Control method of bending testing machine and bending testing machine

Abstract

The present invention relates to the field of testing machine control technology, solves the problem in the prior art that it is difficult to accurately control the bending angle and loading rate, which affects the bending performance evaluation of steel bars, and provides a control method for a bending testing machine and a bending testing machine. The method comprises: obtaining forward and reverse bending test control parameters and a target span according to the material parameters and target bending angle of the steel bar sample; clamping the steel bar sample, and adjusting the spacing between the first clamping mechanism and the second clamping mechanism according to the target span; performing a forward bending test according to the forward bending test control parameters to obtain a forward bending test result; performing a reverse bending test according to the reverse bending test control parameters to obtain a reverse bending test result; and obtaining a target bending test result according to the reverse bending test result and the forward bending test result. The present invention can improve the accuracy and reliability of the steel bar bending test results.

Description

Technical Field

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

[0002] Bending test is one of the important methods to evaluate the mechanical properties of materials, and is widely used in testing materials such as metals and plastics. In the field of construction, steel bars are the main structural materials, and their bending properties are directly related to the safety and durability of the structure. Therefore, the steel bar bending test has become a key link in evaluating the performance of steel bars when subjected to bending stress during construction.

[0003] Bending tests are usually conducted by placing the specimen in a bending test machine under predetermined loading conditions. The test process usually includes clamping and loading the steel bar sample to simulate the bending conditions in actual use. Traditional bending test machine control methods usually control the bending process by simply fixing the displacement rate, ignoring the influence of the specific performance and dimensional parameters of the specimen.

[0004] The control method of existing bending testers is usually based on a pre-set fixed displacement rate, and the operation process is relatively simple. The advantage of this control scheme is that it is easy to implement, but its disadvantages are also very obvious. Due to the failure to fully consider the material properties of the sample such as yield strength and elastic modulus, as well as the dimensional parameters of the sample such as length and diameter, the accuracy and reliability of the test results are often low, which in turn affects the final bending performance evaluation of the steel bar. Summary of the invention

[0005] In view of this, an embodiment of the present invention provides a control method and device for a bending testing machine, so as to solve the problem in the prior art that it is difficult to perform a bending test on a specimen at a fixed displacement rate, resulting in inaccurate final bending performance evaluation.

[0006] In a first aspect, an embodiment of the present invention provides a control method for a bending test machine, characterized in that the bending test machine comprises: a frame, a bending pressurizing assembly, a sensor assembly, and a first supporting assembly and a second supporting assembly arranged relatively to each other, wherein the bending pressurizing assembly comprises a bending head and a vertical driving mechanism for driving the bending head to move in a vertical direction, the first supporting assembly comprises a first support roller and a first horizontal driving mechanism for driving the first support roller to move in a horizontal direction, the second supporting assembly comprises a second support roller and a second horizontal driving mechanism for driving the second support roller to move in a horizontal direction, the sensor assembly comprises a first displacement sensor for obtaining a displacement of the bending head, a load sensor for obtaining a load value of the bending head, a second displacement sensor for obtaining a displacement value of the first support roller, and a third displacement sensor for obtaining a displacement value of the second support roller, and the control method comprises:

[0007] According to the material parameters of the sample and the target bending angle, the test control parameters are obtained, wherein the test control parameters include the spacing between the support rollers, the displacement rate, the target displacement amount, and the maximum displacement threshold;

[0008] The sample is placed between the first support roller and the second support roller, and according to the support roller spacing, the first horizontal driving mechanism and the second horizontal driving mechanism are controlled to move synchronously to adjust the spacing between the first support roller and the second support roller;

[0009] Controlling the bending and pressurizing assembly to perform a bending test on the sample according to the test control parameters, and monitoring the displacement value and the load value of the bending head in real time through the first displacement sensor and the load sensor, and obtaining the displacement values ​​of the first support assembly and the second support assembly through the second displacement sensor and the third displacement sensor, to obtain bending test data;

[0010] When the bending test data meets the preset test stop condition, the bending pressurizing assembly is controlled to stop, and the surface detection result of the sample after the bending test is obtained;

[0011] When the surface detection result meets the bending test success condition, a bending test result is obtained according to the bending test data.

[0012] Preferably, obtaining the test control parameters according to the material parameters of the sample and the target bending angle includes:

[0013] Acquiring material parameters of the sample, wherein the material parameters include dimensional parameters and material properties, the material properties include yield strength, elastic modulus and elongation, and the dimensional parameters include the sample length and sample thickness;

[0014] Obtaining the support roller spacing according to the sample length and a preset spacing coefficient;

[0015] Determining the target displacement and the maximum displacement threshold according to the sample thickness, the target bending angle and the support roller spacing;

[0016] According to the target displacement and the material property, a displacement control curve is obtained, wherein the displacement rate control curve includes the displacement rate at each moment during the bending test;

[0017] The test control parameters are obtained according to the displacement control curve, the support roller spacing, the target displacement and the maximum displacement threshold.

[0018] Preferably, acquiring a displacement control curve according to the target displacement and the material property includes:

[0019] Determine the displacement stage of the bending head according to the material properties and the target displacement, wherein the displacement stage of the bending head includes an initial stage, a stable loading stage and a termination stage in sequence;

[0020] Determining a first displacement rate in the initial stage according to the elastic modulus and the first displacement rate range, wherein the first displacement rate is negatively correlated with the elastic modulus;

[0021] Determining a second displacement rate in the stable loading stage according to the yield strength, the elongation, and the second displacement rate range, wherein the second displacement rate is positively correlated with both the yield strength and the elongation;

[0022] Determining a third displacement rate in the termination stage according to the yield strength and a third displacement rate range, wherein the third displacement rate is negatively correlated with the yield strength;

[0023] acquiring the displacement control curve according to the first displacement rate, the second displacement rate, and the third displacement rate;

[0024] Among them, the lower limit value of the first displacement rate range is smaller than the lower limit value of the third displacement rate range, and the lower limit value of the third displacement rate range is smaller than the lower limit value of the second displacement rate range; the upper limit value of the first displacement rate range is smaller than the upper limit value of the third displacement rate range, and the upper limit value of the third displacement rate range is smaller than the upper limit value of the second displacement rate range.

[0025] Preferably, determining the displacement stage of the bending head according to the material properties and the target displacement comprises:

[0026] Determining a first proportion of the target displacement in the initial stage according to the elastic modulus and a first preset proportion range, wherein the first proportion is positively correlated with the elastic modulus;

[0027] Determining a second proportion of the target displacement in the stable loading stage according to the yield strength, the elongation, and a second preset proportion range, wherein the second proportion is positively correlated with both the yield strength and the elongation;

[0028] Determine, according to the elastic modulus, the yield strength and a third preset proportion range, a third proportion of the target displacement in the stable loading stage, wherein the third proportion is positively correlated with the elastic modulus and negatively correlated with the yield strength;

[0029] The target displacement is divided according to the first proportion, the second proportion and the third proportion to obtain the bending head displacement stage.

[0030] Preferably, acquiring the displacement control curve according to the first displacement rate, the second displacement rate and the third displacement rate includes:

[0031] According to the elastic modulus and the yield strength, respectively obtaining a fourth initial proportion of the first transition stage and a fifth initial proportion of the second transition stage, wherein the first transition stage is between the initial stage and the stable loading stage, the second transition stage is between the stable loading stage and the termination stage, and the elastic modulus and the yield strength are negatively correlated with the fourth initial proportion and the fifth initial proportion;

[0032] According to the elongation rate, adjusting the fourth initial proportion and the fifth initial proportion to obtain a fourth intermediate proportion and a fifth intermediate proportion, wherein the fourth intermediate proportion and the fifth intermediate proportion are positively correlated with the elongation rate;

[0033] Adjusting the fourth intermediate proportion according to a first rate difference between the first displacement rate and the second displacement rate to obtain a fourth proportion;

[0034] The fourth intermediate proportion is adjusted according to a second rate difference between the second displacement rate and the third displacement rate to obtain a fifth proportion;

[0035] According to the first rate difference and the fourth ratio, a displacement rate curve of the first transition stage is obtained by a linear difference method or a curve difference method;

[0036] According to the second rate difference and the fifth ratio, a displacement rate curve of the second transition stage is obtained by a linear difference method or a curve difference method;

[0037] The displacement control curve is generated according to the first displacement rate, the second displacement rate and the third displacement rate in combination with the displacement rate curves of the first transition stage and the second transition stage.

[0038] Preferably, the bending pressurizing assembly is controlled to perform a bending test on the specimen according to the test control parameters, and the displacement value and the load value of the bending press are monitored in real time by the first displacement sensor and the load sensor, and the displacement values ​​of the first support assembly and the second support assembly are obtained by the second displacement sensor and the third displacement sensor, so as to obtain bending test data, including:

[0039] According to the displacement rate control curve, respectively obtaining the displacement rates and corresponding durations of the initial stage, the stable loading stage and the termination stage;

[0040] According to the displacement rate and the preset minimum sampling displacement, respectively obtaining the sampling frequencies of the initial stage, the stable loading stage and the termination stage;

[0041] Determining sampling time points of the initial stage, the stable loading stage and the termination stage respectively according to the sampling frequency and the corresponding duration;

[0042] According to the displacement rate control curve, the vertical drive mechanism is controlled to drive the bending press to pressurize the sample, and according to the sampling time point, the first displacement sensor and the load sensor are controlled to monitor the displacement value and load value of the bending press in real time, and the displacement values ​​of the first support assembly and the second support assembly are obtained through the second displacement sensor and the third displacement sensor to obtain bending test data.

[0043] Preferably, when the bending test data meets the preset test stop condition, the bending pressurizing assembly is controlled to stop and reset after a preset time, and a surface inspection is performed on the sample after the bending test to obtain a surface inspection result, including:

[0044] According to the bending test data, the real-time displacement value of the bending press, the real-time spacing between the first support roll and the second support roll, and the load value at each moment during the bending test are obtained to obtain a load value sequence;

[0045] Obtaining a real-time bending angle of the sample according to the real-time displacement value and the real-time spacing;

[0046] Determining whether the real-time bending angle and the load value sequence meet the preset test stop condition, wherein the preset test stop condition includes a normal stop condition and an emergency stop condition;

[0047] If the normal stop condition is met, the bending and pressing assembly is controlled to stop and reset after a preset time;

[0048] Performing surface inspection on the sample after the bending test to obtain the surface inspection result;

[0049] If the emergency stop condition is met, the bending and pressing assembly is controlled to stop and reset after a preset time;

[0050] Adjusting the test control parameter according to the load value sequence and the real-time displacement value to obtain an adjusted test control parameter;

[0051] According to the adjusted test control parameters, the bending pressurizing assembly is controlled according to the test control parameters to perform a bending test on the sample, and the displacement value and the load value of the bending head are monitored in real time through the first displacement sensor and the load sensor, and the displacement values ​​of the first support assembly and the second support assembly are obtained through the second displacement sensor and the third displacement sensor to obtain bending test data.

[0052] Preferably, the determining whether the real-time bending angle and the load value sequence satisfy the preset test stop condition comprises:

[0053] Obtaining a load change rate sequence according to the difference between the load value at the current moment and the load value at the previous moment in the load value sequence;

[0054] According to the preset time window and the load change rate sequence, obtaining a change rate mean and a change rate variance;

[0055] According to the change rate variance, a dynamic fluctuation threshold is obtained;

[0056] Determining each abnormal fluctuation value in the load change rate sequence according to the dynamic fluctuation threshold, wherein the abnormal fluctuation value is greater than the dynamic fluctuation threshold;

[0057] According to the abnormal fluctuation value, obtaining the abnormal fluctuation frequency and the abnormal fluctuation duration;

[0058] If the frequency of the abnormal fluctuation within the time window is greater than a preset frequency threshold, or the duration of the abnormal fluctuation is greater than a preset duration threshold, then the emergency stop condition is met;

[0059] If the emergency stop condition is not met and the real-time bending angle reaches the target bending angle, the normal stop condition is met.

[0060] Preferably, the adjusting the test control parameter according to the load value sequence and the real-time displacement value to obtain the adjusted test control parameter includes:

[0061] According to the abnormal fluctuation value and the real-time displacement value, the displacement stage of the bending head where the abnormal fluctuation occurs is determined, which is recorded as the stage to be adjusted;

[0062] Acquiring abnormal fluctuation intensity according to the abnormal fluctuation value and the dynamic fluctuation threshold;

[0063] According to the abnormal fluctuation intensity and the preset deceleration coefficient, the displacement rate in the to-be-adjusted stage is adjusted to obtain a target displacement rate;

[0064] According to the abnormal fluctuation intensity and the preset proportion increase coefficient, the proportion of the to-be-adjusted stage in the bending head displacement stage is adjusted to obtain a target proportion;

[0065] The test control parameter is adjusted according to the target proportion and the target displacement rate to obtain an adjusted test control parameter.

[0066] In a second aspect, an embodiment of the present invention further provides a bending testing machine, comprising: at least one processor, at least one memory, and computer program instructions stored in the memory, wherein when the computer program instructions are executed by the processor, the method described in any one of the first aspects is implemented.

[0067] In summary, the beneficial effects of the present invention are as follows:

[0068] The control method and bending tester provided by the embodiments of the present invention accurately obtain the test control parameters according to the material parameters of the sample and the target bending angle, thereby ensuring accurate control during the test and adapting to the needs of different material properties. Different materials and geometric properties of the sample require different test schemes. Control parameters are dynamically generated based on these parameters, so that the test conditions are more in line with actual needs, human intervention is reduced, and test efficiency and accuracy are improved; subsequently, the sample is stably supported during the bending process by adjusting the spacing of the support components to prevent irregular bending of the sample or unnecessary deformation caused by uneven support. The spacing can be adjusted according to samples of different sizes to ensure that each test meets the actual needs of the sample and adapts to the test. Strong stability; by precisely controlling the movement of the bending head, ensuring that the bending test process is carried out according to the set parameters, it helps to ensure the reliability and stability of the test results. Combined with sensors to monitor the displacement value, load value and displacement of the bending head in real time, the test status can be tracked in real time, the test process can be adjusted, and accidents or errors can be avoided; after setting the test stop conditions, the testing machine can automatically detect and stop the test when the conditions are met, without manual intervention, reducing manual operation errors, and the surface inspection results can help determine whether the sample meets the success conditions of the bending test, and further provide a reliable basis for evaluating whether the test meets the standards. By combining the surface inspection results with the bending test data, it can comprehensively evaluate whether the test is successful and ensure the quality of the sample during the test. By accurately calculating the test control parameters, automatically adjusting the support spacing, real-time data collection and analysis, setting the automatic stop conditions, and combining the surface inspection results, the accuracy and reliability of the bending test can be greatly improved, human operation errors can be reduced, and the stability and efficiency of the test process can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] 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.

[0070] Figure 1 A schematic structural diagram of a bending testing machine provided in an embodiment of the present invention.

[0071] Figure 2 The present invention is a flow chart of a control method of a bending testing machine according to an embodiment of the present invention.

[0072] Figure 3 The present invention is another flowchart of a control method for a bending testing machine according to an embodiment of the present invention.

[0073] Figure 4 Schematic diagram of the structure of a bending testing machine according to an embodiment of the present invention.

[0074] Reference numerals:

[0075] 1. Frame; 11. First horizontal driving mechanism; 12. First support roller; 21. Second horizontal driving mechanism; 22. Second support roller; 31. Bending head; 32. Vertical driving mechanism; 4. First displacement sensor. DETAILED DESCRIPTION

[0076] 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.

[0077] 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.

[0078] 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.

[0079] Example 1

[0080] See also Figure 1 The embodiment of the present invention provides a control method for a bending test machine, the bending test machine comprising: a frame 1, a bending pressurizing assembly, a sensor assembly, and a first supporting assembly and a second supporting assembly arranged opposite to each other, wherein the bending pressurizing assembly comprises a bending head 31 and a vertical driving mechanism 32 for driving the bending head to move in a vertical direction, the first supporting assembly comprises a first support roller 12 and a first horizontal driving mechanism 11 for driving the first support roller to move in a horizontal direction, the second supporting assembly comprises a second support roller and a second horizontal driving mechanism 21 for driving the second support roller 22 to move in a horizontal direction, the sensor assembly comprises a first displacement sensor for obtaining a displacement of the bending head, a load value and a load sensor for obtaining a load value of the bending head, a second displacement sensor for obtaining a displacement value of the first support roller, and a third displacement sensor for obtaining a displacement value of the second support roller,

[0081] Specifically, the frame is the main supporting structure of the bending test machine, carrying all other components, providing physical support and stability. It ensures that all components remain in a stable position during work;

[0082] The bending and pressurizing assembly includes a bending press and a vertical drive mechanism. The bending press is responsible for applying direct pressure to bend the specimen. It changes the shape of the specimen by contacting the specimen and using vertical force to ultimately achieve the target bending angle. The vertical drive mechanism controls the vertical movement of the bending press. It can control the bending press to rise or fall to apply a predetermined pressure to bend the specimen. By controlling the displacement and pressure of the bending press, the bending and pressurizing assembly is responsible for providing the necessary load and deformation during the test to simulate the stress in actual use.

[0083] The first support assembly and the second support assembly include a first support roller, a second support roller, and a first horizontal drive mechanism and a second horizontal drive mechanism that drive them respectively. The first support roller and the second support roller are used to support and fix the two ends of the sample. They provide support by contacting the sample to prevent excessive deformation or displacement of the sample during bending. The first horizontal drive mechanism and the second horizontal drive mechanism: These drive mechanisms control the movement of the support rollers in the horizontal direction and adjust the spacing between the support rollers. This can adjust the support distance according to the size and requirements of the sample to ensure the stability of the sample during the bending process. The two support assemblies and the drive mechanism ensure the support effect of the sample during the bending process by adjusting the support spacing to prevent uneven deformation or instability.

[0084] The sensor assembly is responsible for real-time monitoring of key parameters during the test and obtaining test data for feedback control and real-time adjustment of the test process. The first displacement sensor is used to obtain the displacement of the bending head. By measuring the vertical displacement of the bending head, the moving distance of the bending head can be understood. The load sensor is used to obtain the load value of the bending head. It obtains the applied force by measuring the pressure between the bending head and the specimen, thereby calculating the load during the bending process. The second displacement sensor and the third displacement sensor are used to monitor the displacement of the first roller and the second roller respectively. This can help understand the position change of the support assembly during the test and ensure that the support spacing is consistent with the test requirements.

[0085] The control method includes:

[0086] S1. According to the material parameters of the sample and the target bending angle, the test control parameters are obtained, wherein the test control parameters corresponding to the displacement control mode include the support roller spacing, the displacement rate, the target displacement amount, and the maximum displacement threshold;

[0087] Specifically, material parameters refer to the physical and mechanical properties of the specimen, such as yield strength, elastic modulus, elongation, etc., which determine the bending characteristics of the material. The target bending angle is the bending angle that the specimen is expected to achieve during the test, which is usually set according to the material of the specimen and the application scenario. The test control parameters are key factors affecting the bending test process, including the spacing between the support rollers, the displacement rate, the target displacement, and the maximum displacement threshold.

[0088] The purpose of this step is to pre-set appropriate test control parameters according to the material properties of the specimen and the target bending angle. These control parameters will directly affect factors such as pressure, displacement, bending speed, etc. during the test, ensuring the smooth progress of the test process and achieving the expected bending effect. Through the input of material parameters and target bending angle, the test control system can determine the optimal test parameters according to specific calculation models and rules to achieve precise control of different materials and specimens.

[0089] By combining the test control parameters with the material properties and the target bending angle, the test can be customized according to the characteristics of different specimens to ensure the accuracy and consistency of the bending test. By setting the control parameters reasonably, the test can achieve the best bending effect without exceeding the material bearing capacity, thus avoiding excessive bending or damage to the specimen.

[0090] Preferably, see Figure 3 , the test control parameters are obtained according to the material parameters of the sample and the target bending angle, including:

[0091] S11, obtaining material parameters of the sample, wherein the material parameters include dimensional parameters and material properties, the material properties include yield strength, elastic modulus and elongation, and the dimensional parameters include the sample length and sample thickness;

[0092] Specifically, the material properties include yield strength, elastic modulus and elongation. The yield strength material can withstand the maximum stress value before permanent deformation occurs. Yield strength affects the deformation characteristics of the material and is an important basis for designing test parameters. The elastic modulus represents the elastic properties of the material and is used to describe the degree of elastic deformation of the material under stress. Elongation is the deformation capacity of the specimen before it breaks, which is used to evaluate the ductility of the material. Dimensional parameters refer to the physical dimensions of the specimen, including length and thickness, which directly affect the setting of the support roller spacing and the calculation of the displacement. Material properties such as yield strength, elastic modulus, and elongation determine the bending tolerance of the specimen, while dimensional parameters such as length and thickness affect the support and force conditions.

[0093] Obtain the yield strength, elastic modulus and elongation of the specimen through existing material standard data, laboratory tests or data provided by suppliers. Obtain physical dimension data such as length and thickness of the specimen by measurement or from technical specifications.

[0094] S12, obtaining the support roller spacing according to the sample length and a preset spacing coefficient;

[0095] Specifically, preset spacing coefficient: a coefficient set according to the test type and specimen characteristics, used to adjust the support roller spacing. This coefficient is usually based on experience or standard specifications. The purpose of this step is to determine the support roller spacing based on the length of the specimen and the spacing coefficient to ensure that the specimen has a suitable support point distance in the bending test. Reasonable setting of the support roller spacing can ensure the stability of the specimen during the force process. Multiply the length of the specimen by the preset spacing coefficient to obtain the support roller spacing. This value ensures the support effect of the specimen in the test, while avoiding uneven stress distribution of the specimen caused by improper support spacing. By calculating the standardized spacing, the consistency of the same type of specimens during the test is ensured, and the comparability of the test data is improved.

[0096] S13, determining the target displacement and the maximum displacement threshold according to the sample thickness, the target bending angle and the support roller spacing;

[0097] Specifically, the target displacement is the displacement that the specimen needs to reach in the bending test to achieve the target bending angle. The maximum displacement threshold is the maximum displacement allowed for the specimen during the bending process. Exceeding this threshold may cause the specimen to break or be damaged. The purpose of this step is to calculate the target displacement and maximum displacement threshold of the specimen during the bending process based on the thickness of the specimen, the target bending angle, and the spacing between the support rollers to ensure that the specimen does not deform excessively or break during the test. The target displacement directly determines the displacement value that the bending head needs to apply, while the maximum displacement threshold is a protective limit for the safety of the specimen.

[0098] According to the spacing between the support rollers, the thickness of the specimen and the bending angle, the target displacement is determined by the bending mechanics formula (such as the material deflection calculation formula) to ensure that the specimen can reach the target bending angle when the displacement is applied. The maximum displacement threshold of the specimen is calculated based on the material properties (such as yield strength and ductility) to ensure that the specimen does not exceed the safe displacement limit while reaching the target bending angle.

[0099] S14, acquiring a displacement control curve according to the target displacement and the material property, wherein the displacement rate control curve includes the displacement rate at each moment during the bending test;

[0100] Specifically, the displacement control curve describes the displacement rate curve of the press bend at different time points during the bending test to ensure smooth and accurate control of the entire bending process. The displacement rate refers to the displacement of the press bend per unit time, which affects the bending speed and the distribution of force on the specimen. The purpose of this step is to generate a displacement control curve based on the target displacement and material properties, so that the press bend can run smoothly according to the set rate during the bending process, avoiding uneven force or local damage to the specimen caused by excessive rate changes. The generation of the displacement rate control curve takes into account the material properties and target displacement of the specimen to ensure the smoothness and controllability of the entire test process. Based on the target displacement and material properties (such as ductility and yield strength), a curve is generated to control the displacement rate of the press bend. The curve can be linear or nonlinear, depending on the material properties, to ensure the smoothness of the bending process. During the test, the displacement rate of the press bend is adjusted in real time according to the generated displacement control curve to ensure that the rate remains within a reasonable range throughout the test.

[0101] Preferably, acquiring a displacement control curve according to the target displacement and the material property includes:

[0102] S141, determining a bending head displacement stage according to the material properties and the target displacement, wherein the bending head displacement stage includes an initial stage, a stable loading stage and a termination stage in sequence;

[0103] Specifically, during the bending process of the specimen, the displacement of the bending head is divided into different stages, and each stage has a different displacement rate to adapt to the force requirements of the material in different displacement ranges. The initial stage refers to the stage when the bending head begins to work, and usually a lower displacement rate is required to avoid impact; the stable loading stage is the stage where the specimen is mainly deformed, and usually a constant displacement rate needs to be maintained; the termination stage is used to end the specimen when it approaches the target displacement to reduce the risk of overshoot.

[0104] The purpose of this step is to divide the bending head movement into different stages according to the material properties (such as yield strength, elastic modulus) and the target displacement. The division of each stage helps to achieve more refined bending control, ensuring that the material characteristics requirements are met at different stages to better control the stress distribution and deformation during the bending process.

[0105] By analyzing the elastic modulus and yield strength of the material, the displacement process is divided into the initial stage, the stable loading stage and the termination stage according to the target displacement. The initial stage is usually a stage with small displacement and low rate; the stable loading stage is the process of main bending deformation of the specimen; the termination stage is the closing process when the displacement is close to the target value. The displacement rate of each stage is determined according to the material properties and bending requirements to adapt to the stress characteristics of the material at different stages, so as to obtain a better displacement control effect.

[0106] Staged control makes the displacement process more stable and controllable, avoiding the impact or instability of a single displacement rate on the specimen. Staged control of the displacement rate can more accurately approach the target displacement and reduce the bending error caused by too fast or too slow displacement rate.

[0107] Preferably, determining the displacement stage of the bending head according to the material properties and the target displacement comprises:

[0108] S1411, determining a first proportion of the target displacement in the initial stage according to the elastic modulus and a first preset proportion range, wherein the first proportion is positively correlated with the elastic modulus;

[0109] Specifically, the first proportion is the proportion of the target displacement amount in the initial stage during the displacement of the bending head. This proportion determines the displacement amount in the initial stage. The first preset proportion range sets upper and lower limits for the proportion in the initial stage.

[0110] Determine the displacement in the initial stage so that the displacement process of the specimen can start smoothly and avoid stress concentration caused by the rigidity of the material. This step is based on the elastic properties of the material to control the initial loading rate and displacement to ensure that the material is not subjected to excessive impact at the beginning of the test. According to the elastic modulus of the material, a specific first proportion value is selected within the first preset proportion range. The larger the elastic modulus, the larger the proportion in the initial stage, so as to ensure that the material with greater rigidity has sufficient initial loading buffer.

[0111] Setting the proportion in the initial stage ensures that the material is loaded smoothly at the beginning of the bending process, reduces the risk of initial stress concentration, and improves the durability of the specimen and the stability of the bending test.

[0112] S1412, determining a second proportion of the target displacement in the stable loading stage according to the yield strength, the elongation, and a second preset proportion range, wherein the second proportion is positively correlated with both the yield strength and the elongation;

[0113] Specifically, in the stable loading stage, the material has begun to plastically deform, which is suitable for higher displacements and stable loading rates. The purpose of this step is to allocate a reasonable displacement according to the ductility and strength of the material to ensure test efficiency and specimen stability. Select a second proportion value that is suitable for the yield strength and elongation within the second preset proportion range. The higher the yield strength and the greater the elongation of the material, the greater the displacement proportion in the stable loading stage. By selecting a reasonable second proportion, the displacement in the stable loading stage can meet the needs of plastic deformation of the specimen, while reducing unnecessary buffering processes, making the main deformation stage of the bending test smooth and efficient.

[0114] S1413, determining a third proportion of the target displacement in the stable loading stage according to the elastic modulus, the yield strength, and a third preset proportion range, wherein the third proportion is positively correlated with the elastic modulus, and the third proportion is negatively correlated with the yield strength;

[0115] Specifically, the proportion of the termination stage is selected within the third preset proportion range according to the elastic modulus and the yield strength. Materials with high elastic modulus require a larger termination proportion to slow down the loading rate; materials with high yield strength require a smaller termination proportion to avoid overloading the specimen. Ensure that the displacement rate gradually decreases when approaching the target displacement to achieve precise control. This step controls the displacement of the termination stage to ensure a smooth end to the bending process and prevent the material from deforming beyond expectations. Controlling the displacement of the termination stage of the bending test allows the specimen to gradually decelerate when approaching the target displacement, preventing the specimen from being overloaded or overshooting, and improving the accuracy and safety of the test.

[0116] S1414. Divide the target displacement amount according to the first proportion, the second proportion, and the third proportion to obtain the bending head displacement stage.

[0117] Specifically, the target displacement is multiplied by the first, second, and third proportions to obtain the displacement of each stage, and the different rate controls are corresponding to each stage. During the test, different stages are entered according to the displacement progress to adapt to the stress and deformation characteristics of the material.

[0118] S142, determining a first displacement rate in the initial stage according to the elastic modulus and the first displacement rate range, wherein the first displacement rate is negatively correlated with the elastic modulus;

[0119] Specifically, the first displacement rate is the displacement rate in the initial stage, which is used to ensure that the stress of the sample increases slowly when it is initially stressed to avoid impact. The negative correlation between the elastic modulus and the displacement rate is because the higher the elastic modulus, the more difficult it is for the material to deform, so the rate in the initial stage is lower to avoid impact when the sample is just beginning to be stressed. The purpose of this step is to control the stress increase of the sample by a low displacement rate in the initial stage of the test. Especially for materials with a higher elastic modulus, the rate needs to be lower to prevent the impact of sudden loading. This rate control helps to ensure a smooth start of bending and avoid abnormal deformation of the sample due to initial impact. Set the displacement rate in the initial stage according to the elastic modulus of the material. When the elastic modulus is high, the initial rate is correspondingly low to ensure slow loading; when the elastic modulus is low, the initial rate can be appropriately increased to maintain test efficiency.

[0120] S143, determining a second displacement rate in the stable loading stage according to the yield strength, the elongation, and the second displacement rate range, wherein the second displacement rate is positively correlated with both the yield strength and the elongation;

[0121] Specifically, the second displacement rate is the displacement rate in the stable loading stage, which is the loading rate in the main deformation stage and affects the main stress of the specimen. The positive correlation between yield strength and elongation and displacement rate is because the greater the yield strength and elongation, the higher the loading rate that the specimen can withstand, and therefore the higher the second displacement rate.

[0122] The purpose of this step is to select a suitable displacement rate according to the yield strength and elongation of the material during the stable loading stage, so that the specimen is stably stressed and effectively deformed during this stage. Materials with high yield strength and elongation can adapt to higher displacement rates during the stable loading stage, thereby improving the test efficiency. According to the yield strength and elongation of the material, a suitable rate is selected within the second displacement rate range. Materials with high yield strength and high elongation can be stably loaded at a higher displacement rate to fully demonstrate their ability to resist deformation. At this rate, the bending test enters a stable loading stage, ensuring that the rate remains constant during this stage, so as to obtain the main deformation data of the specimen.

[0123] Under the condition of ensuring the stability of the specimen, the loading efficiency is improved and the test time is shortened by using a higher displacement rate. The constant displacement rate makes the specimen more evenly stressed during the deformation process, thus improving the accuracy of the test data.

[0124] S144, determining a third displacement rate in the termination stage according to the yield strength and a third displacement rate range, wherein the third displacement rate is negatively correlated with the yield strength;

[0125] Specifically, the third displacement rate is the displacement rate in the termination stage, which is usually a lower rate to ensure that the target displacement can be accurately reached when the bending is nearly completed. The negative correlation between yield strength and displacement rate is because the higher the yield strength, the lower the displacement rate in the termination stage, to ensure that the specimen will not be excessively deformed or suddenly ruptured when the target displacement is reached. The purpose of this step is to achieve precise control through a lower displacement rate in the termination stage to avoid damage to the specimen in the final stage due to excessive loading. Especially for materials with higher yield strength, a lower rate is required to gradually approach the target displacement. According to the yield strength, the displacement rate in the termination stage is determined. Materials with higher yield strength use a lower rate in the termination stage to ensure that the target displacement is gradually approached without mutation. The deceleration control in the termination stage improves the accuracy of the test and enables the specimen to better maintain force stability when approaching the target displacement.

[0126] S145, acquiring the displacement control curve according to the first displacement rate, the second displacement rate, and the third displacement rate;

[0127] The purpose of this step is to combine the rates of each stage to form a complete displacement control curve, provide accurate displacement control basis for the bending test, and ensure that the test process conforms to the preset force and deformation path. Ensure the continuity and smoothness of the curve, avoid sudden rate changes, and improve the stability of displacement control during the test.

[0128] Among them, the lower limit value of the first displacement rate range is less than the lower limit value of the third displacement rate range, and the lower limit value of the third displacement rate range is less than the lower limit value of the second displacement rate range; the upper limit value of the first displacement rate range is less than the upper limit value of the third displacement rate range, and the upper limit value of the third displacement rate range is less than the upper limit value of the second displacement rate range. The purpose of this description is to ensure that the displacement rate is gradually adjusted as the test stage changes, so as to more reasonably control the deformation process of the specimen. Specifically, by making the initial stage rate the lowest, the stable loading stage rate the highest, and the termination stage rate between the two, the bending test can better adapt to the material characteristics: the initial stage rate is the lowest (first displacement rate range) to load slowly and avoid initial impact. The stable loading stage rate is the highest (second displacement rate range), at this time the specimen deformation is large, suitable for a higher rate. The termination stage rate is between the initial and stable loading (third displacement rate range) so as to decelerate to approach the target displacement and ensure precise control.

[0129] The lower limit of the first displacement rate range < the lower limit of the third displacement rate range < the lower limit of the second displacement rate range. This means: the lower limit of the rate is the lowest in the initial stage; the lower limit of the rate is the highest in the stable loading stage; and the lower limit of the rate is in the middle in the terminal stage. This ensures that the test rate increases gradually from the initial stage to the terminal stage, avoiding a sudden increase in rate. The upper limit of the first displacement rate range < the upper limit of the third displacement rate range < the upper limit of the second displacement rate range. This means: the upper limit of the rate is the lowest in the initial stage; the upper limit of the rate is the highest in the stable loading stage; and the upper limit of the rate is in the middle in the terminal stage. This allows a higher rate to be selected in the stable loading stage, thereby improving efficiency in the main deformation stage of the test, while the rates in the initial and terminal stages are limited, resulting in smooth loading and precise stopping. The rate range setting helps to achieve smooth loading, reduce impact during the bending process, and avoid instability caused by sudden increases or decreases in rate. The optimization of the rate range in each stage balances the test efficiency and accuracy, which can not only speed up the displacement process in the stable loading stage, but also start and stop smoothly in the initial and terminal stages.

[0130] The smooth displacement rate curve reduces the stress concentration caused by rate fluctuations and protects the specimen. The precise rate control makes the entire bending process smoother and helps to obtain stable test data.

[0131] In one embodiment, the step S145 specifically includes:

[0132] S1451. According to the elastic modulus and the yield strength, respectively obtain a fourth initial proportion of the first transition stage and a fifth initial proportion of the second transition stage, wherein the first transition stage is between the initial stage and the stable loading stage, the second transition stage is between the stable loading stage and the termination stage, and the elastic modulus and the yield strength are negatively correlated with the fourth initial proportion and the fifth initial proportion;

[0133] Specifically, the length of the first transition interval between the initial stage and the stable loading stage, and the length of the second transition interval between the stable loading stage and the termination stage are determined according to the elastic modulus and yield strength of the material. The larger the elastic modulus and yield strength, the more resistant the material is to deformation during loading, and therefore it is suitable for a shorter transition interval, so the fourth initial proportion and the fifth initial proportion are negatively correlated with the elastic modulus and yield strength.

[0134] S1452. According to the elongation rate, adjust the fourth initial proportion and the fifth initial proportion to obtain a fourth intermediate proportion and a fifth intermediate proportion, wherein the fourth intermediate proportion and the fifth intermediate proportion are positively correlated with the elongation rate;

[0135] Next, the fourth initial proportion and the fifth initial proportion are adjusted according to the elongation (ε) of the material to obtain the fourth intermediate proportion and the fifth intermediate proportion. Materials with higher elongation can withstand greater deformation during the transition process, so the length of the transition interval can be increased. Through this adjustment, the fourth intermediate proportion and the fifth intermediate proportion are positively correlated with the elongation.

[0136] S1453: adjusting the fourth intermediate proportion according to a first rate difference between the first displacement rate and the second displacement rate to obtain a fourth proportion;

[0137] On the basis of determining the fourth intermediate proportion, the fourth intermediate proportion is further fine-tuned in combination with the difference (first rate difference) between the displacement rate in the initial stage (first displacement rate) and the displacement rate in the stable loading stage (second displacement rate) to obtain the final fourth proportion. A larger rate difference means that a longer transition time is required to avoid stress concentration, so the proportion of the fourth proportion can be appropriately increased; a smaller rate difference will reduce the fourth proportion accordingly.

[0138] S1454, adjusting the fourth intermediate proportion according to a second rate difference between the second displacement rate and the third displacement rate to obtain a fifth proportion;

[0139] Similarly, after determining the fifth intermediate proportion, the fifth intermediate proportion is fine-tuned by considering the difference (second rate difference) between the displacement rate in the stable loading stage (second displacement rate) and the displacement rate in the termination stage (third displacement rate) to obtain the final fifth proportion. The larger the second rate difference, the longer the transition time is required for rate smoothing, and the fifth proportion is appropriately increased; if the second rate difference is small, the fifth proportion can be appropriately shortened.

[0140] S1455. Obtain a displacement rate curve of the first transition stage by a linear difference method or a curve difference method according to the first rate difference and the fourth ratio;

[0141] After determining the proportion of the fourth ratio, a displacement rate curve with a smooth transition is generated between the first displacement rate in the initial stage and the second displacement rate in the stable loading stage using the linear interpolation method or the curve interpolation method. The linear interpolation method is suitable for cases where the rate changes smoothly, while the curve interpolation method can more finely control the gradual change of the rate. An easing function (such as a quadratic function or a cubic Bezier curve) can be used to define the change of the rate to make the rate change smoother.

[0142] S1456. Obtain a displacement rate curve of the second transition stage by a linear difference method or a curve difference method according to the second rate difference and the fifth proportion;

[0143] Similarly, after determining the fifth proportion, a linear or curve difference method is used to generate a smooth transition rate curve between the second displacement rate in the stable loading stage and the third displacement rate in the termination stage, so that the loading process smoothly transitions between different stages and reduces mutations.

[0144] S1457. Generate the displacement control curve according to the first displacement rate, the second displacement rate, and the third displacement rate in combination with the displacement rate curves of the first transition stage and the second transition stage.

[0145] Finally, the displacement rates in the initial stage, stable loading stage and terminal stage are integrated with the smooth rate curves of the first and second transition stages to generate a complete displacement control curve. This curve can provide a continuous change of displacement rate from initial loading to the end of the test, making the entire bending test process smoother and more controllable.

[0146] By introducing a transition interval between the initial, stable loading and termination stages, the displacement rate is smoothly connected between stages, avoiding sudden changes in rate, which helps to reduce stress concentration problems caused by sudden rate changes, thereby reducing local strain and damage risks of the specimen and extending the service life of the test equipment and specimens.

[0147] This embodiment flexibly adjusts the length and rate curve of the transition interval according to material properties (such as elastic modulus, yield strength and elongation), so that the transition interval can better adapt to the deformation behavior of different materials, thereby achieving more accurate test control. This can provide a more consistent loading process when testing different materials, and improve the accuracy and reliability of the test results. While adjusting the loading rate, the influence of the rate difference on the transition interval is considered to ensure that the sample has a buffer zone between large rate changes. For materials with low yield strength and large elongation, this transition scheme can effectively alleviate the impact of large loading rates on the sample, thereby preventing sudden deformation and fracture, and improving the safety and stability of the test. A smooth displacement control curve means that there will be no sudden changes in the experimental data between stages, and the data changes are more coherent and stable. Such a data curve is easier to analyze and process later, which helps to improve the reliability and consistency of the test data. At the same time, through smooth transition, the true mechanical properties of the material in each stage can be better identified, reducing the interference of human factors.

[0148] S15. Obtain test control parameters according to the displacement control curve, the support roller spacing, the target displacement and the maximum displacement threshold.

[0149] The purpose of this step is to summarize all the above parameters to obtain the final test control parameters, which are used to guide the test system to perform precise bending operations on the specimen. Through comprehensive control parameters, comprehensive control of the bending process can be achieved to ensure the smooth progress of the test. Through a series of parameter settings, the bending test can be automatically controlled to reduce errors caused by human intervention. The precise setting of all parameters ensures the accuracy and consistency of the bending test and improves the reliability and reproducibility of the test results.

[0150] S2, placing the sample between the first support roller and the second support roller, and controlling the first horizontal driving mechanism and the second horizontal driving mechanism to move synchronously according to the support roller spacing, so as to adjust the spacing between the first support roller and the second support roller;

[0151] Specifically, the spacing between the first and second support rollers refers to the distance between the first and second support rollers, which supports both ends of the specimen. Adjusting the spacing between the support rollers can ensure that the specimen is properly supported during the bending test. The purpose of this step is to ensure the correct support of the specimen during the bending test by adjusting the spacing between the support rollers, and to avoid uneven bending or misalignment of the specimen due to improper support.

[0152] First, place the specimen between the first and second support rollers to ensure that the specimen is stable and not loose at both ends. According to the test control parameters (support roller spacing) obtained in step S1, adjust the distance between the support components by synchronously controlling the first and second horizontal drive mechanisms to ensure that the support spacing at both ends of the specimen is consistent with the target requirements. By accurately controlling the support roller spacing, the specimen is ensured to be properly supported, avoiding bending errors or unevenness caused by improper support. By adjusting the support roller spacing, the force conditions during the bending process can be optimized according to different specimen sizes and characteristics, ensuring that the specimen remains stable throughout the bending process.

[0153] S3, controlling the bending pressurizing assembly to perform a bending test on the sample according to the test control parameters, and monitoring the displacement value and load value of the bending press in real time through the first displacement sensor and the load sensor, and obtaining the displacement values ​​of the first support assembly and the second support assembly through the second displacement sensor and the third displacement sensor, to obtain bending test data;

[0154] Specifically, the purpose of this step is to control the bending and pressing assembly to perform the bending test according to the test control parameters (such as displacement rate, target displacement, etc.), and monitor the key parameters through sensors to obtain real-time data. The acquisition of real-time data helps to adjust and monitor the test process in real time to ensure the accuracy and reliability of the test data.

[0155] According to the test control parameters obtained in step S1, the movement of the bending press component is precisely controlled. The vertical drive mechanism causes the bending head to apply pressure at a set displacement rate. The displacement value, load value, and displacement change of the bending head and the supporting component are measured in real time using sensors. These data are collected in real time and fed back to the control system for further analysis and adjustment of the test parameters. Through real-time feedback control, key parameters such as pressure and displacement during the test are ensured to be within the specified range, thereby ensuring the accuracy and consistency of the test.

[0156] Preferably, the bending pressurizing assembly is controlled to perform a bending test on the sample according to the test control parameters, and the displacement value and load value of the bending press and the displacement of the support assembly are monitored in real time by the sensor assembly to obtain bending test data, including:

[0157] S31, according to the displacement rate control curve, respectively obtaining the displacement rates and corresponding durations of the initial stage, the stable loading stage and the termination stage;

[0158] Specifically, the duration is the time required to apply displacement in each stage, which is equal to the displacement amount of the stage divided by the displacement rate of the stage. The displacement rate and the corresponding duration of each stage are determined by analyzing the displacement rate control curve.

[0159] S32, acquiring sampling frequencies of the initial stage, the stable loading stage, and the termination stage respectively according to the displacement rate and the preset minimum sampling displacement;

[0160] Specifically, the preset minimum sampling displacement is the displacement increment standard during the sampling process, which determines the size of the sampling frequency. In order to capture the details of the displacement change, this value is usually set small.

[0161] The sampling frequency is calculated by the formula: Sampling frequency = displacement rate / preset minimum sampling displacement

[0162] Determine the sampling frequency for each stage to ensure the accuracy of data collection. This setting ensures that the changes in displacement and load during the test are carefully recorded, improving the reliability and accuracy of the data. Since the displacement rates at different stages are different, the sampling frequencies at each stage are also different to accommodate the loading speeds at each stage. Setting an accurate sampling frequency ensures that the changes in displacement and load are carefully tracked, making the test data more comprehensive and avoiding data omissions or inaccurate records.

[0163] S33, determining sampling time points of the initial stage, the stable loading stage and the termination stage respectively according to the sampling frequency and the corresponding duration;

[0164] Specifically, the sampling time point refers to the specific time of each data collection to ensure the accuracy and consistency of data collection. The sampling time points of each stage are determined by the sampling frequency and the duration of the stage. The interval of the sampling time points is 1 / sampling frequency. Each sampling time point is mapped to the specific time of the stage to ensure that data can be collected in chronological order.

[0165] Accurate sampling time points can ensure the continuity and consistency of data, improve the temporal integrity of test data, and make subsequent analysis more reliable.

[0166] S34, controlling the vertical drive mechanism to drive the bending press to press the sample according to the displacement rate control curve, and controlling the sensor assembly to monitor the displacement value and load value of the bending press and the displacement value of the support assembly in real time according to the sampling time point to obtain bending test data.

[0167] Specifically, the loading process of the bending test machine is controlled, and the displacement and load information of the specimen is accurately obtained at each sampling time point. This step ensures that the loading process conforms to the target curve, and obtains complete test data by monitoring the state changes at the sampling points. The movement speed of the vertical drive mechanism is set according to the displacement rate control curve, and the loading is performed according to the displacement rate at different stages. The displacement value, load value and displacement value of the bending head and the support component are recorded at each sampling time point through the sensor assembly.

[0168] Through real-time control and monitoring, the bending testing machine can accurately reflect the state changes at each stage of the loading process, ensure the integrity and accuracy of data collection, and help to more accurately evaluate the bending properties of the material.

[0169] S4. When the bending test data meets the preset test stop condition, the bending pressurizing assembly is controlled to stop, and the surface detection result of the sample after the bending test is obtained;

[0170] Specifically, the preset test stop condition refers to a set of standards or conditions set according to the test design, which are used to determine whether the test is completed, such as whether the bending angle, load value, etc. meet the predetermined standards. The purpose of this step is to determine whether the preset stop condition is met based on the real-time test data. Once the stop condition is met, the system automatically stops the bending and pressurizing component and starts the surface inspection process to evaluate the surface quality of the sample through visual inspection or other methods. By automatically stopping when the stop condition is met, excessive bending caused by operating errors or system lags is avoided. Surface inspection ensures the bending effect of the sample and prevents cracks or excessive deformation during the bending process.

[0171] Preferably, when the bending test data meets the preset test stop condition, the bending pressurizing assembly is controlled to stop and reset after a preset time, and a surface inspection is performed on the sample after the bending test to obtain a surface inspection result, including:

[0172] S41, according to the bending test data, obtaining the real-time displacement value of the bending head, the real-time spacing between the first support roll and the second support roll, and the load value at each moment during the bending test to obtain a load value sequence;

[0173] Specifically, the real-time displacement value is the displacement value of the bending head collected by the sensor in real time during the test. The real-time spacing is the real-time distance between the first support roller and the second support roller, reflecting the distance change of the support component during the loading process. The load value sequence is a sequence of load values ​​collected at each moment of the bending test, which is used to analyze the load changes during the entire loading process. The collected real-time displacement, support roller spacing and load data can fully reflect the stress state of the bending process, providing a basis for real-time judgment of test conditions and subsequent data analysis.

[0174] S42, obtaining a real-time bending angle of the sample according to the real-time displacement value and the real-time spacing;

[0175] Specifically, the real-time data is used to calculate the real-time bending angle of the sample, which is convenient for real-time monitoring of the bending state of the sample to ensure that the bending angle meets expectations. According to the changes in the real-time displacement value and the spacing between the support rollers, the real-time bending angle of the sample is calculated by a geometric formula. The specific calculation can be divided into a trigonometric solution or a bending radius estimation formula. The real-time data is input into the preset formula to obtain the real-time bending angle. The acquisition of the real-time bending angle provides an angle parameter for the judgment of subsequent test conditions, making the judgment of the test stop conditions more accurate.

[0176] S43, judging whether the real-time bending angle and the load value sequence meet the preset test stop condition, wherein the preset test stop condition includes a normal stop condition and an emergency stop condition;

[0177] Specifically, the normal stop condition refers to the condition under which the equipment can stop normally after the bending test reaches the preset bending angle or load value. The emergency stop condition is the condition under which the system needs to stop the test immediately when an abnormal situation occurs, such as when the load value rises or falls sharply beyond the preset range. Determine whether the test has reached the termination condition based on the real-time monitoring data to ensure that the equipment can be reasonably controlled in both normal and emergency situations. Compare the real-time calculated bending angle and load value sequence with the preset stop conditions to determine whether it meets the normal or emergency stop conditions. By setting normal and emergency stop conditions, the equipment can be prevented from continuing to work when an abnormality occurs, protecting the safety of the specimen and equipment.

[0178] Preferably, the determining whether the real-time bending angle and the load value sequence satisfy the preset test stop condition comprises:

[0179] S431, obtaining a load change rate sequence according to the difference between the load value at the current moment and the load value at the previous moment in the load value sequence;

[0180] Specifically, the load change rate sequence refers to the change of the load value at each moment during the test, which is used to reflect the change of the force of the specimen during the loading process. The rate of change of the load value is calculated to evaluate the fluctuation of the load at different time points, thereby providing basic data for subsequent judgment of whether there is an abnormality. Take the load value at the current moment and the load value at the previous moment in the load value sequence, and calculate the difference between the two: record the calculated load change value at each moment in sequence to form a load change rate sequence.

[0181] The load change rate sequence can reveal whether there is a sudden load change during the loading process of the specimen, thus providing a basis for subsequent anomaly detection.

[0182] S432, obtaining a change rate mean and a change rate variance according to a preset time window and the load change rate sequence;

[0183] Specifically, the preset time window refers to the time period selected when calculating the load change, which is usually a collection of multiple sampling points for statistical analysis. The mean of the rate of change is the average value of the load change rate within the window, which is used to describe the general trend of load fluctuations. The variance of the rate of change reflects the degree of dispersion of the rate of change. The larger the variance, the more drastic the fluctuation. By statistically analyzing the mean and variance of the load change rate, we can understand the overall situation of load changes within the set time window and provide a quantitative standard for judging abnormal fluctuations.

[0184] S433, obtaining a dynamic fluctuation threshold according to the change rate variance;

[0185] Specifically, a dynamic threshold is determined so that it can be used in subsequent steps to determine whether the load change is abnormal and ensure safe operation. The dynamic fluctuation threshold is a value calculated based on the variance of the change rate, which is used to determine whether the load fluctuation exceeds the normal range. The dynamic fluctuation threshold can usually be defined by combining the variance with a constant (such as 2 or 3 times the standard deviation). The dynamic fluctuation threshold provides a flexible standard that can adapt to the load change characteristics under different materials and loading conditions, thereby improving the accuracy of judgment.

[0186] S434, determining each abnormal fluctuation value in the load change rate sequence according to the dynamic fluctuation threshold, wherein the abnormal fluctuation value is greater than the dynamic fluctuation threshold;

[0187] Specifically, it identifies abnormal conditions that occur during load changes, providing a basis for determining whether the test needs to be stopped urgently. The abnormal fluctuation value refers to the value in the load change rate sequence that exceeds the dynamic fluctuation threshold, which usually indicates an abnormal condition during the test. By identifying abnormal fluctuation values, the system can monitor in real time whether there is a dangerous trend in load changes, and then take timely countermeasures to protect equipment and samples.

[0188] S435. Obtaining the abnormal fluctuation frequency and the abnormal fluctuation duration according to the abnormal fluctuation value;

[0189] Specifically, the load change rate sequence is traversed, and the number of abnormal fluctuation values ​​within the preset time window is counted. The abnormal fluctuation frequency is the number of abnormal fluctuation values ​​detected within the set time window. The duration is calculated by recording the start time and end time of the abnormal fluctuation. If abnormal fluctuations occur continuously, the duration will accumulate. The abnormal fluctuation duration is the time period during which abnormal fluctuations occur continuously, reflecting the degree of persistence of the abnormal state. The statistics of frequency and duration can help the system quickly assess the severity of the abnormal situation, which is an important basis for deciding whether to shut down immediately.

[0190] S436: If the frequency of the abnormal fluctuation within the time window is greater than a preset frequency threshold, or the duration of the abnormal fluctuation is greater than a preset duration threshold, then the emergency stop condition is met;

[0191] The statistical abnormal fluctuation frequency is compared with the preset frequency threshold; at the same time, the abnormal fluctuation duration is compared with the duration threshold. If any of the conditions are met, it can be determined that the emergency stop condition is met. This mechanism can detect and respond to potential dangerous situations in a timely manner, ensuring the safety and reliability of the test process.

[0192] S437: If the emergency stop condition is not met and the real-time bending angle reaches the target bending angle, the normal stop condition is met.

[0193] If the emergency stop condition is not met after the previous judgment, then it is judged whether the real-time bending angle reaches the preset target bending angle. If it reaches it, the normal stop condition is met. The determination of the normal stop condition ensures that the test can be completed in a safe and effective state, reducing the risk of material damage and equipment wear.

[0194] S44, if the normal stop condition is met, controlling the bending and pressing assembly to stop and reset after a preset time;

[0195] Specifically, after the test reaches the preset target, the pressure is stopped and the equipment is reset to provide conditions for the next test step. The system's automatic shutdown and reset function ends the loading in time after the test reaches the expected effect, reduces equipment idling, improves test efficiency, and also reduces equipment wear and energy consumption, preparing for quick switching to the next test.

[0196] S45, performing surface inspection on the sample after the bending test to obtain a surface inspection result;

[0197] Specifically, the quality assessment of the sample after the bending test usually includes observing whether there are cracks, creases or other structural defects on the surface to determine whether the performance of the sample meets the design standards. Use high-resolution testing equipment or manual visual inspection to check the surface of the sample and record cracks, peeling or other surface abnormalities after the sample is bent. The test results are input into the system for analysis to determine whether the surface quality of the sample meets the standard requirements.

[0198] S46, if the emergency stop condition is met, controlling the bending and pressing assembly to stop and reset after a preset time;

[0199] During the bending test, if an abnormal situation occurs, the system can respond quickly and stop loading immediately to ensure the safety of the equipment and the specimen. After detecting the emergency stop condition, the control system issues a shutdown command and the bending pressurization component stops working immediately. After the shutdown, the system resets the equipment in a short time to facilitate subsequent operation and inspection. The emergency stop function provides safety protection to avoid damage or accidents caused by abnormal load, ensuring the safety of the specimen and the long life of the equipment.

[0200] S47, adjusting the test control parameter according to the load value sequence and the real-time displacement value to obtain an adjusted test control parameter;

[0201] Specifically, the test control parameters are adjusted based on the data feedback from the previous test so that the loading process and mechanical response can be better controlled in the next test. By analyzing the change trend of the load value sequence and the real-time displacement value, the control parameters such as displacement rate and loading angle are adjusted. The sampling frequency and duration of the initial stage, loading stage, etc. are updated according to the actual situation to make them more consistent with the mechanical properties of the specimen.

[0202] Preferably, the adjusting the test control parameter according to the load value sequence and the real-time displacement value to obtain the adjusted test control parameter includes:

[0203] S471, determining the displacement stage of the bending head at which the abnormal fluctuation occurs according to the abnormal fluctuation value and the real-time displacement value, and recording it as the stage to be adjusted;

[0204] Using the real-time displacement value and the time point of the abnormal fluctuation value, find the displacement of the elbow when the abnormal fluctuation occurs. According to the displacement curve, determine the displacement stage (such as the initial stage, stable loading stage or termination stage) corresponding to the fluctuation. For example, if the abnormal fluctuation occurs in the stable loading stage, this stage will be marked as the stage to be adjusted. Determine the specific displacement stage so that targeted adjustments can be made to the stage to ensure that the test can proceed normally under abnormal conditions. By accurately locating the stage to be adjusted, the adjustment measures can be made more accurate, improving the safety and effectiveness of the test.

[0205] S472, acquiring abnormal fluctuation intensity according to the abnormal fluctuation value and the dynamic fluctuation threshold;

[0206] Specifically, the abnormal fluctuation intensity refers to the degree of relationship between the abnormal fluctuation value and the dynamic fluctuation threshold, reflecting the severity of the abnormal fluctuation. Quantitative analysis of the abnormal fluctuation intensity helps to formulate corresponding adjustment strategies to improve the stability and safety of the test process.

[0207] S473, adjusting the displacement rate in the to-be-adjusted stage according to the abnormal fluctuation intensity and the preset deceleration coefficient to obtain a target displacement rate;

[0208] The abnormal fluctuation intensity is multiplied by the preset deceleration coefficient to obtain a new displacement rate, and the formula is as follows: Target displacement rate = original displacement rate − (abnormal fluctuation intensity × preset deceleration coefficient). Through this formula, the displacement rate of the stage to be adjusted can be dynamically adjusted to adapt to the current abnormal conditions. In the bending test, stress concentration is easy to occur in the material during the stress process. Abnormal fluctuations may mean that some areas of the material are close to their yield limit. By reducing the displacement rate, the load applied to the specimen can be slowed down, the instantaneous stress can be reduced, and the potential risk of damage can be reduced. When abnormal fluctuations occur, the material may have shown some form of plastic deformation or microcrack formation. By slowing down, more time can be provided for the material to adapt to the current stress state and prevent further damage or failure. Speed ​​reduction can make the test process smoother, which is conducive to the real-time monitoring system to collect data, reduce measurement errors caused by rapid changes, and enable the control system to adjust the applied force more effectively.

[0209] S474, adjusting the proportion of the to-be-adjusted stage in the bending head displacement stage according to the abnormal fluctuation intensity and a preset proportion increase coefficient to obtain a target proportion;

[0210] After an abnormal fluctuation occurs, increasing the proportion of the waiting-for-adjustment stage can give the material more time to adapt to the current stress state and help the material return to a more stable state. This can reduce the fatigue accumulation of the material to a certain extent. During abnormal fluctuations, extending the time of the waiting-for-adjustment stage can provide more data points for the monitoring system, making the analysis of material behavior more comprehensive and accurate. This is crucial to understanding the behavior of materials when they are close to failure. In some cases, the response of the material is nonlinear, and rapid changes may make it impossible to accurately capture the true behavior of the material. Increasing the proportion time can alleviate this nonlinear effect and ensure that the test data is more repeatable and reliable. Therefore, this step controls the displacement time of the waiting-for-adjustment stage by adjusting the proportion to ensure that the abnormal fluctuations are fully handled. By adjusting the proportion, effective control of abnormal fluctuations can be achieved to ensure the stability and safety of the material when it is under load.

[0211] S475. Adjust the test control parameter according to the target proportion and the target displacement rate to obtain an adjusted test control parameter.

[0212] By using the calculated target proportion and target displacement rate, the test control parameters are reset. By dynamically adjusting the test control parameters, the entire test process can be more flexible to respond to emergencies and improve the effectiveness and safety of the test. By implementing the strategy of reducing speed and increasing proportion during the abnormal fluctuation stage, the risk of material failure can be effectively reduced and the accuracy and reliability of the test data can be ensured. These measures complement each other and are aimed at handling materials in a more gentle way to ensure the safety and success of the test process.

[0213] S48. According to the adjusted test control parameters, return to control the bending pressurizing assembly according to the test control parameters to perform a bending test on the sample, and monitor the displacement value and load value of the bending head in real time through the first displacement sensor and the load sensor, and obtain the displacement values ​​of the first support assembly and the second support assembly through the second displacement sensor and the third displacement sensor to obtain bending test data.

[0214] The target proportion and target displacement rate obtained by calculation are used to reset the test control parameters, and the test is conducted again according to the adjusted parameters. The control effect of the bending test is further optimized through real-time data feedback.

[0215] S5. When the surface detection result satisfies the bending test success condition, obtaining the bending test result according to the bending test data.

[0216] Specifically, the bending test success conditions are used to determine whether the sample maintains the required quality standards during the bending process, usually including no surface cracks, no fractures, and meeting the target angle. The purpose of this step is to verify the success of the bending test through the surface inspection results and record the data that meets the conditions as the final test results. If the success conditions are met, it means that the test results meet the requirements. The system records the test data and generates a final bending test report, including key data such as angle and load value.

[0217] By determining the success conditions, the reliability and validity of the test results are ensured, and misjudgment due to missing tests or operational errors is avoided. The generated test report can be used as a basis for subsequent research or product testing, with good traceability and reference value.

[0218] Example 2

[0219] In addition, combined Figure 1 The control method of the bending testing machine according to the embodiment of the present invention described above can be implemented by the bending testing machine. Figure 4 A schematic diagram of the hardware structure of a bending testing machine provided in an embodiment of the present invention is shown.

[0220] The bend testing machine may include a processor and a memory storing computer program instructions.

[0221] Specifically, the processor may include a central processing unit (CPU), or an application specific integrated circuit (ASIC), or may be configured to implement one or more integrated circuits of the embodiment of the present invention.

[0222] In one example, the bending test machine may further include a communication interface and a bus. Figure 4 As shown, the processor 401, the memory 402, and the communication interface 403 are connected via a bus 410 and communicate with each other.

[0223] The communication interface is mainly used to implement communication between the modules, devices, units and / or equipment in the embodiments of the present invention.

[0224] The bending test machine may also include a loading mechanism (such as a hydraulic or servo drive system) responsible for applying bending force to the specimen; a sensor system, including a displacement sensor, a load sensor, etc., which collects information such as displacement and load of the specimen during the bending process in real time; and a display and control panel for human-computer interaction. The operator can set experimental parameters (such as target bending angle, loading rate, etc.) through the panel, and view the test status, collected data, and test results in real time. The control panel is usually equipped with a touch screen or buttons for easy operation.

[0225] The independence of each module (such as processor, memory and communication interface) makes the test machine structure easy to expand and upgrade, able to adapt to a variety of experimental needs, and provides good adaptability and scalability for subsequent experimental expansion or different types of experimental designs.

[0226] 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.

[0227] 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.

[0228] 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.

[0229] 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 bending testing machine, characterized in that: The bending test machine comprises: a frame, a bending pressurizing assembly, a sensor assembly, and a first supporting assembly and a second supporting assembly arranged opposite to each other, wherein the bending pressurizing assembly comprises a bending press head and a vertical driving mechanism for driving the bending press head to move in a vertical direction, the first supporting assembly comprises a first support roller and a first horizontal driving mechanism for driving the first support roller to move in a horizontal direction, the second supporting assembly comprises a second support roller and a second horizontal driving mechanism for driving the second support roller to move in a horizontal direction, the sensor assembly comprises a first displacement sensor for obtaining a displacement of the bending press head, a load sensor for obtaining a load value of the bending press head, a second displacement sensor for obtaining a displacement value of the first support roller, and a third displacement sensor for obtaining a displacement value of the second support roller, and the control method comprises: According to the material parameters of the sample and the target bending angle, the test control parameters are obtained, wherein the test control parameters include the spacing between the support rollers, the displacement rate, the target displacement amount, and the maximum displacement threshold; The sample is placed between the first support roller and the second support roller, and according to the support roller spacing, the first horizontal driving mechanism and the second horizontal driving mechanism are controlled to move synchronously to adjust the spacing between the first support roller and the second support roller; Controlling the bending and pressurizing assembly to perform a bending test on the sample according to the test control parameters, and monitoring the displacement value and the load value of the bending head in real time through the first displacement sensor and the load sensor, and obtaining the displacement values ​​of the first support assembly and the second support assembly through the second displacement sensor and the third displacement sensor, to obtain bending test data; When the bending test data meets the preset test stop condition, the bending pressurizing assembly is controlled to stop, and the surface detection result of the sample after the bending test is obtained; When the surface detection result meets the bending test success condition, obtaining the bending test result according to the bending test data; Wherein, obtaining the test control parameters according to the material parameters and the target bending angle of the sample includes: Acquiring material parameters of the sample, wherein the material parameters include dimensional parameters and material properties, the material properties include yield strength, elastic modulus and elongation, and the dimensional parameters include sample length and sample thickness; According to the sample length and the preset spacing coefficient, the support roller spacing is obtained; Determining the target displacement and the maximum displacement threshold according to the sample thickness, the target bending angle and the support roller spacing; According to the target displacement and the material property, a displacement control curve is obtained, wherein the displacement control curve includes a displacement rate at each moment during the bending test; The test control parameters are obtained according to the displacement control curve, the support roller spacing, the target displacement and the maximum displacement threshold.

2. The control method of the bending testing machine according to claim 1, characterized in that: The step of obtaining a displacement control curve according to the target displacement and the material property includes: Determine the displacement stage of the bending head according to the material properties and the target displacement, wherein the displacement stage of the bending head includes an initial stage, a stable loading stage and a termination stage in sequence; Determining a first displacement rate in the initial stage according to the elastic modulus and the first displacement rate range, wherein the first displacement rate is negatively correlated with the elastic modulus; Determining a second displacement rate in the stable loading stage according to the yield strength, the elongation, and the second displacement rate range, wherein the second displacement rate is positively correlated with both the yield strength and the elongation; Determining a third displacement rate in the termination stage according to the yield strength and a third displacement rate range, wherein the third displacement rate is negatively correlated with the yield strength; acquiring the displacement control curve according to the first displacement rate, the second displacement rate, and the third displacement rate; Among them, the lower limit value of the first displacement rate range is smaller than the lower limit value of the third displacement rate range, and the lower limit value of the third displacement rate range is smaller than the lower limit value of the second displacement rate range; the upper limit value of the first displacement rate range is smaller than the upper limit value of the third displacement rate range, and the upper limit value of the third displacement rate range is smaller than the upper limit value of the second displacement rate range.

3. The control method of the bending testing machine according to claim 2, characterized in that: According to the material properties and the target displacement, the displacement stage of the bending head is determined, including: Determining a first proportion of the target displacement in the initial stage according to the elastic modulus and a first preset proportion range, wherein the first proportion is positively correlated with the elastic modulus; Determining a second proportion of the target displacement in the stable loading stage according to the yield strength, the elongation, and a second preset proportion range, wherein the second proportion is positively correlated with both the yield strength and the elongation; Determine, according to the elastic modulus, the yield strength and a third preset proportion range, a third proportion of the target displacement in the stable loading stage, wherein the third proportion is positively correlated with the elastic modulus and negatively correlated with the yield strength; The target displacement is divided according to the first proportion, the second proportion and the third proportion to obtain the bending head displacement stage.

4. The control method of the bending testing machine according to claim 3, characterized in that: The acquiring the displacement control curve according to the first displacement rate, the second displacement rate, and the third displacement rate comprises: According to the elastic modulus and the yield strength, respectively obtaining a fourth initial proportion of the first transition stage and a fifth initial proportion of the second transition stage, wherein the first transition stage is between the initial stage and the stable loading stage, the second transition stage is between the stable loading stage and the termination stage, and the elastic modulus and the yield strength are negatively correlated with the fourth initial proportion and the fifth initial proportion; According to the elongation rate, adjusting the fourth initial proportion and the fifth initial proportion to obtain a fourth intermediate proportion and a fifth intermediate proportion, wherein the fourth intermediate proportion and the fifth intermediate proportion are positively correlated with the elongation rate; Adjusting the fourth intermediate proportion according to a first rate difference between the first displacement rate and the second displacement rate to obtain a fourth proportion; The fourth intermediate proportion is adjusted according to a second rate difference between the second displacement rate and the third displacement rate to obtain a fifth proportion; According to the first rate difference and the fourth ratio, a displacement rate curve of the first transition stage is obtained by a linear difference method or a curve difference method; According to the second rate difference and the fifth ratio, a displacement rate curve of the second transition stage is obtained by a linear difference method or a curve difference method; The displacement control curve is generated according to the first displacement rate, the second displacement rate and the third displacement rate in combination with the displacement rate curves of the first transition stage and the second transition stage.

5. The control method of the bending testing machine according to claim 3, characterized in that: The method controls the bending pressurizing assembly to perform a bending test on the sample according to the test control parameters, monitors the displacement value and load value of the bending press in real time through the first displacement sensor and the load sensor, and obtains the displacement values ​​of the first support assembly and the second support assembly through the second displacement sensor and the third displacement sensor, to obtain bending test data, including: According to the displacement control curve, respectively obtaining the displacement rates and corresponding durations of the initial stage, the stable loading stage and the termination stage; According to the displacement rate and the preset minimum sampling displacement, respectively obtaining the sampling frequencies of the initial stage, the stable loading stage and the termination stage; Determining sampling time points of the initial stage, the stable loading stage and the termination stage respectively according to the sampling frequency and the corresponding duration; According to the displacement control curve, the vertical drive mechanism is controlled to drive the bending press to pressurize the sample, and according to the sampling time point, the first displacement sensor and the load sensor are controlled to monitor the displacement value and load value of the bending press in real time, and the displacement values ​​of the first support assembly and the second support assembly are obtained through the second displacement sensor and the third displacement sensor to obtain bending test data.

6. The control method of the bending testing machine according to any one of claims 2 to 5, characterized in that: When the bending test data meets the preset test stop condition, the bending pressurizing assembly is controlled to stop and reset after a preset time, and a surface inspection is performed on the sample after the bending test to obtain a surface inspection result, including: According to the bending test data, the real-time displacement value of the bending press, the real-time spacing between the first support roll and the second support roll, and the load value at each moment during the bending test are obtained to obtain a load value sequence; Obtaining a real-time bending angle of the sample according to the real-time displacement value and the real-time spacing; Determining whether the real-time bending angle and the load value sequence meet the preset test stop condition, wherein the preset test stop condition includes a normal stop condition and an emergency stop condition; If the normal stop condition is met, the bending and pressing assembly is controlled to stop and reset after a preset time; Performing surface inspection on the sample after the bending test to obtain the surface inspection result; If the emergency stop condition is met, the bending and pressing assembly is controlled to stop and reset after a preset time; Adjusting the test control parameter according to the load value sequence and the real-time displacement value to obtain an adjusted test control parameter; According to the adjusted test control parameters, the bending pressurizing assembly is controlled according to the test control parameters to perform a bending test on the sample, and the displacement value and the load value of the bending head are monitored in real time through the first displacement sensor and the load sensor, and the displacement values ​​of the first support assembly and the second support assembly are obtained through the second displacement sensor and the third displacement sensor to obtain bending test data.

7. The control method of the bending testing machine according to claim 6, characterized in that: The determining whether the real-time bending angle and the load value sequence meet the preset test stop condition includes: Obtaining a load change rate sequence according to the difference between the load value at the current moment and the load value at the previous moment in the load value sequence; According to the preset time window and the load change rate sequence, obtaining a change rate mean and a change rate variance; According to the change rate variance, a dynamic fluctuation threshold is obtained; Determining each abnormal fluctuation value in the load change rate sequence according to the dynamic fluctuation threshold, wherein the abnormal fluctuation value is greater than the dynamic fluctuation threshold; According to the abnormal fluctuation value, obtaining the abnormal fluctuation frequency and the abnormal fluctuation duration; If the frequency of the abnormal fluctuation within the time window is greater than a preset frequency threshold, or the duration of the abnormal fluctuation is greater than a preset duration threshold, then the emergency stop condition is met; If the emergency stop condition is not met and the real-time bending angle reaches the target bending angle, the normal stop condition is met.

8. The control method of the bending testing machine according to claim 7, characterized in that: The step of adjusting the test control parameter according to the load value sequence and the real-time displacement value to obtain the adjusted test control parameter includes: According to the abnormal fluctuation value and the real-time displacement value, the displacement stage of the bending head where the abnormal fluctuation occurs is determined, which is recorded as the stage to be adjusted; Acquiring abnormal fluctuation intensity according to the abnormal fluctuation value and the dynamic fluctuation threshold; According to the abnormal fluctuation intensity and the preset deceleration coefficient, the displacement rate in the to-be-adjusted stage is adjusted to obtain a target displacement rate; According to the abnormal fluctuation intensity and the preset proportion increase coefficient, the proportion of the to-be-adjusted stage in the bending head displacement stage is adjusted to obtain a target proportion; The test control parameter is adjusted according to the target proportion and the target displacement rate to obtain an adjusted test control parameter.

9. A bending test machine, characterized in that: include: At least one processor, at least one memory and computer program instructions stored in the memory, when the computer program instructions are executed by the processor, implement the method according to any one of claims 1 to 8.

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