An adjustable elastic boundary experimental device for plate and shell structures

Abstract

An adjustable plate-shell structure elastic boundary test device is composed of a clamp and a lead screw slider mechanism. The lead screw slider mechanism includes a fixed end fan and a movable end fan arranged oppositely. The clamp is an even number of clamps, and each pair of clamps is symmetrically mounted on the fixed end fan and the movable end fan. The clamp includes a clamping bracket, the outer side of the clamping bracket is mounted on the fixed end fan or the movable end fan, and the two inner ends extend horizontal rods inward. A spring column is connected between the two horizontal rods. The middle part of the inner side of the clamping bracket is connected to the lower clamp plate through a rotating pair. The spring column runs through the lower clamp plate. Springs and spring pressure covers are provided on both sides of the spring column. The proximal ends of the springs on both sides are connected to the lower clamp plate, and the distal ends are connected to the spring pressure cover. An upper clamp plate is installed on the lower clamp plate, and a space for clamping a test piece is formed between the upper clamp plate and the lower clamp plate. The present invention can test the mechanical vibration characteristics of straight beams, curved beams, plates, and curved shell-shaped test pieces under elastic boundary conditions.

Description

Technical Field

[0001] The invention belongs to the technical field of test clamping devices, and in particular relates to an adjustable elastic boundary test device for a plate-shell structure. Background Art

[0002] Beams, thin plates and shells are among the components used in large quantities in many industrial sectors such as aerospace. Such structures are generally subjected to in-plane pressure loads, and buckling is the main form of structural failure. Buckling usually occurs suddenly. For plates and shells subjected to compression loads, the bearing capacity of the structure is greatly reduced after buckling, and the deformation increases sharply, eventually leading to damage and even catastrophic consequences. Mechanical vibration tests on beams, thin plates and shells are helpful to understand their dynamic characteristics and failure mechanisms.

[0003] Elastic boundary is one of the most common working conditions, and simulating elastic boundary is one of the keys to mechanical vibration-related tests of test pieces. During the process of implementing experimental operations, the inventors of the present application found that the existing clamping test bench is not applicable or universal for related tests of beams, plates, shells, stiffened plates and stiffened shells, and it is very difficult to test the various mechanical properties of beam, thin plate and shell structure test pieces.

[0004] Therefore, when testing a variety of beams, plates, shells, stiffened plates and stiffened shells, an adjustable plate and shell structure elastic boundary test device is needed that can not only meet the clamping requirements of a variety of different materials at the same time, but also be simple and convenient to operate, so as to replace the existing clamping test bench, which is conducive to controlling experimental variables, reducing experimental errors and reducing experimental costs.

[0005] At the same time, in the process of simulating the elastic boundary, the clamping device is required to meet the needs of mechanical vibration related tests. Therefore, it is necessary to design a clamping device that can adjust the elastic boundary stiffness and cooperate with test pieces of different shapes to realize the simulation of various elastic boundaries. Summary of the invention

[0006] In order to overcome the shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide an adjustable plate and shell structure elastic boundary test device, which changes the rotation angle of the workpiece clamp by changing the expansion and contraction amount of the spring on the clamp, and changes the distance between the fan plates at both ends to match different test pieces, thereby realizing the fixation of test pieces of different shapes and sizes to meet the requirements of relevant tests. It can be used for resin-based composite beams, plates, shells and stiffened plates, and stiffened plate test pieces to carry out modal, transient response, and steady-state response fluctuation characteristic tests.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is:

[0008] A flexible boundary test device for adjustable plate and shell structure, characterized in that it is composed of a clamping jaw 1 and a screw slider mechanism 2, wherein the screw slider mechanism 2 includes a fixed end fan 21 and a movable end fan 25 arranged opposite to each other, the clamping jaw 1 is an even number, and each pair of clamping jaws 1 is symmetrically mounted on the fixed end fan 21 and the movable end fan 25, the clamping jaw 1 includes a clamping bracket 11, the outer side of the clamping bracket 11 is mounted on the fixed end fan 21 or the movable end fan 25, and the two inner ends extend inwardly with horizontal rods, and a spring column 14 is connected between the two horizontal rods, the middle part of the inner side of the clamping bracket 11 is connected to a lower clamping plate 18 through a rotating pair, the spring column 14 penetrates the lower clamping plate 18, and springs 110 and spring pressure covers 15 are arranged on both sides of the lower clamping plate 18 on the spring column 14, the proximal ends of the springs 110 on both sides are connected to the lower clamping plate 18, and the distal ends are connected to the spring pressure covers 15, an upper clamping plate 17 is mounted on the lower clamping plate 18, and a space for clamping a test piece is formed between the upper clamping plate 17 and the lower clamping plate 18.

[0009] The upper clamping plate 17 is connected to the inner end of the lower clamping plate 18 through clamping plate bolts 16 and nuts 19 .

[0010] The compression amount of the spring 110 is controlled by rotating the spring gland 15, thereby changing the stiffness of the elastic boundary.

[0011] The screw slider mechanism 2 includes a screw shaft 24 and a base 27 with a plurality of parallel slide rails 26. A bearing mounting seat 29 for supporting the screw shaft 24 is fixed on the base 27. The screw shaft 24 is arranged on the bearing mounting seat 29 through a rolling bearing 23. One end of the screw shaft 24 is connected to the fixed end fan 21, and the other end is connected to the turntable 28 through a set screw 210. The screw part in the middle section is connected to the movable end fan 25. The bottom of the movable end fan 25 has a slider structure matching the slide rail 26.

[0012] The inner side surfaces of the fixed end fan 21 and the movable end fan 25 are both provided with mounting grooves for mounting the clamping bracket 11. There are multiple mounting grooves on each end fan. On the same end fan, the mounting grooves are distributed horizontally in parallel, or in a scattered fan-shaped distribution, or in a cross-distribution of horizontal parallel and scattered fan-shaped distribution.

[0013] Compared with the prior art, the present invention can test the mechanical vibration characteristics of straight beam, curved beam, plate and curved shell shaped test pieces under elastic boundary conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 Schematic diagram of the elastic boundary experimental device for adjustable plate and shell structures.

[0015] Figure 2 Schematic diagram of the screw slider mechanism.

[0016] Figure 3 Schematic diagram of the clamp.

[0017] Figure 4 This is a schematic diagram of the flat panel assembly.

[0018] Figure 5 This is a schematic diagram of the straight beam assembly.

[0019] Figure 6 This is a schematic diagram of the curved beam assembly.

[0020] Figure 7 This is a schematic diagram of the curved plate assembly. DETAILED DESCRIPTION

[0021] The embodiments of the present invention are described in detail below with reference to the accompanying drawings and examples.

[0022] like Figure 1 As shown, the present invention provides an adjustable plate-shell structure elastic boundary experimental device, which is composed of a clamping jaw 1 and a lead screw slider mechanism 2.

[0023] refer to Figure 2 The lead screw slider mechanism 2 mainly includes a fixed end fan 21 and a movable end fan 25 which are relatively arranged on a base 27, and a lead screw 24 is used to control the distance between the fixed end fan 21 and the movable end fan 25. In its specific structure, four parallel slide rails 26 are installed on the base 27 by bolts, and a bearing mounting seat 29 is fixed by bolts 211. The fixed end fan 21 is fixed to the base 27 by bolts 22, and the lead screw shaft 24 is supported and arranged on the bearing mounting seat 29 by rolling bearings 23. The rolling bearings 23 are used to reduce friction and rotation lubrication, and deep groove ball bearings can be used specifically. The left end of the lead screw shaft 24 is connected to the fixed end fan 21, and the right end is connected to the turntable 28 by a set screw 210. The lead screw part in the middle section is connected to the movable end fan 25, and a slider structure matching the slide rails 26 is provided at the bottom of the movable end fan 25. When adjusting the distance between the fixed end fan 21 and the movable end fan 25 , the rotation of the turntable 28 drives the screw shaft 24 to rotate, thereby pushing the movable end fan 25 to move linearly along the slide rail 26 , thereby controlling the distance between the fixed end fan 21 and the movable end fan 25 .

[0024] The inner side surfaces of the fixed end fan 21 and the movable end fan 25 are both provided with mounting grooves for mounting the clamping bracket 11. There are multiple mounting grooves on each end fan. On the same end fan, the mounting grooves are distributed horizontally in parallel, or in a scattered fan-shaped distribution, or in a cross-distribution of horizontal parallel and scattered fan-shaped distribution to meet different experimental needs.

[0025] The clamping jaws 1 are the core clamping device, which are mainly responsible for clamping the test workpiece and providing elastic constraints for the test workpiece. The number of the clamping jaws 1 should be an even number, and each pair of clamping jaws 1 is symmetrically installed on the fixed end fan 21 and the movable end fan 25.

[0026] refer to Figure 3The clamping jaw 1 includes a clamping bracket 11, which is the main component of the clamping jaw 1. The outer side of the clamping bracket 11 is installed on the fixed end fan 21 or the movable end fan 25 through a nut 3 12 and a bolt 3 13. The two ends of the inner side extend horizontal rods inward. A spring column 14 is fixedly connected between the two horizontal rods through a nut 4 111. The spring column 14 can adopt a long threaded column structure. The middle part of the inner side of the clamping bracket 11 is connected to the lower clamping plate 18 through a rotating pair. The spring column 14 penetrates the lower clamping plate 18. The spring column 14 is provided with springs 110 and spring pressure caps 15 on both sides of the lower clamping plate 18. The proximal ends of the springs 110 on both sides are connected to the lower clamping plate 18, and the distal ends are connected to the spring pressure caps 15. The spring pressure caps 15 press the upper and lower springs 110 of the spring column 14. The compression amount of the spring 110 is controlled by rotating the spring pressure caps 15, thereby changing the stiffness of the elastic boundary and adjusting the stiffness of the elastic boundary.

[0027] The upper clamping plate 17 is connected to the upper inner end of the lower clamping plate 18 by means of the clamping plate bolts 16 and the nuts 19. A space for clamping the test piece is formed between the upper clamping plate 17 and the lower clamping plate 18. The lower clamping plate 18 can adjust its angle and fix the test piece between the upper and lower clamping plates by means of the clamping plate bolts 16 and the upper clamping plate 17.

[0028] The present invention freely selects the number of clamps 1 installed and sets them on the fixed end fan 21 and the movable end fan 25, and adjusts the expansion and contraction of the elastic boundary to clamp different test pieces to be tested. It is suitable for clamping different test pieces such as straight beams, curved beams, plates, shells, etc. of resin-based composite materials, and is also suitable for clamping other test pieces of different materials with similar sizes and shapes. The overall structural design of the experimental device is ingenious, the processing is not complicated, and the scope of application is relatively wide.

[0029] The implementation process of the present invention is as follows:

[0030] Install the clamp: Arrange the clamp 1 at a suitable position and connect it with the fixed end fan 21 and the movable end fan 25 through nuts 3 12 and bolts 3 13.

[0031] Adjust the fan plate spacing: Turn the turntable 28 to change the fixed end fan 21 and the movable end fan 25 to a predetermined distance.

[0032] Install the test piece: adjust the angle of the lower clamping plate 18 of the clamp 1 and fix the test piece with the upper clamping plate 17 through the clamping plate bolts 16.

[0033] Adjusting the stiffness of the elastic boundary: rotating the spring pressure cap 15, adjusting the compression amount of the spring 110, and thereby changing the stiffness of the elastic boundary.

[0034] In a specific experiment, the arrangement of the clamping jaws 1 can be changed along the mounting groove on the end fan according to the needs of the test piece to match test pieces of different shapes and types, as shown below:

[0035] like Figure 4 As shown, for the flat test piece, firstly, multiple clamps 1 are installed on the fixed end fan 21 and the movable end fan 25 on the left and right sides, that is, multiple point supports are arranged on the left and right sides of the end fans, and then the turntable 28 is rotated to move the movable end fan 25 to a predetermined position, and finally the flat test piece is clamped on the clamps 1, and the stiffness of the elastic boundary is changed by rotating the spring pressure cover 15.

[0036] like Figure 5 As shown, for the straight beam test piece, firstly, a clamp 1 is installed on each of the fixed end fan 21 and the movable end fan 25, and then the distance between the fixed end fan 21 and the movable end fan 25 is adjusted by rotating the turntable 28. Finally, the straight beam test piece is fixed by the clamp 1, and the elastic constraint is adjusted by rotating the spring pressure cover 15 to achieve elastic support.

[0037] like Figure 6 As shown, for the curved beam test piece, the assembly method is similar to that of the straight beam test piece. The difference is that when clamping the test piece, the angle of the lower clamping plate 18 should be properly adjusted to match the curvature of the curved beam, thereby achieving elastic support for the test piece.

[0038] like Figure 7 As shown, for the curved plate test piece, firstly, a plurality of clamps 1 should be arranged at the fixed end fan 21 and the movable end fan 25 according to the curvature of the curved plate to serve as multiple point supports. Secondly, the turntable 28 is rotated to move the movable end fan 25 to a predetermined position, and then the flat plate test piece is clamped onto the clamps 1. Finally, the stiffness of the elastic boundary is changed by rotating the spring pressure cover 15 and adjusting the angle of the lower clamp 18.

Claims

1. An adjustable plate and shell structure elastic boundary test device, characterized in that: The invention is composed of a clamping jaw (1) and a screw slider mechanism (2), wherein the screw slider mechanism (2) comprises a fixed end fan (21) and a movable end fan (25) arranged opposite to each other, wherein the clamping jaws (1) are an even number, and each pair of clamping jaws (1) is symmetrically mounted on the fixed end fan (21) and the movable end fan (25), wherein the clamping jaw (1) comprises a clamping bracket (11), wherein the outer side of the clamping bracket (11) is mounted on the fixed end fan (21) or the movable end fan (25), and the inner two ends extend inwardly with horizontal rods, and a spring column (14) is connected between the two horizontal rods, and the inner middle part of the clamping bracket (11) is rotated. The lower clamping plate (18) is connected to the auxiliary clamping plate (18), the spring column (14) passes through the lower clamping plate (18), and springs (110) and spring pressure covers (15) are arranged on the spring column (14) on both sides of the lower clamping plate (18). The proximal ends of the springs (110) on both sides are connected to the lower clamping plate (18), and the distal ends are connected to the spring pressure covers (15). An upper clamping plate (17) is installed on the lower clamping plate (18), and a space for clamping the test piece is formed between the upper clamping plate (17) and the lower clamping plate (18). The compression amount of the spring (110) is controlled by rotating the spring pressure cover (15), thereby changing the stiffness of the elastic boundary; The inner side surfaces of the fixed end fan (21) and the movable end fan (25) are both provided with mounting grooves for mounting the clamping bracket (11), and each end fan has a plurality of mounting grooves. On the same end fan, the mounting grooves are distributed in horizontal parallel, or in a scattered fan-shaped distribution, or in a cross distribution of horizontal parallel and scattered fan-shaped distribution.

2. The adjustable plate and shell structure elastic boundary test device according to claim 1 is characterized in that: The upper clamping plate (17) is connected to the inner end of the lower clamping plate (18) through a clamping plate bolt (16) and a nut (19).

3. The adjustable plate and shell structure elastic boundary test device according to claim 1 is characterized in that: The screw slider mechanism (2) comprises a screw shaft (24) and a base (27) with a plurality of parallel slide rails (26); a bearing mounting seat (29) for supporting the screw shaft (24) is fixed on the base (27); the screw shaft (24) is arranged on the bearing mounting seat (29) via a rolling bearing (23); one end of the screw shaft (24) is connected to a fixed end fan (21), and the other end is connected to a turntable (28) via a set screw (210); the screw part in the middle section is connected to a movable end fan (25); and a slider structure matching the slide rail (26) is provided at the bottom of the movable end fan (25).

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