Massive equipment interface strength test device and method for a load-carrying cylinder

Abstract

The application discloses a kind of strength test device of force cylinder large mass equipment interface, including first loading tooling, second loading tooling, distributed force loading tooling and concentrated force loading tooling;First loading tooling evenly distributes the concentrated force F1 applied by uniaxial tensile testing machine to two second loading tooling, and the stress of each second loading tooling is 1 / 2F1;Second loading tooling decomposes 1 / 2F1 into F2 and F3;Wherein F2 is converted into distributed load loaded on the top of test piece by distributed force loading tooling, and F3 is converted into concentrated load loaded on the load interface of test piece by concentrated force loading tooling.The application also discloses a kind of strength test method realized by above-mentioned device, comprising: preparing test piece, and setting load interface on test piece;Using above-mentioned device to load distributed load and concentrated load, and obtaining equipment interface strength.The application can realize complex load stress by uniaxial tensile test, and has wide application prospect in spacecraft structure technical field.

Description

Technical Field

[0001] This invention belongs to the field of spacecraft structure technology, specifically relating to a test device and method for the interface strength of large-mass equipment with load-bearing cylinders. Background Technology

[0002] Plate-and-box satellite structures with a load-bearing cylinder as the main load-bearing structure are widely used in large communication and navigation satellites due to their light weight and high load-bearing capacity. During the satellite launch phase, the central load-bearing cylinder bears the overload load of all satellite equipment. For the interfaces of large-mass equipment (such as storage tanks) on the load-bearing cylinder, they must withstand both the distributed force load transmitted from the entire satellite and the concentrated force of the large-mass equipment itself. The local structural load is large and the stress mode is relatively complex, requiring the design of interface strength tests for evaluation.

[0003] Currently, traditional strength tests for the interfaces of large-mass load-bearing cylinders require the entire load-bearing cylinder as the test specimen for verification. In the early stages of model development, the development cycle of load-bearing cylinders for production is long and the cost is high; moreover, if there are problems with the interface design, there is a risk of failure in the development of the load-bearing cylinder. Therefore, it is necessary to consider a simple strength testing device and method to reasonably assess and verify this. Summary of the Invention

[0004] The purpose of this invention is to overcome the aforementioned shortcomings and provide a testing device and method for the interface strength of large-mass load-bearing cylinder equipment, solving the technical problem that existing methods for testing the interface strength of large-mass load-bearing cylinder equipment are difficult to implement. This invention can achieve complex load-bearing through uniaxial tensile testing, and has broad application prospects in the field of spacecraft structural technology.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0006] A test device for the interface strength of a large-mass load-bearing cylinder includes a first loading fixture, a second loading fixture, a distributed force loading fixture, and a concentrated force loading fixture;

[0007] The first loading fixture distributes the concentrated force F1 applied by the uniaxial tensile testing machine evenly to the two second loading fixtures, with each second loading fixture receiving a force of 1 / 2 F1;

[0008] The second loading fixture decomposes 1 / 2F1 into F2 and F3 through leverage; F2 is converted into a distributed load applied to the top of the test piece by the distributed force loading fixture, and F3 is converted into a concentrated load applied to the load interface of the test piece by the concentrated force loading fixture.

[0009] Furthermore, the cross-section of the first loading fixture is an isosceles triangle, with a concentrated force F1 applied at the vertex of the isosceles triangle, and the two base angles of the isosceles triangle are respectively connected to two second loading fixtures.

[0010] Furthermore, the cross-section of the second loading fixture is triangular, and the apex of the triangle is connected to the first loading fixture;

[0011] The lever ratio is adjusted by adjusting the side length ratio of the second loading fixture, thereby adjusting the ratio of distributed load and concentrated load applied to the test piece.

[0012] Furthermore, the distributed force loading fixture includes a support part and cantilever parts connected to both sides of the support part. The support part contacts the top of the test piece, and the contact surface is a plane. The cantilever parts on both sides are respectively connected to one of the bottom corners of the two second loading fixtures, so that F2 is transferred from the second loading fixtures to the distributed force loading fixture.

[0013] Furthermore, the concentrated force loading fixture includes vertical beams, horizontal beams, and connecting parts;

[0014] There are two vertical beams. The first end of the two vertical beams is connected to the other bottom corner of the two second loading fixtures, and the second end of the two vertical beams is connected to the horizontal beam; F3 is transferred from the second loading fixture to the horizontal beam;

[0015] The crossbeam connects to the load interface of the test specimen via a connector, transferring F3 to the load interface of the test specimen.

[0016] Furthermore, the test specimen has three load interfaces, with the middle load interface located on the line of symmetry of the test specimen, and the two load interfaces on both sides being symmetrical about the line of symmetry of the test specimen;

[0017] By adjusting the positions of the two connection points between the two vertical beams and the horizontal beam, the load ratio transmitted from the vertical beams to the intermediate load interface and the load interfaces on both sides can be adjusted.

[0018] Furthermore, the first loading fixture and the second loading fixture, the second loading fixture and the distributed force loading fixture, and the distributed force loading fixture and the concentrated force loading fixture are all connected by column hinges.

[0019] The hinge hole at the connection between the second loading fixture and the distributed force loading fixture is a transverse elliptical hole.

[0020] A method for testing the interface strength of a large-mass load-bearing cylinder equipment, comprising:

[0021] S1 prepares the test specimen and sets the load interface on the test specimen;

[0022] S2 uses the aforementioned test device for the interface strength of a large-mass load-bearing cylinder to apply distributed loads and concentrated loads to obtain the interface strength of the equipment.

[0023] Furthermore, the test specimen is a straight plate specimen, and the thickness of the straight plate specimen is the same as that of the load-bearing cylinder.

[0024] Furthermore, a reinforcing beam is pre-embedded at the top of the test specimen; the top of the test specimen has chamfers at both ends, with a slope of 45°, and the side length of each chamfer is 1 / 9 to 1 / 7 of the width of the top of the test specimen.

[0025] Compared with the prior art, the present invention has at least one of the following advantages:

[0026] (1) This invention creatively proposes a symmetrical load loading device, which utilizes a special structural design to enable complex loads to be applied through a uniaxial tensile test, saving time and costs and providing significant economic benefits.

[0027] (2) The experimental loading fixture of the present invention is simple in design, easy to process and implement, and can reasonably distribute the structural distributed force and the interface concentrated force;

[0028] (3) This invention provides a simplified method for test specimens, which greatly improves test efficiency while ensuring test accuracy and has strong applicability. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the test specimen for the present invention;

[0030] Figure 2 This is a schematic diagram of the top boundary design of the test piece of the present invention;

[0031] Figure 3 This is a schematic diagram of the symmetrical load loading device of the present invention;

[0032] Figure 4 This is a schematic diagram of the load distribution in the static test of the present invention;

[0033] Figure 5 This is a schematic diagram of the lateral constraint of the load loading device of the present invention. Detailed Implementation

[0034] The features and advantages of the present invention will become clearer and more apparent from the following detailed description.

[0035] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments. Although various aspects of embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless specifically indicated otherwise.

[0036] This invention proposes a test method for assessing the interface strength of large-mass load-bearing cylinder equipment, which can ensure reasonable and sufficient assessment and verification, and can be implemented using a simple uniaxial tensile testing machine.

[0037] This invention provides a method for testing the interface strength of a large-mass load-bearing cylinder, comprising:

[0038] 1) To simplify the design of the test specimen while meeting the experimental objectives, the specimen design needs to be simplified. The load-bearing cylinder is a cylindrical arc-shaped shell structure. For the cylindrical shell structure, the curvature parameter of the curved plate is...

[0039]

[0040] Where R: radius of curvature of the shell skin;

[0041] t: Skin thickness;

[0042] b: Width of the skin curved plate;

[0043] μ: Poisson's ratio of the material

[0044] When Z≤40, the performance of the curved plate after wrinkling is close to that of a flat plate. The diameter of the load-bearing cylinder is generally above 1m, and the curvature parameter is less than 40; therefore, a straight plate can be used as a substitute for the curved test specimen. See [link to relevant documentation]. Figure 1 To ensure uniformity of the concentrated force loading at the interfaces and to simplify the design of the loading device, three device interfaces need to be selected for loading.

[0045] The design parameters for the structural plates and interfaces of the straight-plate test specimen are the same as those for the load-bearing cylinder structure. The dimensions of the test specimen are based on the assumption that the stress at the large-mass interface under test loading is comparable to the actual situation under full-scale launch. Figure 1 For example, through comparative simulation analysis, it was determined that the width of the test piece is approximately 4 interface spacings (in addition to the two interface spacings, there is 1 interface spacing on each side of the interface); the height of the test piece is approximately 5 interface spacings (specifically, there is 2 interface spacings above the interface and 3 interface spacings below the interface).

[0046] The test specimen has an axisymmetric structure (see Figure 2 To ensure the stiffness of the loading interface at the top of the test specimen, a reinforcing beam 6 needs to be pre-embedded in the top structural plate of the test specimen. At the same time, to ensure the uniformity of the force after the top distributed force is transferred to the interface section, the top two ends of the test specimen need to adopt a chamfer design with a chamfer slope of 45 degrees and the side length of each chamfer is approximately 1 / 8 of the top width.

[0047] 2) A symmetrical load loading device is used to apply distributed and concentrated loads to the test specimen, such as... Figure 3 and Figure 4The test loading device adopts a combination of a first loading fixture 1, a second loading fixture 2, a distributed force loading fixture 3, and a concentrated force loading fixture 4. The first loading fixture 1, the second loading fixture 2, the distributed force loading fixture 3, and the concentrated force loading fixture 4 are all connected by column hinges. The column hinge holes on one side of the first loading fixture 1 and the second loading fixture 2, the second loading fixture 2, and the distributed force loading fixture 3 are transverse elliptical holes to release the lateral degree of freedom and avoid the generation of additional bending moments in the connection links during load transfer, which would affect the load distribution.

[0048] Loading fixture 2 distributes concentrated force F1 through a lever system to satisfy the load distribution of the test piece distributed force and the concentrated force of the equipment interface.

[0049] To ensure that the forces at the three concentrated load interfaces are equal, the concentrated load loading fixture 4 transmits the load to the crossbeam and then distributes it through a lever system. The load ratio transmitted from each vertical beam to the side interface and the center interface is approximately 2:1.

[0050] During the distribution process of a single load applied by a tensile testing machine, a bending moment along the transverse direction of the specimen can be introduced, causing the specimen to bend. In this case, the transverse displacement of the distributed force loading fixture 3 should be constrained, such as... Figure 5 The distributed force loading fixture 3 is equipped with a lateral constraint structure 7. The lateral constraint structure 7 can be implemented by using a triangular support structure installed on the fixing fixture at the root of the test piece.

[0051] Example:

[0052] The experimental method provided by the present invention will be further described in detail below with reference to the accompanying drawings.

[0053] First, test specimen 5 is mounted on a uniaxial tensile testing machine using a fixed fixture. The uniaxial tensile testing machine applies a concentrated force F1 to test specimen 5 through the first loading fixture 1. The concentrated force F1 is evenly distributed and transmitted from the first loading fixture 1 to the second loading fixture 2 via lever action (both lever arms are a), decomposing into 1 / 2F1. Through the lever action of the second loading fixture 2 (lever arms b and c respectively), 1 / 2F1 is decomposed into F2 and F3. The force of F2 on both sides is distributed and applied to the top of the test specimen through the distributed force loading fixture 3 (i.e., distributed force 2F3 on the test specimen); the force of F3 on both sides is applied to the interface of the large-mass equipment through the concentrated force loading fixture 4 (i.e., concentrated force 2F2 at the interface).

[0054] The total load on the test specimen was obtained through whole-plane mechanical analysis.

[0055] The distribution ratio of the force distributed at the top of the test piece and the concentrated force at the interface is adjusted by adding the lever ratio of the second loading fixture 2.

[0056] During the distribution process, a single load applied by the tensile testing machine can introduce a bending moment along the transverse direction of the specimen, causing the specimen to bend. In this case, the transverse displacement of the distributed force loading fixture 3 should be constrained.

[0057] The present invention has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and embodiments of the present invention without departing from the spirit and scope of the invention, and all such modifications and improvements fall within the scope of the present invention. The scope of protection of the present invention is defined by the appended claims.

[0058] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A test device for the interface strength of a large-mass load-bearing cylinder, characterized in that, It includes a first loading fixture (1), a second loading fixture (2), a distributed force loading fixture (3), and a concentrated force loading fixture (4); The first loading fixture (1) distributes the concentrated force F1 applied by the uniaxial tensile testing machine evenly to the two second loading fixtures (2), and each second loading fixture (2) is subjected to a force of 1 / 2F1; The second loading fixture (2) decomposes 1 / 2F1 into F2 and F3 through lever action; F2 is converted into a distributed load applied to the top of the test piece by the distributed force loading fixture (3), and F3 is converted into a concentrated load applied to the load interface of the test piece by the concentrated force loading fixture (4); The cross section of the first loading fixture (1) is an isosceles triangle. A concentrated force F1 is applied at the vertex of the isosceles triangle, and the two base corners of the isosceles triangle are connected to two second loading fixtures (2). The cross section of the second loading fixture (2) is triangular, and the first loading fixture (1) is connected at the apex of the triangle. The lever ratio is adjusted by adjusting the side length ratio of the second loading fixture (2), thereby adjusting the ratio of distributed load and concentrated load applied to the test piece; The distributed force loading fixture (3) includes a support part and cantilever parts connected to both sides of the support part. The support part is in contact with the top of the test piece, and the contact surface is a plane. The cantilever parts on both sides are respectively connected to one of the bottom corners of the two second loading fixtures (2) to transfer F2 from the second loading fixtures (2) to the distributed force loading fixture (3). The concentrated force loading fixture (4) includes a vertical beam, a horizontal beam, and connecting parts; There are two vertical beams. The first end of the two vertical beams is connected to the other bottom corner of the two second loading fixtures (2), and the second end of the two vertical beams is connected to the horizontal beam. F3 is transferred from the second loading fixture (2) to the horizontal beam. The crossbeam connects to the load interface of the test specimen via a connector, transferring F3 to the load interface of the test specimen.

2. The test device for the interface strength of a large-mass load-bearing cylinder according to claim 1, characterized in that, The test specimen has three load interfaces, with the middle load interface located on the line of symmetry of the test specimen, and the two load interfaces on both sides symmetrical about the line of symmetry of the test specimen; By adjusting the positions of the two connection points between the two vertical beams and the horizontal beam, the load ratio transmitted from the vertical beams to the intermediate load interface and the load interfaces on both sides can be adjusted.

3. The test device for the interface strength of a large-mass load-bearing cylinder according to claim 1, characterized in that, The first loading fixture (1) and the second loading fixture (2), the second loading fixture (2) and the distributed force loading fixture (3), and the distributed force loading fixture (3) and the concentrated force loading fixture (4) are all connected by column hinges; The hinge hole at the connection between the second loading fixture (2) and the distributed force loading fixture (3) is a transverse elliptical hole.

4. A method for testing the interface strength of a large-mass load-bearing cylinder, characterized in that, include: S1 prepares the test specimen and sets the load interface on the test specimen; S2 uses the load-bearing cylinder large mass equipment interface strength test device according to any one of claims 1-3 to apply distributed load and concentrated load to obtain the equipment interface strength.

5. The method for testing the interface strength of a large-mass load-bearing cylinder according to claim 4, characterized in that, The test specimen is a straight plate specimen, and the thickness of the straight plate specimen is the same as that of the load-bearing cylinder.

6. The method for testing the interface strength of a large-mass load-bearing cylinder according to claim 5, characterized in that, A reinforcing beam is pre-embedded at the top of the test specimen; the top of the test specimen is provided with chamfers at both ends, the slope of the chamfers is 45°, and the side length of each chamfer is 1 / 9 to 1 / 7 of the width of the top of the test specimen.

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