Test method and system for simulating wave mode of equivalent stress field of cold-rolled thin strip

Abstract

The present application relates to the test method and system of the effect stress field simulation wave shape mode of cold-rolled thin strip, the method comprises the following steps: obtaining the cold-rolled thin strip sample, treating the cold-rolled thin strip sample to form the original speckle, detecting and calibrating the original speckle, and obtaining the test result by heating the local heating area to simulate the wave shape evolution process.The present application simulates the residual stress and wave shape evolution process of the cold-rolled thin strip by using thermal stress and records, which is convenient for the research of elastic buckling theory and strip shape control technology.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of non-contact detection of wave shape of cold-rolled thin strip, and particularly relates to a test method and system for simulating wave shape mode of equivalent stress field of cold-rolled thin strip. BACKGROUND

[0002] Cold-rolled thin strip is widely used in the fields of automobile manufacturing, mechanical manufacturing, household appliances, electronic instruments, building and aviation due to its excellent performance, and with the rapid development of various industries, higher requirements are put forward for the quantity and quality of the cold-rolled thin strip. In order to meet these needs, researchers in the relevant field have made outstanding contributions in production process, production equipment and the like. It is found that the strip shape is one of the factors that cannot be ignored in restricting the yield and quality of the cold-rolled thin strip. On the one hand, the strip shape is an important quality index of the strip product; on the other hand, the strip shape also has an impact on the subsequent process of the strip, thereby affecting the product quality and yield.

[0003] In order to obtain cold-rolled thin strip products with good strip shape, it is necessary to study the mechanism of the occurrence of product strip shape defects. It can be known from relevant literatures that there are many factors affecting the strip shape, such as elastic deflection of the roll, thermal deformation of the roll, strip shape at the inlet, elastic flattening between the work roll and the rolled piece and the like. However, it can be known through analysis that the essence of these factors is to cause uneven plastic deformation of the thin strip product, residual stress in the strip, and different strip shape defects under the action of residual stress with different distributions. Therefore, it is an effective method to study the theory of strip shape defects by directly exploring the corresponding relationship between different residual stress distribution forms in the thin strip product and various strip shape defects without considering the specific forms of different external influences. SUMMARY

[0004] The purpose of the present application is to provide a test method and system for simulating wave shape mode of equivalent stress field of cold-rolled thin strip. Residual stress is generated by heating to simulate the evolution process of strip shape defects, and data such as temperature, strain and displacement field are tested to obtain the evolution process and geometric characteristic parameters of the wave shape, thereby facilitating the research of elastic buckling theory and strip shape control technology.

[0005] In order to achieve the above-mentioned purpose, the present application provides the following solutions.

[0006] The test method for simulating wave shape mode of equivalent stress field of cold-rolled thin strip comprises the following steps:

[0007] A cold-rolled thin strip sample is obtained, and the cold-rolled thin strip sample is treated to form a local heating area;

[0008] The local heating area is heated to obtain simulation wave shape mode parameters, and the evolution process of the wave shape is simulated based on the simulation wave shape mode parameters to obtain a test result.

[0009] Preferably, the process of forming the locally heated region in the cold-rolled thin strip sample includes:

[0010] The surface of the cold-rolled thin strip sample is cleaned and the heated surface is polished. The observation surface and the heated surface of the cold-rolled thin strip sample are selected. A heated area is planned on the heated surface of the cold-rolled thin strip sample and the heated area is sprayed to form a local heated area.

[0011] Preferably, forming the localized heating area further includes:

[0012] The observation surface of the cold-rolled thin strip sample is sprayed to cover the surface gloss, and different colors of paint are sprayed on top of the paint layer to create irregular scattered spots, forming the original scattered spots.

[0013] Different wave-shaped defects are simulated by varying the heating zones.

[0014] Preferably, different wavy defects are simulated by varying the heating zone, including:

[0015] Heating the entire first preset width and rolling direction of the heating surface simulates a central wave; heating the entire second preset width and rolling direction of the heating surface simulates an edge wave; heating the entire third preset width and rolling direction of the heating surface simulates a quarter wave; heating the area of ​​the heating surface within the preset width and rolling direction simulates a local wave.

[0016] Preferably, the heating process includes, before heating the localized heating area:

[0017] The quality of the original speckle was evaluated using the Vic-3D full-field strain testing system. The original speckle that passed the quality test was calibrated using a calibration plate to determine the conversion relationship between the physical size of the original speckle and pixels.

[0018] Preferably, obtaining simulated wave-shaped modal parameters by heating the locally heated area includes:

[0019] The cold-rolled thin strip sample is placed on an observation platform, and the locally heated area is heated. The temperature field data of the locally heated area is tested. The locally heated area is photographed according to the set photographing trigger and cutoff conditions to obtain the shape, displacement and strain data of the cold-rolled thin strip sample. The temperature field data and the shape, displacement and strain data of the cold-rolled thin strip sample are compared and analyzed to obtain the simulated wave mode parameters.

[0020] The simulated wave modal parameters include the temperature range in which deformation occurs and the temperature range in which buckling instability occurs.

[0021] Preferably, taking a picture of the locally heated area by setting the picture-taking trigger condition and the cutoff condition includes:

[0022] Based on temperature signal triggering, when the temperature of the local heating area is lower than the left value of the temperature range where deformation occurs, a photo is triggered at intervals of the first temperature interval; when the temperature of the local heating area is higher than the left value of the temperature range where deformation occurs, a photo is triggered at intervals of the second temperature interval; when the temperature of the local heating area is higher than the left value of the temperature range where buckling instability occurs, a photo is triggered at intervals of the third temperature interval; when the local heating area reaches a preset value, the photo triggering stops.

[0023] Preferably, simulating the wave pattern evolution process to obtain the test results includes:

[0024] Based on the temperature range where deformation occurs and the temperature range where buckling instability occurs, a photo-taking trigger condition and a cutoff condition are set. By setting the photo-taking trigger condition and the cutoff condition, the cold-rolled thin strip sample is photographed. The photograph of the cold-rolled thin strip sample is imported into the Vic-3D full-field strain testing system for data processing. The test results are obtained under the action of residual stress simulated by local heating.

[0025] The test results include the entire evolution process and geometric characteristic parameters of the wavy defect, as well as the shape, displacement, and strain data of the cold-rolled thin strip sample.

[0026] To achieve the above objectives, the present invention provides a testing system for simulating the wave-shaped modes of the equivalent force field of cold-rolled thin strip, comprising:

[0027] Clamping device, infrared emitting device, temperature monitoring device, image capturing device, supplementary lighting device, and image processing device;

[0028] The clamping device is used to position the thin strip sample at the observation position;

[0029] The infrared emitting device is used to heat the thin strip sample;

[0030] The temperature monitoring device is used to record the temperature field data of the thin strip sample during the heating process, and to transmit the temperature signal.

[0031] The image capturing device is used to record the wave-like evolution process of the thin strip sample during the heating process;

[0032] The supplementary lighting device is used to compensate for lighting during the shooting process;

[0033] The image processing device is used to post-process the photographs captured by the image capture unit to obtain the geometric characteristic parameters, shape, displacement and strain data of the thin strip sample during the wave evolution process.

[0034] The beneficial effects of this invention are as follows:

[0035] This invention simulates the evolution of sheet shape defects by sampling and cleaning a well-shaped cold-rolled thin strip, creating irregular speckles on the surface, spraying a high-temperature black matte paint to form a localized heating zone, clamping the strip sample, evaluating and calibrating the speckle quality of the sample surface, and generating residual stress through heating. At the same time, it tests data such as temperature, strain, and displacement field to obtain the evolution process of the wave-shaped morphology and geometric characteristic parameters, which facilitates the research on elastic buckling theory and strip shape control technology. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 This is a flowchart of a test method for simulating the wave-shaped mode of the equivalent stress field of cold-rolled thin strip according to an embodiment of the present invention;

[0038] Figure 2 This is a schematic diagram of the heating area simulating several basic wave shapes in an embodiment of the present invention;

[0039] in, Figure 2 (a) represents the middle wave. Figure 2 (b) refers to the edge wave. Figure 2 (c) represents a quarter wave. Figure 2 (d) represents a local wave;

[0040] Figure 3 Two-view diagrams of the heating surface and observation surface of the thin strip sample after generating the original speckle pattern and the black matte heating area in an embodiment of the present invention.

[0041] in, Figure 3 (a) is the observation surface. Figure 3 (b) is the heating surface;

[0042] Figure 4 This is a structural diagram of a test system for simulating the wave-shaped mode of equivalent force field of cold-rolled thin strip according to an embodiment of the present invention;

[0043] Figure 5 This is a schematic diagram of the strip clamp structure according to an embodiment of the present invention. Detailed Implementation

[0044] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0045] Test methods for simulating wave-shaped modes in the equivalent stress field of cold-rolled thin strip include:

[0046] Obtain a cold-rolled thin strip sample, and process the cold-rolled thin strip sample to form a localized heating area;

[0047] By heating the local heating area, simulated wave mode parameters are obtained. Based on the simulated wave mode parameters, the wave evolution process is simulated to obtain test results.

[0048] Further, the cold-rolled thin strip sample is processed to form the localized heating region, including:

[0049] The surface of the cold-rolled thin strip sample is cleaned and the heated surface is polished. The observation surface and the heated surface of the cold-rolled thin strip sample are selected. A heated area is planned on the heated surface of the cold-rolled thin strip sample and the heated area is sprayed to form a local heated area.

[0050] Furthermore, forming the localized heating region also includes:

[0051] The observation surface of the cold-rolled thin strip sample is sprayed to cover the surface gloss, and different colors of paint are sprayed on top of the paint layer to create irregular scattered spots, forming the original scattered spots.

[0052] Different wave-shaped defects are simulated by varying the heating zones.

[0053] Furthermore, by varying the heating zones, different wavy defects can be simulated, including:

[0054] Heating the entire first preset width and rolling direction of the heating surface simulates a central wave; heating the entire second preset width and rolling direction of the heating surface simulates an edge wave; heating the entire third preset width and rolling direction of the heating surface simulates a quarter wave; heating the area of ​​the heating surface within the preset width and rolling direction simulates a local wave.

[0055] Further, before heating the locally heated area, the following steps are included:

[0056] The quality of the original speckle was evaluated using the Vic-3D full-field strain testing system. The original speckle that passed the quality test was calibrated using a calibration plate to determine the conversion relationship between the physical size of the original speckle and pixels.

[0057] Furthermore, obtaining simulated wave-shaped modal parameters by heating the locally heated area includes:

[0058] The cold-rolled thin strip sample is placed on an observation platform, and the locally heated area is heated. The temperature field data of the locally heated area is tested. The locally heated area is photographed according to the set photographing trigger and cutoff conditions to obtain the shape, displacement and strain data of the cold-rolled thin strip sample. The temperature field data and the shape, displacement and strain data of the cold-rolled thin strip sample are compared and analyzed to obtain the simulated wave mode parameters.

[0059] The simulated wave modal parameters include the temperature range in which deformation occurs and the temperature range in which buckling instability occurs.

[0060] Furthermore, taking pictures of the locally heated area by setting the picture-taking trigger conditions and the cutoff conditions includes:

[0061] Based on temperature signal triggering, when the temperature of the local heating area is lower than the left value of the temperature range where deformation occurs, a photo is triggered at intervals of the first temperature interval; when the temperature of the local heating area is higher than the left value of the temperature range where deformation occurs, a photo is triggered at intervals of the second temperature interval; when the temperature of the local heating area is higher than the left value of the temperature range where buckling instability occurs, a photo is triggered at intervals of the third temperature interval; when the local heating area reaches a preset value, the photo triggering stops.

[0062] Furthermore, by simulating the wave pattern evolution process, the test results obtained include:

[0063] Based on the temperature range where deformation occurs and the temperature range where buckling instability occurs, a photo-taking trigger condition and a cutoff condition are set. By setting the photo-taking trigger condition and the cutoff condition, the cold-rolled thin strip sample is photographed. The photograph of the cold-rolled thin strip sample is imported into the Vic-3D full-field strain testing system for data processing. The test results are obtained under the action of residual stress simulated by local heating.

[0064] The test results include the entire evolution process and geometric characteristic parameters of the wavy defect, as well as the shape, displacement, and strain data of the cold-rolled thin strip sample.

[0065] To achieve the above objectives, the present invention provides a testing system for simulating the wave-shaped modes of the equivalent force field of cold-rolled thin strip, comprising:

[0066] Clamping device, infrared emitting device, temperature monitoring device, image capturing device, supplementary lighting device, and image processing device;

[0067] The clamping device is used to position the thin strip sample at the observation position;

[0068] The infrared emitting device is used to heat the thin strip sample;

[0069] The temperature monitoring device is used to record the temperature field data of the thin strip sample during the heating process, and to transmit the temperature signal.

[0070] The image capturing device is used to record the wave-like evolution process of the thin strip sample during the heating process;

[0071] The supplementary lighting device is used to compensate for lighting during the shooting process;

[0072] The image processing device is used to post-process the photographs captured by the image capture unit to obtain the geometric characteristic parameters, shape, displacement and strain data of the thin strip sample during the wave evolution process.

[0073] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0074] like Figures 1-5 As shown, this embodiment provides a test method and apparatus for simulating the wave-shaped mode of the equivalent stress field of cold-rolled thin strip, including:

[0075] Step 1: Select two well-shaped samples from the cold-rolled thin strip obtained through rolling, ensuring both samples have the same geometric parameters. Clean the surface oil using anhydrous ethanol and acetone. Polish the heated surfaces of both thin strip samples. Select a specific surface of the thin strip sample as the observation surface, such as... Figure 3 As described in (a), the other surface is a heating surface, such as Figure 3 (b) as stated;

[0076] Step Two: A localized heating area is formed on the heating surface of the thin strip sample using high-temperature matte black spray paint, and the original speckle pattern is formed on the observation surface of the thin strip sample using black and white spray paint. Specifically:

[0077] On the observation surfaces of the two thin strip samples, white matte spray paint was first used to spray the entire surface of the sample to cover the metallic luster of the observation surfaces. Then, irregular black speckles were made on the black and white spray paint layers to obtain the original speckle pattern.

[0078] Step 3: Based on the wave shape to be simulated, plan the heating area on the heating surface of the thin strip sample, and then spray the planned heating area with black matte paint.

[0079] Step 4: Install the high-speed camera and supplementary lighting to assemble the Vic-3D full-field strain testing system. Simultaneously, install the infrared emitter and non-contact temperature measurement device, and connect the temperature signal to the Vic-3D full-field strain testing system. Figure 4 The above;

[0080] Step 5: Evaluate the original speckle quality of the two thin strip samples using the Vic-3D full-field strain testing system. After the original speckle quality meets the requirements, calibrate the original speckle of the two thin strip samples based on the calibration plate. Specifically:

[0081] The thin strip sample is placed on the observation stage using a clamping device. The software module is opened to evaluate the quality of the original speckle on the observation surface of the two thin strip samples. If the speckle is not up to standard, the speckle is remade. If the speckle quality is up to standard, a calibration plate of appropriate size is selected, and then the original speckle of the sample is calibrated using the selected calibration plate.

[0082] The calibration of the original speckle refers to the calibration work performed by selecting a calibration plate of appropriate size and placing it in the corresponding position based on the size of the speckle area drawn on the thin strip and the position of the thin strip on the observation platform during shooting. The main purpose of calibration is to correct the distortion of the lens itself and to determine the relationship between the three-dimensional geometric position of a point on the surface of a spatial object and its corresponding point in the image (i.e., to determine the conversion relationship between physical size and pixels).

[0083] Here, physical dimensions refer to the size of an object described in units of length (such as millimeters). This establishes a conversion relationship between pixels and length units; that is, after capturing an image, one pixel on the image corresponds to a few millimeters of actual length. This allows for the capture of the deformation process of the thin strip in subsequent experiments, obtaining information about the strip's deformation through the captured images.

[0084] Step Six: Take a thin strip sample for preliminary experiments to obtain the temperature range in which deformation occurs and the temperature at which buckling occurs and a significant shape change occurs. Specifically:

[0085] A thin strip sample was selected for the preliminary experiment. The sample was placed on the observation stage using a clamping device. The speckle image mode was selected in the software, the time interval for triggering the photo was set, and the photo start button was clicked. At the same time, the infrared emitting device and the temperature monitoring device were turned on. When the sample buckled and became unstable, and a significant change in shape occurred, the infrared emitting device and the temperature monitoring device were turned off and the photo was stopped.

[0086] Step 7: Process the measured temperature and strain field data to obtain the temperature range in which the sample deforms and the temperature range in which buckling instability occurs. Based on this, reset the high-speed camera's photo triggering and cutoff conditions.

[0087] Step 8: Replace with the second thin strip sample, click the "Start Photo" button, and simultaneously turn on the infrared heating emitter and temperature monitoring device. Photo taking will stop once the cutoff condition is triggered, and then the infrared emitter and temperature monitoring device will be turned off. Specifically:

[0088] After the preliminary experiment was completed, the second thin strip sample was placed on the observation stage using the clamping device, and the photo triggering and cutoff conditions were set according to the temperature.

[0089] The thin strip sample is heated in a pre-set heating area using an infrared emitting device;

[0090] After heating begins, the temperature field data of the thin strip sample is measured using an infrared camera, and the shape, displacement, and strain data of the thin strip sample are acquired using a high-speed camera.

[0091] Once the non-contact temperature measuring device (infrared camera, non-contact temperature sensor) detects that the temperature has reached the preset temperature, it stops heating and simultaneously shuts down the high-speed camera and the non-contact temperature measuring device.

[0092] Step 9: Save the experimental records, post-process the photographs to obtain the entire evolution process and geometric characteristic parameters of the wavy defects generated by the cold-rolled thin strip with good sheet shape under the action of residual stress simulated by local heating. At the same time, the shape, displacement and strain data of the thin strip sample in three-dimensional space are also extracted.

[0093] Furthermore, there are various ways to create the original speckle pattern, such as spray painting or hand-drawing with markers. To obtain a qualified speckle pattern, the black and white spots should each occupy 50% of the sample observation surface, and the overlapping distribution of spots of the same color should be avoided. At the same time, gently shaking the paint bottle to increase the irregularity of the spots is beneficial for image processing software to recognize the speckle image features.

[0094] Furthermore, the process of forming a localized heating area on the heating surface of the thin strip sample based on high-temperature matte black spray paint and forming the original speckle pattern on the observation surface of the thin strip sample based on black and white spray paint includes:

[0095] Clean the surface oil stains of the thin strip sample;

[0096] Polish the heated surface of the thin strip sample;

[0097] Based on the wave-shaped defect to be simulated, a heating area is planned on the heating surface of the thin strip sample;

[0098] A localized heating area is formed on the heating surface of the thin strip sample based on high-temperature matte black spray paint.

[0099] The entire observation surface of the thin strip sample is coated with white paint to cover the surface gloss, and irregular black speckles are created on the white paint layer with black paint to obtain the original speckle pattern.

[0100] Furthermore, different heating areas on the heating surface of the thin strip sample can simulate different wavy defects. For example, selecting the middle of the width direction and the entire rolling direction of the heating surface of the thin strip sample as the heating area can simulate medium wavy defects. Figure 2 (a) Selecting the edge of the heating surface of the thin strip sample in the width direction and the entire area in the rolling direction as the heating region can simulate edge waves, such as... Figure 2 (b); Selecting a quarter-width section of the heating surface of the thin strip sample, with the entire rolling direction as the heating area, can simulate a quarter wave, such as... Figure 2 (c) Selecting a small area formed by the finite dimensions of the heating surface width and rolling direction of the thin strip sample as the heating region can simulate local waves, such as... Figure 2 (d) etc.;

[0101] When simulating the various wave shapes described above, the width of the heating zone is generally taken as 20% to 25% of the width of the cold-rolled thin strip. Especially when simulating local waves, the length of the heating zone is taken as 2 to 3 times its width. Overall, the heating zone is heated and deformed. This deformation is limited by the overall material properties, generating residual compressive stress to inhibit its deformation. Under the action of this residual stress, the heating zone produces a wave shape.

[0102] Furthermore, there are various ways to create the original speckle pattern, such as spray painting or hand-drawing with markers. To obtain a qualified speckle pattern, the black and white spots should each occupy 50% of the sample observation surface, and the overlapping distribution of spots of the same color should be avoided. At the same time, gently shaking the paint bottle to increase the irregularity of the spots is beneficial for image processing software to recognize the speckle image features.

[0103] Furthermore, while preserving the deformation allowance of the sample, the sample should fill the entire field of view of the high-speed camera as much as possible. This can be achieved by adjusting the internal parameters (image ratio, focal length, lens distortion, etc.) and external parameters (angle and distance between cameras) of the camera before the experiment begins. The supplementary light should not be placed in the middle of the camera. It is recommended that the supplementary light be placed at an angle, and the angle of the light should be greater than the angle between the cameras.

[0104] Furthermore, a calibration plate that occupies 75-80% of the camera's field of view is generally selected for calibration. During calibration, it is recommended to adjust the exposure to just overexposed levels. Hold the calibration plate in the sample clamping position and twist it slightly in different directions. Observe the recognition of the calibration plate in the high-speed camera's field of view and take photos manually as needed. Take no less than 25 sets of photos to ensure the reliability of the results. Analyze the results, and the software will generate a calibration score. The smaller the value, the better. Here, a value less than 0.03 is considered a successful calibration.

[0105] Furthermore, the preliminary experiment includes the following steps:

[0106] The first thin strip sample is placed on the observation stage using the clamping device;

[0107] The thin strip sample is heated in a pre-set heating area using an infrared emitting device;

[0108] While heating, the temperature field data of the thin strip sample is tested using a non-contact temperature measurement device (infrared camera, non-contact temperature sensor), and the shape, displacement and strain data of the thin strip sample are obtained by taking pictures at the same time interval using a high-speed camera.

[0109] When the thin strip sample undergoes buckling deformation, i.e., when a significant abrupt change in shape occurs, the experiment should be manually stopped.

[0110] By comparing and analyzing the data acquired by the temperature measuring device and the high-speed camera, the temperature range in which the thin strip sample deforms and the temperature range in which buckling instability occurs can be obtained.

[0111] Furthermore, the preset temperature value is the right value of the temperature range where buckling occurs plus 20 to 30°C.

[0112] Furthermore, in the formal experiment, the high-speed camera triggers photography based on the temperature signal. When the temperature is lower than the left value of the temperature range, it triggers once every 5 to 10°C; when the temperature is higher than the left value of the temperature range, it triggers once every 3 to 5°C; when the temperature is higher than the left value of the temperature range where buckling instability occurs, it triggers once every 1 to 3°C; after the temperature reaches the preset value, the triggering of photography stops. The specific temperature interval is set based on the requirement that no less than 25 sets of photos are taken.

[0113] The temperature ranges are related as follows: the left value of the temperature range where deformation occurs is less than the left value of the temperature range where buckling instability occurs. Therefore, when the temperature of the locally heated area is lower than the left value of the temperature range where deformation occurs, a photo is triggered at intervals of the first temperature range. When the temperature of the locally heated area is higher than the left value of the temperature range where deformation occurs, a photo is triggered at intervals of the second temperature range. When the temperature of the locally heated area is higher than the left value of the temperature range where buckling instability occurs, a photo is triggered at intervals of the third temperature range. Once the locally heated area reaches a preset value, the photo triggering stops.

[0114] Furthermore, since the thin strip sample has initial defects, buckling instability changes from an instantaneous instability deformation without warning to a process of deformation development and evolution. Therefore, on the one hand, considering that the initial defects of the two thin strip samples are not completely consistent, and on the other hand, considering that the instantaneous large deformation of buckling instability becomes insignificant during the deformation development process, it is difficult to obtain a definite buckling temperature value. Therefore, a temperature range is determined based on the preliminary experimental results to estimate the buckling temperature.

[0115] Furthermore, the buckling deformation temperature range is selected to increase the imaging density in the temperature range where deformation changes rapidly with temperature, so as to better describe the deformation. If the instantaneous large deformation caused by buckling instability of the thin strip sample is not visible in the preliminary experiment, then there is no need to increase the imaging density, and only the deformation temperature range needs to be selected.

[0116] Furthermore, all the photos taken during the experiment were imported into the Vic-3D system for data processing to obtain a full-field strain cloud map showing the change of the wave-like shape of the thin strip sample over time under the residual stress simulated by local heating.

[0117] like Figures 4-5 As shown, the testing device for simulating the wave-shaped mode of the equivalent stress field of cold-rolled thin strip in this embodiment includes a clamping device, an infrared emitting device, a temperature monitoring device, an image capturing unit, a supplementary lighting device, and an image processing module.

[0118] The device includes a clamping device for positioning the thin strip sample at the observation position; an infrared emitting device for heating the thin strip sample; a temperature monitoring device for recording the temperature field data of the thin strip sample during heating and transmitting the temperature signal; an image capturing unit for recording the wavy evolution process of the thin strip sample; a supplementary lighting device for providing illumination compensation during the wavy evolution process of the thin strip sample; and an image processing module for acquiring the geometric characteristic parameters, shape, displacement, and strain data of the thin strip sample during the wavy evolution process.

[0119] Furthermore, the clamping device should not restrict the deformation of the cold-rolled strip sample caused by heating in the main deformation direction of the strip.

[0120] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A test method for simulating the wave-shaped mode of equivalent stress field in cold-rolled thin strip, characterized in that, include: Obtain a cold-rolled thin strip sample, and process the cold-rolled thin strip sample to form a localized heating area; The process of forming the locally heated region by processing the cold-rolled thin strip sample includes: The surface of the cold-rolled thin strip sample is cleaned and the heated surface is polished. The observation surface and the heated surface of the cold-rolled thin strip sample are selected. A heated area is planned on the heated surface of the cold-rolled thin strip sample and the heated area is sprayed to form a local heated area. The formation of the localized heating area also includes: The observation surface of the cold-rolled thin strip sample is sprayed to cover the surface gloss, and different colors of paint are sprayed on top of the paint layer to create irregular scattered spots, forming the original scattered spots. Different wave-shaped defects are simulated by varying the heating zones. By varying the heating zones, different wavy defects can be simulated, including: Heating the entire first preset width and rolling direction of the heating surface simulates a central wave; heating the entire second preset width and rolling direction of the heating surface simulates an edge wave; heating the entire third preset width and rolling direction of the heating surface simulates a quarter wave; heating the area of ​​the heating surface within the preset width and rolling direction simulates a local wave. By heating the local heating area, simulated wave mode parameters are obtained. Based on the simulated wave mode parameters, the wave evolution process is simulated to obtain test results.

2. The test method for simulating the wave-shaped mode of the equivalent stress field of cold-rolled thin strip according to claim 1, characterized in that, Before heating the localized heating area, the following steps are included: The quality of the original speckle was evaluated using the Vic-3D full-field strain testing system. The original speckle that passed the quality test was calibrated using a calibration plate to determine the conversion relationship between the physical size of the original speckle and pixels.

3. The test method for simulating the wave-shaped mode of the equivalent stress field of cold-rolled thin strip according to claim 1, characterized in that, The simulated wave modal parameters are obtained by heating the localized heating region, including: The cold-rolled thin strip sample is placed on an observation platform, and the locally heated area is heated. The temperature field data of the locally heated area is tested. The locally heated area is photographed according to the set photographing trigger and cutoff conditions to obtain the shape, displacement and strain data of the cold-rolled thin strip sample. The temperature field data and the shape, displacement and strain data of the cold-rolled thin strip sample are compared and analyzed to obtain the simulated wave mode parameters. The simulated wave modal parameters include the temperature range in which deformation occurs and the temperature range in which buckling instability occurs.

4. The test method for simulating the wave-shaped mode of the equivalent stress field of cold-rolled thin strip according to claim 3, characterized in that, Taking pictures of the locally heated area by setting the picture-taking trigger conditions and the cutoff conditions includes: Based on temperature signal triggering, when the temperature of the local heating area is lower than the left value of the temperature range where deformation occurs, a photo is triggered at intervals of the first temperature interval; when the temperature of the local heating area is higher than the left value of the temperature range where deformation occurs, a photo is triggered at intervals of the second temperature interval; when the temperature of the local heating area is higher than the left value of the temperature range where buckling instability occurs, a photo is triggered at intervals of the third temperature interval; when the local heating area reaches a preset value, the photo triggering stops.

5. The test method for simulating the wave-shaped mode of the equivalent stress field of cold-rolled thin strip according to claim 3, characterized in that, The test results obtained by simulating the wave pattern evolution process include: Based on the temperature range where deformation occurs and the temperature range where buckling instability occurs, a photo-taking trigger condition and a cutoff condition are set. By setting the photo-taking trigger condition and the cutoff condition, the cold-rolled thin strip sample is photographed. The photograph of the cold-rolled thin strip sample is imported into the Vic-3D full-field strain testing system for data processing. The test results are obtained under the action of residual stress simulated by local heating. The test results include the entire evolution process and geometric characteristic parameters of the wavy defect, as well as the shape, displacement, and strain data of the cold-rolled thin strip sample.

6. A system for testing the equivalent stress field simulation wave-shaped mode of cold-rolled thin strip as described in any one of claims 1-5, characterized in that, include: Clamping device, infrared emitting device, temperature monitoring device, image capturing device, supplementary lighting device, and image processing device; The clamping device is used to position the thin strip sample at the observation position; The infrared emitting device is used to heat the thin strip sample; The temperature monitoring device is used to record the temperature field data of the thin strip sample during the heating process, and to transmit the temperature signal. The image capturing device is used to record the wave-like evolution process of the thin strip sample during the heating process; The supplementary lighting device is used to compensate for lighting during the shooting process; The image processing device is used to post-process the photographs captured by the image capturing device to obtain the geometric characteristic parameters, shape, displacement and strain data of the thin strip sample during the wave evolution process.

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