A device and method for actively controlling lateral pressure of anti-buckling

Abstract

The present invention relates to the technical field of basic tests on the plastic forming properties of metal materials, and provides an anti-buckling lateral pressure active control device and method. The device includes a bracket, a cylinder, a cylinder mounting plate, a first pressure supply component, a sample clamping component, and a second pressure supply component; the cylinder mounting plate is reciprocatingly mounted on the bracket; one end of the cylinder is connected to the cylinder mounting plate; the other end of the cylinder is connected to the first pressure supply component; the first pressure supply component and the second pressure supply component are relatively arranged at the two ends of the cylinder mounting plate; the sample clamping component is movably arranged between the first pressure supply component and the second pressure supply component. 1. The anti-buckling lateral pressure active control device of the present invention can improve the accuracy of test results and facilitate strain measurement, and is easy to reflect the changing law of thin plate forming performance under cyclic tension and compression loading paths.

Description

Technical Field

[0001] The invention relates to the technical field of basic test of plastic forming performance of metal materials, and in particular to an anti-buckling lateral pressure active control device and method. Background Art

[0002] During the sheet metal forming process, the sheet metal usually undergoes a complex deformation loading path. For example, during the stamping process, when the sheet metal undergoes drawbead and die radius operations, it will experience a loading-unloading-reverse loading-reloading process. Its deformation characteristics cannot be characterized only by the deformation characteristics under unidirectional tension. The use of tension-compression cyclic loading can well characterize the deformation characteristics of the material under a complex loading path.

[0003] For tension-compression cycle loading test, when the thin plate is in a state of compression deformation, the specimen will buckle and bend. Therefore, an additional anti-buckling device is needed to suppress the occurrence of buckling on the thin plate specimen, such as the anti-buckling device disclosed in CN112557176A and CN113418806A. The lateral pressure generated by the existing anti-buckling device will cause additional lateral pressure and friction on the thin plate specimen. At the same time, during the tension-compression cycle loading of the thin plate specimen, the thinning and thickening of the specimen will cause the size of the lateral pressure applied by the anti-buckling device to change, causing errors in the test results. Summary of the invention

[0004] In view of this, the present invention provides an anti-buckling lateral pressure active control device and method to solve the problem of inaccurate test measurement results in the prior art.

[0005] The present invention provides an anti-buckling lateral pressure active control device, comprising a bracket, a cylinder, a cylinder mounting plate, a first pressure providing component, a sample clamping component, and a second pressure providing component;

[0006] The cylinder mounting plate is mounted on the bracket in a reciprocating manner;

[0007] One end of the cylinder is connected to the cylinder mounting plate;

[0008] The other end of the cylinder is connected to the first pressure providing assembly;

[0009] The first pressure providing assembly and the second pressure providing assembly are arranged at two ends of the cylinder mounting plate in a relative manner;

[0010] The sample clamping assembly is detachably disposed between the first pressure providing assembly and the second pressure providing assembly.

[0011] Furthermore, guide pillars are provided on the outer sides of both ends of the cylinder mounting plate.

[0012] Furthermore, a bearing is provided; a through hole is provided on the bracket, and the bearing sleeve is arranged on the guide column and passes through the through hole together with the guide column.

[0013] Furthermore, a follower translation assembly is also provided; the follower translation assembly is arranged on the cylinder mounting plate.

[0014] Furthermore, the first pressure providing assembly is also connected to the follower translation assembly.

[0015] Furthermore, the bracket includes a first clamping plate and a second clamping plate; the first clamping plate includes a first side plate, a bottom plate and a second side plate, the bottom plate connects the first side plate and the second side plate, and the first side plate and the second side plate are arranged in parallel.

[0016] Furthermore, the cylinder mounting plate comprises a first support plate, an intermediate plate and a second support plate; the first support plate and the second support plate are arranged in parallel, and the intermediate plate is connected between the first support plate and the second support plate of the cylinder mounting plate.

[0017] Furthermore, the follow-up translation assembly includes a guide rail and a slider, and the slider is slidably arranged on the guide rail.

[0018] Furthermore, it also includes a first pressure roller connecting plate; one end of the first pressure roller connecting plate is connected to the side of the first side pressure providing component toward the follow-up translation component, and the other end of the first pressure roller connecting plate is connected to the side of the follow-up translation component toward the first side pressure providing component.

[0019] The present invention also provides a method for using the above-mentioned anti-buckling lateral pressure active control device, comprising the following steps:

[0020] S1. Calculate the required lateral pressure according to the strength of the sample; place the sample in the sample clamping assembly;

[0021] S2. Fix the bracket to the single-pulling machine; clamp the sample with the upper and lower clamps of the single-pulling machine;

[0022] S3, setting a target lateral pressure for the cylinder controller, and the cylinder applies pressure according to the control of the cylinder controller to obtain a constant lateral pressure, so that the first pressure providing component and the second pressure providing component jointly press the sample, so that the sample does not buckle and become unstable;

[0023] S4, applying tension and compression cyclic loading deformation trajectory to the specimen through the upper clamp and the lower clamp;

[0024] S5. Obtain the deformation-force curve of the sample under the deformation trajectory of tension-compression cyclic loading, process the obtained deformation-force curve into a stress-strain curve by solid mechanics method, and analyze the flow behavior of the sample under tension-compression cyclic loading.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. The anti-buckling lateral pressure active control device of the present invention can provide a constant and stable lateral pressure during the thin plate tension and compression cycle loading test, thereby improving the accuracy of the test results;

[0027] 2. The anti-buckling lateral pressure active control device of the present invention can quantitatively control the force applied, facilitate strain measurement, and reflect the changing law of the sheet metal forming performance under the cyclic tension and compression loading path;

[0028] 3. The anti-buckling lateral pressure active control device of the present invention can reduce the additional lateral pressure and friction generated, thereby improving the accuracy of the measurement data. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0030] Figure 1 It is a structural schematic diagram of the anti-buckling lateral pressure active control device provided by the present invention;

[0031] Figure 2 is a front view of the anti-buckling lateral pressure active control device provided by the present invention;

[0032] Figure 3 is a top view of the anti-buckling lateral pressure active control device provided by the present invention;

[0033] Figure 4 It is a schematic diagram of the cylinder structure of the anti-buckling lateral pressure active control device provided by the present invention;

[0034] Figure 5 It is a schematic diagram of a first clamping plate of the anti-buckling lateral pressure active control device provided by the present invention;

[0035] Figure 6 It is a schematic diagram of a cylinder mounting plate of the anti-buckling lateral pressure active control device provided by the present invention;

[0036] Figure 7 It is a cross-sectional view of a cylinder mounting plate of the anti-buckling lateral pressure active control device provided by the present invention;

[0037] Figure 8 It is a schematic diagram of a first pressure roller of the anti-buckling lateral pressure active control device provided by the present invention;

[0038] Fig. 9It is a schematic diagram of a first pressure plate of the anti-buckling lateral pressure active control device provided by the present invention;

[0039] Fig.10 is a schematic diagram of a test specimen of the anti-buckling lateral pressure active control device provided by the present invention;

[0040] Fig.11 The active control device of the present invention is used to measure the deformation-force curve of the sample under the tension-compression cycle loading path;

[0041] Fig.12 The active control device of the present invention is used to measure the stress-strain curve of the sample under the tension-compression cycle loading path.

[0042] Figure markings: 1-first clamping plate, 2-cylinder, 3-cylinder mounting plate, 4-guide column, 5-first pressure roller, 6-guide rail, 7-sample, 8-slider, 9-first pressure roller connecting plate, 10-second pressure plate, 11-second pressure roller, 12-second pressure roller connecting plate, 13-second clamping plate, 14-first pressure plate, 15-pin, 16-second lubricating paper, 17-first lubricating paper, 18-bearing, 19-bolt. DETAILED DESCRIPTION

[0043] An anti-buckling lateral pressure active control device according to the present invention will be described in detail below with reference to the accompanying drawings.

[0044] like Figure 1-9 As shown, a specific embodiment of the present invention discloses an anti-buckling lateral pressure active control device, comprising a bracket, a cylinder 2, a cylinder mounting plate 3, a follower translation assembly, a first pressure providing assembly, a sample clamping assembly and a second pressure providing assembly. Preferably, the cylinder 2 is a telescopic cylinder.

[0045] Optionally, the cylinder mounting plate 3 includes a first support plate, an intermediate plate and a second support plate; the first support plate and the second support plate are arranged in parallel, and the intermediate plate of the cylinder mounting plate 3 is connected between the first support plate and the second support plate of the cylinder mounting plate 3 to form a U-shaped frame structure.

[0046] Optionally, the cylinder mounting plate 3 is driven by the cylinder 2 to be reciprocatingly slidably arranged inside the bracket; the cylinder 2, the follower translation assembly and the second pressure providing assembly are respectively arranged on the first support plate, the middle plate and the second support plate of the cylinder mounting plate 3; a plurality of guide pillars are arranged on the first support plate and the second support plate of the cylinder mounting plate 3, preferably, 2 guide pillars are arranged on the first support plate and the second support plate; the first pressure providing assembly is respectively connected to the follower translation assembly and the end of the cylinder 2; the sample clamping assembly is slidably arranged up and down between the first pressure providing assembly and the second pressure providing assembly; preferably, the cylinder 2 and the cylinder mounting plate 3 are connected by bolts 19.

[0047] By providing the first pressure providing component and the second pressure providing component with predetermined pressures of the same magnitude and opposite directions through the cylinder 2, thin plate buckling phenomenon can be prevented in the tensile and compressive cyclic loading test of the sample 7, and the curve of the change of the lateral pressure magnitude with time in the experiment can be obtained through the detection element set on the cylinder 2.

[0048] See also Figure 3-7 The bracket includes a first card plate 1 and a second card plate 13. The first card plate 1 includes two parallel first side plates, a bottom plate and a second side plate. The bottom plate connects the first side plate and the second side plate to form a U-shaped frame structure. A plurality of through holes for guide columns to pass through are arranged in parallel on the upper parts of the first side plate and the second side plate.

[0049] Optionally, a bearing 18 is also provided, and the bearing 18 is sleeved on the guide column and passes through the through hole together with the guide column, so that the cylinder mounting plate 3 can slide along the axis of the through hole through the bearing 18, providing automatic balance for the side pressures on the opposite sides of the sample 7. Preferably, the bearing 18 is a linear bearing; a special-shaped slot hole is opened on the bottom plate for installing the second clamping plate 13 and clamping the clamp under the single pulling machine together with the second clamping plate 13, so as to provide a support point for the anti-buckling lateral pressure active control device.

[0050] During use, when the sample 7 is in a tensioned or compressed state, the sample will become slightly thinner or thicker. In order to keep the lateral pressure balanced, the cylinder's push rod will extend or retract to keep the lateral pressure balanced. At this time, the cylinder mounting plate 3 will passively slide along the axial direction of the through hole toward the first side plate or the second side plate, thereby ensuring that the sample 7 is always in an axial position unchanged throughout the entire tension and compression cycle loading test, thereby avoiding the occurrence of sample buckling and improving the accuracy of the test structure.

[0051] Further, see Appendix Figure 1 The follower translation assembly includes a guide rail 6 and a slider 8, which are connected by a dovetail groove structure; the guide rail 6 is horizontally arranged on the middle plate of the cylinder mounting plate 3, and preferably, the guide rail 6 is parallel to and at the same height as the first pressure providing assembly.

[0052] See also Figure 8 The first pressure providing assembly includes a first pressure roller 5 and a first pressure roller connecting plate 9; a plurality of parallel pressure rollers that can rotate around respective axes are provided on the side of the first pressure roller 5 facing the second side pressure providing assembly; one end of the first pressure roller connecting plate 9 is connected to the side of the middle plate of the first pressure roller 5 facing the cylinder mounting plate 3, and the other end of the first pressure roller connecting plate 9 is connected to the side of the slider 8 of the follow-up translation assembly facing the first pressure roller 5, which can avoid shaking when the first pressure roller 5 moves, so that the force on the left and right sides of the sample 7 is uneven.

[0053] Fig. 9The sample clamping assembly includes a first pressing plate 14, a first lubricating paper 17, a second lubricating paper 16 and a second pressing plate 10. The first lubricating paper 17 and the second lubricating paper 16 are used to separate the sample 7 from the first pressing plate 14 and the second pressing plate 10 respectively; the sample clamping assembly can be slidably arranged between the first pressure providing assembly and the second pressure providing assembly. Preferably, the material of the first lubricating paper 17 and the second lubricating paper 16 is polytetrachloroethylene.

[0054] Optionally, the first pressing plate 14 and the second pressing plate 10 have the same structure, including a pressing plate body and connecting parts arranged at the four corner ends of the pressing plate body, each connecting part is provided with a mounting hole for the connecting bolt to pass through; when in use, the pins 15 are inserted into the mounting holes of the first pressing plate 14 and the second pressing plate 10 and fixed, and the sample 7 is clamped between the first lubricating paper 17 and the second lubricating paper 16. During the tension-compression cycle loading test, the sample 7 is clamped in the sample clamping assembly, and as the test proceeds, the sample 7 is stretched or compressed, and the sample 7 is slidably arranged between the first pressing plate 14 and the second pressing plate 10 through the first lubricating paper 17 and the second lubricating paper 16, so as to reduce the sliding friction generated between the sample 7 and the first pressing plate 14 and the second pressing plate 10 during the test.

[0055] Optionally, the second pressure providing assembly includes a second pressure roller 11 and a second pressure roller connecting plate 12; a plurality of parallelly arranged pressure rollers capable of rotating around respective axes are provided on the side of the second pressure roller 11 facing the first pressure providing assembly; the second pressure roller 11 is connected to the second side plate of the cylinder mounting plate 3 via the second pressure roller connecting plate 12.

[0056] Through the design of the present invention, the lateral pressure on both sides of the thin plate under the tension and compression loading path can be kept constant during the tension and compression cyclic loading test of the thin plate, and the sample 7 does not produce buckling instability, so the mechanical behavior under tension and compression cyclic loading conditions can be accurately measured.

[0057] The present invention also discloses an anti-buckling lateral pressure active control method, which is used to implement the aforementioned anti-buckling lateral pressure active control device, and comprises the following steps:

[0058] S1. Calculate the lateral pressure according to the strength of the sample 7; place the sample 7 between the first lubricating paper 17 and the second lubricating paper 16, the first lubricating paper 17 and the second lubricating paper 16 are placed between the first pressing plate 14 and the second pressing plate 10, and connect the first pressing plate 14 and the second pressing plate 10 in sequence with the pin 15, so that the sample 7 is located in the sample clamping assembly;

[0059] S2, fix the front clamp 1 and the rear clamp 13 of the bracket to the lower clamp of the single-pulling machine; clamp the sample 7 with the upper clamp and the lower clamp of the single-pulling machine;

[0060] S3, placing the sample clamping assembly holding the sample 7 between the first pressure roller 5 of the first pressure providing assembly and the second pressure roller 11 of the second pressure providing assembly, setting the target lateral pressure for the cylinder controller, and applying pressure by the cylinder 2 according to the control of the cylinder controller to obtain a constant lateral pressure, so that the first pressure providing assembly and the second pressure providing assembly jointly press the sample 7, so that the sample 7 does not buckle and become unstable;

[0061] S4, applying tension and compression cyclic loading deformation trajectory to the sample 7 through the upper clamp and the lower clamp;

[0062] S5. Obtain the deformation-force curve of sample 7 under the tensile-compression cyclic loading deformation trajectory, process the obtained deformation-force curve into a stress-strain curve by solid mechanics method, and analyze the tensile-compression cyclic loading flow behavior of sample 7.

[0063] Example 1

[0064] Sample 7 selected 7075-T6 high-strength aluminum alloy; see Fig.10 The sample is I-shaped, and the dimensions of sample 7 are: total length 193mm; length of the first end and the second end is 40mm, width 40mm; length of the middle end is 73mm, width 12.5mm; the ends of the first end and the second end are respectively smoothly connected with the two ends of the middle end; its yield strength is 530MPa, and according to the strength calculation, a lateral pressure of 3500N is required; the sample 7 is clamped by the upper and lower clamps of the single-pulling machine; the first clamp 1 and the second clamp 13 of the bracket are fixed to the lower clamp of the single-pulling machine; the calculated lateral pressure is applied to the sample 7 by the cylinder 2; then, a tensile displacement of 2mm is applied to the sample 7, followed by a compressive displacement of 2mm, and then a tensile displacement of 1.5mm is applied to obtain the deformation-force curve of the sample 7 under the tension-compression cyclic loading path under this loading path, and the obtained deformation-force curve is processed into a stress-strain curve by the solid mechanics method to analyze the tension-compression cyclic loading flow behavior of the sample 7, see Figure 11-12 .

Claims

1. An anti-buckling lateral pressure active control device, It is characterized in that It comprises a bracket, a cylinder (2), a cylinder mounting plate (3), a first pressure providing component, a sample clamping component and a second pressure providing component; The cylinder mounting plate (3) is mounted on the bracket in a reciprocating manner; One end of the cylinder (2) is connected to the cylinder mounting plate (3); The other end of the cylinder (2) is connected to the first pressure providing component; The first pressure providing assembly and the second pressure providing assembly are arranged at two ends of the cylinder mounting plate (3) opposite to each other; The sample clamping assembly is detachably arranged between the first pressure providing assembly and the second pressure providing assembly; guide pillars are arranged on the outer sides of both ends of the cylinder mounting plate (3); A bearing (18) is also provided; a through hole is provided on the bracket, and the bearing (18) is sleeved on the guide column and passes through the through hole together with the guide column; A follower translation assembly is also provided; the follower translation assembly is arranged on the cylinder mounting plate (3); The first pressure providing assembly is also connected to the follower translation assembly; The follow-up translation assembly comprises a guide rail (6) and a slider (8), wherein the slider (8) is slidably arranged on the guide rail (6); It also includes a first pressure roller connecting plate (9); one end of the first pressure roller connecting plate (9) is connected to the side of the first side pressure providing component facing the follower translation component, and the other end of the first pressure roller connecting plate (9) is connected to the side of the follower translation component facing the first side pressure providing component.

2. The anti-buckling lateral pressure active control device according to claim 1, It is characterized in that The bracket comprises a first clamping plate (1) and a second clamping plate (13); the first clamping plate (1) comprises a first side plate, a bottom plate and a second side plate, the bottom plate connects the first side plate and the second side plate, and the first side plate and the second side plate are arranged in parallel.

3. The anti-buckling lateral pressure active control device according to claim 1 or 2, It is characterized in that The cylinder mounting plate (3) comprises a first supporting plate, an intermediate plate and a second supporting plate; the first supporting plate and the second supporting plate are arranged in parallel, and the intermediate plate is connected between the first supporting plate and the second supporting plate of the cylinder mounting plate (3).

4. A method for using the anti-buckling lateral pressure active control device according to any one of claims 1 to 3, comprising the following steps: S1. Calculate the required lateral pressure according to the strength of the sample (7); place the sample (7) in the sample clamping assembly; S2. Fix the bracket to the single-pulling machine; clamp the sample with the upper clamp and the lower clamp of the single-pulling machine (7); S3, setting a target lateral pressure for the cylinder controller, and the cylinder (2) applying pressure according to the control of the cylinder controller to obtain a constant lateral pressure, so that the first pressure providing component and the second pressure providing component jointly press the sample (7) so that the sample (7) does not buckle and become unstable; S4, applying a tensile and compressive cyclic loading deformation trajectory to the specimen (7) through the upper clamp and the lower clamp; S5. Obtain a deformation-force curve of the sample (7) under the deformation trajectory of tension-compression cyclic loading, process the obtained deformation-force curve into a stress-strain curve by solid mechanics method, and analyze the flow behavior of the sample (7) under tension-compression cyclic loading.

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