Universal device for measuring side pressure strength of sandwich structure

Abstract

The utility model belongs to the field of testing of material performance tests, and particularly relates to a universal device for measuring the lateral pressure strength of a sandwich structure, which comprises a test piece, a first fixing device and a second fixing device, the first fixing device and the second fixing device respectively support the upper and lower ends of the test piece; the first fixing device and the second fixing device each comprise a base, a lateral tightening screw, a clamping plate, an L-shaped limiting strip, a second tightening screw, a bottom tightening nut and a locking nut. The lateral tightening screws are in threaded connection with the interiors of the lateral threaded holes of the base, and the bottom tightening nuts are connected with the interiors of the kidney-shaped holes in the bottom of the base in a penetrating mode. By adjusting the position of the centering limiting strip for the first time, the device can be used for fixing the mounting position of the test piece with the same size every time, and errors caused by centering of the test piece are reduced. The clamping plates are connected with the base through screws, tight contact of the clamping plates and the base can be achieved, and insufficient supporting of the test piece caused by rotation of the clamping plates is prevented.

Description

Technical Field

[0001] The present application belongs to the field of material performance testing, and in particular relates to a universal device for measuring the lateral compressive strength of a sandwich structure. Background Art

[0002] A sandwich structure is a composite plate and shell structure, with two thin panels formed from thin sheet metal, sandwiched between a lightweight core. The former requires high strength, while the latter requires light weight, a combination that yields excellent bending resistance and lightweight performance. Currently, honeycomb sandwich structures are widely used in aircraft applications such as ailerons, horizontal tails, and rudders due to their excellent performance. To fully understand the mechanical properties of sandwich structures, lateral pressure tests are often used to measure the structure's compressive properties parallel to the sandwich panels.

[0003] The main test standard at present is ASTM C364, which uses Figure 1 The lateral pressure device shown here primarily comprises a base 1, lateral tightening screws 2, and a clamping plate 3. One end of a lateral pressure specimen 8 is placed vertically in the center of base 1. Lateral tightening screws 2 on either side of the base are tightened until clamping plate 3 contacts specimen 8. The other end is similarly installed. The completed assembly is then placed on the compression platform to complete the test.

[0004] This test device has the following disadvantages:

[0005] 1. The specimen lacks a centering device during installation, which can easily lead to errors in placement position each time.

[0006] 2. There is no constraint connection between the splint and the base. When tightening the screws on both sides, it is easy to lift the splint, making the splint unable to support the specimen well. Figure 2 .

[0007] 3. The splints on both sides of the specimen are in a free-moving state. The screws on both sides of the base may loosen during each installation and disassembly process, causing the splints to move left and right during each installation, resulting in deviation.

[0008] In summary, it is very important to conduct lateral compression performance tests on sandwich structures by designing and improving a universal test device suitable for lateral pressure tests. Summary of the Invention

[0009] The purpose of the present application is to provide a universal device for measuring the lateral compressive strength of a sandwich structure, so as to solve the problem that the existing universal testing devices lack a centering device.

[0010] The technical solution of the present application is: a universal device for measuring the lateral compressive strength of a sandwich structure, comprising a test piece, a first fixing device and a second fixing device; the first fixing device and the second fixing device respectively support the upper and lower ends of the test piece;

[0011] The first fixing device and the second fixing device both include a base, a lateral tightening screw, a splint, an L-shaped limit strip, a second tightening screw, a bottom tightening nut and a locking nut; the cross-section of the base is a U-shaped structure, the side of the base is provided with a threaded hole, and the bottom is provided with a waist-shaped hole, the lateral tightening screw is threadedly connected to the threaded hole on the side of the base, and the bottom tightening nut is connected to the waist-shaped hole at the bottom of the base, there are two groups of splints and they are symmetrically arranged inside the opening of the base, the L-shaped limit strip is horizontally arranged above the splint, and the inner wall of the L-shaped limit strip is in contact with the specimen; the top of the splint is provided with a threaded hole, and the second tightening screw is threadedly connected to the top of the L-shaped fiber strip and the splint; the locking nut is connected to the end of the lateral tightening nut.

[0012] Preferably, a threaded hole is provided at the bottom of the splint, and the bottom tightening nut passes through the waist-shaped hole and is threadably engaged with the threaded hole at the bottom of the splint.

[0013] Preferably, the L-shaped limiting strips are provided in a group and are arranged on one of the clamping plates.

[0014] Preferably, the waist-shaped hole on the base is stepped.

[0015] The universal device for measuring the lateral compressive strength of sandwich structures of the present application has the following advantages:

[0016] By adjusting the position of the centering limit strip for the first time, this device can achieve a fixed installation position for specimens of the same size each time, reducing errors caused by specimen centering.

[0017] Using screws to connect the splint to the base can achieve close contact between the splint and the base, preventing the splint from rotating and causing insufficient support for the specimen; the waist-shaped hole at the bottom of the base can be used to adjust the position of the splint to meet the needs of specimens of different thicknesses.

[0018] Install locking nuts on the inside of the screws on both sides. For specimens of the same size, adjust the center position of the splint and the specimen for the first time, tighten the screws on both sides, and tighten the nuts to fix the position of the splint and the specimen each time and improve the installation accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions provided by this application, the following is a brief introduction to the accompanying drawings. Obviously, the accompanying drawings described below are only some embodiments of this application.

[0020] Figure 1 Schematic diagram of a common device for lateral compression testing of existing sandwich structures;

[0021] Figure 2 This is a schematic diagram of the problems encountered in the installation of the existing lateral compression test fixture;

[0022] Figure 3 This is the overall structure diagram of the universal device for lateral compression testing of sandwich structures used in this application;

[0023] Figure 4 This is an axonometric and partially exploded view of the overall structure of the first fixing device of this application;

[0024] Figure 5 This is an overall exploded view of the first fixing device of this application.

[0025] 1. Base; 2. Lateral tightening screws; 3. Clamp; 4. L-shaped limit strip; 5. Second tightening screw; 6. Bottom tightening nut; 7. Locking nut; 8. Test piece; 9. First fixing device; 10. Second fixing device. DETAILED DESCRIPTION

[0026] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0027] A universal device for measuring the lateral compressive strength of sandwich structures can achieve test piece adjustment and alignment during installation, ensure full contact between the clamping plate and the test piece, and prevent errors caused by the position of the clamping plate shifting during each installation, thereby accurately measuring the lateral compressive strength performance.

[0028] like Figure 3 As shown, it includes a test piece 8, a first fixing device 9 and a second fixing device 10. The first fixing device 9 and the second fixing device 10 support the upper and lower ends of the test piece 8 respectively.

[0029] The first fixing device 9 and the second fixing device 10 have the same structure. The first fixing device 9 is used as an example for description. Figure 4-Figure 5 As shown, the first fixing device 9 includes a base 1, lateral tightening screws 2, a clamping plate 3, an L-shaped limiting strip 4, a second tightening screw 5, a bottom tightening nut 6, and a locking nut 7. The base 1 has a U-shaped cross-section, with threaded holes on the sides and a waist-shaped hole on the bottom. The lateral tightening screws 2 are threadedly connected to the lateral threaded holes of the base 1, and the bottom tightening nut 6 is connected to the waist-shaped hole at the bottom of the base 1. There are two sets of clamping plates 3 and they are symmetrically arranged inside the opening of the base 1. The L-shaped limiting strip 4 is horizontally arranged above the clamping plates 3. The inner wall of the L-shaped limiting strip 4 is in contact with the test piece 8 to limit the test piece 8. The top of the clamping plate 3 has a threaded hole, and the second tightening screw 5 is threadedly connected to the top of the L-shaped fiber strip and the clamping plate 3. The locking nut 7 is connected to the end of the lateral tightening nut.

[0030] Preferably, a threaded hole is provided at the bottom of the splint 3 , and the bottom tightening nut 6 passes through the waist-shaped hole and is threadedly engaged with the threaded hole at the bottom of the splint 3 to meet the needs of test pieces 8 with different thicknesses.

[0031] Preferably, there is a group of L-shaped limiting strips 4 and they are arranged on one of the clamping plates 3. Since only one side of the L-shaped limiting strips 4 is needed to limit the test piece 8, this design can effectively simplify the structure.

[0032] Preferably, the waist-shaped hole on the base 1 is stepped to prevent the bottom tightening nut 6 from falling off.

[0033] During the implementation process, first install one end of the specimen 8 with the fixture, and then install the other end in reverse. First, calculate the size of the limit strip from the front side of the splint 3 according to the width of the specimen 8, and adjust the limit strip to the appropriate position; center the two splints 3 in the middle of the base 1, separate them to the sides by the distance of the thickness of the specimen 8, install the specimen 8, make the sides of the specimen 8 press against the limit strip, use a caliper to measure whether the distance between the specimen 8 and the left and right sides of the base 1 is consistent, and make fine adjustments; tighten the left and right lateral tightening screws 2 of the base 1 several times to make the side of the splint 3 in close contact with the specimen 8, and then tighten the bottom tightening screws to make the bottom of the splint 3 in full contact with the surface of the base 1, fix its position, and screw the locking nut 7 to prevent the lateral tightening screw 2 from loosening. After one side is installed, install the other side in the same way to complete the installation of the lateral pressure test device.

[0034] When replacing a test piece 8 of the same size after completing a test, it is only necessary to loosen the lateral tightening screw 2 on one side of the clamp to allow the splint 3 on one side to move, keep the splint 3 with the limit strip in place, remove the damaged test piece 8, put in a new test piece 8, and tighten the lateral tightening screw 2 again to complete the installation.

[0035] It has the following advantages:

[0036] By adjusting the position of the centering limit strip for the first time, this device can achieve a fixed installation position for specimens of the same size each time, reducing errors caused by specimen centering.

[0037] Using screws to connect the splint to the base can achieve close contact between the splint and the base, preventing the splint from rotating and causing insufficient support for the specimen; the waist-shaped hole at the bottom of the base can be used to adjust the position of the splint to meet the needs of specimens of different thicknesses.

[0038] Install locking nuts on the inside of the screws on both sides. For specimens of the same size, adjust the center position of the splint and the specimen for the first time, tighten the screws on both sides, and tighten the nuts to fix the position of the splint and the specimen each time and improve the installation accuracy.

[0039] Finally, it should be noted that the drawings of the embodiments disclosed in the present invention only involve structures related to the embodiments disclosed in the present invention. Other structures can refer to common designs. In the absence of conflicts, the same embodiment and different embodiments of the present invention can be combined with each other.

[0040] Finally: The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A general device for measuring the lateral compressive strength of a sandwich structure, characterized by: It comprises a test piece (8), a first fixing device (9) and a second fixing device (10); the first fixing device (9) and the second fixing device (10) respectively support the upper and lower ends of the test piece (8); The first fixing device (9) and the second fixing device (10) both comprise a base (1), a lateral tightening screw (2), a clamp (3), an L-shaped limit strip (4), a second tightening screw (5), a bottom tightening nut (6) and a locking nut (7); the base (1) has a U-shaped cross-section, a threaded hole is provided on the side of the base (1), and a waist-shaped hole is provided on the bottom, the lateral tightening screw (2) is threadedly connected to the threaded hole on the side of the base (1), and the bottom tightening screw (5) is screwed to the bottom of the base (1). The nut (6) is connected to the waist-shaped hole at the bottom of the base (1), and there are two groups of splints (3) symmetrically arranged inside the opening of the base (1). The L-shaped limit strip (4) is horizontally arranged above the splint (3), and the inner wall of the L-shaped limit strip (4) is in contact with the test piece (8); a threaded hole is provided on the top of the splint (3), and the second tightening screw (5) is threadedly connected to the top of the L-shaped fiber strip and the splint (3); the locking nut (7) is connected to the end of the lateral tightening nut.

2. The universal device for measuring the lateral compressive strength of a sandwich structure according to claim 1, characterized in that: A threaded hole is provided at the bottom of the splint (3), and the bottom tightening nut (6) passes through the waist-shaped hole and is threadably engaged with the threaded hole at the bottom of the splint (3).

3. The universal device for measuring the lateral compressive strength of a sandwich structure according to claim 1, characterized in that: There is a total of one set of L-shaped limiting strips (4) which are arranged on one of the clamping plates (3).

4. The universal device for measuring the lateral compressive strength of a sandwich structure according to claim 1, characterized in that: The waist-shaped hole on the base (1) is stepped.

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