ultrasonic detection simulation method for the rough contact interface of silicone rubber provided by the present invention is defined according to the equivalent roughness σ of the contact surface, and its expression is:

[0028]

[0029] Wherein, in formula (3), p is the pth sampling point, N is the total number of sampling points; h(z) is the height distribution of the rough surface profile.

[0030] Preferably, the ultrasonic detection simulation method for the rough contact interface of silicone rubber provided by the present invention, based on the law of conservation of energy, combines equations (2) and (3), and obtains the relationship expression between the equivalent roughness σ of the contact surface and the power spectral density function C(q) of the surface profile height:

[0031]

[0032] In formula (4), m and n represent the number of sampling points in different directions of the sampling section.

[0033] Preferably, the ultrasonic detection simulation method for the rough contact interface of silicone rubber provided by the present invention, after establishing the ultrasonic simulation model of the two-dimensional rough contact interface according to the surface roughness, and before performing ultrasonic simulation calculation on the ultrasonic simulation model of the two-dimensional rough contact interface, also includes: setting material parameters, excitation signals, boundary conditions and simulation model grids.

[0034] In another aspect, the present invention provides an ultrasonic detection simulation device for a rough contact interface of silicone rubber, comprising:

[0035] Surface roughness acquisition module, used to obtain the surface roughness of stress cone semi-conductive silicone rubber;

[0036] The hyperelastic material parameter acquisition module is used to perform curve fitting on the data obtained from the tensile test to obtain the hyperelastic material parameters required for the material in the simulation;

[0037] An ultrasonic simulation model establishment module, used to establish an ultrasonic simulation model of a two-dimensional rough contact interface according to the surface roughness;

[0038] The ultrasonic simulation calculation module is used to input parameters into the ultrasonic simulation model of the two-dimensional rough contact interface to perform ultrasonic simulation calculation, wherein the parameters include material parameters, excitation signals, boundary conditions and simulation model grids.

[0039] On the other hand, the present invention provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the steps of the ultrasonic detection simulation method for the rough contact interface of silicone rubber are executed.

[0040] To sum up, the beneficial technical effects of the present invention are as follows: the ultrasonic detection simulation method, device and storage medium for the rough contact interface of silicone rubber provided in this application include the following steps: obtaining the surface roughness of the stress cone semi-conductive silicone rubber; performing curve fitting on the data obtained from the tensile test to obtain the hyperelastic material parameters required for the material in the simulation; establishing an ultrasonic simulation model of a two-dimensional rough contact interface based on the surface roughness; inputting the parameters into the ultrasonic simulation model of the two-dimensional rough contact interface for ultrasonic simulation calculation; such a setting can establish a mapping relationship between the interface pressure and the ultrasonic nonlinear coefficient, providing a reference for the engineering application feasibility of the ultrasonic nonlinear detection method in the interface pressure detection of high-voltage cable terminals. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is a flow chart of a simulation method for ultrasonic detection of a silicone rubber rough contact interface provided by an embodiment of the present invention.

[0042] Figure 2 This is a diagram of the measurement position of the prefabricated silicone rubber terminal stress cone in the silicone rubber rough contact interface ultrasonic detection simulation method provided by an embodiment of the present invention.

[0043] Figure 3 It is the measured three-dimensional morphology of the inner surface of the silicone rubber stress cone in the silicone rubber rough contact interface ultrasonic detection simulation method provided by the embodiment of the present invention.

[0044] Figure 4 It is the two-dimensional profile of the inner surface of the silicone rubber stress cone in the silicone rubber rough contact interface ultrasonic detection simulation method provided by the embodiment of the present invention.

[0045] Figure 5 The invention relates to a semi-conductive silicone rubber tensile test specimen in a silicone rubber rough contact interface ultrasonic detection simulation method provided by an embodiment of the invention.

[0046] Figure 6 This is a uniaxial tensile stress-strain fitting diagram of semi-conductive silicone rubber in the ultrasonic detection simulation method for the silicone rubber rough contact interface provided by an embodiment of the present invention.

[0047] Figure 7 It is a stress cone ultrasonic detection simulation model in the ultrasonic detection simulation method for the rough contact interface of silicone rubber provided by an embodiment of the present invention.

[0048] Figure 8This is an ultrasonic time domain waveform diagram in the ultrasonic detection simulation method for the silicone rubber rough contact interface provided by an embodiment of the present invention.

[0049] Figure 9 This is a primary echo spectrum diagram of the contact interface in the ultrasonic detection simulation method of the silicone rubber rough contact interface provided by an embodiment of the present invention.

[0050] Figure 10 This is a curve showing the change of ultrasonic nonlinear coefficient and interface pressure in the ultrasonic detection simulation method for the silicone rubber rough contact interface provided by an embodiment of the present invention.

[0051] Figure 11 It is a structural schematic diagram of an ultrasonic detection simulation device for a rough contact interface of silicone rubber provided by another embodiment of the present invention. DETAILED DESCRIPTION

[0052] The present invention will be further described in detail below with reference to the accompanying drawings.

[0053] Reference Figure 1 , a simulation method for ultrasonic detection of a rough contact interface of silicone rubber disclosed in the present invention, comprising the following steps:

[0054] S101. Obtain the surface roughness of the stress cone semi-conductive silicone rubber.

[0055] S102 , performing curve fitting on the data obtained from the tensile test to obtain the hyperelastic material parameters required for the material in the simulation.

[0056] S103. Establish an ultrasonic simulation model of a two-dimensional rough contact interface according to the surface roughness.

[0057] S104 , inputting parameters into an ultrasonic simulation model of a two-dimensional rough contact interface to perform ultrasonic simulation calculations, wherein the parameters include material parameters, excitation signals, boundary conditions, and simulation model grids.

[0058] With this setting, a mapping relationship between interface pressure and ultrasonic nonlinear coefficient can be established, providing a reference for the feasibility of engineering application of ultrasonic nonlinear detection method in high-voltage cable terminal interface pressure detection.

[0059] Continue to refer to Figures 2 to 4 In this embodiment, S101, obtaining the surface roughness of the stress cone semi-conductive silicone rubber, includes:

[0060] S1011. Plane the prefabricated silicone rubber stress cone along the axial direction, and use a white light interferometer to measure the inner surface of the stress cone semi-conductive silicone rubber to obtain the three-dimensional morphology.

[0061] S1012. Based on the three-dimensional morphology, the surface roughness is obtained by white light interferometry.

[0062] Among them, the white light interferometer randomly selects a straight line along the longitudinal axis of the three-dimensional topography to obtain two-dimensional profile data.

[0063] It should be noted that the two-dimensional contour data is used to provide actual reference and basis for the two-dimensional rough contact interface generated in ultrasonic simulation modeling.

[0064] Continue to refer to Figure 5 and Figure 6 In this embodiment, S102, curve fitting is performed on the data obtained from the tensile test to obtain the hyperelastic material parameters required for the material in the simulation, including:

[0065] S1021. Use a high-temperature vulcanizing machine to stamp out silicone rubber samples.

[0066] Specifically, a high-temperature vulcanizer is used to stamp the silicone sample to a preset size. The sample is then cut into dumbbell II-shaped specimens according to HG / T 2645-2011. The central parallel portion of the dumbbell II specimen is 4 mm wide and 25 mm long, for a total length of 75 mm. Of course, other dimensions of the central parallel portion of the dumbbell II specimen may also be used.

[0067] In this embodiment, the stamping area of ​​the high temperature vulcanizer is 10×10 cm 2 , silicone rubber specimens with a thickness of 2mm. Of course, the high temperature vulcanizing press can also be used for silicone rubber specimens of other sizes.

[0068] S1022. Conduct a tensile test on the silicone rubber specimen to obtain uniaxial tensile data.

[0069] Specifically, a tensile test was conducted on a semi-conductive silicone rubber specimen in accordance with GB / T 528-2009. The specimen was positioned symmetrically and perpendicular to the upper and lower fixtures of the testing machine. The sensor accuracy was set to 1%, the tensile speed was 500 mm / min, and the test was stopped when the specimen broke.

[0070] S1023. Obtain a uniaxial tensile stress-strain fitting curve of the semi-conductive silicone rubber through curve analysis and fitting, so as to obtain the hyperelastic material parameters required for the material in the simulation.

[0071] Specifically, the obtained uniaxial tensile data were fitted using the curve analysis in Origin, and the determination coefficient R of the fitting curve was 2 A value of 0.99 indicates a good fitting effect.

[0072] Among them, the stress-stretch fitting formula is:

[0073]

[0074] Continue to refer to Figure 7In this embodiment, S103, establishing an ultrasonic simulation model of a two-dimensional rough contact interface according to the surface roughness, includes:

[0075] S1031. Calculate the equivalent roughness σ of the contact surface.

[0076] Among them, the calculation formula of the equivalent roughness σ of the contact surface is:

[0077]

[0078] Wherein, in formula (1), σ1 is the surface roughness; σ2 is the surface roughness of the cable insulation outer shielding layer.

[0079] It should be noted that σ2 is the surface roughness of the cable insulation outer shielding layer. Referring to the industry installation standard, σ2 is generally taken as 1.

[0080] S1032: Acquire three-dimensional modeling data of a simulated rough surface.

[0081] Wherein, S1032, obtaining three-dimensional modeling data of a simulated rough surface, includes:

[0082] The power spectrum density function C(q) of the surface profile height is assigned according to the equivalent roughness σ of the contact surface to generate three-dimensional modeling data of the simulated rough surface.

[0083] Specifically, the calculation formula of the power spectral density function C(q) of the surface profile height is:

[0084]

[0085] Where, in formula (2), B(q) is the wave vector amplitude function; q is the total wave vector including the component 2π / L; A represents the sampling cross-sectional area. Since the sampling lengths in the x-direction and the y-direction are the same, A = L 2 .

[0086] According to the definition of the equivalent roughness σ of the contact surface, its expression is:

[0087]

[0088] Wherein, in formula (3), p is the pth sampling point, N is the total number of sampling points; h(z) is the height distribution of the rough surface profile.

[0089] According to the law of conservation of energy, combined with equations (2) and (3), the relationship between the equivalent roughness σ of the contact surface and the power spectrum density function C(q) of the surface profile height is obtained as follows:

[0090]

[0091] In formula (4), m and n represent the number of sampling points in different directions of the sampling section.

[0092] S1033. The simulation model uses a two-dimensional model. In the generated three-dimensional modeling data, the corresponding y and z column data are randomly intercepted along a certain x column. The "polygon" command is selected in the geometry command of the COMSOL software, and the generated object is selected as "open curve". The three-dimensional modeling data is imported to generate a rough interface contour. By generating line segments and converting the solid modeling steps, an ultrasonic simulation model of a two-dimensional rough contact interface is generated.

[0093] It should be noted that the two-dimensional rough contact interface uses the power spectral density function C(q) of the surface profile height combined with the inverse Fourier transform method to construct a random rough surface.

[0094] Specifically, a simulation model was established based on the ultrasonic testing model, with the semiconductive silicone rubber layer set to a first predetermined thickness, the cable insulation outer shielding layer to a second predetermined thickness, and the XLPE layer to a third predetermined thickness. Because the ultrasonic longitudinal wave detection direction coincides with the propagation direction, a two-dimensional model was used to simulate the propagation of ultrasonic longitudinal waves at the composite interface.

[0095] Among them, the first preset thickness range is 20mm-40mm, the second preset thickness range is 1.5mm-2.0mm, and the third preset thickness range is 5mm-15mm. In this embodiment, the first preset thickness is 30mm, the second preset thickness is 1.8mm, and the third preset thickness is 10mm.

[0096] Furthermore, in this embodiment, S104 , parameters are input into the ultrasonic simulation model of the two-dimensional rough contact interface to perform ultrasonic simulation calculations, wherein the parameters include material parameters, excitation signals, boundary conditions, and simulation model grids.

[0097] Among them, in the material parameter settings: Figure 7 The figure shows the XLPE (cross-linked polyethylene)-insulating outer shielding layer-semi-conductive silicone rubber composite interface model, in which the upper silicone rubber material is set as a hyperelastic material, and the model parameters are substituted into the stress tensile fitting formula in step S102. The lower layer is a linear elastic material, and other material parameters are shown in Table 1.

[0098] Table 1 Simulation material parameters

[0099]

[0100] In this embodiment, in the excitation signal setting: the excitation signal is a Hamming window modulated sine pulse with a frequency of 1.5 MHz and an amplitude of 100 μm. At the same time, in order to avoid waveform aliasing, the excitation signal takes 5 cycles.

[0101] In addition, the boundary conditions were set to low-reflection boundaries on both sides of the model to prevent boundary reflection waves from mixing with the echo signal. The stress and acoustic field simulations were performed in the Solid Mechanics (Elastic Wave) module.

[0102] In this embodiment, in the simulation model grid setting: In the finite element simulation calculation, the solution area needs to be divided into multiple independent and non-overlapping grid units, and connected to each other through boundary nodes. The size of the grid division has an important influence on the simulation results and is directly related to the stability and accuracy of the numerical solution. If the grid size is too small, although it will not reduce the accuracy of the simulation calculation, it will significantly increase the calculation time and reduce the simulation efficiency. On the contrary, if the grid size is too large, it is difficult to effectively capture the model features and cannot accurately analyze the ultrasonic wavelength, which may cause the solution process to not converge or the calculation results to deviate too much.

[0103] In the stress steady-state analysis model, the standard level in COMSOL software is usually used to divide the grid to ensure a balance between calculation accuracy and solution efficiency. In ultrasonic simulation, it is necessary to ensure that the model grid size is at least less than 1 / 8 of the second harmonic (3MHz) wavelength.

[0104] In the simulation research calculation, the acoustic field and stress field are coupled sequentially, that is, static force analysis is first performed on the contact interface, and then ultrasonic simulation is completed in the transient study.

[0105] According to ultrasound simulation, Figure 8 is the time domain diagram of the first echo signal of the rough contact interface during ultrasonic propagation, Figure 8 It can be seen from the changes in the echo signals under different pressures that as the interface pressure increases, the amplitude of the echo signal gradually decreases.

[0106] Since it is difficult to analyze the changes in harmonic components in the signal from the time domain echo, the echo signal is subjected to Fourier transform to obtain Figure 9 is the Fourier spectrum of the echo signal under different pressures, Figure 9 It can be seen that under the influence of material nonlinearity and contact nonlinearity, the echo signal has a peak at the second harmonic (3MHz). Comparing the changes in the fundamental and second harmonic components of the echo signal under different pressures, it is found that as the interface pressure increases, both the fundamental and second harmonic components show a downward trend.

[0107] Among them, the relative nonlinear coefficient β is commonly used in the experiment ′ To characterize the nonlinear characteristics of the material, the nonlinear coefficient β ′ The calculation formula is:

[0108]

[0109] Where A1 is the signal fundamental amplitude, and A2 is the second harmonic amplitude.

[0110] According to the fundamental wave and second harmonic amplitude of the echo signal and formula (5), the ultrasonic nonlinear coefficient under different pressures is calculated. Figure 10 is the variation curve of ultrasonic nonlinear coefficient under different interface pressures. Figure 8 and Figure 9 It can be found that the fundamental wave and second harmonic amplitude of the echo signal show regular changes with the interface pressure, which shows that there is an obvious connection between the interface pressure and the ultrasonic response. Figure 10 It can be seen that there is an obvious mapping relationship between the interface pressure and the ultrasonic nonlinear coefficient, and the simulation confirms the feasibility of the ultrasonic nonlinear detection method in interface pressure detection.

[0111] Continue to refer to Figure 11 , Figure 11 This is a schematic diagram of the structure of an ultrasonic detection simulation device for a rough contact interface of silicone rubber provided by another embodiment of the present invention. Figure 3 As shown, the ultrasonic detection simulation device for the rough contact interface of silicone rubber includes:

[0112] Surface roughness acquisition module, used to obtain the surface roughness of stress cone semi-conductive silicone rubber;

[0113] The hyperelastic material parameter acquisition module is used to perform curve fitting on the data obtained from the tensile test to obtain the hyperelastic material parameters required for the material in the simulation;

[0114] Ultrasonic simulation model building module, used to build an ultrasonic simulation model of a two-dimensional rough contact interface according to surface roughness;

[0115] The ultrasonic simulation calculation module is used to input parameters into the ultrasonic simulation model of the two-dimensional rough contact interface for ultrasonic simulation calculation, wherein the parameters include material parameters, excitation signals, boundary conditions and simulation model grids.

[0116] Furthermore, in this embodiment, when the surface roughness acquisition module is used to acquire the surface roughness of the stress cone semi-conductive silicone rubber, the surface roughness acquisition module is specifically used to:

[0117] The prefabricated silicone rubber stress cone was planed along the axial direction, and the inner surface of the semi-conductive silicone rubber of the stress cone was measured using a white light interferometer to obtain the three-dimensional morphology.

[0118] Based on the three-dimensional topography, white light interferometry obtains the surface roughness.

[0119] Furthermore, in this embodiment, when the hyperelastic material parameter acquisition module performs curve fitting on the data obtained from the tensile test to obtain the hyperelastic material parameters required for the material in the simulation, the hyperelastic material parameter acquisition module is specifically used to:

[0120] Use a high-temperature vulcanizer to stamp out silicone rubber samples;

[0121] Conduct tensile tests on silicone rubber specimens to obtain uniaxial tensile data;

[0122] Through curve analysis and fitting, the uniaxial tensile stress-strain fitting curve of the semi-conductive silicone rubber is obtained to obtain the hyperelastic material parameters required for the material in the simulation.

[0123] Furthermore, in this embodiment, when the ultrasonic simulation model establishment module establishes the ultrasonic simulation model of the two-dimensional rough contact interface according to the surface roughness, the ultrasonic simulation model establishment module is specifically used to:

[0124] The equivalent roughness σ of the contact surface is calculated;

[0125] Acquire three-dimensional modeling data of simulated rough surface;

[0126] The simulation model adopts a two-dimensional model. The corresponding y and z column data are randomly intercepted along a certain x column in the generated three-dimensional modeling data. The "polygon" command is selected in the geometry command of the COMSOL software, and the generated object is selected as "open curve". The three-dimensional modeling data is imported to generate the rough interface contour. By generating line segments and converting the solid modeling steps, an ultrasonic simulation model of the two-dimensional rough contact interface is generated.

[0127] Furthermore, in this embodiment, the ultrasonic simulation model building module determines the equivalent roughness σ of the contact surface by the following formula:

[0128]

[0129] Wherein, in formula (1), σ1 is the surface roughness; σ2 is the surface roughness of the cable insulation outer shielding layer.

[0130] Among them, the ultrasonic simulation model building module determines the power spectrum density function C(q) of the surface profile height through the following formula:

[0131]

[0132] Where, in formula (2), B(q) is the wave vector amplitude function; q is the total wave vector including the component 2π / L; A represents the sampling cross-sectional area. Since the sampling lengths in the x-direction and the y-direction are the same, A = L 2 .

[0133] In this embodiment, the ultrasonic simulation model building module determines the equivalent roughness σ of the contact surface by the following formula:

[0134]

[0135] Wherein, in formula (3), p is the pth sampling point, N is the total number of sampling points; h(z) is the height distribution of the rough surface profile.

[0136] According to the law of conservation of energy, combined with equations (2) and (3), the relationship between the equivalent roughness σ of the contact surface and the power spectrum density function C(q) of the surface profile height is obtained as follows:

[0137]

[0138] In formula (4), m and n represent the number of sampling points in different directions of the sampling section.

[0139] Another embodiment of the present invention further provides a computer-readable storage medium having a computer program stored thereon, which can execute the above-mentioned Figures 1 to 10 The specific implementation of the steps of the ultrasonic detection simulation method for the rough contact interface of silicone rubber in the method embodiment shown can be found in the method embodiment and will not be repeated here.

[0140] The present application provides a method, device and storage medium for ultrasonic detection simulation of a rough contact interface of silicone rubber, comprising the following steps: obtaining the surface roughness of a stress cone semi-conductive silicone rubber; performing curve fitting on the data obtained from a tensile test to obtain the hyperelastic material parameters required for the material in the simulation; establishing an ultrasonic simulation model of a two-dimensional rough contact interface based on the surface roughness; inputting the parameters into the ultrasonic simulation model of the two-dimensional rough contact interface for ultrasonic simulation calculation; such an arrangement can establish a mapping relationship between the interface pressure and the ultrasonic nonlinear coefficient, providing a reference for the engineering application feasibility of the ultrasonic nonlinear detection method in interface pressure detection at high-voltage cable terminals.

[0141] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus comprising the element.

[0142] Finally, it should be noted that the above embodiments are merely examples for the purpose of illustrating the present invention and are not intended to limit the embodiments. Those skilled in the art will readily appreciate that other variations or modifications based on the above description are possible. It is not necessary and impossible to provide an exhaustive list of all embodiments. However, obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A simulation method for ultrasonic detection of a rough contact interface of silicone rubber, characterized by: The steps include: Obtain the surface roughness of stress cone semi-conductive silicone rubber; The data obtained from the tensile test are curve fitted to obtain the hyperelastic material parameters required for the material in the simulation; Establishing an ultrasonic simulation model of a two-dimensional rough contact interface according to the surface roughness; Parameters are input into the ultrasonic simulation model of the two-dimensional rough contact interface to perform ultrasonic simulation calculations, wherein the parameters include material parameters, excitation signals, boundary conditions, and simulation model grids.

2. The ultrasonic detection simulation method for silicone rubber rough contact interface according to claim 1, characterized in that: The method of obtaining the surface roughness of the stress cone semi-conductive silicone rubber comprises: The prefabricated silicone rubber stress cone was planed along the axial direction, and the inner surface of the semi-conductive silicone rubber of the stress cone was measured using a white light interferometer to obtain the three-dimensional morphology. Based on the three-dimensional topography, the white light interferometer obtains the surface roughness.

3. The ultrasonic detection simulation method for silicone rubber rough contact interface according to claim 1, characterized in that: The data obtained from the tensile test are subjected to curve fitting to obtain the hyperelastic material parameters required for the material in the simulation, including: Use a high-temperature vulcanizer to stamp out silicone rubber samples; Performing a tensile test on the silicone rubber sample to obtain uniaxial tensile data; Through curve analysis and fitting, the uniaxial tensile stress-strain fitting curve of the semi-conductive silicone rubber is obtained to obtain the hyperelastic material parameters required for the material in the simulation.

4. The ultrasonic detection simulation method for silicone rubber rough contact interface according to claim 1, characterized in that: The method of establishing an ultrasonic simulation model of a two-dimensional rough contact interface according to the surface roughness includes: The equivalent roughness σ of the contact surface is calculated; Acquire three-dimensional modeling data of simulated rough surface; The simulation model uses a two-dimensional model. The corresponding y and z column data are randomly intercepted along a certain x column in the generated three-dimensional modeling data. The "polygon" command is selected in the geometry command of the COMSOL software, and the generation object is selected as "open curve". The three-dimensional modeling data is imported to generate the rough interface contour. By generating line segments, the solid modeling steps are converted to generate a two-dimensional ultrasonic simulation model of the rough contact interface.

5. The ultrasonic detection simulation method for silicone rubber rough contact interface according to claim 4, characterized in that: The calculation formula of the equivalent roughness σ of the contact surface is: Wherein, in formula (1), σ1 is the surface roughness; σ2 is the surface roughness of the cable insulation outer shielding layer.

6. The ultrasonic detection simulation method for silicone rubber rough contact interface according to claim 5, characterized in that: The calculation formula of the power spectrum density function C(q) of the surface profile height is: Where, in formula (2), B(q) is the wave vector amplitude function; q is the total wave vector including the component 2π / L; A represents the sampling cross-sectional area. Since the sampling lengths in the x-direction and the y-direction are the same, A = L 2 .

7. The ultrasonic detection simulation method for silicone rubber rough contact interface according to claim 6, characterized in that: According to the definition of the equivalent roughness σ of the contact surface, its expression is: Wherein, in formula (3), p is the pth sampling point, N is the total number of sampling points; h(z) is the height distribution of the rough surface profile.

8. The ultrasonic detection simulation method for silicone rubber rough contact interface according to claim 7, characterized in that: According to the law of conservation of energy, combining equations (2) and (3), the relationship between the equivalent roughness σ of the contact surface and the power spectrum density function C(q) of the surface profile height is obtained as follows: In formula (4), m and n represent the number of sampling points in different directions of the sampling section.

9. An ultrasonic detection simulation device for a rough contact interface of silicone rubber, characterized by: include: Surface roughness acquisition module, used to obtain the surface roughness of stress cone semi-conductive silicone rubber; The hyperelastic material parameter acquisition module is used to perform curve fitting on the data obtained from the tensile test to obtain the hyperelastic material parameters required for the material in the simulation; An ultrasonic simulation model establishment module, used to establish an ultrasonic simulation model of a two-dimensional rough contact interface according to the surface roughness; The ultrasonic simulation calculation module is used to input parameters into the ultrasonic simulation model of the two-dimensional rough contact interface to perform ultrasonic simulation calculation, wherein the parameters include material parameters, excitation signals, boundary conditions and simulation model grids.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the ultrasonic detection simulation method for the rough contact interface of silicone rubber according to any one of claims 1 to 8 are executed.

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