Creep age forming on-line monitoring and repair method

Abstract

The present application relates to the technical field of creep age forming, and particularly relates to an online monitoring and repairing method for creep age forming, which realizes closed-loop intelligent control of the creep age forming process through integration of real-time acoustic emission monitoring and online electric pulse repairing. The present application collects and extracts real-time acoustic emission characteristic parameters in real time, can capture the damage initiation activity in the material immediately, compares the real-time acoustic emission characteristic parameters with a creep age damage information library in real time, can early identify and accurately quantitatively diagnose the current damage according to historical damage evolution data, accurately determine the damage type and damage degree, call the optimal electric pulse parameter combination determined in advance for the damage type and damage degree of the target damage as the repairing parameter, and immediately apply electric pulse repairing, so as to realize accurate intervention of damage self-adaption. After the repairing is completed, the process automatically returns to the monitoring step to form the whole-process closed-loop control of damage monitoring, damage diagnosis and damage repairing.

Description

Technical Field

[0001] This invention relates to the field of creep aging forming technology, specifically to an online monitoring and repair method for creep aging forming. Background Technology

[0002] Creep aging forming technology is an advanced forming process that combines creep deformation with age hardening of materials. It is widely used in the manufacturing of large and complex curved surface components (such as wing skin) in the aerospace field. This technology, by holding the components at specific temperatures and pressures for extended periods, allows the components to undergo plastic deformation while simultaneously age hardening, ensuring forming accuracy and improving the mechanical properties of the material. However, during the precision creep aging forming manufacturing of critical aerospace components, factors such as inappropriate critical structural design, mismatched forming process selection, and inadequate component sealing often lead to damage such as microcracks and voids within the material. This ultimately results in component damage and cracking, severely reducing production efficiency and significantly increasing manufacturing costs.

[0003] During creep aging forming, materials are subjected to high temperature and high pressure environments for extended periods, which can easily lead to internal damage such as microcracks and pores. If these damages are not detected and addressed in a timely manner, they will continue to expand and cause the following problems: First, they reduce the mechanical properties of the formed components and may even cause quality hazards such as post-forming cracks; second, once the damage exceeds a critical value, the material must be scrapped, resulting in material waste and increased production costs; third, traditional monitoring methods (such as offline ultrasonic testing and phase analysis) cannot capture the damage evolution in real time during the forming process and can only rely on testing after forming, which results in a lag and makes it impossible to adjust the process in a timely manner to intervene and repair the damage.

[0004] In existing technologies, patent application number 202410639803.5 discloses a novel high-temperature pipeline creep fatigue damage monitoring mechanism, which uses an ultrasonic sensor installed on the pipeline to monitor signs of damage such as fine cracks caused by creep on the high-temperature pipeline. Application number 202110107227.6 discloses a method for repairing creep damage in alloys, repairing third-generation single-crystal high-temperature alloy turbine blades through isothermal static pressing and heat treatment. In these patented methods, damage monitoring and repair methods during the creep aging forming process are mostly independent. This means that after damage occurs during the creep aging forming process, the test must be interrupted, and the sample removed from the line and transferred to equipment for repair. This leads to problems such as untimely material repair, cumbersome operation, and large test errors due to frequent sample loading and unloading. Summary of the Invention

[0005] The main objective of this invention is to provide an online monitoring and repair method for creep aging forming, in order to solve the technical problem that the damage monitoring and damage repair processes in the creep aging forming process of materials are independent of each other, resulting in untimely material repair, cumbersome operation, and large experimental errors.

[0006] To achieve the above objectives, the present invention provides an online monitoring and repair method for creep aging forming, comprising the following steps:

[0007] S1. Perform a creep aging test on the second sample and collect the real-time acoustic emission signal of the second sample in real time, and extract the real-time acoustic emission characteristic parameters characterizing the damage from the real-time acoustic emission signal.

[0008] S2. Obtain a pre-established creep aging damage information database, and compare the real-time acoustic emission characteristic parameters with the acoustic emission characteristic values ​​in the creep aging damage information database in real time to obtain the comparison result; wherein, the creep aging damage information database contains the damage type and damage degree determined according to the mapping relationship between acoustic emission characteristic values ​​and material strain data.

[0009] S3. Determine whether the comparison result meets the preset matching conditions; when the comparison result meets the preset matching conditions, determine that the second sample has suffered target damage, and output the damage type and damage degree of the target damage;

[0010] S4. Obtain a predetermined optimal combination of electrical pulse parameters for different damage types and damage degrees. Based on the damage type and damage degree of the target damage, call the optimal combination of electrical pulse parameters corresponding to the target damage as repair parameters, and apply an electrical pulse based on the repair parameters to the second sample to repair the damaged area.

[0011] S5. After completing the electrical pulse repair, continue to perform creep aging test on the second sample; determine whether the second sample has broken; if not, return to step S1; if yes, end the creep aging test.

[0012] Furthermore, the following steps are included before step S1:

[0013] S01. A creep aging test is performed on the first specimen, and acoustic emission signal data and strain data of the first specimen are collected simultaneously throughout the entire test process until the first specimen breaks; the acoustic emission signal data is processed to extract acoustic emission characteristic values ​​characterizing the damage; wherein, the first specimen and the second specimen are the same.

[0014] S02. Establish a mapping relationship between the acoustic emission characteristic values ​​and the damage evolution stages in the strain data, thereby forming a creep aging damage information database containing damage initiation time, damage location, damage degree and damage type.

[0015] S03. Construct an embedded damage model with the same properties as the first sample based on the damage degree and damage type in the creep aging damage information database; apply electrical pulses with different parameters to the embedded damage model to perform repair simulation and obtain repair effect data;

[0016] S04. Based on the repair effect data, determine the optimal combination of electrical pulse parameters for different damage types and degrees.

[0017] More preferably, the following steps are included before step S01:

[0018] It also includes a third sample, the third sample, the first sample, and the second sample are surface polished, wiped with alcohol, and dried for later use; wherein the first sample, the second sample, and the third sample are all the same;

[0019] A high-temperature tensile test is performed on the third specimen to obtain the high-temperature mechanical properties of the material of the third specimen at the temperature corresponding to the creep aging test; wherein the test temperature of the high-temperature tensile test is the same as the test temperature of the creep aging test.

[0020] More preferably, before performing the creep aging test in step S01, the following steps are also included:

[0021] The surface-treated first or second sample is placed on the fixed rod of the creep testing machine. Extension rods are fixed on both sides of the first or second sample. Electrode plates are inserted into both sides of the first or second sample, and the electrode plates are connected to an electrical pulse device. A displacement sensor for real-time displacement measurement is connected below the extension rod. At least two acoustic emission sensors are coupled to the surface of the first or second sample through a high-temperature coupling agent. The acoustic emission sensors are connected to a preamplifier, the preamplifier is connected to an acoustic emission acquisition device, and the acoustic emission acquisition device is connected to a display device. The creep testing machine includes a fixed rod, extension rods, a preamplifier, acoustic emission sensors, displacement sensors, an electrical pulse device, an acoustic emission acquisition device, and a display device.

[0022] More preferably, the creep aging test on the first sample specifically includes the following steps:

[0023] The creep testing machine also includes a heating furnace. The first sample, after installation, is pushed into the heating furnace, the heating furnace is sealed, the creep aging process parameters and acoustic emission monitoring parameters are set, and then the creep aging test on the first sample is started. The change process of the acoustic emission signal of the first sample during the creep aging test is monitored in real time through the display device until the first sample breaks.

[0024] The creep aging process parameters include the test temperature and load value of the creep aging test; the load value is set according to the high-temperature mechanical property results obtained from the high-temperature tensile test, and the load value is lower than the tensile strength of the material of the third sample at the test temperature;

[0025] The acoustic emission monitoring parameters include threshold value, sampling rate, sampling length, waveform length, filtering frequency, maximum duration, and acoustic emission sensor location information.

[0026] More preferably, before applying the electrical pulse based on the repair parameters to the second sample in step S4, the step of pausing the application of creep load to the second sample is further included.

[0027] More preferably, establishing the mapping relationship between the acoustic emission characteristic values ​​and the damage evolution stages in the strain data in step S02 specifically includes the following steps:

[0028] Based on the temporal changes of the strain data, the strain-time curve of the first specimen is determined, the moment when the acoustic emission characteristic value changes abruptly is identified, and the moment is associated with the starting point of the accelerated strain change on the strain-time curve to determine the damage initiation time and the damage initiation strain.

[0029] More preferably, the degree of damage is determined by the following steps:

[0030] When the acoustic emission characteristic value changes abruptly, it indicates that damage has occurred in either the first or second sample. Based on the damage degree obtained from the strain-time curve, the damage degree is calculated using the following formula:

[0031]

[0032] In the formula, D represents the degree of damage, and ε s ε is the damage initiation strain. r Let ε be the strain at any moment during the damage process. f This represents the fracture strain.

[0033] More preferably, the damage type and damage location are determined by the following steps:

[0034] The acoustic emission characteristics include amplitude, energy, count, duration, rise time, and average frequency;

[0035] After damage occurs, the acoustic emission waveform is subjected to waveform pattern recognition or wavelet analysis to determine the damage type; among them, high amplitude, short duration, sudden acoustic emission characteristic values ​​correspond to microcrack initiation; low amplitude, continuous acoustic emission characteristic values ​​correspond to dislocation slip or pore accumulation.

[0036] The propagation speed of sound waves in the material is obtained, and the time difference of the moment when the acoustic emission characteristic value changes abruptly is identified using multiple sensors. The spatial coordinates of the damage occurrence are calculated based on the propagation speed of sound waves in the material using the time difference positioning method.

[0037] Furthermore, the following steps are included after step S5:

[0038] S6. Obtain the first total creep aging duration and the first total creep value of the first sample, and obtain the second total creep aging duration and the second total creep value of the second sample.

[0039] S7. Determine whether the total duration of the second creep aging is greater than the total duration of the first creep aging, and whether the total creep variable is greater than the total creep variable.

[0040] S8. If the total duration of the second creep aging is greater than the total duration of the first creep aging, and the total creep variable is greater than the total creep variable, then the electrical pulse repair effect is deemed effective.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] This invention achieves closed-loop intelligent control of the creep aging forming process by integrating real-time acoustic emission monitoring and online electrical pulse repair. The invention collects and extracts real-time acoustic emission characteristic parameters, enabling immediate capture of damage initiation activities within the material. By comparing these parameters with a creep aging damage information database in real time, it can perform early identification and precise quantitative diagnosis of current damage based on historical damage evolution data, accurately determining the damage type and severity. It then calls upon the optimal combination of electrical pulse parameters pre-determined for the target damage type and severity as repair parameters and immediately applies electrical pulses for repair, achieving precise adaptive intervention. After repair, the process automatically cycles back to the monitoring step, forming a closed-loop control from damage monitoring, damage diagnosis, and damage repair. In practical engineering applications, this invention seamlessly integrates damage monitoring, damage diagnosis, and damage repair into a continuous automated process, not only achieving early damage elimination and performance recovery but also, through closed-loop iterative optimization, effectively extending the creep life of components and improving their forming limits.

[0043] This invention not only allows for timely introduction of damage repair methods to protect the integrity of materials after damage is detected, but also enables this process to be repeated throughout the creep aging test. This eliminates the need for cumbersome steps and reduced efficiency caused by removing the sample, and the sample fixation is not frequently changed, significantly improving the reliability of the test results. Furthermore, the electrical pulse repair parameters can be adjusted according to different damage degrees and types to better adapt to material damage repair and achieve optimal repair results, realizing creep aging forming with online monitoring and online repair. Attached Figure Description

[0044] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0045] Figure 1 This is a schematic flowchart of an embodiment of the creep aging forming online monitoring and repair method of the present invention;

[0046] Figure 2 This is a simplified schematic diagram illustrating the structural principle of a creep testing machine according to one embodiment of the present invention.

[0047] In the picture:

[0048] 1. Electrical pulse device; 2. Current transmission line; 3. Heating furnace; 4. Fixing rod; 5. Electrode plate; 6. Acoustic emission sensor; 7. Display device; 8. Sample; 9. Extension rod; 10. Acoustic signal transmission line; 11. Preamplifier; 12. Acoustic emission acquisition device.

[0049] The objectives, features, and advantages of this invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0050] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0051] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0052] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0053] Furthermore, the use of terms such as "first" and "second" in this invention is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this invention.

[0054] Please see Figure 1 This embodiment provides an online monitoring and repair method for creep aging forming, including the following steps:

[0055] S1. Perform a creep aging test on the second sample and collect the real-time acoustic emission signal of the second sample in real time, and extract the real-time acoustic emission characteristic parameters characterizing the damage from the real-time acoustic emission signal.

[0056] S2. Obtain a pre-established creep aging damage information database, and compare the real-time acoustic emission characteristic parameters with the acoustic emission characteristic values ​​in the creep aging damage information database in real time to obtain the comparison result; wherein, the creep aging damage information database contains the damage type and damage degree determined according to the mapping relationship between acoustic emission characteristic values ​​and material strain data.

[0057] Specifically, the real-time comparison is achieved by calculating the similarity between the feature vectors of the real-time acoustic emission feature parameters and the acoustic emission feature values ​​in the creep aging damage information database. When the similarity exceeds a preset threshold, it is determined to be a successful match.

[0058] S3. Determine whether the comparison result meets the preset matching conditions; when the comparison result meets the preset matching conditions, determine that the second sample has suffered target damage, and output the damage type and damage degree of the target damage;

[0059] S4. Obtain a predetermined optimal combination of electrical pulse parameters for different damage types and damage degrees. Based on the damage type and damage degree of the target damage, call the optimal combination of electrical pulse parameters corresponding to the target damage as repair parameters, and apply an electrical pulse based on the repair parameters to the second sample to repair the damaged area.

[0060] S5. After completing the electrical pulse repair, continue to perform creep aging test on the second sample; determine whether the second sample has broken; if not, return to step S1; if yes, end the creep aging test.

[0061] This embodiment achieves closed-loop intelligent control of the creep aging forming process by integrating real-time acoustic emission monitoring and online electrical pulse repair. The invention collects and extracts real-time acoustic emission characteristic parameters, enabling immediate capture of damage initiation activities within the material. By comparing these parameters with a creep aging damage information database in real time, it can perform early identification and precise quantitative diagnosis of current damage based on historical damage evolution data, thereby accurately determining the damage type and severity. It then calls upon the optimal combination of electrical pulse parameters pre-determined for the target damage type and severity as repair parameters and immediately applies electrical pulse repair, achieving precise intervention for damage adaptation. After repair, the process automatically cycles back to the monitoring step, forming a closed-loop control throughout the entire process from damage monitoring, damage diagnosis, and damage repair. In practical engineering applications, this invention seamlessly integrates damage monitoring, damage diagnosis, and damage repair into a continuous and automated process, not only achieving early damage elimination and performance recovery but also, through closed-loop iterative optimization, effectively extending the creep life of components and improving their forming limits.

[0062] This embodiment not only allows for timely introduction of damage repair methods to protect the integrity of materials after damage is detected, but also enables this process to be repeated throughout the creep aging test. This eliminates the need for cumbersome steps and reduced efficiency caused by removing the sample, and the sample fixation is not frequently changed, significantly improving the reliability of the test results. Furthermore, the electrical pulse repair parameters can be adjusted according to different damage degrees and types to better adapt to material damage repair and achieve optimal repair results, realizing creep aging forming with online monitoring and online repair.

[0063] Furthermore, the following steps are included before step S1:

[0064] S01. A creep aging test is performed on the first specimen, and acoustic emission signal data and strain data of the first specimen are collected simultaneously throughout the entire test process until the first specimen breaks; the acoustic emission signal data is processed to extract acoustic emission characteristic values ​​characterizing the damage; wherein, the first specimen and the second specimen are the same.

[0065] S02. Establish a mapping relationship between the acoustic emission characteristic values ​​and the damage evolution stages in the strain data, thereby forming a creep aging damage information database containing damage initiation time, damage location, damage degree and damage type.

[0066] S03. Construct an embedded damage model with the same properties as the first sample based on the damage degree and damage type in the creep aging damage information database; apply electrical pulses with different parameters to the embedded damage model to perform repair simulation and obtain repair effect data; the model features of the embedded damage model in this embodiment include, but are not limited to, damage shape, damage size, etc.

[0067] In this embodiment, there are two types of embedded damage models: one is a sphere with a diameter of 1 mm, and the other is an ellipsoid with a major semi-axis of 1.5 mm and a minor semi-axis of 0.5 mm.

[0068] S04. Based on the repair effect data, determine the optimal combination of electrical pulse parameters for different damage types and degrees. The optimal combination of electrical pulse parameters includes, but is not limited to, current density, pulse duration, and pulse width.

[0069] The corresponding optimal combination of electrical pulse parameters is a pulse current density of 30 A / mm. 2 The pulse frequency is 50kHz and the pulse width is 50μs.

[0070] More preferably, the following steps are included before step S01:

[0071] The sample also includes a third sample. The third sample, the first sample, and the second sample are surface polished, wiped with alcohol, and dried for later use. The first sample, the second sample, and the third sample are all the same. The materials of the first sample, the second sample, and the third sample in this embodiment include, but are not limited to, steel, aluminum alloy, magnesium alloy, titanium alloy, copper alloy, metal matrix composite material, and non-metal matrix composite material. The surface polishing treatment methods include, but are not limited to, sandpaper grinding, mechanical polishing, and electrolytic polishing.

[0072] A high-temperature tensile test is performed on the third specimen to obtain the high-temperature mechanical properties of the material of the third specimen at the temperature corresponding to the creep aging test; wherein the test temperature of the high-temperature tensile test is the same as the test temperature of the creep aging test.

[0073] Specifically, the test temperature is 140℃, and the high-temperature mechanical properties of the third sample are obtained through a high-temperature tensile test. These high-temperature mechanical properties include yield strength, tensile strength, and elongation.

[0074] In this embodiment, sample 8 includes a first sample, a second sample, and a third sample.

[0075] Specifically, a threshold condition is preset, and a mutation point in the sequence of acoustic emission feature values ​​is identified based on the threshold condition. Each mutation point that meets the threshold condition is determined as a damage event.

[0076] For each identified damage event, perform the following information association and quantification operations:

[0077] Determine the damage initiation time: Match the moment when the damage event is identified with the synchronous strain data, and obtain the strain value at that moment as the damage initiation strain;

[0078] Calculate the degree of damage: The degree of damage of the damage event is calculated according to the following formula:

[0079]

[0080] In the formula, D represents the degree of damage, and ε s ε is the damage initiation strain. r Let ε be the strain at any moment during the damage process. f This represents the fracture strain.

[0081] Determine the damage type: Analyze the acoustic emission waveform characteristics corresponding to the damage event, and determine the damage type of the damage event based on the waveform pattern recognition results;

[0082] Location of damage: The location of the damage event on the first sample is calculated based on the speed of sound wave propagation by using the time difference between the receipt of the same damage event signal by multiple acoustic emission sensors 6.

[0083] The damage start time, damage degree, damage type and damage location information obtained after information association and quantification of each damage event are structured and stored as a damage feature vector;

[0084] The damage feature vectors captured by the first specimen throughout the entire test are integrated to form the creep aging damage information database.

[0085] Please see Figure 2 In one embodiment, before performing the creep aging test in step S01, the following steps are also included:

[0086] The surface-treated first or second sample is placed on the fixed rod 4 of the creep testing machine. Extension rods 9 are fixed on both sides of the first or second sample. Electrode plates 5 are inserted into both sides of the first or second sample, and the electrode plates 5 are connected to the electrical pulse device 1 via a current transmission line 2. A displacement sensor for real-time displacement measurement is connected below the extension rods 9. At least two acoustic emission sensors 6 are coupled to the surface of the first or second sample using a high-temperature coupling agent. The acoustic emission sensors 6 are connected to a preamplifier 11 via an acoustic signal transmission line 10. The preamplifier 11 is connected to an acoustic emission acquisition device 12, and the acoustic emission acquisition device 12 is connected to a display device 7. The creep testing machine includes the fixed rod 4, extension rods 9, preamplifier 11, acoustic emission sensors 6, displacement sensors, electrical pulse device 1, acoustic emission acquisition device 12, and display device 7. In this embodiment, the number of acoustic emission sensors 6 is greater than or equal to two, used for synchronous monitoring of damage and locating the damage position. The material of the motor plate includes, but is not limited to, copper alloy and iron alloy.

[0087] In this embodiment, the creep aging test on the first sample further includes the following steps:

[0088] The creep testing machine also includes a heating furnace 3. The first sample, after installation, is pushed into the heating furnace 3, the heating furnace 3 is sealed, the creep aging process parameters and acoustic emission monitoring parameters are set, and then the creep aging test on the first sample is started. The change process of the acoustic emission signal of the first sample during the creep aging test is monitored in real time through the display device 7 until the first sample breaks.

[0089] The creep aging process parameters include the test temperature and load value of the creep aging test; the load value is set according to the high-temperature mechanical property results obtained from the high-temperature tensile test, and the load value is lower than the tensile strength of the material of the third sample at the test temperature; the creep aging process parameters include, but are not limited to, creep temperature, heating rate, creep holding time and load value.

[0090] The acoustic emission monitoring parameters include a threshold value, sampling rate, sampling length, waveform length, filtering frequency, maximum duration, and the position information of the acoustic emission sensor 6. Specifically, the threshold value is set to 40dB, the sampling rate to 5MSPS, the waveform length to 4k, the lower limit of the filtering frequency to 100kHz, the upper limit of the filtering frequency to 3MHz, and the distance between the acoustic emission sensors 6 to 30mm.

[0091] This embodiment utilizes the acoustic emission acquisition device 12 to monitor the damage status of materials during the entire creep aging forming process in real time. It can determine online whether the material is currently damaged or in a damaged state, eliminating the need for post-creep data processing and measurement, thus providing a more convenient analysis of the material's creep aging process. Based on acoustic emission monitoring of the creep aging damage process, this embodiment allows for timely electrical pulse repair of the material, improving material deformation and creep life. It achieves real-time monitoring and damage repair of material creep aging, ultimately guiding integrated forming manufacturing process adjustments and providing strong technical support for improving the material's forming limits. Furthermore, the display device 7 in the creep testing machine allows for real-time monitoring of the creep aging process of the internal material in the heating furnace 3 from outside the furnace. It can promptly determine the material's state during forming based on changes in acoustic emission characteristics, enabling corresponding repair processes and process adjustments, significantly improving the efficiency of creep aging forming.

[0092] As a further preferred embodiment, before applying an electrical pulse based on the repair parameters to the second sample in step S4, the step of pausing the application of creep load to the second sample is further included.

[0093] In one embodiment, step S02, establishing the mapping relationship between the acoustic emission characteristic values ​​and the damage evolution stages in the strain data, specifically includes the following steps:

[0094] Based on the temporal changes of the strain data, the strain-time curve of the first specimen is determined, the moment when the acoustic emission characteristic value changes abruptly is identified, and the moment is associated with the starting point of the accelerated strain change on the strain-time curve to determine the damage initiation time and the damage initiation strain.

[0095] Among them, abrupt changes in acoustic emission characteristic values ​​include situations where the cumulative amplitude jumps significantly beyond the threshold value, and situations where the cumulative energy exhibits a stepped distribution.

[0096] Specifically, when the acoustic emission characteristic value changes abruptly, it indicates that the first or second sample has been damaged, and the degree of damage is obtained in conjunction with the strain-time curve.

[0097] The acoustic emission characteristics include amplitude, energy, count, duration, rise time, and average frequency. Among the damage types, high-amplitude, short-duration burst acoustic emission characteristics correspond to microcrack initiation; low-amplitude, continuous acoustic emission characteristics correspond to dislocation slip or pore accumulation.

[0098] Specifically, for 7050 aluminum alloy in the T4 heat-treated state, the creep aging damage information database includes abrupt changes in acoustic emission characteristic values ​​at 1h, 1.2h, 1.4h, and 1.5h, finally reaching the maximum value at 1.56h, at which point the sample fractures. This indicates that the first sample began to show damage after 1h of creep, and different degrees of damage appeared at 1.2h, 1.4h, and 1.5h, with a final creep life of 1.56h. Simultaneously, the creep length of the first sample at 1h, 1.2h, 1.4h, and 1.5h is obtained, and the damage location is determined by the position calibration of acoustic emission sensor 6 to be 10mm from the upper acoustic emission sensor and 20mm from the lower acoustic emission sensor.

[0099] Among them, the damage degree of the first sample at 1h, 1.2h, 1.4h and 1.5h of creep was 0, 36%, 56% and 85%, respectively.

[0100] In one embodiment, the following steps are included after step S5:

[0101] S6. Obtain the first total creep aging duration and the first total creep value of the first sample, and obtain the second total creep aging duration and the second total creep value of the second sample.

[0102] S7. Determine whether the total duration of the second creep aging is greater than the total duration of the first creep aging, and whether the total creep variable is greater than the total creep variable.

[0103] S8. If the total duration of the second creep aging is greater than the total duration of the first creep aging, and the total creep variable is greater than the total creep variable, then the electrical pulse repair effect is deemed effective.

[0104] This embodiment establishes an objective and quantitative repair effect evaluation mechanism, enhancing the reliability of the experiment and the completeness of the process closed loop. By comparing the total creep time and total creep amount of the first and second samples, direct and quantifiable performance indicators are provided for the repair effect. By determining whether the data of the second sample is comprehensively superior to that of the first sample, it can be definitively confirmed that the electrical pulse repair not only restores the material's load-bearing capacity but also actively improves the material's creep performance. This data comparison-based judgment logic transforms the evaluation of the repair effect from subjective experience into an objective conclusion driven by experimental data. This completes the aforementioned process closed loop by adding a feedback link for repair effect verification and provides a clear decision-making basis for further optimization of process parameters.

[0105] The above are merely preferred embodiments of the present invention and do not limit the scope of the patent. Any equivalent structural or procedural transformations made based on the description and drawings of the present invention, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of the present invention.

Claims

1. A method for online monitoring and repair of creep aging forming, characterized in that, Includes the following steps: S1. Perform a creep aging test on the second sample and collect the real-time acoustic emission signal of the second sample in real time, and extract the real-time acoustic emission characteristic parameters characterizing the damage from the real-time acoustic emission signal. S2. Obtain a pre-established creep aging damage information database, and compare the real-time acoustic emission characteristic parameters with the acoustic emission characteristic values ​​in the creep aging damage information database in real time to obtain the comparison result; wherein, the creep aging damage information database contains the damage type and damage degree determined according to the mapping relationship between acoustic emission characteristic values ​​and material strain data. S3. Determine whether the comparison result meets the preset matching conditions; when the comparison result meets the preset matching conditions, determine that the second sample has suffered target damage, and output the damage type and damage degree of the target damage; S4. Obtain a predetermined optimal combination of electrical pulse parameters for different damage types and damage degrees. Based on the damage type and damage degree of the target damage, call the optimal combination of electrical pulse parameters corresponding to the target damage as repair parameters, and apply an electrical pulse based on the repair parameters to the second sample to repair the damaged area. S5. After completing the electrical pulse repair, determine whether the creep aging test has ended; if not, return to step S1. The following steps are included before step S1: S01. A creep aging test is performed on the first specimen, and acoustic emission signal data and strain data of the first specimen are collected simultaneously throughout the entire test process until the first specimen breaks; the acoustic emission signal data is processed to extract acoustic emission characteristic values ​​characterizing the damage; wherein, the first specimen and the second specimen are the same. S02. Establish a mapping relationship between the acoustic emission characteristic values ​​and the damage evolution stages in the strain data, thereby forming a creep aging damage information database containing damage initiation time, damage location, damage degree and damage type. S03. Construct an embedded damage model with the same properties as the first sample based on the damage degree and damage type in the creep aging damage information database; apply electrical pulses with different parameters to the embedded damage model to perform repair simulation and obtain repair effect data; S04. Based on the repair effect data, determine the optimal combination of electrical pulse parameters for different damage types and degrees.

2. The method for online monitoring and repair of creep aging forming according to claim 1, characterized in that, The following steps are included before step S01: It also includes a third sample, the third sample, the first sample, and the second sample are surface polished, wiped with alcohol, and dried for later use; wherein the first sample, the second sample, and the third sample are all the same; A high-temperature tensile test is performed on the third specimen to obtain the high-temperature mechanical properties of the material of the third specimen at the temperature corresponding to the creep aging test; wherein the test temperature of the high-temperature tensile test is the same as the test temperature of the creep aging test.

3. The method for online monitoring and repair of creep aging forming according to claim 2, characterized in that, Before performing the creep aging test in step S01, the following steps are also included: The surface-treated first or second sample is placed on the fixed rod of the creep testing machine. Extension rods are fixed on both sides of the first or second sample. Electrode plates are inserted into both sides of the first or second sample, and the electrode plates are connected to an electrical pulse device. A displacement sensor for real-time displacement measurement is connected below the extension rod. At least two acoustic emission sensors are coupled to the surface of the first or second sample through a coupling agent. The acoustic emission sensors are connected to a preamplifier, the preamplifier is connected to an acoustic emission acquisition device, and the acoustic emission acquisition device is connected to a display device. The creep testing machine includes a fixed rod, extension rods, a preamplifier, acoustic emission sensors, displacement sensors, an electrical pulse device, an acoustic emission acquisition device, and a display device.

4. The method for online monitoring and repair of creep aging forming according to claim 3, characterized in that, The creep aging test on the first sample specifically includes the following steps: The creep testing machine also includes a heating furnace. The first sample, after installation, is pushed into the heating furnace, the heating furnace is sealed, the creep aging process parameters and acoustic emission monitoring parameters are set, and then the creep aging test on the first sample is started. The change process of the acoustic emission signal of the first sample during the creep aging test is monitored in real time through the display device until the first sample breaks. The creep aging process parameters include the test temperature and load value of the creep aging test; the load value is set according to the high-temperature mechanical property results obtained from the high-temperature tensile test, and the load value is lower than the tensile strength of the material of the third sample at the test temperature; The acoustic emission monitoring parameters include threshold value, sampling rate, sampling length, waveform length, filtering frequency, maximum duration, and acoustic emission sensor location information.

5. The method for online monitoring and repair of creep aging forming according to claim 1, characterized in that, Before applying an electrical pulse based on the repair parameters to the second sample in step S4, the process further includes pausing the application of creep load to the second sample.

6. The method for online monitoring and repair of creep aging forming according to claim 1, characterized in that, Step S02 establishes the mapping relationship between the acoustic emission characteristic values ​​and the damage evolution stages in the strain data, specifically including the following steps: Based on the temporal changes of the strain data, the strain-time curve of the first specimen is determined, the moment when the acoustic emission characteristic value changes abruptly is identified, and the moment is associated with the starting point of the accelerated strain change on the strain-time curve to determine the damage initiation time and the damage initiation strain.

7. The method for online monitoring and repair of creep aging forming according to claim 6, characterized in that, The degree of damage is determined by the following steps: When the acoustic emission characteristic value changes abruptly, it indicates that damage has occurred in the first or second sample. The degree of damage is obtained by combining the strain-time curve, and the formula for calculating the degree of damage is as follows: In the formula, D represents the degree of damage, and ε s ε is the damage initiation strain. r Let ε be the strain at any moment during the damage process. f This represents the fracture strain.

8. The method for online monitoring and repair of creep aging forming according to claim 6, characterized in that, The damage type and location are determined by the following steps: The acoustic emission characteristics include amplitude, energy, count, duration, rise time, and average frequency; After damage occurs, the acoustic emission waveform is subjected to waveform pattern recognition or wavelet analysis to determine the damage type; among them, high amplitude, short duration, sudden acoustic emission characteristic values ​​correspond to microcrack initiation; low amplitude, continuous acoustic emission characteristic values ​​correspond to dislocation slip or pore accumulation. The propagation speed of sound waves in the material is obtained, and the time difference of the moment when the acoustic emission characteristic value changes abruptly is identified using multiple sensors. The spatial coordinates of the damage occurrence are calculated based on the propagation speed of sound waves in the material using the time difference positioning method.

9. The method for online monitoring and repair of creep aging forming according to claim 1, characterized in that, Step S5 is followed by the following steps: S6. Obtain the first total creep aging duration and the first total creep value of the first sample, and obtain the second total creep aging duration and the second total creep value of the second sample. S7. Determine whether the total duration of the second creep aging is greater than the total duration of the first creep aging, and whether the total creep value of the second creep is greater than the total creep value of the first creep. S8. If the total duration of the second creep aging is greater than the total duration of the first creep aging, and the total creep value of the second creep is greater than the total creep value of the first creep, then the electrical pulse repair effect is determined to be effective.

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