Method and system for predicting influence of earthquake on fatigue life of epoxy resin

Abstract

The invention discloses a method and system for predicting the influence of earthquake on the fatigue life of epoxy resin, and relates to the technical field of fatigue life, and the method comprises the steps: obtaining epoxy resin sample data, and constructing a defect-free epoxy resin sample; applying a seismic spectrum to the defect-free epoxy resin sample based on seismic intensity; performing crack setting on the defect-free epoxy resin sample to obtain a crack-containing epoxy resin model; and performing analysis based on the seismic spectrum and the crack-containing epoxy resin model to obtain a relationship among the seismic spectrum, the stress intensity factor and the fatigue extension life, so as to predict the influence of the earthquake on the fatigue life of the epoxy resin. According to the invention, the FRANC3D and ABAQUS joint simulation method is utilized to research the influence of different factors on the fatigue life of the epoxy resin material in the basin-type insulator under the condition that the epoxy resin material contains micro cracks, reveal the crack formation and expansion mechanism of the epoxy resin material under the earthquake working condition, and reduce the caused economic loss of a power system.

Description

Technical Field

[0001] The invention relates to the technical field of fatigue life, in particular to a method and a system for predicting the effect of earthquake on the fatigue life of epoxy resin. Background Art

[0002] Basin insulators are mainly used in high-voltage and ultra-high-voltage AC and DC transmission lines and electrical equipment in power plants and substations. They play the role of insulation, support and electrical isolation, can effectively prevent the occurrence of power accidents, and can withstand greater mechanical stress in normal operation. They have the characteristics of excellent insulation performance, high strength and long life. Epoxy resin composite materials are one of the main components in the casting process of basin insulators. Due to the uneven force during the curing process and installation and transportation, it is easy to produce tiny cracks on the surface and inside that are difficult to find. In the normal operation process, these tiny cracks do not pose a huge threat to safety, so they are often ignored, but When these tiny cracks are subjected to extreme working conditions, such as earthquake conditions, the expansion of cracks in epoxy resin castings will be accelerated. Since China is located between the Pacific Rim and the Eurasian Seismic Belt, and pot insulators are installed in the overhead section of power lines, the earthquake damage is relatively serious. For example, the 8.0 magnitude Wenchuan earthquake in 2008 caused serious damage to power equipment, among which the damage to pot insulators was concentrated in the epoxy resin castings. In 2013, a magnitude 7.0 earthquake occurred in Lushan, Sichuan, resulting in the shutdown of more than 30 substations and damage to more than 600 substation equipment. Therefore, there is an even greater need to study epoxy resin composite materials.

[0003] At present, scholars have conducted a lot of research work on material crack propagation. For example, the stress intensity factor of steel materials was obtained by using three-dimensional isoparametric degenerate singular elements; the expansion variation law of three-dimensional single cracks in 42CrMo materials at different positions was analyzed by using the method of Abaqus combined with Franc3d; the stress intensity factor in the three-dimensional crack body of steel materials was calculated by using a virtual crack closure method that is insensitive to the mesh size, and the fatigue life was predicted; the stress intensity factor of the three-dimensional surface crack of the rail was simulated and analyzed as the wheel moved, and the fatigue propagation behavior of the three-dimensional surface crack of the rail was analyzed based on the Paris formula; a three-dimensional semi-elliptical surface crack model of Q235 structural steel material was established, and the crack propagation and stress intensity factor of the model at different inclination angles were obtained; however, although the research on the crack propagation life of materials has received widespread attention, the related research on the variation law of the stress intensity factor at the crack tip of the basin insulator under seismic load and the expansion life is still blank, which has important theoretical application value. Summary of the invention

[0004] In view of the above-mentioned problems, the present invention is proposed.

[0005] Therefore, the problem to be solved by the present invention is how to provide a method for predicting the effect of earthquake on the fatigue life of epoxy resin, and to study the effect of different factors on the fatigue life of epoxy resin material in pot-type insulators when containing microcracks by using the joint simulation method of FRANC3D and ABAQUS.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] In the first aspect, an embodiment of the present invention provides a method for predicting the effect of earthquake on the fatigue life of epoxy resin, which includes acquiring epoxy resin sample data and constructing a defect-free epoxy resin sample; applying an earthquake spectrum to the defect-free epoxy resin sample based on the earthquake intensity; setting cracks on the defect-free epoxy resin sample to obtain an epoxy resin model containing cracks; analyzing the earthquake spectrum and the cracked epoxy resin model to obtain the relationship between the earthquake spectrum, stress intensity factor and fatigue extension life, thereby predicting the effect of earthquake on the fatigue life of epoxy resin.

[0008] As a preferred solution of the method for predicting the effect of earthquake on the fatigue life of epoxy resin described in the present invention, the stress intensity factor includes type I stress intensity factor, type II stress intensity factor and type III stress intensity factor.

[0009] As a preferred embodiment of the method for predicting the effect of earthquake on the fatigue life of epoxy resin of the present invention, the relationship between the earthquake spectrum, the stress intensity factor and the fatigue extension life is obtained, which includes: selecting N different accelerations to calculate the standard response spectrum, wherein the accelerations are k1, k2, ... and k N ; Under different accelerations, the cracked epoxy resin model is analyzed, and the changing trends of type I stress intensity factor, type II stress intensity factor and type III stress intensity factor are detected respectively, and the change curves of the expansion rate and stress intensity factor in the crack expansion stage under different conditions are obtained; Under different accelerations, the fatigue expansion life of the pot-type insulator with crack defects is predicted based on the change curves of the expansion rate and stress intensity factor in the crack expansion stage, and the fatigue expansion life under different earthquake accelerations is compared to obtain the influence of seismic intensity factors on the expansion behavior of the pot-type insulator with crack defects.

[0010] As a preferred solution of the method for predicting the effect of earthquake on fatigue life of epoxy resin described in the present invention, the epoxy resin sample data includes the size and material parameters of the epoxy resin sample; the material parameters include density, Young's modulus, Poisson's ratio and plasticity; the construction of a defect-free epoxy resin sample includes the following steps: based on the size of the epoxy resin sample, constructing an epoxy resin sample with a length, width and height of A1mm*A2mm*A3mm in ABAQUS software; setting the material parameters of the epoxy resin sample.

[0011] As a preferred scheme of the method for predicting the effect of earthquake on the fatigue life of epoxy resin described in the present invention, applying the earthquake spectrum to the defect-free epoxy resin sample means fixing the lower end of the defect-free epoxy resin sample using ABAQUS software, and applying earthquake waves to the upper and right ends of the defect-free epoxy resin sample at the same time.

[0012] As a preferred scheme of the method for predicting the effect of earthquake on fatigue life of epoxy resin described in the present invention, setting cracks on the defect-free epoxy resin sample to obtain an epoxy resin model containing cracks means importing the defect-free epoxy resin sample into the crack life analysis software FRANC3D, and using the crack life analysis software FRANC3D to set a crack at the left center edge position of the defect-free epoxy resin sample, thereby obtaining an epoxy resin model containing cracks.

[0013] As a preferred solution of the method for predicting the effect of earthquake on the fatigue life of epoxy resin described in the present invention, for the defect-free epoxy resin specimen constructed by ABAQUS software, when importing the corresponding inp file into the crack life analysis software FRANC3D, in order to reduce unnecessary calculation amount of the model, it is necessary to split the inp file to obtain the GLOBLE model and the LOCLE model.

[0014] In the second aspect, in order to further solve the safety problems existing in fatigue life, the present invention provides a system for predicting the impact of earthquakes on the fatigue life of epoxy resin, which includes: a data acquisition module, used to acquire epoxy resin sample data and construct epoxy resin samples in ABAQUS software; an earthquake spectrum module, used to apply an earthquake spectrum to the constructed epoxy resin sample in ABAQUS software; a crack setting module, used to import the epoxy resin sample into the crack life analysis software FRANC3D and set cracks to obtain an epoxy resin model containing cracks; a fatigue life module, used to analyze the stress intensity factor according to the earthquake spectrum and the epoxy resin model containing cracks, obtain the relationship between the earthquake spectrum, the stress intensity factor and the fatigue extension life, and realize the prediction of the impact of earthquakes on the fatigue life of epoxy resin.

[0015] In a third aspect, an embodiment of the present invention provides a computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: when the computer program is executed by the processor, any step of a method for predicting the effect of earthquake on the fatigue life of epoxy resin as described in the first aspect of the present invention is implemented.

[0016] In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein: when the computer program is executed by a processor, any step of a method for predicting the effect of earthquake on the fatigue life of epoxy resin as described in the first aspect of the present invention is implemented.

[0017] Beneficial effects of the invention: The invention proposes a method for effectively predicting the crack propagation life of pot-type insulators, and uses the FRANC3D and ABAQUS joint simulation method to study the influence of different factors on the fatigue life of epoxy resin materials in pot-type insulators containing tiny cracks, and explores the influence of dominant factors and other factors on epoxy resin materials, revealing the crack formation and propagation mechanism of epoxy resin materials under earthquake conditions, effectively alleviating the electric field concentration phenomenon caused by the existence of cracks, thereby preventing the degradation and failure of insulation performance and reducing the economic losses of the power system caused thereby. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. Among them:

[0019] Figure 1 This is an overall flow chart of a method for predicting the effect of earthquake on the fatigue life of epoxy resin in Example 1.

[0020] Figure 2 This is a 3D diagram of the crack tip load under the seismic load in Example 1.

[0021] Figure 3 This is a schematic diagram of the structure of the computer device in Example 3.

[0022] Figure 4 This is the seismic spectrum diagram of different accelerations in Example 4.

[0023] Figure 5 This is a comparison curve of type I stress intensity factors under different earthquake accelerations in Example 4.

[0024] Figure 6 This is a comparison curve of type II stress intensity factors under different earthquake accelerations in Example 4.

[0025] Figure 7 This is a comparison curve of type III stress intensity factors under different earthquake accelerations in Example 4.

[0026] Figure 8 This is a schematic diagram of fatigue life under different seismic accelerations in Example 4. DETAILED DESCRIPTION

[0027] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

[0028] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0029] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0030] Example 1

[0031] Reference Figure 1 and Figure 2 , which is the first embodiment of the present invention, provides a method for predicting the effect of earthquake on the fatigue life of epoxy resin.

[0032] The existing research on the crack propagation life of materials mainly has the following problems: At present, scholars have carried out a lot of research work on material crack propagation. For example, the stress intensity factor of steel materials was obtained by using three-dimensional isoparametric degenerate singular elements; the propagation variation law of three-dimensional single cracks in 42CrMo materials at different positions was analyzed by using the Abaqus combined with Franc 3d method; the stress intensity factor in the three-dimensional crack body of steel materials was calculated by using a virtual crack closure method that is insensitive to the mesh size, and the fatigue life was predicted; the stress intensity factor of the three-dimensional surface crack of the rail was simulated and analyzed as the wheel moved, and the fatigue propagation behavior of the three-dimensional surface crack of the rail was analyzed based on the Paris formula; a three-dimensional semi-elliptical surface crack model of Q235 structural steel material was established, and the crack propagation and stress intensity factor of the model at different inclination angles were obtained; however, although the research on the crack propagation life of materials has received widespread attention, the related research on the variation law of the stress intensity factor at the crack tip of the basin insulator under seismic load and the propagation life is still blank, which has important theoretical application value.

[0033] The present application provides a method that can effectively solve the above-mentioned problems. Next, a plurality of embodiments will be combined to explain in detail how to implement the method for predicting the effect of earthquake on the fatigue life of epoxy resin.

[0034] Figure 1 The overall flow chart of a method for predicting the impact of earthquake on epoxy resin fatigue life is shown, including:

[0035] S1: Acquire epoxy resin specimen data and construct defect-free epoxy resin specimens.

[0036] Preferably, the epoxy resin sample data includes dimensions and material parameters of the epoxy resin sample.

[0037] Specifically, material parameters include density, Young's modulus, Poisson's ratio, and plasticity.

[0038] Furthermore, constructing a defect-free epoxy resin sample includes the following steps: based on the size of the epoxy resin sample, constructing an epoxy resin sample with a length, width and height of A1mm*A2mm*A3mm in ABAQUS software.

[0039] The material parameters of the epoxy resin sample were set, with a density of 1.2×10 -9 tonne / mm 3 , Young's modulus is 3340MPa, Poisson's ratio is 0.31, and the Johnson-Cook constitutive model is selected for plasticity.

[0040] Preferably, the present invention constructs epoxy resin specimens in ABAQUS software and adopts the Johnson-Cook constitutive model to describe the unique value of material plasticity, wherein the Johnson-Cook model can accurately describe the mechanical behavior of materials at different strain rates and temperatures, which is particularly important for simulating the response of materials under transient dynamic loads such as earthquakes. The constructed defect-free epoxy resin specimens take into account strain hardening, strain rate effect and temperature softening effect, so that the simulation of the mechanical behavior of epoxy resin under seismic loads is closer to the actual situation.

[0041] S2: Applying seismic spectrum to defect-free epoxy resin specimens based on seismic intensity.

[0042] Preferably, Figure 2 Shown is a 3D diagram of the crack tip load under seismic load. Applying the seismic spectrum to the defect-free epoxy resin sample includes the following steps: Since the service life of the pot insulator will be affected when it is subjected to seismic loads of different intensities and accelerations, the lower end of the defect-free epoxy resin sample is fixed using ABAQUS software.

[0043] Seismic waves were applied simultaneously to the upper and right ends of the defect-free epoxy resin specimen.

[0044] Furthermore, for the earthquake spectrum, according to the response spectrum concept first proposed by Professor MABiot of the United States, for a single-degree-of-freedom elastic system, the inertial force is usually regarded as an equivalent action that reflects the influence of the earthquake on the structural system, that is, the dynamic action is converted into a static action, and the maximum value of the static action is used to perform seismic verification on the structure; the response spectrum concept takes into account the ground motion characteristics and the dynamic characteristics of the structure itself, and maintains the basic form of the original static theory. It is most widely used in current engineering design. Therefore, the present invention selects different earthquake intensities for simulation calculation by referring to the national standard GB50011-2010, and adopts the response spectrum analysis method to calculate the earthquake spectrum under different earthquake intensities.

[0045] Specifically, the specific formula for seismic calculation of the structure using the maximum value of static action is as follows:

[0046]

[0047] Where F is the maximum seismic base shear or seismic load experienced by the structure during the earthquake; F(t) max is the absolute value of the maximum earthquake force; m is the mass of the structure; x”(t) is the second derivative of the earthquake response of the system at time t; x g "(t) is the ground acceleration; S a is the maximum acceleration of the particle; g is the acceleration due to gravity, which is 9.81 m / s 2; k is the seismic coefficient, that is, the ratio of the absolute value of the maximum acceleration of ground motion to the gravity acceleration g; β is the dynamic coefficient, which is related to the natural vibration period and damping ratio of the structure, that is, the ratio of the maximum reaction acceleration of a single-particle elastic system under earthquake action to the maximum acceleration of ground motion; G is the gravity load of the structure.

[0048] Furthermore, since the seismic coefficient k is actually the peak acceleration of seismic motion in units of gravity acceleration, the greater the ground acceleration, the stronger the earthquake impact, that is, the greater the earthquake intensity; usually the maximum value in the acceleration record of a strong earthquake is the seismic coefficient k (in units of gravity acceleration) of the earthquake at that location. At the same time, the seismic intensity I at that location can also be assessed according to the destruction of the surface or the degree of damage to the building at that location according to the seismic intensity scale, where the analysis step settings of the peak acceleration of seismic motion and the corresponding relationship between the seismic coefficients corresponding to different levels of seismic intensities are shown in Tables 1 and 2.

[0049] Table 1 Analysis step setting table of peak acceleration of ground motion

[0050] Acceleration 0.05g 0.1g 0.15g 0.2g Analysis step length 200s 3000s 1200s 5μm

[0051] Table 2 Correspondence between the design basic earthquake acceleration values ​​and the seismic fortification intensity

[0052] Earthquake Intensity I 6 7 8 9 Seismic coefficient k 0.05 0.10 / 0.15 0.20 / 0.3 0.40

[0053] Specifically, the calculation formula of the seismic coefficient k is as follows:

[0054]

[0055] Where k is the seismic coefficient, which is the ratio of the absolute value of the maximum acceleration of ground motion to the gravitational acceleration g; x g "(t) is the ground acceleration; g is the acceleration due to gravity, which is 9.81m / s 2 .

[0056] Furthermore, since the dynamic coefficient β mainly reflects the dynamic effect of the structure, it is the maximum acceleration of the particle S a Relative to ground acceleration x g The specific formula of the maximum value of "(t) is as follows:

[0057]

[0058] Among them, β is the dynamic coefficient, which is related to the natural vibration period and damping ratio of the structure, that is, the ratio of the maximum reaction acceleration of a single-particle elastic system under earthquake action to the maximum acceleration of ground motion; S a is the maximum acceleration of the particle; x g"(t) is the ground acceleration; g is the acceleration due to gravity, which is 9.81m / s 2 .

[0059] Preferably, the present invention combines the Biot response spectrum theory with the national standard GB50011-2010 and converts dynamic effects into static effects, thereby greatly simplifying the calculation process. By setting different seismic peak acceleration analysis steps, the main earthquake intensity range that may be encountered in actual engineering is covered. At the same time, the use of step-by-step setting ensures the balance between calculation accuracy and efficiency, and can effectively capture the mechanical response characteristics of epoxy resin under different earthquake intensities.

[0060] S3: Setting cracks on the defect-free epoxy resin sample to obtain an epoxy resin model with cracks.

[0061] It should be noted that for the defect-free epoxy resin specimen constructed by ABAQUS software, when importing the corresponding inp file into the crack life analysis software FRANC3D, in order to reduce the unnecessary calculation amount of the model, the inp file needs to be split to obtain the GLOBLE model and the LOCLE model.

[0062] Preferably, setting a crack on a defect-free epoxy resin sample to obtain an epoxy resin model containing a crack means importing the defect-free epoxy resin sample into the crack life analysis software FRANC3D, and using the crack life analysis software FRANC3D to set a crack at the left center edge position of the defect-free epoxy resin sample, and the size of the crack is A4mm*A5mm, thereby obtaining the epoxy resin model containing a crack.

[0063] Preferably, the present invention divides the inp file by combining the GLOBLE model and the LOCLE model, improves the calculation accuracy of the crack tip stress field by utilizing local refined grids, reduces the overall calculation amount, improves the simulation efficiency, and ensures the accuracy of subsequent crack extension analysis.

[0064] S4: Based on the analysis of the earthquake spectrum and the epoxy resin model with cracks, the relationship between the earthquake spectrum, stress intensity factor and fatigue extension life is obtained, so as to predict the impact of earthquake on the fatigue life of epoxy resin.

[0065] Preferably, the stress intensity factor includes a type I stress intensity factor, a type II stress intensity factor and a type III stress intensity factor.

[0066] Specifically, the relationship between the earthquake spectrum, stress intensity factor and fatigue growth life includes: due to different accelerations in different regions, the growth speeds in the crack growth stage are also different. Therefore, the present invention refers to the national standard GB50011-2010 and selects N different accelerations to calculate the standard response spectrum, where the accelerations are k1, k2, ... and k N .

[0067] Under different earthquake accelerations, the crack life analysis software FRANC3D was used to analyze the epoxy resin model with cracks. The changing trends of type I stress intensity factor, type II stress intensity factor and type III stress intensity factor were detected respectively, and the change curves of the crack propagation speed and stress intensity factor in the crack propagation stage under different conditions were obtained.

[0068] Under different earthquake accelerations, the fatigue extension life of pot-type insulators with crack defects is predicted based on the change curves of the expansion rate and stress intensity factor in the crack extension stage. The fatigue extension life under different earthquake accelerations is compared to obtain the influence of seismic intensity factors on the expansion behavior of pot-type insulators with crack defects, and to predict the influence of earthquakes on the fatigue life of epoxy resin. Among them, epoxy resin composite materials, as one of the main components in the casting process of pot-type insulators, play an important role in the fatigue extension life of pot-type insulators.

[0069] Preferably, the present invention simultaneously examines the changing trends of three types of stress intensity factors, namely, the changing trends of type I stress intensity factor, type II stress intensity factor and type III stress intensity factor, and then constructs the correlation between the earthquake spectrum, stress intensity factor and fatigue extension life, which can comprehensively reflect the expansion behavior of cracks under complex stress states, more accurately identify the influence of seismic intensity factors on the expansion behavior of pot-type insulators containing crack defects, improve the accuracy of life prediction, and provide a reliable basis for evaluating the influence of earthquakes on the fatigue life of epoxy resins; through the joint simulation of FRANC3D and ABAQUS, it not only solves the problem that traditional single software is difficult to take into account crack extension analysis and earthquake response analysis at the same time, but also provides a theoretical basis for the seismic design of pot-type insulators, which has important engineering application value.

[0070] In summary, the present invention proposes a method for effectively predicting the crack propagation life of pot-type insulators. The FRANC3D and ABAQUS joint simulation method is used to study the influence of different factors on the fatigue life of epoxy resin materials in pot-type insulators with tiny cracks, and explore the influence of dominant factors and other factors on epoxy resin materials. The crack formation and propagation mechanism of epoxy resin materials under seismic conditions is revealed, and the electric field concentration phenomenon caused by the existence of cracks is effectively alleviated, thereby preventing the degradation and failure of insulation performance and reducing the economic losses of the power system caused thereby.

[0071] Example 2 is an embodiment of the present invention, which provides a system for predicting the effect of earthquake on the fatigue life of epoxy resin, including: a data acquisition module, used to acquire epoxy resin sample data and construct the epoxy resin sample in ABAQUS software; an earthquake spectrum module, used to apply the earthquake spectrum to the constructed epoxy resin sample in ABAQUS software; a crack setting module, used to import the epoxy resin sample into the crack life analysis software FRANC3D and set the crack to obtain an epoxy resin model containing cracks; a fatigue life module, used to analyze the stress intensity factor according to the earthquake spectrum and the epoxy resin model containing cracks, obtain the relationship between the earthquake spectrum, the stress intensity factor and the fatigue extension life, and realize the prediction of the effect of earthquake on the fatigue life of epoxy resin.

[0072] Embodiment 3 is an embodiment of the present invention, which is different from the previous embodiment in that:

[0073] like Figure 3 As shown, if the function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0074] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in conjunction with such instruction execution systems, devices or apparatuses. For the purposes of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in conjunction with such instruction execution systems, devices or apparatuses.

[0075] More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk case (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be a paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, deciphering or, if necessary, processing in another suitable manner, and then stored in a computer memory.

[0076] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, a plurality of steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0077] Example 4 is an embodiment of the present invention, which provides a method for predicting the effect of earthquake on the fatigue life of epoxy resin. In order to verify the beneficial effects of the present invention, scientific demonstration is carried out through simulation experiments.

[0078] In this example, a flawless epoxy resin specimen with a length, width and height of 0.2 mm*0.4 mm*0.05 mm was constructed in ABAQUS software and material parameters were calculated, with a density of 1.2×10 -9 tonne / mm 3, Young's modulus is 3340MPa, Poisson's ratio is 0.31, and the plasticity is selected as Johnson-Cook constitutive model; because the service life of the pot-type insulator will be affected when it is subjected to seismic loads of different intensities and accelerations, the lower end of the flawless epoxy resin specimen is fixed in the ABAQUS software, and seismic waves are applied to the upper and right ends at the same time; then the flawless epoxy resin specimen after the seismic wave is applied is imported into the crack life analysis software FRANC3D for crack setting, and the set crack is located at the left center edge of the flawless epoxy resin specimen, with a size of 0.05mm*0.02mm, and finally a cracked epoxy resin model is obtained. When the corresponding inp file is imported into the crack life analysis software FRANC3D, the inp file is segmented to reduce the unnecessary calculation amount of the model, and then the GLOBLE and LOCLE models are obtained.

[0079] For the obtained cracked epoxy resin model, five different acceleration values ​​were selected to calculate the standard response spectrum by referring to the national standard GB50011-2010, as follows: Figure 4 As shown in Figure 1, the type I stress intensity factor, type II stress intensity factor and type III stress intensity factor are analyzed under the earthquake conditions of 0.3g (8), 0.2g (8), 0.15g (7), 0.1g (7) and 0.05g (6), respectively. Figure 5 The figure shows the comparison curve of type I stress intensity factor under different seismic accelerations. It can be seen from the figure that when the seismic acceleration is 0.3g, the epoxy resin model with cracks reaches fracture toughness in the initial stage of crack propagation. Under the seismic conditions of 0.15g, 0.1g and 0.05g, the increase rate of type I stress intensity factor decreases successively.

[0080] like Figure 6 The figure shows the comparison curve of type II stress intensity factor under different earthquake accelerations. It can be seen from the figure that the type II stress intensity factor under different earthquake accelerations reaches the peak value in the initial stage of crack extension (0μm), and as the earthquake acceleration increases from 0.05g to 0.2g, the initial stage type II stress intensity factor increases from 0.12MPa·m 1 / 2 Increase to 0.20MPa·m 1 / 2 Therefore, with the increase of crack extension steps, the change curves of stress intensity factor II under different earthquake accelerations fluctuate within a small range.

[0081] like Figure 7 The figure shows the comparison curve of type III stress intensity factor under different earthquake accelerations. It can be seen from the figure that the type III stress intensity factor under different earthquake accelerations is close to 0 in the initial stage of crack extension, and then increases to ±5KPa·m 1 / 2When the crack is about to end the fatigue growth stage, the mode III stress intensity factor drops rapidly. When the fatigue crack growth ends, the mode III stress intensity factor under different earthquake accelerations reaches the minimum value.

[0082] Finally, the fatigue extension life is predicted by comparing the curves based on different earthquake accelerations and different stress intensity factors. Figure 8 As shown in the figure, it can be seen that under the conditions of 0.2g, 0.15g, 0.1g and 0.05g earthquake acceleration, the service life of the pot-type insulator with crack defects affected by the earthquake decreases in turn. The fatigue life value of the pot-type insulator under the 0.15g earthquake acceleration is 5374s, the fatigue life value of the pot-type insulator affected by the 0.2g earthquake acceleration is 746s, and the fatigue life value of the pot-type insulator under the 0.1g earthquake acceleration is 14956s. Compared with the 0.15g earthquake acceleration, the fatigue life value of the pot-type insulator affected by the 0.2g earthquake is 14956s. The fatigue life of the pot-type insulator affected by the 0.2g earthquake was reduced by 86%, and the fatigue life of the pot-type insulator affected by the 0.1g earthquake was reduced by 95% compared with the 0.1g earthquake acceleration. Therefore, it can be seen from this example that under different dynamic load seismic waves, as the seismic acceleration decreases, the expansion life of the pot-type insulator with crack defects increases instead. Due to the large acceleration of the 0.3g seismic wave, the stress intensity factor at the tip is greater than the critical value when the crack has not expanded, so the fatigue expansion stage does not occur, and it directly enters the rapid expansion stage.

[0083] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for predicting the effect of earthquake on epoxy resin fatigue life, characterized in that: include: Acquire epoxy resin specimen data and construct defect-free epoxy resin specimens; Applying a seismic spectrum to the defect-free epoxy resin sample based on the seismic intensity; Setting cracks on the defect-free epoxy resin sample to obtain an epoxy resin model containing cracks; Based on the analysis of the earthquake spectrum and the cracked epoxy resin model, the relationship between the earthquake spectrum, stress intensity factor and fatigue extension life is obtained, so as to predict the influence of earthquake on the fatigue life of epoxy resin.

2. The method for predicting the effect of earthquake on the fatigue life of epoxy resin according to claim 1, characterized in that: The stress intensity factor includes type I stress intensity factor, type II stress intensity factor and type III stress intensity factor.

3. The method for predicting the effect of earthquake on the fatigue life of epoxy resin as claimed in claim 2, characterized in that: The relationship between the earthquake spectrum, stress intensity factor and fatigue growth life includes: Select N different accelerations to calculate the standard response spectrum, where the accelerations are k1, k2, ... and k N ; Under different accelerations, the cracked epoxy resin model is analyzed to detect the change trends of type I stress intensity factor, type II stress intensity factor and type III stress intensity factor respectively, and obtain the change curves of the expansion speed and stress intensity factor in the crack expansion stage under different conditions; Under different accelerations, the fatigue growth life of pot-type insulators with crack defects is predicted based on the change curves of the growth rate and stress intensity factor in the crack growth stage. The fatigue growth life under different earthquake accelerations is compared to obtain the influence of seismic intensity factors on the growth behavior of pot-type insulators with crack defects.

4. The method for predicting the effect of earthquake on the fatigue life of epoxy resin as claimed in claim 3, characterized in that: The epoxy resin sample data includes the size and material parameters of the epoxy resin sample; The material parameters include density, Young's modulus, Poisson's ratio and plasticity; The method of constructing a defect-free epoxy resin specimen comprises the following steps: Based on the size of the epoxy resin sample, an epoxy resin sample with a length, width and height of A1mm*A2mm*A3mm is constructed in ABAQUS software; The material parameters of the epoxy resin sample are set.

5. The method for predicting the effect of earthquake on the fatigue life of epoxy resin as claimed in claim 4, characterized in that: Applying a seismic spectrum to the defect-free epoxy resin sample refers to fixing the lower end of the defect-free epoxy resin sample using ABAQUS software, and applying seismic waves to the upper end and the right end of the defect-free epoxy resin sample at the same time.

6. The method for predicting the effect of earthquake on the fatigue life of epoxy resin as claimed in claim 5, characterized in that: Setting a crack on the defect-free epoxy resin sample to obtain an epoxy resin model containing a crack refers to importing the defect-free epoxy resin sample into the crack life analysis software FRANC3D, using the crack life analysis software FRANC3D to set a crack at the left center edge position of the defect-free epoxy resin sample, and then obtaining the epoxy resin model containing a crack.

7. The method for predicting the effect of earthquake on the fatigue life of epoxy resin as claimed in claim 6, characterized in that: For the defect-free epoxy resin specimen constructed by ABAQUS software, when importing the corresponding inp file into the crack life analysis software FRANC3D, in order to reduce the unnecessary calculation amount of the model, it is necessary to split the inp file into GLOBLE model and LOCLE model.

8. A system for predicting the effect of earthquake on epoxy resin fatigue life, based on the method for predicting the effect of earthquake on epoxy resin fatigue life according to any one of claims 1 to 7, characterized in that: include, A data acquisition module is used to acquire epoxy resin sample data and construct epoxy resin samples in ABAQUS software; Seismic spectrum module, used to apply seismic spectrum to the constructed epoxy resin specimens in ABAQUS software; A crack setting module is used to import epoxy resin samples into the crack life analysis software FRANC3D and set cracks to obtain an epoxy resin model with cracks; The fatigue life module is used to analyze the stress intensity factor according to the earthquake spectrum and the epoxy resin model with cracks, obtain the relationship between the earthquake spectrum, stress intensity factor and fatigue extension life, and predict the impact of earthquake on the fatigue life of epoxy resin.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of a method for predicting the effect of earthquake on the fatigue life of epoxy resin as described in any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of a method for predicting the effect of earthquake on the fatigue life of epoxy resin as claimed in any one of claims 1 to 7 are implemented.

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