An equivalent simulation method and device for post-waving buckling deformation of a cold-rolled thin wide strip

Abstract

The application discloses a method and device for simulating the post-waving buckling deformation of a cold-rolled thin wide strip, and comprises the following steps: determining the size of a cold-rolled thin strip sample and the deformation area and size thereof, determining the base plate material and the initial heating final temperature based on the size of the deformation area, determining the size of the base plate, cutting the cold-rolled thin strip sample with good plate shape and drawing an original speckle pattern, performing original speckle quality evaluation, calibrating the original speckle based on the calibration plate after the quality is qualified, heating the base plate and the thin strip sample to the heating final temperature, bonding the connecting surface of the thin strip sample and the base plate through a rolling coating mechanism, observing and recording the data of the bonded thin strip sample through a high-speed camera, and determining the photographing trigger condition according to the temperature interval, and processing the recorded data. The obtained results can be used for the research on the elastic buckling theory and the plate shape control.

Description

Technical Field

[0001] This invention relates to the field of non-contact corrugation detection technology for cold-rolled thin strip, and in particular to an equivalent simulation method and apparatus for post-corrugation buckling deformation of cold-rolled thin strip. Background Technology

[0002] Cold-rolled strip materials possess excellent surface quality and dimensional accuracy. With appropriate heat treatment processes, their mechanical and processing properties can also be guaranteed. Therefore, the demand for cold-rolled thin and even ultra-thin strip materials is increasing in industries such as automotive manufacturing, electrical products, locomotives, aerospace, and precision instruments. However, when the required strip thickness is very small, cold rolling easily leads to various shape problems, such as central waviness, edge waviness, quarter waviness, and localized waviness, which are very common shape defects in cold-rolled thin strip materials.

[0003] To obtain high-quality cold-rolled thin strip materials, various shape control theories, technologies, and equipment have emerged and been applied in production practice, achieving good results. However, as demand places higher requirements on the thickness, output, and quality of cold-rolled thin strips, and as the demands for production efficiency and yield continue to increase to achieve higher profits, shape issues remain a significant obstacle. Therefore, finding a method to simulate and observe the occurrence and development of different shape defects, and then analyzing these defects using relevant theories, will be beneficial to the further development of shape control technology in the cold rolling process.

[0004] Therefore, there is an urgent need for a novel equivalent simulation method and apparatus for the post-buckling deformation of cold-rolled thin and wide strips to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide an equivalent simulation method and apparatus for the buckling deformation of cold-rolled thin and wide strips after corrugation, so as to solve the problems existing in the prior art.

[0006] To achieve the above objectives, the present invention provides the following solution: The present invention provides an equivalent simulation method for the buckling deformation of cold-rolled thin and wide strips after waviness, comprising the following steps:

[0007] S1: Determine the dimensions of the cold-rolled thin strip sample and its deformation area and dimensions, and determine the base plate material and initial heating final temperature based on the deformation area dimensions;

[0008] S2: Determine the dimensions of the base plate;

[0009] S3: Cut a well-shaped cold-rolled thin strip sample and draw the original speckle pattern;

[0010] S4: Perform original speckle quality assessment, and calibrate the original speckle based on the calibration plate after the quality is qualified;

[0011] S5: Heat the base plate and the thin strip sample to the final heating temperature, and use a roller coating mechanism to bond the connecting surface of the thin strip sample to the base plate.

[0012] S6: The thin strip sample bonded in step S5 is observed and data is recorded using a high-speed camera. The triggering conditions for taking pictures are determined according to the temperature interval.

[0013] S7: Process the data recorded in step S6.

[0014] Preferably, the deformation area of ​​the thin strip sample in step S1 is rectangular.

[0015] Preferably, the steps for determining the base plate material and the initial final heating temperature in step S1 are as follows:

[0016] Given a pre-defined deformation region, and under the same temperature change, the ratio of the dimensional change of a thin strip sample to that of a base plate in the large deformation direction within the pre-defined deformation region is:

[0017]

[0018] Δl1—Dimensional change in the large deformation direction of the deformation region of the thin strip sample;

[0019] Δl2—Dimensional change in the large deformation direction of the base plate deformation zone;

[0020] Select a suitable base plate material and a preliminary preset temperature based on the following formula:

[0021]

[0022] L—Initial length of the deformation region in the direction of large deformation;

[0023] α1—Coefficient of thermal expansion of the thin strip sample;

[0024] α2—Coefficient of thermal expansion of the base plate;

[0025] T1 — Initial final heating temperature;

[0026] T2—room temperature;

[0027] Require:

[0028] N1 < N.

[0029] Preferably, the thickness of the base plate in step S2 is 3 to 5 mm.

[0030] Preferably, step S3 involves cutting a well-shaped cold-rolled thin strip sample based on the determined sample size, using one surface of the thin strip as the observation surface and the other surface as the connection surface, and drawing an original speckle pattern on the observation surface of the thin strip sample using black and white spray paint.

[0031] Preferably, the temperature interval for triggering the photo taking in step S6 is obtained by the following formula:

[0032]

[0033] Rounding down the obtained ΔT gives ΔT1, which is used as the temperature interval for triggering the photograph in the experiment.

[0034] Preferably, in step S6, during calibration, the calibration plate is sized to occupy 75-80% of the high-speed camera's field of view. The calibration plate is placed at the sample observation position and rotated slightly in various directions while simultaneously capturing calibration images for calibration.

[0035] Preferably, the final heating temperature is determined based on the initial final heating temperature plus 30 to 50°C.

[0036] Preferably, the formula for calculating the temperature interval for triggering image capture in step S6 is:

[0037]

[0038] Rounding down the obtained ΔT gives ΔT1, which is used as the temperature interval for triggering the photograph in the experiment.

[0039] An equivalent simulation device for the corrugated buckling deformation of cold-rolled thin and wide strip includes a heating box, a roller coating mechanism, a clamping mechanism, a temperature monitoring mechanism, a supplementary light, an image collection unit, and an image processing unit.

[0040] The heating chamber is used to heat the base plate and the thin strip sample to the final heating temperature and maintain the temperature; the roller coating mechanism is used to apply high-temperature resistant adhesive to the edge of the upper heating area; the clamping mechanism is used to constrain the base plate in the observation position; the temperature monitoring mechanism is used to acquire the temperature change of the thin strip sample during the cooling process; the supplementary light is used to provide supplementary lighting for the high-speed camera during the photography process; the image acquisition unit records the wave evolution process of the thin strip sample by taking pictures; and the image processing unit is used to post-process the images acquired by taking pictures to obtain the shape, displacement and strain data of the thin strip sample during the wave evolution process.

[0041] The present invention discloses the following technical effects: The present invention utilizes the difference in the coefficients of thermal expansion between the thin strip sample and the base plate during the cooling process, which causes the deformation to be inconsistent. This allows the base plate to drive the thin strip sample to deform locally at a faster rate through the bonding area, causing the thin strip sample to buckle and recording the deformation evolution process. The results can be used for the study of elastic buckling theory and plate shape control. Attached Figure Description

[0042] 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.

[0043] Figure 1 This is a flowchart of the equivalent simulation method and apparatus for the buckling deformation of cold-rolled thin and wide strips after waviness according to the present invention;

[0044] Figure 2 A schematic diagram simulating the distribution of the deformation zone between the base plate and the thin strip sample and the bonding between the two under different corrugations;

[0045] Figure 3 Layout diagram of the monitoring device for wave-shaped post-buckling deformation;

[0046] Figure 4 This is a schematic diagram of the roller coating mechanism in this invention;

[0047] Figure 5 This is a schematic diagram of the structure of the clamp holding the thin strip sample in this invention;

[0048] Among them, 1. clamp; 2. supplementary light; 3. high-speed camera; 4. infrared non-contact temperature sensor. Detailed Implementation

[0049] 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.

[0050] 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.

[0051] Reference Figure 1-5 This invention provides an equivalent simulation method for the buckling deformation of cold-rolled thin and wide strips after waviness, comprising the following steps:

[0052] S1: Determine the dimensions of the cold-rolled thin strip sample, determine the location and dimensions of the deformation area of ​​the thin strip sample based on the simulated wave shape, and then determine the base plate material and the initial final heating temperature based on the dimensions of the deformation area; determine the dimensions of the cold-rolled thin strip sample to be used, draw a two-dimensional sketch representing the sample according to the determined thin strip dimensions, and determine the location and dimensions of the deformation area of ​​the thin strip sample on the two-dimensional sketch according to the wave shape to be simulated, select a suitable base plate material based on the dimensions of the deformation area, and initially determine the final heating temperature;

[0053] S2: Determine the base plate size. The base plate size is determined based on the size of the thin strip sample. The base plate is then processed based on the location and size of the deformation area of ​​the thin strip sample. The required base plate size is determined according to the size of the thin strip sample. The thin strip sample is pre-positioned and bonded on the base plate in the center. This determines the corresponding position of the deformation area of ​​the thin strip sample on the base plate. The material at the corresponding position on the base plate is removed. Then, the surface of the base plate used to bond the thin strip sample is polished smooth and flat.

[0054] S3: Cut a well-shaped cold-rolled thin strip sample and draw the original speckle pattern. Based on the determined sample size, cut a well-shaped cold-rolled thin strip sample, take one surface of the thin strip as the observation surface and the other surface as the connection surface, and draw the original speckle pattern on the observation surface of the thin strip sample using black and white spray paint. According to the determined sample size, obtain a thin strip sample with a good shape, clean the oil stains on the surface of the thin strip sample with anhydrous ethanol and acetone, select one surface of the thin strip sample as the observation surface and the other surface as the connection surface, and then draw the original speckle pattern on the observation surface using black and white spray paint.

[0055] S4: Perform original speckle quality assessment. The original speckle pattern is assessed using a full-field strain testing system. If the quality is unsatisfactory, it is redrawn. Once the original speckle quality is satisfactory, it is calibrated using a calibration plate. A high-speed camera (3), an infrared non-contact temperature sensor (4), a supplementary light (2), and a control computer are deployed to construct a non-contact full-field strain testing system. The Vic-Snap software is used to inspect the quality of the original speckle pattern on the observation surface of the thin strip sample. If it is unsatisfactory, the original speckle pattern is redrawn. Once the original speckle quality is satisfactory, a calibration plate of suitable size is selected for calibration.

[0056] The high-speed camera 3, the supplementary light 2, and the infrared non-contact temperature sensor 4 are all arranged on the same side. The two high-speed cameras 3 are placed at a certain angle, with their lenses pointing towards the sample location. By adjusting the angle between the cameras, the distance, and parameters such as focal length and lens distortion, the sample is made to fill the entire field of view of the high-speed camera 3 as much as possible. The supplementary light 2 is placed outside the high-speed camera 3 at a larger angle than the two high-speed cameras 3, while the infrared non-contact temperature sensor 4 is placed between the two cameras.

[0057] After determining the internal and external parameters of the high-speed camera 3, place calibration plates of different sizes at the location of the sample, select a calibration plate that occupies 75-80% of the camera's field of view, set the exposure to just overexposure, rotate the calibration plate slightly in all directions, and manually take calibration images at the same time. Take no less than 25 calibration images, and analyze them with software to obtain the calibration score. Here, a value less than 0.03 is considered a successful calibration.

[0058] S5: Place the base plate and the thin strip sample into the heating chamber and heat to the final heating temperature. Then take out the base plate and the thin strip sample. Apply high-temperature resistant adhesive to the surface of the base plate using a roller coating device after the base plate has been polished. Bond the connecting surface of the thin strip sample to the base plate. After completion, place the base plate and the thin strip sample into the heating chamber together and keep them warm for a period of time until the adhesive solidifies.

[0059] S6: The thin strip sample bonded in step S5 is observed and data is recorded by high-speed camera 3. The photo triggering condition is determined according to the temperature interval. The bonded base plate and thin strip sample are taken out and placed on the observation stage based on clamp 1. At the same time, the high-speed camera 3 is used to take pictures to obtain the shape, displacement and strain data of the thin strip sample during the cooling process. The photo triggering condition is determined according to the temperature interval.

[0060] S7: Process the data recorded in step S6. After the temperature reaches room temperature, stop the experiment and transfer all the photos to the Vic-3D system for processing to obtain the full-field strain cloud map of the buckling deformation of the thin strip sample under the deformation drive of the base plate over time.

[0061] Further optimization of the scheme: In step S1, the deformation region of the thin strip sample is rectangular. To simplify the experiment while meeting requirements, the deformation region of the thin strip sample is generally taken as a rectangle. Depending on the wave shape to be simulated, the location and size of the rectangular deformation region are different. For example, to simulate a central wave, an edge wave, or a quarter wave, the deformation region is placed in the middle, edge, or quarter point of the thin strip sample in the width direction, respectively, while it is completely covered in the length direction. To simulate a local wave, a rectangle with limited length and width is used to cover the area where the local wave shape is desired. In addition, for other more complex wave shapes, the position, size, and even shape of the deformation region can be changed for simulation.

[0062] Further optimization of the scheme: the steps for determining the base plate material and the initial final heating temperature in step S1 are as follows:

[0063] Given a pre-defined deformation region, and under the same temperature change, the ratio of the dimensional change of a thin strip sample to that of a base plate in the large deformation direction within the pre-defined deformation region is:

[0064]

[0065] Δl1—Dimensional change in the large deformation direction of the deformation region of the thin strip sample;

[0066] Δl2—Dimensional change in the large deformation direction of the base plate deformation zone;

[0067] Select a suitable base plate material and a preliminary preset temperature based on the following formula:

[0068]

[0069] L—Initial length of the deformation region in the direction of large deformation;

[0070] α1—Coefficient of thermal expansion of the thin strip sample;

[0071] α2—Coefficient of thermal expansion of the base plate;

[0072] T1 — Initial final heating temperature;

[0073] T2—room temperature;

[0074] Require:

[0075] N1 < N.

[0076] To further optimize the scheme, in step S2, the thickness of the base plate is 3-5mm, and the length and width are determined based on the length and width of the thin strip sample plus 30-50mm. The thin strip sample is pre-positioned and bonded in the center on the base plate. Based on the position and size of the deformation area of ​​the thin strip sample, the corresponding area on the base plate is determined. The corresponding area on the base plate is then cut off, and the bonding surface of the base plate is polished smooth and flat.

[0077] The base plate is made of a certain thickness to avoid deformation of the base plate itself in the direction perpendicular to the surface, which would affect the buckling deformation of the thin strip sample. It is also conducive to completing the bonding of the two and the clamping process of the base plate. At the same time, the area on the base plate corresponding to the deformation area of ​​the thin strip sample is cut off to prevent the base plate from restricting the thin strip sample from buckling in the direction of the base plate.

[0078] Further optimize the scheme. The specific steps of step S3 are as follows: based on the determined thin strip sample size, cut a cold-rolled thin strip sample with good plate shape, take one surface of the thin strip as the observation surface and the other surface as the connection surface, and draw the original speckle pattern on the observation surface of the thin strip sample based on black and white spray paint.

[0079] When drawing the original speckle pattern on the observation surface of a thin strip sample, first apply a base coat of white paint to the surface, and then use black spray paint to draw randomly arranged black speckles on the white base. When drawing, pay attention to the fact that black and white each account for about 50%, avoid overlapping of spots of the same color, and increase the irregularity of the spots as much as possible. This is more conducive to obtaining a qualified original speckle pattern.

[0080] To further optimize the scheme, the temperature interval for triggering image capture in step S6 is obtained by the following formula:

[0081]

[0082] Rounding down the obtained ΔT gives ΔT1, which is used as the temperature interval for triggering the photograph in the experiment.

[0083] Further optimize the scheme. In step S6, during calibration, the calibration plate is sized to occupy 75-80% of the field of view of the high-speed camera. The calibration plate is placed at the sample observation position and rotated in a small range in various directions while simultaneously taking calibration images for calibration.

[0084] The scheme was further optimized, and the final heating temperature was determined based on the initial final heating temperature plus 30-50°C.

[0085] The scheme is further optimized, and the calculation formula for the temperature interval that triggers the photo taking in step S6 is as follows:

[0086]

[0087] Rounding down the obtained ΔT gives ΔT1, which is used as the temperature interval for triggering the photograph in the experiment.

[0088] An equivalent simulation device for the corrugated buckling deformation of cold-rolled thin and wide strip includes a heating box, a roller coating mechanism, a clamping mechanism, a temperature monitoring mechanism, a supplementary light 2, an image collection unit, and an image processing unit;

[0089] The heating chamber and the roller coating device are separate modules with no specific positional requirements between them and other parts. The clamping mechanism, temperature monitoring mechanism (infrared non-contact temperature sensor 4), supplementary lighting 2, and the high-speed camera in the image acquisition unit are arranged as follows: Figure 3 The positions shown are arranged as follows: the clamping mechanism is placed on the observation platform, and with the clamping mechanism as the center, the two high-speed cameras and two supplementary lights 2 are placed symmetrically at a certain angle towards the clamping device, with the angle between the two supplementary lights 2 being larger. The infrared non-contact temperature sensor 4 is placed opposite the clamping mechanism, in the same row as the high-speed cameras and supplementary lights 2. The control computer is then placed behind the high-speed cameras, connecting them to the infrared non-contact temperature sensor 4. It receives signals from the high-speed cameras and the infrared non-contact temperature sensor 4 and performs control. The image processing unit is the image processing module of the Vic-Snap software in the control computer.

[0090] The heating chamber is used to heat the base plate and the thin strip sample to the final heating temperature and maintain the temperature; the roller coating mechanism is used to apply high-temperature resistant adhesive to the edge of the upper heating area; the clamping mechanism is used to constrain the base plate (and the thin strip sample bonded to it) in the observation position; the temperature monitoring mechanism is used to acquire the temperature change of the thin strip sample during the cooling process; the supplementary light 2 is used to provide supplementary lighting for the high-speed camera 3 during the photography process; the image acquisition unit records the wave evolution process of the thin strip sample by taking pictures; the image processing unit is used to post-process the images acquired by the pictures to obtain the shape, displacement and strain data of the thin strip sample during the wave evolution process.

[0091] This invention involves obtaining a desired thin strip sample and a base plate. The thin strip sample is then subjected to original speckle mapping, monitoring, and calibration. The base plate is cut and polished. After heating, the two are bonded together and kept at a constant temperature. During the cooling process, because the thermal expansion coefficient of the base plate is greater than that of the thin strip sample, the size of the base plate decreases at a faster rate. This, combined with the bonding process, drives the local area of ​​the thin strip sample to deform at a faster rate, ultimately causing the thin strip sample to buckle. Simultaneously, a full-field strain testing system is used to record the occurrence and development of waviness defects on the thin strip sample. The results can be used for research on elastic buckling theory and plate shape control technology.

[0092] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0093] 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. An equivalent simulation method for the buckling deformation of cold-rolled thin and wide strips after waviness, characterized in that... This includes the following steps: S1: Determine the dimensions of the cold-rolled thin strip sample and its deformation area and dimensions, and determine the base plate material and initial heating final temperature based on the deformation area dimensions; S2: Determine the dimensions of the base plate. The dimensions of the base plate are determined based on the dimensions of the thin strip sample, and the base plate is processed based on the location and dimensions of the deformation area of ​​the thin strip sample. S3: Cut a well-shaped cold-rolled thin strip sample and draw the original speckle pattern; S4: Perform original speckle quality assessment, and calibrate the original speckle based on the calibration plate after the quality is qualified; S5: Heat the base plate and the thin strip sample to the final heating temperature, and use a roller coating mechanism to bond the connecting surface of the thin strip sample to the base plate. S6: The thin strip sample bonded in step S5 is observed and the data is recorded by a high-speed camera (3). The triggering condition for taking pictures is determined according to the temperature interval. S7: Process the data recorded in step S6. After the temperature reaches room temperature, stop the experiment and transfer all the photos to the Vic-3D system for processing to obtain the full-field strain cloud map of the buckling deformation of the thin strip sample under the deformation drive of the base plate over time. The steps for determining the base plate material and the initial final heating temperature in step S1 are as follows: Given a pre-defined deformation region, and under the same temperature change, the ratio of the dimensional change of a thin strip sample to that of a base plate in the large deformation direction within the pre-defined deformation region is: ； —Dimensional change in the large deformation direction of the deformation region of the thin strip sample; —Dimensional change in the large deformation direction of the base plate deformation zone; Select a suitable base plate material and a preliminary preset temperature based on the following formula: ； —Initial length of the large deformation direction in the deformation region; —Coefficient of thermal expansion of the thin strip sample; —Coefficient of thermal expansion of the base plate; —Initially determine the final heating temperature; —room temperature; Require: ； The specific steps of step S3 are as follows: based on the determined thin strip sample size, cut a cold-rolled thin strip sample with good plate shape, take one surface of the thin strip as the observation surface and the other surface as the connection surface, and draw the original speckle pattern on the observation surface of the thin strip sample based on black and white spray paint.

2. The equivalent simulation method for the buckling deformation after waviness of cold-rolled thin and wide strips according to claim 1, characterized in that: In step S1, the deformation area of ​​the thin strip sample is rectangular.

3. The equivalent simulation method for buckling deformation after wavy deformation of cold-rolled thin and wide strips according to claim 1, characterized in that: The thickness of the base plate mentioned in step S2 is 3-5 mm.

4. The equivalent simulation method for the buckling deformation after waviness of cold-rolled thin and wide strips according to claim 1, characterized in that: The temperature interval for triggering the photo in step S6 is obtained by the following formula: Where T1 is the initial heating final temperature, and T2 is the room temperature, for the obtained Round down to the nearest integer. , The temperature interval used to trigger photography in the experiment.

5. The equivalent simulation method for the buckling deformation after waviness of cold-rolled thin and wide strips according to claim 1, characterized in that: In step S6, during calibration, the size of the calibration plate occupies 75-80% of the field of view of the high-speed camera (3). The calibration plate is placed at the sample observation position and rotated in a small range in various directions while taking calibration images for calibration.

6. The equivalent simulation method for the buckling deformation after waviness of cold-rolled thin and wide strips according to claim 1, characterized in that: The final heating temperature is determined by adding 30 to 50°C to the initial final heating temperature.

7. An equivalent simulation device for the post-buckling deformation of cold-rolled thin and wide strips after corrugation, based on the equivalent simulation method for the post-buckling deformation of cold-rolled thin and wide strips after corrugation as described in any one of claims 1-6, characterized in that: It includes a heating box, a roller coating mechanism, a clamping mechanism, a temperature monitoring mechanism, a supplementary light (2), an image collection unit, and an image processing unit; The heating chamber is used to heat the base plate and thin strip sample to the final heating temperature and maintain the temperature; the roller coating mechanism is used to apply high-temperature resistant adhesive. The clamping mechanism is used to constrain the base plate at the observation position; the temperature monitoring mechanism is used to obtain the temperature change of the thin strip sample during the cooling process; the supplementary light (2) is used to supplement the light for the high-speed camera (3) during the photography process; the image collection unit records the wave evolution process of the thin strip sample by taking pictures; the image processing unit is used to post-process the images obtained by taking pictures to obtain the shape, displacement and strain data of the wave evolution process of the thin strip sample.

Images