A control method and system for a cupping test machine

Abstract

The present invention relates to the field of testing machine control technology, solves the problem in the prior art that there is a lack of effective integration methods to obtain the status information of the sample in real time, thereby resulting in inaccurate cupping test results, and provides a control method and system for a cupping test machine. The method includes: obtaining a clamping load value and a test control parameter according to material parameters, and clamping a plate-shaped sample according to the clamping load value; controlling a stamping device to perform a cupping test according to the test control parameters, and simultaneously performing data collection during the cupping test to obtain actual displacement values, actual load values, and cupping test video data of the plate-shaped sample; stopping when a preset shutdown condition is met; and obtaining cupping test results according to the actual displacement value, actual load value, and cupping test video data. The present invention overcomes the limitations of independent data analysis through multi-dimensional data integration, making the cupping test results more accurate and the evaluation dimensions more comprehensive.

Description

Technical Field

[0001] The present invention relates to the technical field of testing machine control, and in particular to a control method and system for a cupping testing machine. Background Art

[0002] The cupping test is a standard experimental method for evaluating the plastic deformation capacity of metal sheets. A gradually increasing load is applied to the surface of the sheet through a punching device to observe whether cracks or breaks appear in the sheet during the punching process, thereby judging the formability and crack resistance of the material. This test is widely used in the automotive, aviation, construction and other fields to ensure the reliability and durability of the material in practical applications.

[0003] Traditional cupping tester control schemes usually use simple force or displacement control strategies, combined with sensor data to monitor the test process in real time. For example, when it is detected that the punching load reaches the preset maximum value or the displacement reaches the limit value, the control system will automatically stop the operation of the punching device to protect the equipment and the specimen. However, these control schemes often only focus on the final force or displacement extremes, ignoring the early signals of abnormal material deformation or cracks that may occur during the test. Although the image acquisition device is used to record the test process, it is usually only used for post-analysis and fails to provide valuable feedback in real time during the test.

[0004] Although the existing cupping test machine control scheme collects displacement, load and video data at the same time, these data are usually analyzed independently. There is a lack of an effective integration method to obtain the status information of the specimen in real time, which leads to inaccurate cupping test results. Summary of the invention

[0005] In view of this, an embodiment of the present invention provides a control method and system for a cupping tester to solve the problem that the prior art lacks an effective integration method to obtain the status information of the sample in real time, thereby resulting in inaccurate cupping test results.

[0006] In a first aspect, an embodiment of the present invention provides a control method for a cupping tester, wherein the cupping tester comprises a frame, a punching device, a fixing device, a sensor and an image acquisition device, wherein the punching device comprises a punching head and a hydraulic drive mechanism connected in sequence, the hydraulic drive mechanism drives the punching head to punch a plate-shaped sample, the fixing device is fixedly connected to the frame, the fixing device comprises a sample fixing base and a sample clamping mechanism fixedly arranged on the sample fixing seat, the sample fixing base is provided with a punching head through hole, the image acquisition device is arranged on the frame, the sensor comprises a displacement sensor and a pressure sensor, the displacement sensor is used to obtain the displacement of the punching head, and the pressure sensor is used to obtain the load applied to the plate-shaped sample, and the method comprises:

[0007] According to the material parameters of the plate-shaped specimen, the clamping load value of the plate-shaped specimen and the test control parameters of the cupping tester are obtained, wherein the test control parameters include a punching speed, a maximum punching load value, and a maximum displacement value;

[0008] According to the clamping load value, the plate-shaped sample placed on the sample fixing base is clamped by the sample clamping mechanism;

[0009] According to the test control parameters, the punching device is controlled to perform a cupping test on the plate-shaped specimen, and the sensor and the image acquisition device are controlled to collect data during the cupping test to obtain an actual displacement value, an actual load value, and cupping test video data of the plate-shaped specimen;

[0010] When the actual displacement value and / or the actual load value meets the preset shutdown condition, controlling the stamping device to stop;

[0011] The cupping test result of the plate-shaped specimen is obtained according to the actual displacement value, the actual load value and the cupping test video data.

[0012] Preferably, according to the material parameters of the plate-shaped specimen, obtaining the clamping load value of the plate-shaped specimen and the test control parameters of the cupping tester includes:

[0013] Obtaining material parameters of the plate-shaped sample and dimensional parameters of the punch head, wherein the material parameters include: material type and material thickness;

[0014] Determine the cross-sectional area of ​​the punching area according to the dimension parameters of the punching head;

[0015] According to the material type, obtaining the elastic modulus, yield strength, tensile strength, hardness and elongation of the plate-shaped specimen;

[0016] Determining the punching speed according to the yield strength, the elastic modulus and the material thickness;

[0017] Determining the maximum stamping load value according to the yield strength, the material thickness and the cross-sectional area of ​​the stamping region;

[0018] Determining the maximum displacement value according to the elongation and the material thickness;

[0019] determining an initial clamping load value according to the material thickness and the hardness;

[0020] If the initial clamping load value is greater than or equal to a preset clamping load threshold, the initial clamping load value is used as the clamping load value;

[0021] If the initial clamping load value is less than the preset clamping load threshold, the clamping load value is set according to the preset clamping load value.

[0022] Preferably, according to the test control parameters, the punching device is controlled to perform a cupping test on the plate-shaped specimen, and the sensor and the image acquisition device are controlled to perform data acquisition during the cupping test to obtain an actual displacement value, an actual load value, and cupping test video data of the plate-shaped specimen, including:

[0023] Determining a target lubricant according to the punching speed, the maximum punching load value, and the material type of the plate-shaped sample;

[0024] Uniformly coating the target lubricating oil on the surfaces of the plate-shaped specimen and the punch head;

[0025] Determine the sampling frequency of the displacement sensor and the pressure sensor according to the punching speed, wherein the sampling frequency is positively correlated with the punching speed;

[0026] Controlling the punching device to punch the plate-shaped sample according to the punching speed;

[0027] The displacement sensor and the pressure sensor are controlled according to the sampling frequency to respectively collect the actual displacement value and the actual load value during the stamping process, and the image acquisition device is controlled to obtain the video of the plate-like specimen during the stamping process to obtain the cupping test video data.

[0028] Preferably, when the actual displacement value and / or the actual load value meets a preset shutdown condition, controlling the stamping device to shut down includes:

[0029] Filtering the actual displacement value and the actual load value according to a preset filtering algorithm to obtain a filtered displacement value and a filtered load value;

[0030] Performing curve fitting according to the filtered displacement value and the filtered load value to obtain a pressure-displacement relationship fitting curve in real time;

[0031] Calculate the change rates of the filtered displacement value and the filtered load value respectively according to a preset sliding window to obtain a displacement change rate and a load change rate;

[0032] Perform residual analysis based on the pressure-displacement relationship curve and the actual load value to obtain a load residual value;

[0033] Determine whether the load residual value, the displacement change rate and the load change rate meet the preset shutdown condition, wherein the preset shutdown condition includes: the absolute value of the load residual value is greater than a preset residual threshold, and the load change rate is less than a load change rate threshold and / or the displacement change rate is greater than a displacement change rate threshold;

[0034] When the preset shutdown condition is met, the punching device is controlled to shut down.

[0035] Preferably, the determining whether the load residual value, the displacement change rate and the load change rate meet the preset shutdown condition includes:

[0036] According to the preset sliding window and the filtered displacement value, obtaining a displacement mean and a displacement standard deviation within the preset sliding window;

[0037] According to the preset sliding window and the filtered load value, obtaining a load mean and a load standard deviation within the preset sliding window;

[0038] Perform a first dynamic threshold calculation based on the displacement mean and displacement standard deviation in all the preset sliding windows to obtain the displacement change rate threshold;

[0039] Perform a second dynamic threshold calculation based on the load mean and load standard deviation in all the preset sliding windows to obtain the load change rate threshold;

[0040] Whether the preset shutdown condition is met is determined according to the load change rate threshold, the displacement change rate threshold and the preset residual threshold.

[0041] Preferably, obtaining the cupping test result of the plate-shaped specimen according to the actual displacement value, the actual load value and the cupping test video data comprises:

[0042] Obtaining a load value sequence according to all actual load values ​​of the punching device before shutdown;

[0043] Obtaining a displacement value sequence according to all actual displacement values ​​of the punching device before it stops;

[0044] In response to the cupping test video data satisfying a preset test success condition, the cupping test video data is cropped according to the load value sequence and the displacement value sequence to obtain target cupping test video data;

[0045] The cupping test result is obtained according to the target cupping test video data, the load value sequence and the displacement value sequence.

[0046] Preferably, in response to the cupping test video data satisfying a preset test success condition, the cupping test video data is cropped according to the load value sequence and the displacement value sequence to obtain target cupping test video data, including:

[0047] The first frame image of the cupping test video data is recorded as the first image, and the last frame image is recorded as the second image;

[0048] Determining whether the cupping test satisfies the preset test success condition according to the first image and the second image;

[0049] If satisfied, then smoothing the load value sequence and the displacement value sequence is performed according to a preset smoothing algorithm to obtain a smoothed displacement sequence and a smoothed load sequence;

[0050] According to the polynomial regression algorithm, trend analysis is performed on the smoothed load sequence and the smoothed displacement sequence to obtain a load value trend sequence and a displacement value trend sequence;

[0051] Performing residual analysis on the smoothed load sequence and the load value trend sequence to obtain a load residual sequence;

[0052] Performing residual analysis on the smoothed displacement sequence and the displacement value trend sequence to obtain a displacement residual sequence;

[0053] According to a preset anomaly detection algorithm, abnormal points in the load residual sequence and the displacement residual sequence are monitored to obtain a first abnormal point time sequence;

[0054] Filtering the abnormal points that meet the preset filtering conditions in the first abnormal point time sequence to obtain a second abnormal point time sequence, wherein the preset filtering conditions include that only one abnormal point is included in a preset minimum time window and the residual value corresponding to the abnormal point is less than a preset residual value threshold;

[0055] Clustering the second abnormal point time sequence according to a preset spatial clustering algorithm to obtain a target abnormal point time sequence;

[0056] Determining the time when the initial crack appears according to the target abnormal point time sequence;

[0057] The cupping test video data is cropped according to the initial crack appearance time and the preset advance cropping time to obtain the target cupping test video data.

[0058] Preferably, judging whether the cupping test satisfies the preset test success condition according to the first image and the second image includes:

[0059] Preprocessing the first image and the second image, wherein the preprocessing includes denoising and image normalization;

[0060] Processing the preprocessed first image and the second image according to an edge detection algorithm to obtain a first sample edge image and a second sample edge image respectively;

[0061] Acquire the deformation amount and edge movement distance of the plate-shaped sample according to the first sample edge image and the second sample edge image;

[0062] Performing connected area analysis on the second sample edge image to obtain crack features in the second image, wherein the crack features include crack position, crack length and crack width;

[0063] Whether the cupping test meets the preset test success condition is determined according to the deformation amount, the edge movement distance and the crack characteristics.

[0064] Preferably, obtaining the cupping test result according to the target cupping test video data, the load value sequence and the displacement value sequence includes:

[0065] Preprocessing each frame of the target cupping experiment video data to obtain a preprocessed image sequence;

[0066] Extracting edges of each frame of the image in the preprocessed image sequence according to an edge detection algorithm to obtain a first edge image sequence;

[0067] Processing each edge image in the first edge image sequence according to a morphological processing algorithm to obtain a crack feature data sequence, wherein the crack feature data sequence includes crack feature data in each edge image, and the crack feature data includes a crack position, a crack length, and a crack width;

[0068] Performing time differentiation on the crack characteristic data sequence, calculating the change rates of the crack position, the crack length and the crack width, and obtaining a crack characteristic change rate sequence;

[0069] According to the crack characteristic change rate sequence and the preset crack characteristic change rate threshold, the time point of significant change of the crack characteristic is obtained;

[0070] Taking the time point when the crack characteristics significantly change as the starting point, backtracking from the first edge image sequence to obtain edge images of a preset number of frames, thereby obtaining a second edge image sequence;

[0071] determining the first appearance time of the crack according to the second edge image sequence;

[0072] Acquire the actual load value and the actual displacement value corresponding to the first appearance time of the crack in the load value sequence and the displacement value sequence to obtain the load peak value and the displacement peak value;

[0073] The cupping test result is obtained according to the first occurrence time of the crack, the load peak value and the displacement peak value.

[0074] In the second aspect, an embodiment of the present invention provides a control system for a cupping tester, wherein the control system is used to control the cupping tester, and the control system includes: an image acquisition module, a control module, a stamping module, a sensor module and a power supply module, wherein the stamping module is used to control the stamping device to stamp a plate-shaped specimen, the sensor module is used to control the sensor to monitor the load and displacement applied to the plate-shaped specimen in real time, the power supply module is used to control the power supply to supply energy to the control system, the image acquisition device is used to collect video data during the cupping experiment, and the control module is used to execute the control method of the cupping tester described in any one of the first aspects.

[0075] In summary, the beneficial effects of the present invention are as follows:

[0076] A control method and system for a cupping tester provided in an embodiment of the present invention obtains accurate clamping load values ​​and test control parameters, including stamping speed, maximum stamping load value and maximum displacement value, according to the material parameters of a plate-shaped sample, to ensure that the sample is uniformly stressed during the stamping process, thereby improving the accuracy and reliability of the test results. During the cupping test, the control sensor and the image acquisition device are synchronously collected to acquire the actual displacement value, the actual load value and the test video data, so as to realize real-time monitoring of the test state. Once it is detected that the actual displacement value or the actual load value meets the preset shutdown condition, the stamping device is immediately controlled to stop to avoid sample damage or data distortion caused by excessive stamping. Combining the load value, displacement value and test video data, by comprehensively analyzing the change trends of the three, the state of the sample during the test can be more comprehensively reflected. This multi-dimensional data integration method overcomes the limitations of independent data analysis in traditional solutions, making the test results more accurate and comprehensive. Through automated parameter acquisition, data acquisition, and shutdown control, the errors caused by manual operation and judgment are reduced, and the automation and work efficiency of the test are improved. This method can adapt to specimens of different materials and adjust test control parameters using material parameters, thus being applicable to a variety of materials and test conditions, and expanding the application range of the cupping tester. BRIEF DESCRIPTION OF THE DRAWINGS

[0077] In order to more clearly illustrate the technical solution of the embodiment of the present invention, the drawings required for use in the embodiment of the present invention will be briefly introduced below. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work, and these are all within the protection scope of the present invention.

[0078] Figure 1 It is a structural schematic diagram of a cupping tester according to an embodiment of the present invention.

[0079] Figure 2 The present invention is a flowchart of a control method for a cupping tester according to an embodiment of the present invention.

[0080] Figure 3 The present invention is a flowchart of a control method for a cupping tester according to an embodiment of the present invention.

[0081] Figure 4 The present invention is a flowchart of a control method for a cupping tester according to an embodiment of the present invention.

[0082] Figure 5 The present invention is a schematic diagram of a control system of a cupping tester according to an embodiment of the present invention. DETAILED DESCRIPTION

[0083] The features and exemplary embodiments of various aspects of the present invention will be described in detail below. In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and Examples. It should be understood that the specific embodiments described herein are only configured to explain the present invention and are not configured to limit the present invention. For those skilled in the art, the present invention can be implemented without the need for some of these specific details. The following description of the embodiments is only to provide a better understanding of the present invention by illustrating examples of the present invention.

[0084] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "include..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0085] It should be noted that all actions of acquiring signals, information or data in the present invention are performed in compliance with the corresponding data protection laws and policies of the location and with the authorization given by the owner of the corresponding device.

[0086] Example 1

[0087] See also Figure 1 The embodiment of the present invention provides a control method for a cupping tester, the cupping tester comprising a frame 1, a fixing device 13, a punching device, a sensor 14 and an image acquisition device 11, wherein the punching device comprises a punching head and a hydraulic driving mechanism connected in sequence, the hydraulic driving mechanism drives the punching head to punch a plate-shaped sample, the fixing device is fixedly connected to the frame, the fixing device comprises a sample fixing base and a sample clamping mechanism fixedly arranged on the sample fixing seat, the sample fixing base is provided with a punching head through hole, the image acquisition device is arranged on the frame, the sensor comprises a displacement sensor and a pressure sensor, the displacement sensor is used to obtain the displacement of the punching head, and the pressure sensor is used to obtain the load applied to the plate-shaped sample;

[0088] Specifically, the frame is the main supporting structure of the cupping tester, which is used to carry and fix other key components, such as fixtures, punches, sensors and image acquisition devices. It provides a stable working environment for the test, ensuring that each component maintains precise position and stable operation during the test.

[0089] The fixture is used to firmly fix the plate-shaped specimen on the working platform of the testing machine to ensure that the specimen will not move or slide during the stamping process. The fixture includes the following two key components: the specimen fixing base, which is used to place the base of the specimen and has a punch head through hole on it, which is used to allow the punch head to move freely and contact the specimen during the test; the specimen clamping mechanism, which is installed on the specimen fixing base and is used to clamp and fix the specimen to prevent it from any displacement or loosening during the stamping process.

[0090] The punching device is the core actuator of the cupping test, which is responsible for applying force to the specimen to perform the cupping forming test. It consists of the following two main parts: the punch head, which is the component that directly contacts the specimen and applies pressure. The shape and size of the punch head are usually designed according to the test standard and the specifications of the specimen; the hydraulic drive mechanism, which is used to drive the movement and pressure of the punch head. The displacement and applied force of the punch head are precisely controlled by the hydraulic system to ensure the stability and repeatability of the test process.

[0091] Sensors are used to monitor and record changes in key parameters during the test in real time to ensure the accuracy of the test data. They mainly include: displacement sensors, which are used to detect and record the displacement of the punch head relative to the specimen during the stamping process. Displacement data is crucial for evaluating the forming performance and failure mode of the specimen; pressure sensors: used to measure the load applied to the specimen, that is, the actual force that the specimen is subjected to during the stamping process. The data from the pressure sensor can help analyze the strength and plastic behavior of the material.

[0092] The image acquisition device is used to record the surface changes of the specimen during the test, especially the formation and expansion of cracks. It usually includes a camera, which is installed above the frame to obtain a clear image of the specimen. The imaging data is combined with the displacement and force data to comprehensively analyze the deformation behavior and failure mode of the specimen.

[0093] The method comprises:

[0094] S1. According to the material parameters of the plate-shaped specimen, obtaining the clamping load value of the plate-shaped specimen and the test control parameters of the cupping tester, wherein the test control parameters include a punching speed, a maximum punching load value, and a maximum displacement value;

[0095] Specifically, the mechanical conditions that the specimen needs to withstand during the test are determined according to the material properties of the plate specimen, such as the thickness, strength, hardness, elastic modulus, etc. These parameters directly affect the setting of the clamping load value and other control parameters. The clamping load value refers to the preload force that needs to be applied to the specimen to prevent the specimen from sliding or moving during the stamping process. This load value is usually calculated based on the material parameters and the specimen size to ensure that the specimen is stably fixed during stamping. The test control parameters include the stamping speed, the maximum stamping load value, and the maximum displacement value. The stamping speed is the speed at which the punch moves during the cupping test. Too fast speed may cause the specimen material to break or fail, while too slow speed may affect the test efficiency. Set an appropriate speed based on the material properties and test requirements. The maximum stamping load value is the maximum load value that the specimen can withstand during the stamping process. If this value is exceeded, the specimen may break or fail. Therefore, the stamping force needs to be closely monitored during the test. The maximum displacement value is the maximum displacement distance allowed by the punch during the test. If this distance is exceeded, the specimen may lose its structural integrity. Therefore, this parameter also needs to be set according to the shape and material properties of the specimen.

[0096] Specifically, preferably, obtaining the clamping load value of the plate-shaped specimen and the test control parameters of the cupping tester according to the material parameters of the plate-shaped specimen includes:

[0097] S11, obtaining material parameters of the plate-shaped sample and dimension parameters of the punch head, wherein the material parameters include: material type and material thickness;

[0098] Specifically, by obtaining material parameters and punch head size parameters, basic data can be provided for mechanical calculations in subsequent steps. These parameters are crucial for determining various control parameters in the stamping process (such as stamping speed, maximum stamping load, etc.);

[0099] Material type refers to the material of the specimen, such as steel, aluminum, copper and other different metals or alloys. Each material has specific mechanical properties, such as elastic modulus, yield strength, etc. Material thickness refers to the thickness of the plate specimen, which directly affects the deformation behavior and mechanical response of the specimen. The dimensional parameters of the punch head include the diameter and shape of the punch head, which determine the contact area and stress distribution acting on the specimen during the punching process.

[0100] Obtain the material type and thickness information of the specimen from the material manual or material database. The material type is usually identified by material identification or specification table, and the thickness is obtained by direct measurement or reference to manufacturing standards. The dimensional parameters of the punch head are obtained by measurement or reference to the equipment manual. Common punch head dimensional parameters include diameter, radius, and shape. By accurately obtaining material parameters and punch head dimensional parameters, subsequent calculations and parameter settings can be more accurate, which helps to improve the accuracy and repeatability of the test.

[0101] S12, determining the cross-sectional area of ​​the punching area according to the dimension parameters of the punching head;

[0102] Specifically, the cross-sectional area of ​​the punching area refers to the actual contact area of ​​the punch head on the specimen. During the punching process, this cross-sectional area affects the stress distribution and deformation behavior of the specimen. The purpose of determining the cross-sectional area of ​​the punching area is to provide the necessary geometric parameters for the subsequent calculation of the maximum punching load value. This cross-sectional area determines how the punching force is distributed on the specimen, thereby affecting the yield and deformation of the specimen. According to the shape of the punch head (such as round or rectangular), the cross-sectional area is calculated using a geometric formula. For example, if the punch head is round, its cross-sectional area can be calculated using the formula A=πr 2 Calculate, where r is the radius of the punch. For punches of other shapes, such as rectangles, the corresponding geometric formulas can be used for calculation. Accurate calculation of the cross-sectional area of ​​the punching area helps to reasonably distribute the punching load, ensure that the stress applied during the material test matches the mechanical properties of the material, and reduce the risk of unnecessary failure of the specimen.

[0103] S13. Obtaining elastic modulus, yield strength, tensile strength, hardness and elongation of the plate-shaped specimen according to the material type;

[0104] Specifically, the elastic modulus is the ratio of stress to strain of the material within the elastic range, reflecting the rigidity of the material. The yield strength is the stress value when the material undergoes plastic deformation. The tensile strength is the maximum stress that the material can withstand in a tensile test. Hardness is the ability of the material to resist local plastic deformation (such as indentation or scratching). The elongation is the ratio of the elongation of the material when it is stretched to fracture to the original length, reflecting the plasticity of the material. The purpose of obtaining these material mechanical properties is to accurately set the punching speed, maximum punching load value and maximum displacement value. These parameters directly affect the deformation behavior and failure mode of the specimen in the test. According to the material type, the corresponding elastic modulus, yield strength, tensile strength, hardness and elongation are obtained by consulting the material mechanical properties manual or database. For standard materials, these data are usually known. In some cases, if the performance of the material is unknown or needs further verification, these mechanical properties parameters can be directly determined by experimental means such as tensile tests, hardness tests, etc. By accurately obtaining these mechanical properties parameters, it can be ensured that the mechanical conditions during the test are consistent with the actual characteristics of the material, thereby improving the reliability and accuracy of the test results.

[0105] S14, determining the stamping speed according to the yield strength, the elastic modulus and the material thickness;

[0106] Specifically, the punching speed is the speed at which the punch head moves during the cupping test, which has a significant effect on the deformation behavior and stress state of the material. The punching speed is determined in order to balance the plastic deformation capacity of the specimen with the stress concentration that may be caused during the punching process. A reasonable punching speed helps the specimen to deform smoothly without premature failure. According to the yield strength and elastic modulus of the specimen, combined with the material thickness, a reasonable range of punching speeds is derived. Higher yield strengths and larger elastic moduli usually require lower punching speeds to avoid specimen fracture in the initial stage. The punching speed can be adjusted using empirical formulas or experimental data to ensure that the speed can effectively apply the load while avoiding excessive impact on the specimen. By setting the punching speed reasonably, the safety of the specimen during the test can be improved, ensuring that the material gradually undergoes plastic deformation during the stress process, and reducing the risk of specimen rupture.

[0107] S15, determining the maximum stamping load value according to the yield strength, the material thickness and the cross-sectional area of ​​the stamping region;

[0108] Specifically, the maximum punching load value refers to the maximum load value that the specimen can withstand during the punching process. If this load value is exceeded, the specimen may break or fail in other forms. The maximum punching load value is determined to provide a clear load upper limit during the test process to ensure that the specimen can still maintain structural integrity under maximum stress conditions.

[0109] By the formula Fmax=σ y *A, where Fmax is the maximum punching load value, σ y is the yield strength, and A is the cross-sectional area of ​​the stamping area. The formula shows that the maximum stamping load value is proportional to the yield strength of the material and the area of ​​the stamping area, and the material thickness has been considered in the calculation of the cross-sectional area. Through calculation and deduction, the maximum load that the specimen can withstand is obtained and set as the upper limit during the test to avoid excessive stress on the specimen. By accurately calculating the maximum stamping load value, the specimen can be effectively prevented from rupturing prematurely during the test, ensuring the success rate of the test and the reliability of the data.

[0110] S16, determining the maximum displacement value according to the elongation and the material thickness;

[0111] Specifically, the maximum displacement value refers to the maximum displacement of the punch head on the material sample during the punching process. If the displacement value exceeds this value, the material may lose plasticity or break. The maximum displacement value is determined to prevent the punch head from exceeding the ductility of the material during the test, causing the material to break or fail. According to the elongation of the material ( ) and thickness (t), combined with empirical formulas or test data, the maximum displacement value is derived. In one embodiment, the empirical formula: ,in is the maximum displacement value. The derived maximum displacement value is used as a limit in the stamping process to ensure that the displacement during the stamping process does not exceed the elongation limit of the material. By reasonably determining the maximum displacement value, the material sample can be effectively prevented from being cracked during the test, ensuring a smooth stamping process and obtaining reliable test data.

[0112] S17, determining an initial clamping load value according to the material thickness and the hardness;

[0113] Specifically, the initial clamping load value refers to the initial clamping force applied to the plate specimen before the stamping test begins. This clamping force should be large enough to prevent the specimen from moving or slipping during the stamping process. Based on the thickness and hardness of the material, use empirical formulas or test data to derive the initial clamping load value. Thicker and harder materials generally require higher clamping load values ​​to ensure that the specimen is firmly fixed. The set clamping load value is achieved by adjusting the mechanical parameters of the clamping equipment and is verified and adjusted before the stamping test begins.

[0114] S18, if the initial clamping load value is greater than or equal to a preset clamping load threshold, taking the initial clamping load value as the clamping load value;

[0115] S19. If the initial clamping load value is less than the preset clamping load threshold, setting the clamping load value according to the preset clamping load value.

[0116] Specifically, the preset clamping load threshold is the minimum clamping force value set by the system based on experience or standards. Any clamping force below this threshold may cause the specimen to be unstable during the test. Compare the initial clamping load value with the preset threshold. If the initial clamping load value is greater than or equal to the preset threshold, this value is directly used as the final clamping load value without further adjustment. If the initial clamping load value is lower than the preset clamping load threshold, the system will automatically or manually increase the clamping force until it reaches or exceeds the threshold. This process can be achieved by adjusting the pneumatic, hydraulic or mechanical clamping force of the clamping device. Through this adjustment process, it is ensured that all specimens meet the minimum clamping force requirements before testing, eliminate test deviations caused by insufficient clamping, and improve test consistency and reliability of results.

[0117] S2. clamping the plate-shaped sample placed on the sample fixing base by the sample clamping mechanism according to the clamping load value;

[0118] Specifically, the plate-shaped specimen is placed on the specimen fixing base and fixed by the clamping mechanism. At this time, the clamping load value applied is the key, which ensures that the specimen will not slide or shift during the stamping process; the specimen clamping mechanism needs to apply appropriate pressure to firmly fix the specimen while not exerting excessive stress on the specimen to avoid damage to the specimen before stamping. According to the clamping load value set by the material parameters, the clamping mechanism will automatically adjust the applied pressure.

[0119] S3, according to the test control parameters, controlling the punching device to perform a cupping test on the plate-shaped specimen, and controlling the sensor and the image acquisition device to collect data during the cupping test to obtain an actual displacement value, an actual load value, and video data of the cupping test of the plate-shaped specimen;

[0120] Specifically, the punching device conducts a cupping test under the guidance of preset test control parameters, applying specified force and displacement to gradually compress and deform the specimen. Through the hydraulic drive mechanism, the punch head gradually applies load to the specimen. During the entire test process, the displacement sensor detects the displacement of the punch head in real time and records the position change of the punch head relative to the specimen. The pressure sensor monitors and records the actual load applied by the punch head on the specimen at each time point, helping to evaluate the mechanical response of the specimen under different loads. The image acquisition device records the surface changes of the specimen in real time, including possible cracks, deformations, etc. The video data provides changes in the outer surface of the specimen at different time points, assisting in the analysis of material behavior during the test.

[0121] Preferably, see Figure 3, according to the test control parameters, controlling the punching device to perform a cupping test on the plate-shaped specimen, and controlling the sensor and the image acquisition device to collect data during the cupping test, to obtain an actual displacement value, an actual load value and a cupping test video data of the plate-shaped specimen, including:

[0122] S31, determining a target lubricating oil according to the punching speed, the maximum punching load value, and the material type of the plate-shaped sample;

[0123] Specifically, select the appropriate lubricant based on the material type of the specimen, the expected maximum stamping load, and the set stamping speed. Different lubricants have different viscosities and lubrication properties, and should be selected based on actual working conditions to ensure the smooth progress of the test; by properly selecting lubricants, the friction during the stamping process can be effectively reduced, the wear of the specimen and the stamping head surface can be avoided, and the stability of the stamping process can be ensured;

[0124] By way of example and not limitation, step S31 includes:

[0125] Determine the initial lubricant range based on material type;

[0126] Specifically, metal materials such as low carbon steel, aluminum alloy, stainless steel, etc. usually choose lubricating oil or emulsion. Non-metallic materials (such as polymers, composite materials) may choose solid lubricants or grease lubricants.

[0127] According to the stamping speed, determine the viscosity and type of lubricant. For low-speed stamping, choose a lubricant with higher viscosity, such as grease. For medium- and high-speed stamping, choose a low-viscosity lubricant or emulsion to reduce friction heat and wear. For high-speed stamping, consider high-temperature lubricants or synthetic lubricants to cope with higher friction heat and shear force.

[0128] Determine the temperature resistance of the lubricant according to the test temperature. Standard lubricating oil or emulsion can be used for normal temperature tests. For high temperature tests, choose lubricants with high temperature stability, such as silicone oil or molybdenum disulfide solid lubricant.

[0129] Through these steps, the appropriate lubricant can be reasonably selected and effectively applied in the cupping test according to the specific test requirements and material properties. This systematic selection process can ensure that the performance of the lubricant matches the test conditions, thereby improving the accuracy and reliability of the test.

[0130] S32, uniformly coating the target lubricating oil on the surfaces of the plate-shaped sample and the punch head;

[0131] Specifically, use a special coating tool or equipment to evenly coat the target lubricant on the surface of the plate specimen and the contact surface of the punch head. Ensure that the coating process is uniform to avoid insufficient or excessive local lubrication. Uniform lubricant coverage can effectively reduce the friction between the specimen and the punch head surface, reduce the heat generated during the test, reduce surface damage, and ensure the accuracy of the test data.

[0132] S33, determining the sampling frequency of the displacement sensor and the pressure sensor according to the punching speed, wherein the sampling frequency is positively correlated with the punching speed;

[0133] Specifically, the sampling frequency is the number of times the sensor acquires data per second. According to the set stamping speed, adjust the sampling frequency of the displacement sensor and pressure sensor. The sampling frequency should be positively correlated with the stamping rate. The faster the stamping speed, the higher the sampling frequency should be to capture more precise force and displacement data. By adjusting the sampling frequency, it is ensured that the force and displacement changes at every moment in the stamping process can be accurately recorded to obtain high-precision experimental data.

[0134] S34, controlling the punching device to punch the plate-shaped sample according to the punching speed;

[0135] Specifically, according to the preset stamping speed, the operating speed of the stamping device is adjusted by the control system to ensure that the stamping process is carried out according to the set parameters.

[0136] S35. According to the sampling frequency, the displacement sensor and the pressure sensor are controlled to collect actual displacement values ​​and actual load values ​​during the stamping process, and at the same time, the image acquisition device is controlled to obtain the video of the plate-like specimen during the stamping process to obtain cupping test video data.

[0137] Specifically, the displacement, load and video data during the stamping process are fully captured through sensor acquisition and image acquisition device recording, providing a basis for subsequent analysis. During the stamping process, the actual displacement value and actual load value are collected in real time according to the previously set sampling frequency, and the image acquisition device is controlled to record the video of the stamping process. All data are synchronized with time to ensure the integrity and accuracy of the test data.

[0138] S4. When the actual displacement value and / or the actual load value meets the preset shutdown condition, the stamping device is controlled to shut down;

[0139] Specifically, when the actual displacement value and / or the actual load value meets the preset stop conditions, the control system will automatically stop the operation of the stamping device to ensure the safety and reliability of the test process and avoid damage to the equipment or the sample. In one embodiment, the preset shutdown includes: when the actual displacement value reaches the preset maximum displacement value, it means that the sample has been deformed to the limit, and the stamping needs to be stopped at this time to prevent further deformation or damage to the sample, and when the actual load value reaches the preset maximum stamping load value, the stamping process should be stopped immediately to avoid applying excessive force to the sample, causing failure or damage to the sample.

[0140] Preferably, when the actual displacement value and / or the actual load value meets a preset shutdown condition, controlling the stamping device to shut down includes:

[0141] S41, filtering the actual displacement value and the actual load value according to a preset filtering algorithm to obtain a filtered displacement value and a filtered load value;

[0142] Specifically, in order to process the actual collected data and eliminate the noise introduced by sensor errors or external interference, a preset filtering algorithm (such as low-pass filtering, Kalman filtering, etc.) is used to process the actual displacement value and the actual load value, remove the high-frequency noise therein, and obtain smooth filtered data. Through filtering processing, the accuracy of the data can be effectively improved, the error caused by noise can be reduced, and the subsequent analysis can be more reliable.

[0143] S42, performing curve fitting according to the filtered displacement value and the filtered load value, and obtaining a pressure-displacement relationship fitting curve in real time;

[0144] Specifically, the force-displacement relationship fitting curve is to fit the filtered data using a mathematical model to generate a curve representing the data relationship, specifically representing the relationship curve between the force and the displacement during the stamping process. The data is fitted using the filtered displacement value and the load value to generate a force-displacement relationship curve. The curve can be updated in real time to reflect the current stamping status. Through the force-displacement relationship fitting curve, the progress of the stamping process can be monitored in real time and abnormal conditions can be discovered in time.

[0145] S43, respectively calculating the change rates of the filter displacement value and the filter load value according to a preset sliding window to obtain a displacement change rate and a load change rate;

[0146] Specifically, the changing trend of force and displacement in the stamping process is dynamically monitored by calculating the change rate, and the stamping results are predicted. The sliding window technology is used to calculate the displacement value and load value after filtering in real time to obtain the displacement change rate and load change rate at each moment. The calculation of the change rate can help detect minor anomalies in the stamping process. By monitoring the change rate, abnormal phenomena in the stamping process can be discovered in advance, and timely measures can be taken to avoid test failures.

[0147] S44, performing residual analysis according to the pressure-displacement relationship curve and the actual load value to obtain a load residual value;

[0148] Specifically, residual analysis refers to evaluating the degree of data deviation by analyzing the difference between actual data and fitted curves. By comparing the actual load value during the stamping process with the fitted curve, the difference between the actual load value and the fitted curve is calculated to obtain the load residual value. The residual value can help identify the degree of data deviation and determine whether an abnormality has occurred. Through residual analysis, abnormalities in the stamping process can be effectively identified to ensure the reliability of the test results.

[0149] S45, determining whether the load residual value, the displacement change rate and the load change rate meet the preset shutdown condition, wherein the preset shutdown condition includes: the absolute value of the load residual value is greater than a preset residual threshold, and the load change rate is less than a load change rate threshold and / or the displacement change rate is greater than a displacement change rate threshold;

[0150] Specifically, the three parameters of load residual value, load change rate and displacement change rate are set in the preset stop conditions in order to more comprehensively monitor and identify abnormal conditions during the cupping test, and ensure the safety of the test and the reliability of the data. The residual value represents the difference between the actual measured load value and the force-displacement fitting curve (i.e., the theoretical expected value). When the absolute value of the residual value is too large, it means that the actual load has deviated significantly from the theoretical expected value. If the actual load is much higher or lower than the theoretical value, it may mean that an abnormal condition occurred during the test, such as material failure, equipment failure, or insufficient lubrication. This deviation can lead to inaccurate test results and may even damage the specimen or equipment. Therefore, when the absolute value of the residual value exceeds the preset threshold, the system should stop the test immediately to prevent further damage.

[0151] The load change rate refers to the speed at which the load changes per unit time. If the load change rate suddenly becomes smaller or approaches zero, it indicates that the load growth slows down or stops. In the cupping test, the load change rate is usually closely related to the deformation process of the material. When the load change rate becomes very small, especially in the critical stage of the test, it may mean that the material has reached or is close to its maximum load-bearing capacity. Further pressure may not increase the load, but will cause material rupture or other irreversible damage. Therefore, when the load change rate is less than the preset threshold, the system should consider stopping the test to avoid specimen rupture or equipment damage.

[0152] The displacement rate of change is the speed of change of displacement per unit time. A large displacement rate of change indicates that the displacement increased too quickly during the stamping process, which may be related to sudden instability, sliding or tearing of the specimen. In a normal cupping test, the displacement rate of change should be coordinated with the load increase. If the displacement rate of change increases suddenly, it may indicate that the specimen has slipped, become unstable, or the material has begun to break. In order to protect the specimen and equipment, when the displacement rate of change exceeds the preset threshold, the system should immediately stop the test to prevent further damage.

[0153] The load residual value, load change rate, and displacement change rate are parallel and / or combined conditions, which means that these conditions are multiple monitoring of different abnormal conditions. This setting takes into account the various abnormal conditions that may occur during the stamping process. By simultaneously monitoring the load residual value, load change rate, and displacement change rate, different types of potential risks can be more comprehensively identified and responded to, ensuring the safety of the test and the accuracy of the data.

[0154] Preferably, the determining whether the load residual value, the displacement change rate and the load change rate meet the preset shutdown condition includes:

[0155] S451, obtaining a displacement mean and a displacement standard deviation within the preset sliding window according to the preset sliding window and the filtered displacement value;

[0156] Specifically, the mean and standard deviation of the displacement within the sliding window are calculated to understand the overall change and fluctuation of the displacement within this period of time. This is critical for determining the stability and trend of the displacement. The displacement data of each window is extracted from the filtered displacement value sequence in a sliding window manner. The mean of all displacement data within the window is calculated to represent the average level of displacement within the window. The standard deviation of the displacement within the window is calculated to reflect the magnitude of the displacement fluctuation within the window. This provides local features of the displacement change, which is helpful for subsequent dynamic threshold calculations. The mean and standard deviation can reflect the change trend and fluctuation of the displacement in a short period of time, and provide a basis for determining the displacement change rate.

[0157] S452, obtaining a load mean and a load standard deviation within the preset sliding window according to the preset sliding window and the filtered load value;

[0158] Specifically, similar to the previous step, by calculating the load mean and standard deviation within each sliding window, the local changes and fluctuations of the load are captured, thus laying the foundation for determining the dynamic threshold.

[0159] S453, performing a first dynamic threshold calculation based on the displacement mean and displacement standard deviation in all the preset sliding windows to obtain the displacement change rate threshold;

[0160] Specifically, the displacement mean and standard deviation in all sliding windows are used as input, and the displacement change rate threshold is calculated using a dynamic threshold algorithm (such as the 3σ rule). The displacement change rate threshold is usually based on the mean of the displacement plus or minus several times the standard deviation, and the specific multiple can be adjusted according to application requirements. The dynamic threshold is adjusted according to the actual displacement data, so that the system can effectively determine whether an abnormal displacement change has occurred under various load and displacement conditions.

[0161] S454, performing a second dynamic threshold calculation based on the load mean and load standard deviation in all the preset sliding windows to obtain the load change rate threshold;

[0162] Specifically, similar to the displacement change rate threshold, the load change rate threshold is dynamically calculated to ensure that it can flexibly respond to load fluctuations and abnormal changes under different load conditions. The load change rate threshold is calculated using the load mean and standard deviation in all sliding windows and the same dynamic threshold calculation method as the displacement. The calculation method can adopt a statistical method, such as determining the upper and lower limits of the load change rate by the load mean and standard deviation.

[0163] S455. Determine whether the preset shutdown condition is met according to the load change rate threshold, the displacement change rate threshold and the preset residual threshold.

[0164] Finally, by comparing the load change rate, displacement change rate, and residual value with their respective thresholds, it is determined whether the shutdown conditions are met. If an indicator exceeds the threshold, it may mean that there is an abnormality and the system needs to be shut down for inspection. By comprehensively judging the load change, displacement change, and residual, it is ensured that the system can be shut down in time when an abnormality occurs to prevent further equipment damage or test failure. The dynamically adjusted threshold improves the system's adaptability under different working conditions.

[0165] S46. When the preset shutdown condition is met, the stamping device is controlled to shut down.

[0166] Specifically, when it is detected that the shutdown conditions are met, the system will automatically control the stamping device to stop running, preventing further stamping operations, avoiding damage to the equipment or affecting the test results.

[0167] S5. Obtaining a cupping test result of the plate-shaped specimen according to the actual displacement value, the actual load value and the cupping test video data.

[0168] By analyzing the displacement and load values ​​actually obtained during the stamping process, the material properties of the specimen, such as cupping value, plastic deformation capacity, etc., can be evaluated. The above data are comprehensively analyzed to determine the performance of the specimen in the cupping test. The results may include the maximum deformation of the specimen, the fracture location, the load-displacement curve, and the ultimate strength of the material. Through these results, the quality and performance of the material can be evaluated, and a reference can be provided for subsequent material development or production.

[0169] Preferably, see Figure 4 , obtaining the cupping test result of the plate-shaped specimen according to the actual displacement value, the actual load value and the cupping test video data, comprises:

[0170] S51, obtaining a load value sequence according to all actual load values ​​of the punching device before shutdown;

[0171] S52, obtaining a displacement value sequence according to all actual displacement values ​​of the punching device before shutdown;

[0172] Specifically, the load value sequence refers to the time series of all recorded load values ​​before the end of the test. This sequence shows how the load changes over time. The displacement value sequence refers to the time series of all recorded displacement values ​​before the end of the test. This sequence shows how the displacement changes over time. The load value sequence provides a complete record of the load changes during the test and can be used to analyze the effect of the load on the deformation and rupture of the specimen. The displacement value sequence shows the deformation of the specimen during the test, which can help analyze the deformation behavior and final rupture state of the specimen.

[0173] S53, in response to the cupping test video data satisfying a preset test success condition, cropping the cupping test video data according to the load value sequence and the displacement value sequence to obtain target cupping test video data;

[0174] Specifically, the cupping test video data is a continuous video recording the test process, and the target cupping test video data is a key part of the video related to the load and displacement cut out from the entire video data. This part of the video is directly related to the test results. First, the cupping test is judged whether it is successful according to the cupping test video data, that is, whether the preset test success conditions are met. For example, but not limited to, the crack formation process is confirmed in the video data. If the position and time of crack formation are consistent with the abnormal point in the load and displacement data, the test is considered successful. Check the shape change of the plate specimen in the video, especially the shape integrity before and after the crack formation. If the specimen has cracks at the expected position and the overall deformation is reasonable, the test can be considered successful. By acquiring the first and last frames of the video, the moving distance of the edge of the plate specimen is judged. If there is obvious sliding on the edge, it may indicate that the clamping is not tight or other problems, and the test may be unsuccessful at this time; when the test is successful, the time point most relevant to the final cupping value can be determined according to the load value sequence and the displacement value sequence, and the video is edited according to the time point to obtain the target cupping test video data.

[0175] Preferably, the step of clipping the cupping test video data according to the load value sequence and the displacement value sequence to obtain target cupping test video data comprises:

[0176] S531, obtaining the first frame image of the cupping test video data as the first image, and the last frame image as the second image;

[0177] Specifically, the first frame image of the cupping test video data usually corresponds to the state at the beginning of the test, and the last frame image of the cupping test video data usually corresponds to the state at the end of the test. By obtaining the images at the beginning and end of the test, it can be used as the basis for subsequent analysis to clarify the time span of the test and the starting and end points of the characteristic changes.

[0178] S532, judging whether the cupping test satisfies the preset test success condition according to the first image and the second image;

[0179] Specifically, the preset test success condition refers to the success criteria set before the test, such as the degree of deformation of the sample, whether cracks appear, etc. By comparing the first and second images, it is possible to quickly determine whether the test has achieved the expected results, thereby deciding whether to conduct further data analysis. The image processing algorithm detects the difference between the first image and the second image to determine whether the preset conditions are met, such as the presence of obvious cracks or material damage. It is possible to automatically determine whether the test is successful, reduce human errors, and improve work efficiency.

[0180] By judging only through two frames of images, the amount of data processing can be reduced, and it can be determined whether there is an obvious test failure, thereby avoiding further acquisition of failed test results when the test fails.

[0181] Preferably, judging whether the cupping test satisfies the preset test success condition according to the first image and the second image includes:

[0182] S5321, preprocessing the first image and the second image, wherein the preprocessing includes denoising and image standardization;

[0183] Specifically, this step performs preliminary processing on the image to improve the accuracy of subsequent analysis. Preprocessing usually includes removing noise from the image, unifying the brightness and contrast of the image, etc. De-noising can use filtering algorithms such as Gaussian filtering and median filtering to smooth the image and remove noise. Image standardization can adjust the image histogram to a uniform level of brightness and contrast, or unify the image size through a scaling algorithm.

[0184] S5322, processing the preprocessed first image and the second image according to an edge detection algorithm to obtain a first sample edge image and a second sample edge image respectively;

[0185] Specifically, the edge of the plate-shaped sample is extracted through edge detection to determine the deformation and edge movement of the sample during the stamping process. The edge detection algorithms include the Canny algorithm, the Sobel algorithm, etc. After edge detection processing, the detected edge part is retained to generate the first sample edge image and the second sample edge image, which correspond to the sample state before and after stamping respectively. Edge detection makes the analysis of deformation and edge movement more intuitive and accurate, and facilitates the subsequent calculation of deformation amount and edge movement distance.

[0186] S5323, acquiring a deformation amount and an edge movement distance of the plate-shaped sample according to the first sample edge image and the second sample edge image;

[0187] Specifically, the deformation refers to the amount of shape change that occurs in the sample during the test. It is calculated by comparing the edge image of the first sample with the edge image of the second sample and measuring the shape change of the sample in different directions. The edge movement distance refers to the distance that the edge of the sample moves during the test, reflecting the deformation of the sample under the action of force. It is obtained by calculating the movement distance of the edge before and after the test through the image coordinate system. By quantitatively analyzing the deformation and edge movement distance, the deformation characteristics of the sample can be more accurately judged, providing a basis for subsequent crack feature analysis.

[0188] S5324, performing connected region analysis on the second sample edge image to obtain crack features in the second image, wherein the crack features include crack position, crack length, and crack width;

[0189] Specifically, connected region analysis is used to identify and analyze connected pixel regions in an image. Connected regions can represent parts or defects of an object, such as cracks. In the edge image of the second specimen, continuous pixel regions are identified through the connected region analysis algorithm. These regions may represent cracks. For the identified crack regions, characteristic parameters such as position, length and width are calculated to form a complete crack feature description. Crack features are parameters that describe cracks, including the position, length, width, etc. of the cracks, reflecting the defect characteristics of the specimen during the test. Accurate extraction of crack features helps to evaluate the structural integrity of the specimen and provides a key basis for the judgment of the final test results.

[0190] S5325. Determine whether the cupping test meets the preset test success conditions based on the deformation amount, the edge movement distance, and the crack characteristics.

[0191] Specifically, the deformation amount, edge movement distance and crack characteristics are comprehensively considered to comprehensively evaluate the performance of the sample to determine whether it meets the expected performance indicators, thereby determining whether the test is successful. If these indicators are all within the preset range, the test is considered successful; otherwise, the test does not meet the preset conditions.

[0192] S533: If the conditions are met, smoothing the load value sequence and the displacement value sequence is performed according to a preset smoothing algorithm to obtain a smoothed displacement sequence and a smoothed load sequence;

[0193] Specifically, when the cupping test is judged to be successful, the load value sequence and the displacement value sequence are processed by a preset smoothing algorithm (such as moving average or exponential smoothing). The smoothing process can remove accidental fluctuations in the test data and can more intuitively present the overall trend of the data, which is helpful for subsequent trend analysis and anomaly detection.

[0194] S534, performing trend analysis on the smoothed load sequence and the smoothed displacement sequence according to a polynomial regression algorithm to obtain a load value trend sequence and a displacement value trend sequence;

[0195] Specifically, polynomial regression is used to fit the smoothed data to obtain the trend equation describing the change of load and displacement over time, and the trend sequence is extracted from it. The polynomial regression algorithm is a statistical method for fitting nonlinear data, which describes the trend of data by constructing a polynomial equation. Through trend analysis, the overall change trend of load and displacement can be obtained, providing a benchmark for subsequent anomaly detection.

[0196] S535, performing residual analysis on the smoothed load value sequence and the load value trend sequence to obtain a load residual sequence;

[0197] S536, performing residual analysis on the smoothed displacement value sequence and the displacement value trend sequence to obtain a displacement residual sequence;

[0198] Specifically, residual analysis refers to the difference between the actual value and the fitted value, that is, the residual, which is used to measure the accuracy of the fitted model. Residual analysis is used to evaluate the model fitting effect and find out the part of the data that cannot be explained by the trend model, which may correspond to abnormal events in reality. By calculating the difference between the smoothed load value sequence and the trend sequence, the residual of each data point is obtained and sorted into a sequence, and by calculating the difference between the smoothed displacement value sequence and the trend sequence, the residual of each data point is obtained to form a sequence. Through residual analysis, abnormal behaviors that cannot be explained by the model can be identified, which helps to further understand the key events in the experiment.

[0199] S537, monitoring abnormal points in the load residual sequence and the displacement residual sequence according to a preset abnormality detection algorithm to obtain a first abnormal point time sequence;

[0200] Specifically, preset anomaly detection algorithms such as z-score detection or DBSCAN clustering are used to identify abnormal points in the data sequence. These points are usually points that deviate greatly from the model or stand out in the data trend. Find the abnormal points in the load and displacement residual sequence. These points may correspond to key events in the material test, such as the initial appearance of cracks or the beginning of plastic deformation. The collection of these points is recorded as the first abnormal time point sequence. By monitoring abnormal points, the important event moments in the test can be further analyzed to improve the accuracy of the test results.

[0201] S538, filtering the abnormal points that meet the preset filtering condition in the first abnormal point time sequence to obtain a second abnormal point time sequence, wherein the preset filtering condition includes that only one abnormal point is included in a preset minimum time window and the residual value corresponding to the abnormal point is less than a preset residual value threshold;

[0202] Specifically, outliers that do not meet the requirements are screened out according to preset rules. The preset residual value threshold is a set value used to determine whether the residual value is significant enough. If the intensity of the outlier does not exceed this threshold, the point is excluded. The intensity threshold can be set according to the actual data distribution, for example, the outlier residual exceeds 2 times the standard deviation of the average residual. The preset minimum time window is to check whether the outliers have temporal continuity. Outliers in continuous time are more likely to be related to physical changes, while a single isolated outlier may be noise. If there is only one outlier in the time window, the point can be excluded.

[0203] S539, clustering the second abnormal point time sequence according to a preset spatial clustering algorithm to obtain a target abnormal point time sequence;

[0204] Specifically, clustering algorithms such as DBSCAN are used to cluster outliers and find dense point groups. DBSCAN can identify dense point groups and exclude noise points. The minimum point group size and neighborhood radius are set. Only when the number and density of outliers exceed the set threshold in the same time period, they are considered to be valid outlier point groups and recorded as target outlier point moment sequences. Through the clustering algorithm, outliers with strong correlation are classified together to further reduce noise and find the most representative outlier moments. The outlier point moment sequence is more concentrated and representative, which helps to identify key moments and facilitates the subsequent editing and analysis of the test video.

[0205] S5310, determining the time when the initial crack appears according to the target abnormal point time sequence;

[0206] Specifically, the initial crack appearance time is the time point when cracks are first observed on the surface of the specimen from the data level in the cupping test, which is usually the key moment when the material begins to fail during the test. According to the clustered target abnormal point time sequence, find the time that may represent the initial crack appearance, which is usually the first significant abnormal point in the sequence.

[0207] S5311. According to the initial crack appearance time and the preset advance trimming time, the cupping test video data is trimmed to obtain the target cupping test video data.

[0208] Specifically, after calculating the moment when the initial crack appears, the preset trimming time is moved forward to determine the starting point of the video data, and then the video is trimmed to retain the key moments, remove irrelevant parts, and retain the time period that is most meaningful for result analysis. The trimmed video data is more representative, reduces redundant information, and facilitates more accurate result analysis and summary.

[0209] The steps of this embodiment are to smooth, trend analyze, residual analyze, anomaly detect, cluster and other processing of the load and displacement data during the cupping test, finally determine the time of the initial crack, and cut the relevant video data to ensure that the obtained target cupping test video data focuses on the key parts of the test. This processing method not only improves the accuracy of data analysis, but also reduces unnecessary information interference, which helps to better understand the performance of the material in the test and the final test results.

[0210] S54. Obtain the cupping test result according to the target cupping test video data, the load value sequence and the displacement value sequence.

[0211] Specifically, based on the test analysis conclusions obtained from the load value, displacement value and video data, such as the fracture mode, limit load and deformation characteristics of the specimen, the load value sequence and displacement value sequence are combined with the cropped target video data for comprehensive analysis. The fracture behavior of the specimen is evaluated by analyzing the changes in load and displacement over time. The crack characteristics in the video data are compared with the load and displacement data to confirm the formation point and expansion process of the crack. Based on the analysis results, a test report is generated to describe in detail the test results such as the fracture mode, maximum load, and deformation of the specimen.

[0212] Preferably, obtaining the cupping test result according to the target cupping test video data, the load value sequence and the displacement value sequence includes:

[0213] S541, preprocessing each frame of the target cupping experiment video data to obtain a preprocessed image sequence;

[0214] Specifically, filtering technology is applied to each frame of the image to remove noise, and by adjusting the contrast and brightness, details such as cracks are made more obvious and prominent. Preprocessing reduces noise and unnecessary details in the image, enhances key information in the image (such as cracks), and lays the foundation for subsequent edge detection and feature extraction.

[0215] S542, extracting edges from each frame of the image in the preprocessed image sequence according to an edge detection algorithm to obtain a first edge image sequence;

[0216] Specifically, by applying edge detection algorithms (such as Canny, Sobel, etc.) to the preprocessed image, the crack edges in the image are extracted and an edge image sequence is generated. The crack edges in the image are extracted through edge detection to form a clear edge image, which is convenient for subsequent morphological processing and feature analysis.

[0217] S543, processing each edge image in the first edge image sequence according to a morphological processing algorithm to obtain a crack feature data sequence, wherein the crack feature data sequence includes crack feature data in each edge image, and the crack feature data includes a crack position, a crack length, and a crack width;

[0218] Specifically, the morphological processing algorithm mainly includes operations such as expansion, corrosion, opening and closing, which are used to enhance the features in the image or remove noise. Through morphological processing, the specific characteristic data of the cracks are extracted, including the precise location, length and width of the cracks, providing data support for further feature analysis.

[0219] S544, performing time difference on the crack characteristic data sequence, calculating the change rate of the crack position, the crack length and the crack width, and obtaining a crack characteristic change rate sequence;

[0220] Specifically, the difference between adjacent data points in the time series is calculated to analyze the trend and rate of change over time, and the crack characteristic change rate is obtained, which includes the rate of change of the crack position, length and width over time, reflecting the expansion speed and trend of the crack. By calculating the change rate of the crack characteristics, the expansion speed and dynamic behavior of the crack are analyzed, laying the foundation for identifying the key change points of the crack.

[0221] S545, obtaining a time point at which the crack characteristics significantly change according to the crack characteristic change rate sequence and a preset crack characteristic change rate threshold;

[0222] By comparing the crack characteristic change rate with the preset threshold, the time point when the crack significantly expands is determined, providing a key node for further analysis of crack behavior. Each change rate value in the crack characteristic change rate sequence is compared with the preset threshold, and the time point exceeding the threshold is selected as the time point when the crack characteristic significantly changes.

[0223] S546, starting from the time point when the crack characteristics significantly change, backtracking from the first edge image sequence, acquiring a preset number of edge images, and obtaining a second edge image sequence;

[0224] Specifically, in order to select the number of image frames before and after the significant change time point for analyzing the detailed conditions before and after the crack expansion, taking the time point when the crack characteristics significantly change as the starting point, a preset number of image frames are selected forward to form the second edge image sequence, thereby capturing the key moment of crack expansion and providing detailed data support for subsequent crack behavior analysis.

[0225] S547, determining the first appearance time of the crack according to the second edge image sequence;

[0226] Specifically, in order to determine the time point when the crack begins to form, which is of great significance for understanding the failure process of the material, the second edge image is analyzed by image processing technology to identify the position and time point when the crack first appears and mark it as the time when the crack first appears.

[0227] S548, obtaining the actual load value and the actual displacement value corresponding to the first appearance time of the crack in the load value sequence and the displacement value sequence to obtain the load peak value and the displacement peak value;

[0228] Specifically, the load peak and displacement peak are the maximum load value and corresponding displacement value borne by the specimen when the crack first appears, respectively, representing the ultimate bearing capacity of the specimen. By associating the time when the crack first appears with the load value and displacement value sequence, the load and displacement peak values ​​of the specimen when the crack is formed are determined to evaluate its bearing performance.

[0229] S549. Obtain the cupping test result according to the first appearance time of the crack, the load peak value and the displacement peak value.

[0230] Specifically, the time when the crack first appears is combined with the load peak and displacement peak to analyze the ultimate bearing capacity and failure characteristics of the material, and finally the cupping test results are obtained, thereby providing a comprehensive evaluation of the performance of the specimen in the cupping test and helping to determine the applicability and reliability of the material in practical applications.

[0231] Example 2

[0232] See also Figure 5 An embodiment of the present invention provides a control system for a cupping tester, wherein the control system is used to control the cupping tester, and the control system includes: an image acquisition module, a control module, a stamping module, a sensor module and a power supply module. The stamping module is used to control the stamping device to stamp a plate-shaped specimen, the sensor module is used to control the sensor to monitor the load and displacement applied to the plate-shaped specimen in real time, the power supply module is used to control the power supply to supply energy to the control system, the image acquisition device is used to collect video data during the cupping experiment, and the control module is used to execute the control method of the cupping tester described in Example 1.

[0233] Specifically, the control module can realize intelligent control of the cupping tester, with a high degree of automation, which improves the test efficiency and production efficiency. The sensor module can monitor the load and displacement applied to the specimen in real time to ensure the accuracy and reliability of the test data. The stamping module can apply different stamping to the test specimen according to the test requirements, meet the requirements of different materials and test standards, and has strong applicability and flexibility. Through intelligent control of the testing machine, the control system can realize full monitoring and safety assurance of the test process, reduce operational risks, and ensure the safety of operators. The power module can provide a stable power supply for the entire control system, ensure the continuity and stability of the test process, and improve the reliability and continuous operation capability of the system.

[0234] In summary, the control system can improve test efficiency, ensure the accuracy of test data, meet different test requirements, and ensure operational safety, and has high practical value and economic benefits.

[0235] It should be clear that the present invention is not limited to the specific configuration and processing described above and shown in the figures. For the sake of simplicity, a detailed description of the known method is omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method process of the present invention is not limited to the specific steps described and shown, and those skilled in the art can make various changes, modifications and additions, or change the order between the steps after understanding the spirit of the present invention.

[0236] The functional blocks shown in the structural block diagram described above can be implemented as hardware, software, firmware or a combination thereof. When implemented in hardware, it can be, for example, an electronic circuit, an application specific integrated circuit (ASIC), appropriate firmware, a plug-in, a function card, etc. When implemented in software, the elements of the present invention are programs or code segments used to perform the required tasks. The program or code segment can be stored in a machine-readable medium, or transmitted on a transmission medium or a communication link by a data signal carried in a carrier. "Machine-readable medium" may include any medium capable of storing or transmitting information. Examples of machine-readable media include electronic circuits, semiconductor memory devices, ROMs, flash memories, erasable ROMs (EROMs), floppy disks, CD-ROMs, optical disks, hard disks, optical fiber media, radio frequency (RF) links, etc. The code segment can be downloaded via a computer network such as the Internet, an intranet, etc.

[0237] It should also be noted that the exemplary embodiments mentioned in the present invention describe some methods or systems based on a series of steps or devices. However, the present invention is not limited to the order of the above steps, that is, the steps can be performed in the order mentioned in the embodiments, or in a different order from the embodiments, or several steps can be performed simultaneously.

[0238] The above is only a specific implementation of the present invention. Those skilled in the art can clearly understand that for the convenience and simplicity of description, the specific working process of the system, module and unit described above can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here. It should be understood that the protection scope of the present invention is not limited to this. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should be covered within the protection scope of the present invention.

Claims

1. A control method for a cupping test machine, characterized in that: The cupping tester comprises a frame, a punching device, a fixing device, a sensor and an image acquisition device, wherein the punching device comprises a punching head and a hydraulic drive mechanism connected in sequence, the hydraulic drive mechanism drives the punching head to punch a plate-shaped sample, the fixing device is fixedly connected to the frame, the fixing device comprises a sample fixing base and a sample clamping mechanism fixedly arranged on the sample fixing base, the sample fixing base is provided with a punching head through hole, the image acquisition device is arranged on the frame, the sensor comprises a displacement sensor and a pressure sensor, the displacement sensor is used to obtain the displacement of the punching head, and the pressure sensor is used to obtain the load applied to the plate-shaped sample, and the method comprises: According to the material parameters of the plate-shaped specimen, the clamping load value of the plate-shaped specimen and the test control parameters of the cupping tester are obtained, wherein the test control parameters include a punching speed, a maximum punching load value, and a maximum displacement value; According to the clamping load value, the plate-shaped sample placed on the sample fixing base is clamped by the sample clamping mechanism; According to the test control parameters, the punching device is controlled to perform a cupping test on the plate-shaped specimen, and the sensor and the image acquisition device are controlled to collect data during the cupping test to obtain an actual displacement value, an actual load value, and cupping test video data of the plate-shaped specimen; When the actual displacement value and / or the actual load value meets the preset shutdown condition, the stamping device is controlled to shut down, which specifically includes: Filtering the actual displacement value and the actual load value according to a preset filtering algorithm to obtain a filtered displacement value and a filtered load value; Performing curve fitting according to the filtered displacement value and the filtered load value to obtain a pressure-displacement relationship fitting curve in real time; Calculate the change rates of the filtered displacement value and the filtered load value respectively according to a preset sliding window to obtain a displacement change rate and a load change rate; Perform residual analysis based on the pressure-displacement relationship fitting curve and the actual load value to obtain a load residual value; Determine whether the load residual value, the displacement change rate and the load change rate meet the preset shutdown condition, wherein the preset shutdown condition includes: the absolute value of the load residual value is greater than a preset residual threshold, and the load change rate is less than a load change rate threshold and / or the displacement change rate is greater than a displacement change rate threshold; When the preset shutdown condition is met, controlling the stamping device to shut down; The cupping test result of the plate-shaped specimen is obtained according to the actual displacement value, the actual load value and the cupping test video data.

2. The control method of the cupping tester according to claim 1, characterized in that: According to the material parameters of the plate-shaped specimen, the clamping load value of the plate-shaped specimen and the test control parameters of the cupping tester are obtained, including: Obtaining material parameters of the plate-shaped sample and dimensional parameters of the punch head, wherein the material parameters include: material type and material thickness; Determine the cross-sectional area of ​​the punching area according to the dimension parameters of the punching head; According to the material type, obtaining the elastic modulus, yield strength, tensile strength, hardness and elongation of the plate-shaped specimen; Determining the punching speed according to the yield strength, the elastic modulus and the material thickness; Determining the maximum stamping load value according to the yield strength, the material thickness and the cross-sectional area of ​​the stamping region; Determining the maximum displacement value according to the elongation and the material thickness; determining an initial clamping load value according to the material thickness and the hardness; If the initial clamping load value is greater than or equal to a preset clamping load threshold, the initial clamping load value is used as the clamping load value; If the initial clamping load value is less than the preset clamping load threshold, the clamping load value is set according to the preset clamping load threshold.

3. The control method of the cupping tester according to claim 1, characterized in that: According to the test control parameters, the punching device is controlled to perform a cupping test on the plate-shaped specimen, and the sensor and the image acquisition device are controlled to collect data during the cupping test to obtain an actual displacement value, an actual load value, and cupping test video data of the plate-shaped specimen, including: Determining a target lubricant according to the punching speed, the maximum punching load value, and the material type of the plate-shaped sample; Uniformly coating the target lubricating oil on the surfaces of the plate-shaped specimen and the punch head; Determine the sampling frequency of the displacement sensor and the pressure sensor according to the punching speed, wherein the sampling frequency is positively correlated with the punching speed; Controlling the punching device to punch the plate-shaped sample according to the punching speed; The displacement sensor and the pressure sensor are controlled according to the sampling frequency to respectively collect the actual displacement value and the actual load value during the stamping process, and the image acquisition device is controlled to obtain the video of the plate-like specimen during the stamping process to obtain the cupping test video data.

4. The control method of the cupping tester according to claim 1, characterized in that: The determining whether the load residual value, the displacement change rate, and the load change rate meet the preset shutdown condition includes: According to the preset sliding window and the filtered displacement value, obtaining a displacement mean and a displacement standard deviation within the preset sliding window; According to the preset sliding window and the filtered load value, obtaining a load mean and a load standard deviation within the preset sliding window; Perform a first dynamic threshold calculation based on the displacement mean and displacement standard deviation in all the preset sliding windows to obtain the displacement change rate threshold; Perform a second dynamic threshold calculation based on the load mean and load standard deviation in all the preset sliding windows to obtain the load change rate threshold; Whether the preset shutdown condition is met is determined according to the load change rate threshold, the displacement change rate threshold and the preset residual threshold.

5. The control method of the cupping tester according to any one of claims 1 to 4, characterized in that: The step of obtaining the cupping test result of the plate-shaped specimen according to the actual displacement value, the actual load value and the cupping test video data comprises: Obtaining a load value sequence according to all actual load values ​​of the punching device before shutdown; Obtaining a displacement value sequence according to all actual displacement values ​​of the punching device before it stops; In response to the cupping test video data satisfying a preset test success condition, the cupping test video data is cropped according to the load value sequence and the displacement value sequence to obtain target cupping test video data; The cupping test result is obtained according to the target cupping test video data, the load value sequence and the displacement value sequence.

6. The control method of the cupping tester according to claim 5, characterized in that: In response to the cupping test video data satisfying a preset test success condition, the cupping test video data is cropped according to the load value sequence and the displacement value sequence to obtain target cupping test video data, including: The first frame image of the cupping test video data is recorded as the first image, and the last frame image is recorded as the second image; Determining whether the cupping test satisfies the preset test success condition according to the first image and the second image; If satisfied, then smoothing the load value sequence and the displacement value sequence is performed according to a preset smoothing algorithm to obtain a smoothed displacement sequence and a smoothed load sequence; According to the polynomial regression algorithm, trend analysis is performed on the smoothed load sequence and the smoothed displacement sequence to obtain a load value trend sequence and a displacement value trend sequence; Performing residual analysis on the smoothed load sequence and the load value trend sequence to obtain a load residual sequence; Performing residual analysis on the smoothed displacement sequence and the displacement value trend sequence to obtain a displacement residual sequence; According to a preset anomaly detection algorithm, abnormal points in the load residual sequence and the displacement residual sequence are monitored to obtain a first abnormal point time sequence; Filtering the abnormal points that meet the preset filtering conditions in the first abnormal point time sequence to obtain a second abnormal point time sequence, wherein the preset filtering conditions include that only one abnormal point is included in a preset minimum time window and the residual value corresponding to the abnormal point is less than a preset residual value threshold; Clustering the second abnormal point time sequence according to a preset spatial clustering algorithm to obtain a target abnormal point time sequence; Determining the time when the initial crack appears according to the target abnormal point time sequence; The cupping test video data is cropped according to the initial crack appearance time and the preset advance cropping time to obtain the target cupping test video data.

7. The control method of the cupping tester according to claim 6, characterized in that: The determining, based on the first image and the second image, whether the cupping test satisfies the preset test success condition comprises: Preprocessing the first image and the second image, wherein the preprocessing includes denoising and image normalization; Processing the preprocessed first image and the second image according to an edge detection algorithm to obtain a first sample edge image and a second sample edge image respectively; Acquire the deformation amount and edge movement distance of the plate-shaped sample according to the first sample edge image and the second sample edge image; Performing a connected region analysis on the second sample edge image to obtain crack features in the second image, wherein the crack features include crack position, crack length and crack width; Whether the cupping test meets the preset test success condition is determined according to the deformation amount, the edge movement distance and the crack characteristics.

8. The control method of the cupping tester according to claim 5, characterized in that: The step of obtaining the cupping test result according to the target cupping test video data, the load value sequence and the displacement value sequence comprises: Preprocessing each frame of the target cupping test video data to obtain a preprocessed image sequence; Extracting edges of each frame of the image in the preprocessed image sequence according to an edge detection algorithm to obtain a first edge image sequence; Processing each edge image in the first edge image sequence according to a morphological processing algorithm to obtain a crack feature data sequence, wherein the crack feature data sequence includes crack feature data in each edge image, and the crack feature data includes a crack position, a crack length, and a crack width; Performing time differentiation on the crack characteristic data sequence, calculating the change rates of the crack position, the crack length and the crack width, and obtaining a crack characteristic change rate sequence; According to the crack characteristic change rate sequence and the preset crack characteristic change rate threshold, the time point of significant change of the crack characteristic is obtained; Taking the time point when the crack characteristics significantly change as the starting point, backtracking from the first edge image sequence to obtain edge images of a preset number of frames, thereby obtaining a second edge image sequence; determining the first appearance time of the crack according to the second edge image sequence; Acquire the actual load value and the actual displacement value corresponding to the first appearance time of the crack in the load value sequence and the displacement value sequence to obtain the load peak value and the displacement peak value; The cupping test result is obtained according to the first occurrence time of the crack, the load peak value and the displacement peak value.

9. A control system for a cupping test machine, characterized in that: The control system is used to control a cupping tester, and the control system includes: an image acquisition module, a control module, a stamping module, a sensor module and a power module. The stamping module is used to control a stamping device to stamp a plate-shaped specimen, the sensor module is used to control a sensor to monitor in real time the load and displacement applied to the plate-shaped specimen, the power module is used to control a power supply to supply energy to the control system, the image acquisition module is used to collect video data during a cupping experiment, and the control module is used to execute the control method of the cupping tester described in any one of claims 1 to 8.

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