Serpentine specimen for testing the performance of space continuous multi-bend materials and component bending equipment

Abstract

The present application relates to the technical field of material plastic processing, and discloses a serpentine specimen for testing the performance of spatial continuous multi-bend materials and component bending equipment. The serpentine specimen is composed of a spatial continuous multi-bend structure formed by alternating rotation of a linear unit and a bending unit. The linear unit is composed of a linear segment, and the bending unit includes a horizontal bending area, a vertical bending area, and a torsional bending area. The entire serpentine specimen starts with a linear unit and also ends with a linear unit. The specimen of the present application has high test accuracy, low implementation cost, and a wide range of practical applications. It can avoid test error problems caused by factors such as different material properties, different structural dimensions of spatial continuous multi-bend components, and different bending process parameters.

Description

Technical Field

[0001] The present application relates to the technical field of material plastic processing, and in particular to a serpentine specimen for testing the performance of spatial continuous multi-bend materials and component bending equipment. Background Art

[0002] In the field of plastic processing, bending is the most common processing method for products with continuous, multi-bend structures, such as pipes, plates, profiles, and bars. Due to the special characteristics of plastic forming, the main characteristics of materials after bending are bend elongation and bend springback. Bending elongation and bend springback are related not only to the material properties themselves, but also to the bend radius, bend angle, and bending process parameters (such as bending speed). Therefore, accurately measuring the bending properties of materials is a fundamental prerequisite for achieving precise bending. Currently, there are two main methods. The first method indirectly determines the bending properties of materials through tensile and compression tests and simulation analysis. Because it does not consider the influence of actual bending process parameters, its accuracy and reliability remain to be verified. The second method, described in invention patent publication number CN108956322A, optimizes and improves the first method. Based on the premise that the bending springback relationship is linear, this patent proposes a planar S-shaped specimen. The bending performance parameters are directly obtained through two consecutive forward and reverse plane bending tests. This method can directly and accurately obtain the bending performance parameters of planar components with a bend angle range of 10° to 150°. However, in actual engineering, the product is generally composed of multiple straight segments of different lengths and curved segments of different bending radii, different bending angles, and different rotation angles to form a spatial continuous multi-bend integral component (taking pipes as an example, refer to the instructions for the Figure 1 As shown in the figure, it belongs to the multi-directional bending of spatial three-dimensional structure, and the bending angle exceeds the range of 10° to 150°. The bending rebound is a nonlinear relationship. Therefore, the second method can no longer meet the requirements for accurate testing of spatial continuous multi-bend material performance. Summary of the Invention

[0003] In order to solve the problems and defects existing in the above-mentioned prior art, the present application proposes a serpentine specimen for testing the performance of spatial continuous multi-bend materials and component bending equipment. The serpentine specimen can be clamped at one time to realize the performance test of spatial continuous multi-bend materials such as plates, profiles, square steel, bars, pipes, rectangular tubes, etc. made of various materials such as aluminum, steel, titanium, and copper, as well as the test of the performance accuracy of spatial continuous multi-bend component bending equipment. The specimen of the present application has high testing accuracy, low implementation cost, and wide practical range. It can avoid the testing error problems caused by factors such as different material properties, different structural dimensions of spatial continuous multi-bend components, and different bending process parameters.

[0004] In order to achieve the above-mentioned invention objectives, the technical solutions of this application are as follows:

[0005] A serpentine specimen for testing the performance of spatially continuous multi-bend materials and component bending equipment. The serpentine specimen is composed of linear units and bending units that rotate alternately to form a spatially continuous multi-bend structure. The linear units are composed of linear segments, and the bending units include horizontal bending areas, vertical bending areas, and torsional bending areas. The entire serpentine specimen starts with a linear unit and also ends with a linear unit.

[0006] Furthermore, the horizontal bending area is composed of a plurality of straight segments of different lengths and horizontal positive and negative bending segments of different bending radii and bending angles, and is used to realize horizontal bending performance testing of materials and component bending equipment.

[0007] Furthermore, the vertical bending zone is composed of a plurality of straight segments of different lengths and vertical positive and negative bending segments with different bending radii and bending angles, and is used to implement vertical bending performance testing of material and component bending equipment.

[0008] Furthermore, the torsional bending zone is composed of a plurality of straight segments of different lengths and positive and negative bending segments of different bending radii, different bending angles, and different rotation angles, and is used to realize the torsional direction bending performance test of the material and component bending equipment.

[0009] Furthermore, the lengths of the straight line segments in the bending zone are different and are greater than the minimum clamping length for bending the material.

[0010] Furthermore, the bending angles of the positive and negative bending segments in the bending area are different, and at least five bending segments are provided in the small angle range and the large angle range, and at least three bending segments are provided in the middle angle range.

[0011] Furthermore, the bending radius of each positive and negative bending section in the bending area is different, and the bending radius is not less than the minimum bending radius of the material and not more than three times the minimum bending radius of the material. In order to save molds for making serpentine specimens, the bending radius is preferably not more than three values.

[0012] Furthermore, the torsion direction of the torsion bending zone is directed toward the inflection point of the material cross-section shape, and the range of the rotation angle is -180° to 180°.

[0013] Furthermore, the small angle refers to 0°~20°, but does not include 20°; the large angle refers to 160°~180°, but does not include 160°; the intermediate angle refers to 20°~160°, and the intermediate angle includes both 20° and 160°.

[0014] Beneficial effects of this application:

[0015] (1) When testing the performance of multi-bend materials and multi-bend component bending equipment, the serpentine specimen of this application directly tests the raw materials and bending equipment, and no longer uses indirect measurement. The test data is true and reliable, and the traditional numerical simulation analysis link is abandoned. This not only greatly improves the credibility of the test data, but also can quickly obtain the bending performance parameters, thereby improving work efficiency.

[0016] (2) During the test process, the serpentine specimen of the present application does not need to record intermediate process data, thus avoiding complex stress and strain data collection and data analysis. Therefore, the entire test process is simple, efficient and low-cost.

[0017] (3) The serpentine specimen of this application can be used to test the bending performance parameters of pipes, bars, wires, plates and profiles made of various alloy materials such as aluminum, steel, titanium and copper. It has a wide range of applications and significant effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The foregoing and following detailed description of the present application will become more apparent when read in conjunction with the following drawings, in which:

[0019] Figure 1 It is a spatial continuous multi-bend integral pipe fitting;

[0020] Figure 2 This is a schematic diagram of the serpentine specimen structure for this application;

[0021] Figure 3 This is the torsion structure of the serpentine specimen in this application;

[0022] Figure 4 is the rotation angle of the serpentine specimen in this application;

[0023] Figure 5 It is a standard specimen for spatial continuous multi-bend pipe fittings.

[0024] In the attached figure:

[0025] SL, linear unit; SB, bending unit; QH, horizontal bending area; QV, vertical bending area; QC, torsional bending area; Ln, linear segment; Sb, positive and negative bending segments; Bn, bending angle; Rn, bending radius; Cn rotation angle; DH, horizontal direction; DV vertical direction; DC, torsional direction. DETAILED DESCRIPTION

[0026] In order to enable those skilled in the art to better understand the technical solutions in this application, the following will further illustrate the technical solutions for achieving the invention objectives of this application through several specific embodiments. It should be noted that the technical solutions claimed for protection in this application include but are not limited to the following embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without making any creative efforts should fall within the scope of protection of this application.

[0027] Example 1

[0028] A serpentine specimen for testing the performance of spatial continuous multi-bend materials is used to test the bending performance parameters of stainless steel square tubes (1Cr18Ni9Ti, 10mm*10mm). The basic structure of the serpentine specimen is as follows.

[0029] The serpentine specimen is composed of a spatially continuous multi-bend structure formed by alternating rotation of a straight line unit SL and a bending unit SB. The straight line unit SL is composed of a straight line segment Ln, and the bending unit SB includes a horizontal bending area QH, a vertical bending area QV and a torsional bending area QC. The entire serpentine specimen starts with the straight line unit SL and also ends with the straight line unit SL.

[0030] Furthermore, the horizontal bending zone QH is composed of a plurality of straight line segments Ln of different lengths and horizontal positive and negative bending segments Sb of different bending radii and bending angles, and is used to implement horizontal bending performance testing of materials and component bending equipment.

[0031] Furthermore, the vertical bending zone QV is composed of a plurality of straight segments Ln of different lengths and vertical positive and negative bending segments Sb with different bending radii and bending angles, and is used to implement vertical bending performance testing of materials and component bending equipment.

[0032] Furthermore, the torsional bending zone QC is composed of a plurality of straight segments Ln of different lengths and positive and negative bending segments Sb of different bending radii, different bending angles, and different rotation angles, and is used to realize the torsional direction bending performance test of the material and component bending equipment.

[0033] The process of testing the bending performance parameters of stainless steel square tube (1Cr18Ni9Ti, 10mm*10mm) is as follows:

[0034] Step S1. Determine the length of the straight line segment Ln in each bending area of the serpentine specimen.

[0035] The minimum clamping length of the stainless steel square tube is 20mm. For the convenience of calculation, an arithmetic progression can be used, starting from 20mm, increasing by 1mm each time, and gradually increasing from 20mm to 27mm.

[0036] Step S2: Determine the bending direction and rotation angle of the bending segments in each bending area of the serpentine.

[0037] The material cross-section is a square (10mm*10mm). The horizontal bending direction and the vertical bending direction are two symmetrical sides of the square. When bending forward and backward, the rotation angles are 180° and -180°. The torsion direction should be the four symmetrical corners of the square. The rotation angles can be calculated to be 45° and -135°.

[0038] Step S3: Determine the bending angle of the bending segment in each bending area of the serpentine specimen.

[0039] Taking into account the nonlinear factors of material bending and taking into account both test accuracy and test efficiency, five small-angle bending sections are set (1°, 5°, 9°, 13°, 17°), three medium-angle bending sections are set (30°, 90°, 150°), and five large-angle bending sections are set (163°, 167°, 171°, 175°, 179°).

[0040] Step S4: Determine the bending radius of the bending segments in each bending area of the serpentine specimen.

[0041] The minimum bending radius of the stainless steel square tube is 10 mm, and 10 mm, 20 mm and 30 mm are selected as the bending radius of each bending section.

[0042] Step S5. Based on the above steps S1-S4, the determined straight segment length, bending radius, bending angle and rotation angle are cross-combined to form the final spatial continuous multi-bend serpentine specimen according to the horizontal bending area, vertical bending area and torsional bending area. The specific data are shown in the following table.

[0043]

[0044] Step S6. Input the above data into the CNC machining equipment, and after completing the CNC bending, measure the actual values of the straight line segment, bending radius, bending angle and rotation angle to obtain the measured value data.

[0045] Step S7: Evaluate the bending performance of the spatially continuous multi-bend structure of the material.

[0046] The measured value of the bending radius of each bending section is compared with the theoretical value to obtain the change in bending radius caused by material bending rebound under the current bending angle, bending radius and bending direction conditions; further, the measured value of the bending angle of each bending section is compared with the theoretical value to obtain the change in bending angle caused by material bending rebound under the current bending angle, bending radius and bending direction conditions; further, the measured unfolded length of the entire specimen is compared with the theoretical unfolded length to obtain the change in material bending elongation.

[0047] Similarly, the serpentine specimen in this embodiment can also be applied to the bending performance parameter testing of pipes, rods, wires, plates, and profiles, and only the cross-sectional shape of the specimen needs to be changed.

[0048] Example 2

[0049] A serpentine specimen for testing the performance of spatial continuous multi-bend materials is used to test the rebound compensation processing accuracy of catheter CNC bending equipment. The basic structure of the serpentine specimen shown refers to the basic structure of the serpentine specimen in Example 1.

[0050] The process of testing the springback compensation processing accuracy of the catheter CNC bending equipment is as follows:

[0051] Step S1. Based on the first implementation, considering the axial rotational symmetry of the pipe interface, the test piece is simplified. A 20mm outer diameter pipe is selected, with three equal straight sections of 50mm and two 90° bends. The bending radius of the bends is 40mm and the rotation angle is 90°. The data are shown in the table below. The spatial structure is shown in the attached figure. Figure 5 .

[0052]

[0053] Step S2. Input the above data into the catheter CNC bending equipment, perform springback compensation on the equipment, and after completing the CNC bending, measure the actual values of the straight segment length, bending radius, bending angle, and rotation angle to obtain the measured value data. Compare the measured values with the theoretical values to determine whether the springback compensation processing accuracy of the catheter CNC bending equipment meets the requirements.

[0054] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as an obstacle to the scope of protection of this application.

[0055] It should also be noted that, in the description of this application, unless otherwise expressly specified or limited, the terms "disposed," "installed," and "connected" should be understood broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0056] The above description is only a preferred embodiment of the present application and does not constitute any form of obstruction to the present application. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present application fall within the scope of protection of the present application.

Claims

1. A serpentine specimen for testing the performance of spatial continuous multi-bend materials and component bending equipment, characterized by: The serpentine specimen is composed of a linear unit SL and a bending unit SB that rotate alternately to form a spatial continuous multi-bend structure. The linear unit SL is composed of a linear segment Ln, and the bending unit SB includes a horizontal bending area QH, a vertical bending area QV, and a torsional bending area QC. The entire serpentine specimen starts with the linear unit SL and also ends with the linear unit SL. The horizontal bending zone QH is composed of a plurality of straight segments Ln of different lengths and horizontal positive and negative bending segments Sb of different bending radii and bending angles, and is used to implement horizontal bending performance testing of materials and component bending equipment; The vertical bending zone QV is composed of a plurality of straight segments Ln of different lengths and vertical positive and negative bending segments Sb of different bending radii and bending angles, and is used to test the vertical bending performance of materials and component bending equipment; The torsional bending zone QC is composed of multiple straight segments Ln of different lengths and positive and negative bending segments Sb with different bending radii, different bending angles, and different rotation angles, and is used to realize the torsional direction bending performance test of material and component bending equipment.

2. The serpentine test piece for testing the performance of spatial continuous multi-bend materials and component bending equipment according to claim 1 is characterized by: The lengths of the straight line segments Ln in the bending zone are different and are greater than the minimum clamping length for bending the material.

3. The serpentine test piece for testing the performance of spatial continuous multi-bend materials and component bending equipment according to claim 1 is characterized by: The bending angles of the positive and negative bending segments Sb in the bending area are different, and at least five bending segments are set in the small angle range and the large angle range, and at least three bending segments are set in the intermediate angle range; wherein the small angle refers to 0°~20°, the large angle refers to 160°~180°, and the intermediate angle refers to 20°~160°.

4. The serpentine test piece for testing the performance of spatial continuous multi-bend materials and component bending equipment according to claim 1 is characterized by: The bending radii of the positive and negative bending sections Sb in the bending area are different, and the bending radius is not less than the minimum bending radius of the material and not more than three times the minimum bending radius of the material.

5. The serpentine test piece for testing the performance of spatial continuous multi-bend materials and component bending equipment according to claim 1 is characterized by: The torsion direction of the torsion bending zone QC is directed toward the inflection point of the material cross-section shape, and the range of the rotation angle is -180° to 180°.

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