Device and method for detecting in-plane anti-wrinkling capability of metal sheet under support of multi-layer material

Abstract

The invention relates to a device and a method for detecting the in-plane anti-wrinkling capability of a metal sheet under the support of a multi-layer material, the device comprises a core mechanism, and an integral upper punch mechanism, a pair of chuck mechanisms, a transverse pressurizing and guiding mechanism and a thickness pressurizing and guiding mechanism which are respectively connected with the core mechanism, and a to-be-tested sample is positioned between the integral upper punch mechanism and the core mechanism. According to the method, extra supports such as fiber fabrics are laid in the thickness direction of a metal sample, and controllable thickness and in-plane loads are applied, so that a thin plate material is wrinkled and deformed under the actively applied in-plane compression stress and the supporting action given by the supports; therefore, the anti-wrinkling capability of the thin plate material in different three-way load modes is evaluated, and an effective guidance method and a test analysis means are provided for instability inhibition and prevention of the thin plate under complex contact-support-deformation.

Description

Technical Field

[0001] The present invention relates to a technology in the field of metal sheet forming, specifically a detection device and method for evaluating the in-plane wrinkle resistance of metal sheets with or without adding out-of-plane multi-layer supporting materials and under three-dimensional loading conditions. Background Art

[0002] The collaborative molding of metal sheet and reinforced fiber fabric is an efficient forming process for metal fiber laminated structures (FML). In this new process, wrinkling of metal thin layer materials is a typical defect. Affected by the complex three-dimensional loading path, it is mainly manifested as the instability of the thickness deformation of the sheet caused by the in-plane compressive stress of the sheet. On this basis, the complex metal-fabric thickness contact support will additionally affect the ability of the sheet material to resist the thickness instability, which usually leads to a further increase in the risk of wrinkling defects. Applying a certain blank holder load to resist the thickness instability deformation of the sheet is generally considered to be an effective and main wrinkling suppression method. In the collaborative molding deformation process, affected by the fiber fabric structure, the window of the blank holder force value will be greatly different from that in traditional stamping. In addition, affected by the thickness of the sheet material, its fracture tolerance is often lower. Therefore, in the application and regulation of the blank holder force, the corresponding process window is often smaller, which further puts forward more stringent requirements on the selection and regulation of the blank holder load amplitude. Summary of the invention

[0003] In view of the shortcomings of the prior art that the tensile and compressive loading modes within the sample surface cannot be accurately controlled and the out-of-plane thickness loads cannot be accurately applied, and at the same time, the deformation-wrinkling analysis process under the stacking-contact behavior of multi-layer metal-fiber fabrics cannot be evaluated, the present invention proposes a device and method for detecting the in-plane anti-wrinkling ability of metal thin plates under multi-layer material support. By laying additional fiber fabrics and other supports in the thickness direction of the metal sample and applying controllable thickness and in-plane loads, the thin plate material is wrinkled and deformed under the actively applied in-plane compressive stress and the support provided by the supports, thereby realizing the evaluation of the anti-wrinkling ability of the thin plate material under different three-axis load modes, and providing an effective guidance method and test analysis means for suppressing and preventing instability of the thin plate under complex contact-support-deformation.

[0004] The present invention is achieved through the following technical solutions:

[0005] The present invention relates to a device for detecting the anti-wrinkling ability of a metal sheet in a surface supported by a multilayer material, comprising: a core mechanism and an integral upper punch mechanism respectively connected thereto, a pair of clamp mechanisms, a lateral pressing and guiding mechanism and a thickness pressing and guiding mechanism, wherein a sample to be tested is located between the integral upper punch mechanism and the core mechanism.

[0006] The integral upper punch mechanism comprises: an upper plate, a punch rod fixing plate, a punch rod and a punch, wherein: the punch is connected to the punch rod through a sliding fit in an axial hole and is fixedly connected to the upper pressing plate by means of the punch rod fixing plate, and the punch rod fixing plate is fixedly connected to the upper pressing plate.

[0007] The thickness-direction pressurizing and guiding mechanism comprises: a thickness-direction guide column, a thickness-direction pressurizing block, a thickness-direction pressure plate, a thickness-direction pressure sensor, a thickness-direction pressure cylinder, a cylinder fixing plate, a cylinder seat, a floating fixing plate, a floating force sensor, a thickness-direction floating bottom plate, a thickness-direction nitrogen spring, a floating fixing seat and a sleeve, wherein: the thickness-direction pressure cylinder is fixed to the bottom plate by bolts via the cylinder fixing plate and the cylinder seat, the thickness-direction pressure plate and the thickness-direction pressurizing block are connected and fixed by bolts, and the thickness-direction guide column can realize a smooth sliding along the thickness direction of the horizontal plane sample; one end of the thickness-direction guide column is connected to the thickness-direction pressure plate by an interference fit, and the other end is connected to the thickness-direction pressure plate by an interference fit. The guide sleeves on the vertical support plate are matched with sliding clearances, and the vertical support plate is used to provide guide columns with sufficient support; the thickness pressure sensor and the floating force sensor are respectively fixed to the thickness pressure plate and the floating fixed plate with bolts, and the two respectively record the thickness pressure and thickness floating force provided by the thickness pressure cylinder and the thickness nitrogen spring; the thickness nitrogen spring is close to the floating fixed plate through the thickness floating bottom plate, and the floating fixed plate is fixed to the floating fixed seat through the sleeve with bolts. The thickness pressure of the thickness pressurizing mechanism is provided by the thickness pressure cylinder and transmitted to the punch side through the thickness pressure plate and the thickness pressurizing block.

[0008] The lateral pressure and guiding mechanism includes: a lateral guide rod support seat, a lateral guide rod, a lateral cylinder, a lateral cylinder fixing plate, a lateral pressure plate, a sensor fixing block, a lateral connecting rod, a lateral guide rod support frame and a pull rod, wherein: the bottom of the pull rod is connected to the bottom plate and the top is slidably connected to the twist rod through a slide groove to realize the transmission of tension in the horizontal lateral direction; the pull rod is connected to the lateral pressure plate through a lateral connecting rod; one end of the lateral guide rod is connected to the lateral pressure plate on one side with an interference fit, and the other end is matched with the guide sleeve on the lateral pressure plate, so that the lateral pressure plates on both sides move relative to or towards each other; two lateral cylinders are fixed to the bottom plate through lateral cylinder fixing plates and bolts to provide lateral tension for the lateral pressure mechanism; when the cylinder is pressurized to push its internal piston, the load is transmitted to the blank chuck through the lateral pressure plate, the lateral connecting rod and the lateral pull rod in sequence, thereby realizing the application of lateral tension to the sample.

[0009] The core mechanism includes: a support frame, a vertical support plate, a slide rail and slider mechanism, a thick floating push block, a floating push rod, a thick floating support seat, a fixed cover, a thick support plate, a support block, a floating top plate, a vertical support bottom plate, a vertical nitrogen spring, and a vertical pressure guide rod, wherein: the support frame is fixed to the lower bottom plate; the vertical support plate and the thick floating support seat are fixedly arranged on the support frame; the slide rail and slider mechanism is fixedly arranged on the vertical surface of the vertical support plate and is connected to the chuck mechanism; the fixed cover is fixedly arranged on the upper end of the vertical support plate; the thick support plate and the floating top plate cooperate with the support block through the slide groove and are movably arranged on the support block; the floating push rod is guided by the thick floating support seat to push the thick floating push block and the vertical support bottom plate in turn. Technical Effects

[0010] The outer facade of the thickness support plate of the present invention is laid with support materials such as fiber woven fabrics, so as to achieve the application and introduction of different support effects; the vertical pressure guide rod and the vertical pressure head can achieve a certain degree of movement in the material thickness direction. By adjusting the size position and the gap distance, it can avoid meeting the stacking requirements of support materials of different thicknesses, and avoid additional serious deformation of the support material during the application of vertical metal sheet surface pressure, which is conducive to the decoupling quantitative analysis of the deformation behavior and anti-instability performance of the metal sheet. The present invention uses the floating force of the thickness nitrogen spring and the thickness pressure provided by the thickness pressure cylinder to construct a cavity space that fits tightly with the sheet in the area of ​​the sheet to be tested, that is, a floating deformation chamber surrounded by the punch, the vertical pressure head, the thickness support plate, and the vertical support bottom plate. The cavity structure always exists in the entire process of load application, and can provide a basis and guarantee for the continuous application of the thickness clamping force. The present invention adopts three independent groups of pressure sources to independently control the in-plane and out-plane loads of the sheet to be tested, and can track the instability deformation capacity under different stress states within a larger stress space range without changing the size of the sheet to be tested. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a schematic diagram of the present invention;

[0012] Figure 2 It is a schematic diagram of the overall upper punch mechanism;

[0013] Figure 3 It is a schematic diagram of the thickness direction pressurizing and guiding mechanism;

[0014] Figure 4 It is a schematic diagram of the lateral pressure and guiding mechanism;

[0015] Figure 5 This is a schematic diagram of the core organization;

[0016] Figure 6 A schematic diagram of the structure in direct contact between the sample to be tested and the sample;

[0017] Figure 7 This is a schematic diagram of the core structure of the sheet material to be tested under loading under the support of the fabric layer;

[0018] Figure 8 is a schematic diagram of the chuck mechanism;

[0019] Fig. 9 This is a schematic diagram of the shape of a thin plate sample in an embodiment;

[0020] Fig.10 is a punch displacement-load curve diagram of the embodiment;

[0021] In the figure: upper plate 1-1, punch rod fixing plate 1-2, punch rod 1-3, vertical pressure head 1-4, punch 1-5, thick guide column 2-1, thick pressure block 2-2, thick pressure plate 2-3, thick pressure sensor 2-4, thick pressure cylinder 2-5, cylinder fixing plate 2-6, cylinder seat 2-7, floating fixing plate 2-8, floating force sensor 2-9, thick floating bottom plate 2-10, thick nitrogen spring 2-11, floating fixing seat 2-12, sleeve 2-13, lower bottom plate 3, transverse guide rod support seat 4-1, transverse guide rod 4-2, transverse cylinder 4-3, transverse cylinder fixing plate 4-4, transverse Pressure plate 4-5, sensor fixing block 4-6, transverse connecting rod 4-7, transverse guide rod support frame 4-8, pull rod 4-9, transverse force sensor 4-10, support frame 5-1, vertical support plate 5-2, slide rail slider mechanism 5-3, thickness floating push block 5-4, floating push rod 5-5, thickness floating support seat 5-6, fixed cover 5-7, thickness support plate 5-8, support block 5-9, chuck seat 5-10, chuck rod 5-11, floating top plate 5-12, vertical support bottom plate 5-13, chuck clamping block 5-14, twisting rod 5-15, vertical nitrogen spring 5-16, vertical pressure guide rod 5-17. DETAILED DESCRIPTION

[0022] like Figure 1 As shown, this embodiment relates to an in-plane wrinkle resistance device for a metal sheet, which is fixedly arranged between the upper and lower clamps of a universal testing machine, and the testing machine provides a compressive load in the vertical direction of the sample surface. The device includes: a core mechanism and an integral upper punch mechanism respectively connected thereto, a pair of clamp mechanisms, a lateral pressure and guide mechanism, and a thickness pressure and guide mechanism. The sample to be tested is located between the integral upper punch mechanism and the core mechanism.

[0023] like Figure 2As shown, the integral upper punch mechanism includes: an upper plate 1-1, a punch rod fixing plate 1-2, a punch rod 1-3, and a punch 1-5, wherein: the punch 1-5 is connected to the punch rod 1-3 through a sliding fit in an axial hole and is fixedly connected to the upper pressure plate 1-1 with the aid of the punch rod fixing plate 1-2, and the punch rod fixing plate 1-2 is fixedly connected to the upper pressure plate 1-1.

[0024] The punch 1-5 slides smoothly forward and backward in the direction of the punch rod 1-3, and a vertical pressure head 1-4 is movably provided on the punch 1-5. The vertical pressure head 1-4 is slidably arranged through a groove and can slide forward and backward;

[0025] like Figure 3 As shown, the thickness-direction pressurizing and guiding mechanism comprises: a thickness guide column 2-1, a thickness-direction pressurizing block 2-2, a thickness-direction pressing plate 2-3, a thickness-direction pressure sensor 2-4, a thickness-direction pressure cylinder 2-5, a cylinder fixing plate 2-6, a cylinder seat 2-7, a floating fixing plate 2-8, a floating force sensor 2-9, a thickness-direction floating bottom plate 2-10, a thickness-direction nitrogen spring 2-11, a floating fixing seat 2-12 and a sleeve 2-13, wherein: the thickness-direction pressure cylinder 2-5 is fixed to the bottom plate 3 by bolts via the cylinder fixing plate 2-6 and the cylinder seat 2-7, the thickness-direction pressing plate 2-3 and the thickness-direction pressurizing block 2-2 are connected and fixed by bolts, and then the thickness-direction guide column 2-1 can realize a smooth sliding along the thickness direction of the horizontal plane sample; one end of the thickness guide column 2-1 is connected to the thickness-direction pressing plate 2-3 by interference fit The other side is matched with the guide sleeve on the vertical support plate 5-2 by a sliding clearance, and the vertical support plate 5-2 is used to provide a guide column with sufficient support; the thickness pressure sensor 2-4 and the floating force sensor 2-9 are fixed to the thickness pressure plate 2-3 and the floating fixed plate 2-8 respectively by bolts, and both record the thickness pressure and thickness floating force provided by the thickness pressure cylinder 2-5 and the thickness nitrogen spring 2-11 respectively; the thickness nitrogen spring 2-11 is close to the floating fixed plate 2-8 through the thickness floating bottom plate 2-10, and the floating fixed plate 2-8 is fixed to the floating fixed seat 2-12 through the sleeve 2-13 with bolts. The thickness pressure of the thickness pressurizing mechanism is provided by the thickness pressure cylinder 2-5, and is transmitted to the side of the punch 1-5 through the thickness pressure plate 2-3 and the thickness pressurizing block 2-2.

[0026] The thick guide column 2-1 and the transverse guide rod 4-2 should be able to slide smoothly during assembly. To ensure smooth movement, the diameter of the thick guide column 2-1 should be appropriately increased to reduce the disturbance generated during its installation. In order to eliminate additional errors such as friction, the reading of the transverse force sensor 4-10 should be zeroed and calibrated before the test. The movement and pressurization process of the pistons of the thick pressure cylinder 2-5 and the transverse cylinder 4-3 should be as smooth as possible to avoid impact.

[0027] like Figure 4As shown, the lateral pressure and guiding mechanism includes: a lateral guide rod support seat 4-1, a lateral guide rod 4-2, a lateral cylinder 4-3, a lateral cylinder fixing plate 4-4, a lateral pressure plate 4-5, a sensor fixing block 4-6, a lateral connecting rod 4-7, a lateral guide rod support frame 4-8 and a pull rod 4-9, wherein: the bottom of the pull rod 4-9 is connected to the bottom plate 3 and the top is slidably connected to the twist rod 5-15 through a slide groove to realize the transmission of pulling force in the horizontal lateral direction; the pull rod 4-9 is connected to the lateral pressure plate 4-5 through the lateral connecting rod 4-7; the lateral guide rod 4 -2 One end is connected to the single-side transverse pressure plate 4-5 by interference fit, and the other end cooperates with the guide sleeve on the transverse pressure plate 4-5, so that the transverse pressure plates 4-5 on both sides can move relative to or towards each other; the two transverse cylinders 4-3 are fixed to the bottom plate 3 through the transverse cylinder fixing plate 4-4 and bolts to provide transverse pulling force for the transverse pressurizing mechanism; when the cylinder is pressurized to push its internal piston, the load is transmitted to the blank chuck through the transverse pressure plate 4-5, the transverse connecting rod 4-7, and the transverse pulling rod 4-9 in sequence, thereby realizing the application of transverse pulling force to the sample 6.

[0028] A bidirectionally symmetrical lateral force sensor 4-10 is provided on the inner side of the lateral pressure plate 4-5 for collecting load information. The lateral force sensor 4-10 is fixed by a sensor fixing block 4-6 and bolts.

[0029] like Figure 5 As shown, the core mechanism includes: a support frame 5-1, a vertical support plate 5-2, a slide rail slider mechanism 5-3, a thick floating push block 5-4, a floating push rod 5-5, a thick floating support seat 5-6, a fixed cover 5-7, a thick support plate 5-8, a support block 5-9, a floating top plate 5-12, a vertical support bottom plate 5-13, a vertical nitrogen spring 5-16, and a vertical pressure guide rod 5-17, wherein: the support frame 5-1 is fixed on the lower bottom plate 3; the vertical support plate 5-2 and the thick floating The support seat 5-6 is fixedly arranged on the support frame 5-1; the slide rail slider mechanism 5-3 is fixedly arranged on the vertical surface of the vertical support plate 5-2 and is connected to the clamping mechanism; the fixed cover 5-7 is fixedly arranged on the upper end of the vertical support plate 5-2; the thickness support plate 5-8 and the floating top plate 5-12 cooperate with the support block 5-9 through the slide groove and are movably arranged on the support block 5-9; the floating push rod 5-5 is guided by the thickness floating support seat 5-6 to push the thickness floating push block 5-4 and the vertical support bottom plate 5-13 in turn.

[0030] like Figure 6As shown, the device is in a loading mode for the sample to be tested in a vertical plane, and the sample 6 is placed in a chamber surrounded by the vertical support bottom plate 5-13, the thickness support plate 5-8, the vertical pressure head 1-4, and the punch 1-5. The vertical support bottom plate 5-13 and the floating top plate 5-12 slide up and down smoothly through the square groove in the support block 5-9, and the thickness floating push block 5-4 can push the vertical support bottom plate 5-13, so that they can slide smoothly forward and backward on the floating top plate 5-12.

[0031] The vertical pressure heads 1-4 in the integral upper punch mechanism cooperate with the vertical pressure guide rods 5-17 through the axial holes to achieve smooth sliding in the vertical direction.

[0032] The vertical buoyancy of the floating top plate 5-12 is provided by the vertical nitrogen spring 5-16. Under the action of the vertical buoyancy, the floating top plate 5-12 can float in the vertical direction with a certain amplitude.

[0033] like Figure 6 and Figure 7 As shown, the outer side of the thickness support plate 5-8 is preferably further laid with a support material 7 such as carbon fiber woven fabric to introduce a specific support effect. In this case, the chamber formed by the punch 1-5 and the thickness support plate 5-8 will change in size as the compression of the support material caused by the forward and backward sliding of the vertical pressure head changes, and the punch 1-5 is always in contact with the test sheet 6 during the process. At the same time, the vertical support bottom plate 5-13 is always in contact with the punch 1-5 under the action of the thickness floating force, thereby providing the bottom support required for the deformation of the test sheet 6, and the vertical pressure head 1-4 is always in contact with the outer surface of the support material layer, providing the pressure required for the active compression deformation of the test sheet 6.

[0034] The gap between the vertical pressure head 1-4 and the thickness support plate 5-8 corresponding to the required gap of the support 7 is adjusted by the horizontal position of the vertical pressure guide rod 5-17.

[0035] The sliding fit accuracy between the support block 5-9 and the vertical pressure guide rod 5-17 is the key to ensure the accurate application of the lateral load. The accurate fit between the vertical slide groove inside the support block 5-9 and the thick support plate 5-8 and the floating top plate 5-12 is the key to ensure the accurate application of the load in the vertical direction. The matching surface in the slide groove of the support block 5-9 should have good surface accuracy and surface roughness to minimize the influence of friction on the measured data. In addition, in order to reduce the interference of friction during the test process, it is advisable to adopt an appropriate lubrication method during the specific implementation process.

[0036] The vertical nitrogen spring 5-16 should be selected to avoid pressing the thickness support plate 5-8 upward against the fixed cover 5-7 during assembly. This is to ensure that after the width of the test sample is reduced due to the lateral tensile load, the vertical support bottom plate 5-13 and the floating top plate 5-12 can leave enough vertical floating space to fit the sheet upward to avoid the test sample from being suspended. At the same time, the rated load range of the vertical nitrogen spring 5-16 should be higher than the maximum load value during the test.

[0037] like Figure 8 As shown, there are two chuck mechanisms and they are respectively arranged at both ends of the sample 6, each chuck mechanism includes: a chuck seat 5-10, a chuck rod 5-11, a chuck clamping block 5-14 and a twisting rod 5-15, wherein: the chuck seat 5-10 is fixedly arranged on the slider rail mechanism 5-3, the bottom of the chuck rod 5-11 cooperates with the bottom of the chuck seat 5-10 to limit the rotation of the chuck rod 5-11, and the top of the chuck rod 5-11 is connected to the twisting rod 5-15; the through hole at one end of the sample 6 passes through the axis shown in the chuck rod 5-11, and is locked and fixed through the twisting rod 5-15 and the chuck clamping block 5-14; the chuck clamping block 5-14 is provided with positioning grooves on the upper and lower sides, which are clearance-matched with the positioning boss on the chuck seat 5-10 to achieve positioning; the through hole in the sample 6 and the axis in the chuck rod 5-11 are clearance-matched.

[0038] The thickness-direction nitrogen spring 2-11 should be selected to ensure that it completely pushes out the vertical support base plate 5-13 in the thickness direction, thereby ensuring close contact between the vertical support base plate 5-13 and the punch 1-5.

[0039] This embodiment relates to a testing method based on the above device, including:

[0040] Step 1: Follow Figure 1 The assembly and fixation of the test device are completed as shown. The device is placed on the universal testing machine with the help of the die handle. The upper plate is fixedly connected to the slider of the testing machine. The supporting material and the metal sheet sample are placed in the thickness support plate and the chuck mechanism respectively. The sliding chuck mechanism puts the chuck rod 5-11 into the preset hole of the blank, puts on the chuck clamping block 5-14 and clamps the blank with the screw rod 5-15. The sliding rail slider mechanism 5-3 makes the gauge section of the blank located at the center of the device. In the initial state, the vertical support bottom plate 5-13 protrudes outward from the thickness support plate 5-8 under the action of the thickness floating force, and supports the thickness of the blank.

[0041] Step 2: Place the sheet material to be tested according to Fig. 9 Cut as shown, open a certain groove to avoid shear interference of the edge of the vertical pressure head 1-4, and drill the center of the clamping section The circular hole is ensured to be smoothly matched with the chuck rod 5-11. The clamping section is properly polished with coarse sandpaper to increase the surface roughness to prevent the sample from slipping. The preferred sample gauge section shown has a width of B, a length of L, and a thickness of t. In this implementation, B is 10 mm, the length L is 20 mm, and the thickness t is 0.5 mm.

[0042] Step 3, cutting the support material 7, and its size is the same as the size of the outer facade of the thick support plate 5-8. In this implementation process, the support material is made of carbon fiber woven fabric, with a thickness of 0.25mm, a length and a width of 30mm and 24mm respectively. To facilitate the removal of the support material, a hard gasket can be added. First, the support material is attached to the gasket with an adhesive, and then uniformly installed on the outer facade of the thick support plate 5-8.

[0043] Step 4: Put the vertical pressure head 1-4 on the vertical pressure guide rod 5-17, adjust the horizontal position of the vertical pressure guide rod 5-17, and make the vertical pressure head 1-4 be in the preset thickness pressure position. Move the upper plate 1-1 to the appropriate position, adjust its position with the vertical pressure head 1-4, and complete the sliding fit between the two in the groove.

[0044] Step 5, start the thickness pressure cylinder 2-5 to apply thickness pressure to the punch 1-5. The punch 1-5 moves to one side of the sample 6 under the action of the thickness pressure to compress the blank. There is a certain gap in the groove where the vertical pressure head 1-4 and the punch 1-5 cooperate, so the punch can smoothly pressurize the sample 6 in the thickness direction. When the thickness pressure is greater than the floating force, the vertical support base plate 5-13 retreats in the thickness direction, the thickness nitrogen spring 2-11 is compressed, and the vertical support base plate 5-13 and the punch 1-5 remain in close contact. Record the values ​​of the thickness pressure sensor 2-4 and the floating force sensor 2-9. The difference between the two is the thickness pressure load applied to the sample 6.

[0045] At the same time, two relatively fixed transverse cylinders 4-3 are started to pressurize the transverse pressure plate 4-5. The pressure is transmitted to the chuck mechanism through the transverse connecting rod 4-7 and the pull rod 4-9, and then the sample is subjected to transverse force. In this process, the value of the transverse force sensor 4-10 is recorded, which is the transverse tension exerted on the sample.

[0046] Step 6: Start the testing machine to drive the upper plate 1-1 to move downward at a certain constant speed, record the displacement and load information, and obtain the following information: Fig.10 The typical displacement-load curve is shown in Figure 1. The moment when the load drops is the moment when the sample becomes unstable and wrinkles.

[0047] Step 7: Based on the typical displacement-load curve, record the first load peak as F b , the corresponding displacement value is d bThe critical wrinkling load under this load condition is calculated as The larger the value is, the stronger the material's ability to resist wrinkling under the triaxial load is.

[0048] After specific actual experiments, 0.5mm AA2024-O sheet was used as the test material and 0.25mm single-layer 3K plain carbon fiber woven fabric was used as the support material. The above-mentioned sample structure size was selected, and the above-mentioned device / method was operated with a lateral tension of 346N, a thickness pressure of 490N, and a floating force of 92N. The experimental data that can be obtained are: critical wrinkling d b is 2.08mm, load peak F b It is 2625N, and the calculated critical wrinkling load is 262.5MPa. Under this state, the average equivalent principal stress of the sheet is 69.2MPa, -1.99MPa, and -26.25MPa from large to small.

[0049] Compared with the existing technology, the device can introduce the corresponding contact support effect of the supporting material during the deformation of the sheet material sample to be tested, can realize the independent regulation of the three-dimensional loads inside and outside the sheet material surface without changing the size of the metal sheet material sample, and can describe and track the anti-wrinkling performance of the metal sheet material under different stress states in a larger stress space.

[0050] The above-mentioned specific implementation can be partially adjusted in different ways by those skilled in the art without departing from the principle and purpose of the present invention. The protection scope of the present invention shall be based on the claims and shall not be limited by the above-mentioned specific implementation. Each implementation scheme within its scope shall be subject to the constraints of the present invention.

Claims

1. A device for detecting the in-plane wrinkling resistance of a metal sheet, characterized in that: include: A core mechanism and an integral upper punch mechanism, a pair of clamp mechanisms, a transverse pressing and guiding mechanism and a thickness pressing and guiding mechanism respectively connected thereto, wherein the sample to be tested is located between the integral upper punch mechanism and the core mechanism; The integral upper punch mechanism comprises: an upper plate, a punch rod fixing plate, a punch rod and a punch, wherein: the punch is connected to the punch rod through a sliding fit in an axial hole and is fixedly connected to the upper pressing plate by means of the punch rod fixing plate, and the punch rod fixing plate is fixedly connected to the upper pressing plate; The thickness-direction pressurizing and guiding mechanism comprises: a thickness-direction guide column, a thickness-direction pressurizing block, a thickness-direction pressure plate, a thickness-direction pressure sensor, a thickness-direction pressure cylinder, a cylinder fixing plate, a cylinder seat, a floating fixing plate, a floating force sensor, a thickness-direction floating bottom plate, a thickness-direction nitrogen spring, a floating fixing seat and a sleeve, wherein: the thickness-direction pressure cylinder is fixed to the bottom plate by bolts via the cylinder fixing plate and the cylinder seat, the thickness-direction pressure plate and the thickness-direction pressurizing block are connected and fixed by bolts, and the thickness-direction guide column can realize a smooth sliding along the thickness direction of the horizontal plane sample; one end of the thickness-direction guide column is connected to the thickness-direction pressure plate by an interference fit, and the other end is connected to the thickness-direction pressure plate by an interference fit. The guide sleeves on the vertical support plate are matched with sliding clearance, and the vertical support plate is used to provide the guide column with sufficient support; the thickness pressure sensor and the floating force sensor are respectively fixed to the thickness pressure plate and the floating fixed plate by bolts, and the two respectively record the thickness pressure and thickness floating force provided by the thickness pressure cylinder and the thickness nitrogen spring; the thickness nitrogen spring is close to the floating fixed plate through the thickness floating bottom plate, and the floating fixed plate is fixed to the floating fixed seat through the sleeve with bolts, and the thickness pressure of the thickness pressurizing mechanism is provided by the thickness pressure cylinder, and is transmitted to the punch side through the thickness pressure plate and the thickness pressurizing block; The lateral pressure and guiding mechanism includes: a lateral guide rod support seat, a lateral guide rod, a lateral cylinder, a lateral cylinder fixing plate, a lateral pressure plate, a sensor fixing block, a lateral connecting rod, a lateral guide rod support frame and a pull rod, wherein: the bottom of the pull rod is connected to the bottom plate and the top is slidably connected to the twist rod through a slide groove to realize the transmission of tension in the horizontal lateral direction; the pull rod is connected to the lateral pressure plate through a lateral connecting rod; one end of the lateral guide rod is connected to the lateral pressure plate on one side by an interference fit, and the other end is matched with the guide sleeve on the lateral pressure plate, so that the lateral pressure plates on both sides move relative to or towards each other; two lateral cylinders are fixed to the bottom plate through the lateral cylinder fixing plate and bolts to provide lateral tension for the lateral pressure mechanism; when the cylinder is pressurized to push its internal piston, the load is sequentially transmitted to the blank chuck through the lateral pressure plate, the lateral connecting rod and the lateral pulling rod, thereby realizing the application of lateral tension to the sample; The core mechanism includes: a support frame, a vertical support plate, a slide rail and slider mechanism, a thick floating push block, a floating push rod, a thick floating support seat, a fixed cover, a thick support plate, a support block, a floating top plate, a vertical support bottom plate, a vertical nitrogen spring, and a vertical pressure guide rod, wherein: the support frame is fixed to the lower bottom plate; the vertical support plate and the thick floating support seat are fixedly arranged on the support frame; the slide rail and slider mechanism is fixedly arranged on the vertical surface of the vertical support plate and is connected to the chuck mechanism; the fixed cover is fixedly arranged on the upper end of the vertical support plate; the thick support plate and the floating top plate cooperate with the support block through the slide groove and are movably arranged on the support block; the floating push rod is guided by the thick floating support seat to push the thick floating push block and the vertical support bottom plate in turn.

2. The device for detecting the in-plane wrinkle resistance of a metal sheet according to claim 1, characterized in that: The punch head slides smoothly forward and backward in the direction of the punch head rod. A vertical pressure head is movably arranged on the punch head. The vertical pressure head is slidably arranged through a groove and can slide forward and backward.

3. The device for detecting the in-plane wrinkle resistance of a metal sheet according to claim 1, wherein: The thick guide column and lateral guide rod should slide smoothly during assembly. To ensure smooth movement, the diameter of the thick guide column should be appropriately increased to reduce the disturbance generated during installation. In order to eliminate additional errors such as friction, the lateral force sensor should be zeroed and calibrated before the test begins. The movement and pressurization process of the thick pressure cylinder and the lateral cylinder piston should be as smooth as possible to avoid impact.

4. The device for detecting the in-plane wrinkle resistance of a metal sheet according to claim 1, wherein: The sample is placed in a chamber surrounded by a vertical support bottom plate, a thickness support plate, a vertical pressure head, and a punch. The vertical support bottom plate and the floating top plate slide up and down smoothly through the square grooves in the support blocks, and the thickness floating push block can push the vertical support bottom plate, so that they can slide smoothly forward and backward on the floating top plate together. The vertical pressure head in the integral upper punch mechanism cooperates with the vertical pressure guide rod through the shaft hole to achieve smooth sliding in the vertical direction; The vertical floating force of the floating top plate is provided by the vertical nitrogen spring. Under the action of the vertical floating force, the floating top plate can float with a certain amplitude in the vertical direction.

5. The device for detecting the in-plane wrinkle resistance of a metal sheet according to claim 1, wherein: A support material such as carbon fiber woven fabric is laid on the outside of the thickness support plate to introduce a specific support effect. In this case, the chamber formed by the punch and the thickness support plate will change in size as the compression amount of the support material caused by the forward and backward sliding of the vertical pressure head changes, and the punch is always in contact with the test sheet during the process. At the same time, the vertical support bottom plate is always in contact with the punch under the action of the thickness floating force, thereby providing the bottom support required for the deformation of the test sheet, and the vertical pressure head is always in contact with the outer surface of the support material layer, providing the pressure required for the active compression deformation of the test sheet surface; The gap between the vertical pressure head and the thickness support plate corresponding to the required support is adjusted by the horizontal position of the vertical pressure guide rod.

6. The device for detecting the in-plane wrinkle resistance of a metal sheet according to claim 1, characterized in that: The sliding fit accuracy between the support block and the vertical pressure guide rod is the key to ensuring the accurate application of its lateral load; the accurate fit between the vertical slide groove inside the support block and the floating top plate and the thickness support plate is the key to ensuring the accurate application of the load in the vertical direction; the matching surface in the support block slide groove should have good surface accuracy and surface roughness to minimize the impact of friction on the measured data. In addition, in order to reduce the interference of friction during the test process, appropriate lubrication methods should be adopted during the specific implementation process.

7. The device for detecting the in-plane wrinkle resistance of a metal sheet according to claim 1, wherein: There are two chuck mechanisms, which are respectively arranged at both ends of the sample, and each chuck mechanism includes: a chuck seat, a chuck rod, a chuck clamping block and a twisting rod, wherein: the chuck seat is fixedly arranged on the slider rail mechanism, the bottom of the chuck rod cooperates with the bottom of the chuck seat to limit the rotation of the chuck rod, and the top of the chuck rod is connected to the twisting rod; the through hole at one end of the sample passes through the axis shown in the chuck rod, and is locked and fixed through the twisting rod and the chuck clamping block; positioning grooves are provided on the upper and lower sides of the chuck clamping block, which are clearance-matched with the positioning boss on the chuck seat to achieve positioning; a clearance fit is adopted between the through hole in the sample and the axis in the chuck rod.

8. A method for detecting the in-plane wrinkling resistance of a metal sheet based on the device described in any one of claims 1 to 7, characterized in that: include: Step 1, assembling and fixing the device: the test device is placed on the universal testing machine with the help of the die handle, the upper plate is fixedly connected to the slider of the testing machine, the supporting material and the metal sheet material sample are placed in the thickness support plate and the chuck mechanism respectively, the sliding chuck mechanism sleeves the chuck rod into the preset hole of the blank, the chuck clamping block is put on and the blank is clamped with a screw rod, the sliding rail slider mechanism makes the gauge section of the blank located at the center of the device, in the initial state, the vertical support bottom plate protrudes outward from the thickness support plate under the action of the thickness floating force, and supports the blank in the thickness direction; Step 2: Cut the thin plate material to be tested as shown in the figure, open a certain groove to avoid the shear interference of the edge of the vertical pressure head, and drill the center of the clamping section. Round hole, and ensure that it can cooperate smoothly with the chuck rod, use coarse sandpaper to properly grind the clamping section to increase the surface roughness to prevent the sample from slipping; Step 3: Cut the support material to the same size as the outer surface of the thick support plate. In this implementation, the support material is made of carbon fiber woven fabric, which is attached to the gasket with an adhesive and then uniformly installed on the outer surface of the thick support plate. Step 4: Put the vertical pressure head on the vertical pressure guide rod, adjust the horizontal position of the vertical pressure guide rod, make the vertical pressure head in the preset thickness pressure position, move the upper plate to the appropriate position, adjust its position with the vertical pressure head, and complete the sliding fit between the two in the groove; Step 5, start the thickness pressure cylinder to apply thickness pressure to the punch. Under the action of the thickness pressure, the punch moves to one side of the sample to press the blank. A certain gap is left in the groove where the vertical pressure head and the punch cooperate. When the thickness pressure is greater than the floating force, the vertical support base plate retreats in the thickness direction, and the thickness nitrogen spring is compressed. The vertical support base plate and the punch are still in close contact. The values ​​of the thickness pressure sensor and the floating force sensor are recorded, and the difference between the two is the thickness pressure load applied to the sample; at the same time, start two relatively fixed transverse cylinders to pressurize the transverse pressure plate. The pressure is transmitted to the chuck mechanism after the transverse connecting rod and the pull rod, and then the sample is laterally forced. In this process, the value of the transverse force sensor is recorded, which is the transverse tension exerted on the sample; Step 6: Start the testing machine to drive the upper plate to move downward at a certain constant speed, record the displacement and load information, and obtain a typical displacement-load curve as shown in the figure. The moment when the load drops as shown in the figure is the moment when the sample becomes unstable and wrinkles; Step 7: Based on the typical displacement load curve, record the first load peak as F b , the corresponding displacement value is d b , the critical wrinkling load under this load condition is calculated as The larger the value is, the stronger the material's ability to resist wrinkling under the triaxial load is.

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