Vocal cavity vibration test switching device

Abstract

The invention relates to an acoustic cavity vibration test switching device which comprises a bottom plate part and a supporting part. A plurality of through holes are formed in the bottom plate; the supporting part comprises a plurality of stand columns and reinforcing ribs connected with the adjacent stand columns. One end of the stand column is fixed to the bottom plate part, and the other end is fixedly connected with the reinforcing rib. The switching device can be connected with an M12 steel sleeve of a 10T electric vibration table and is connected with an instrument mounting plate at the same time, the acoustic cavity vibration test switching device meets the requirement of first-order resonant frequency, and the weight of the whole device is further reduced; on the basis of guaranteeing the connection strength, the layout of reinforcing ribs and other structures of the device is reasonably designed, and the first-order frequency of the device is further improved.

Description

Technical Field

[0001] The invention relates to a sound cavity vibration test adapter device, which is used for dynamic vibration test. Background Art

[0002] Solid rocket engines have been widely used in various short-range and long-range missiles and space missions due to their simple structure, easy use, and high reliability. Their energy density is very high, generally tens of megawatts per cubic meter. However, there are weak pressure disturbances inside solid rocket engines. Such high energy density may amplify the pressure disturbances and form strong pressure oscillations. Pressure oscillations are the result of the combined effects of engine acoustic vibrations and internal non-steady-state combustion and flow processes, and are usually called unstable combustion.

[0003] When a solid rocket engine experiences unstable combustion, it is usually manifested as periodic or quasi-periodic changes in parameters such as the combustion chamber pressure and the propellant burning rate. The frequency of the change coincides with the natural frequency of the acoustic cavity, which has a certain impact on the engine's internal ballistics and working performance. When the acoustic cavity vibration is more serious, the strong vibration will cause the engine to disintegrate, resulting in increased development costs, delayed development completion time, and even the failure of the missile flight mission.

[0004] In the prior art, in order to avoid the serious consequences caused by acoustic cavity vibration, it is necessary to conduct acoustic cavity vibration tests on the instrument mounting plate and its equipment during the development of a certain model, so as to assess its structural reliability under the acoustic cavity vibration environment. Therefore, it is necessary to design a special acoustic cavity vibration test tooling to carry out the docking installation of the instrument mounting plate and the vibration table surface, and the test tooling must also meet the relevant requirements of support and frequency.

[0005] See also Figure 1-3 , from the outline drawing of a certain type of instrument mounting plate, the docking interface drawing and the 10T electric vibration table slide, the size of the instrument mounting plate docking interface is not consistent with the vibration table hole position, and a special adapter needs to be designed to meet the docking requirements of the test piece and the vibration table surface; the instrument mounting plate needs to be tested for acoustic cavity vibration in three directions, and the existing vibration adapter cannot meet its connection and test thrust requirements, so a special vibration test adapter needs to be designed. Specifically, the instrument mounting plate acoustic cavity vibration special adapter should meet the following requirements:

[0006] 1. The designed device can be connected to the M12 steel sleeve on the vibration table. At the same time, the upper surface of the device is equipped with a connection hole or a connection steel sleeve, which can be connected to the docking hole of the instrument mounting plate;

[0007] 2. The first-order frequency of the designed device should be high to meet the spectrum range requirements of the vibration test of the vibration specimen and reduce the energy output of the electric vibration table;

[0008] 3. The designed device must meet the requirements of stiffness and connection strength, and minimize the mass of the adapter while improving the vibration transmission efficiency, thereby reducing the energy output of the vibration table. Summary of the invention

[0009] 1. Technical issues to be resolved

[0010] In view of the deficiencies and needs of the above-mentioned prior art, the present invention proposes a sound cavity vibration test adapter device, which can be connected to the M12 steel sleeve of the 10T electric vibration table and the instrument mounting plate at the same time. The sound cavity vibration test adapter device meets the requirements of the first-order resonance frequency and further reduces the weight of the entire device; on the basis of ensuring the connection strength, the layout of the device reinforcement ribs and other structures is reasonably designed to further improve the first-order frequency of the device.

[0011] (II) Technical solution

[0012] A sound cavity vibration test adapter device comprises a bottom plate portion and a support portion; the bottom plate portion is integrated by an isosceles trapezoidal structure located on the upper side and a rectangular structure located on the lower side, the lower bottom side of the trapezoid is equal to the long side of the rectangle, and the two corners of the rectangle away from the trapezoid are chamfered, and a plurality of through holes are processed on the bottom plate; the support portion comprises a plurality of columns and reinforcing ribs connecting adjacent columns; one end of the column is fixed to the bottom plate portion, and the other end is fixedly connected to the reinforcing rib; the sound cavity vibration test adapter device is fixedly connected to a 10T electric vibration table slide through the bottom plate portion, and is fixedly connected to an instrument mounting plate of a vibration specimen through the support portion.

[0013] The bottom plate and the support part are both made of hard aluminum. They are welded after cutting and then optimized by finite element modeling. The thickness of the bottom plate is 20mm.

[0014] The through holes in the bottom plate portion are arranged in vertical parallel rows along the center line of the bottom plate portion, and the through holes are arranged in rows on multiple horizontal lines perpendicular to the center line, and the row spacing and column spacing are the same.

[0015] The spacing between adjacent through holes in the same row and column is 100 mm.

[0016] The columns are arranged along the outer periphery of the bottom plate.

[0017] The through hole is punched according to the distribution size of the M12 steel sleeve of the 10T electric vibration table slide, and the diameter of the through hole is 14mm; the column is inlaid with an M8 steel sleeve to facilitate docking with the instrument mounting plate.

[0018] In order to reduce the deadweight and ensure the test strength at the same time, the columns are connected by reinforcing ribs, and the upper ends of the columns are fixedly connected to the reinforcing ribs.

[0019] The acoustic chamber vibration test can provide full-scale vibration testing, including random vibration and sine sweep with a full-scale level of up to 50Grms.

[0020] When performing the axial vibration sinusoidal scanning test, the scanning rate is 4Oct / min, and the first-order frequency range is 20Hz to 1000Hz.

[0021] (III) Beneficial effects

[0022] The present invention provides a sound cavity vibration test adapter device. To ensure the connection requirements between the instrument mounting plate and the vibration table slide table, the dimensions are coordinated according to the distribution size of the slide steel sleeve and the size of the docking hole of the instrument mounting plate. At the same time, the difficulty of device processing and the effectiveness of the connection are considered, and a column + flat plate type adapter device is adopted. In order to ensure that the first-order frequency of the device is as high as possible, a finite element calculation optimization design is performed on the basis of empirical design, and the first-order natural frequency of the device is increased by continuously changing the external dimensions of the adapter and the material mass distribution. The dimensions of each part, the layout of the mounting holes and the steel sleeves are optimized by calculation, and a reasonable structural layout is summarized. The structural optimization is repeated until it meets the test requirements. Finally, the test fixture is tested to verify that the device meets the vibration test requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Outline drawing of a certain type of instrument mounting plate

[0024] Figure 2 Interface diagram of a certain type of instrument mounting plate

[0025] Figure 310T electric vibration table slide appearance

[0026] Figure 4 Schematic diagram of a sound cavity vibration test adapter device of the present invention

[0027] Figure 5 Schematic diagram of the assembly of a sound cavity vibration test adapter device of the present invention and a certain type of instrument mounting plate

[0028] Figure 6 Schematic diagram of the assembly of a sound cavity vibration test adapter device of the present invention, a certain type of instrument mounting plate, and a 10T electric vibration table slide

[0029] Figure 7 Distribution diagram of the bottom plate through holes of a sound cavity vibration test adapter device of the present invention

[0030] Figure 8 Distribution diagram of columns in a sound cavity vibration test adapter of the present invention

[0031] Fig. 9 Schematic diagram of hollowing treatment of a column in a sound cavity vibration test adapter device of the present invention

[0032] Fig.10 Schematic diagram of the reinforcing ribs in a sound cavity vibration test adapter of the present invention DETAILED DESCRIPTION

[0033] See also Figure 4-6 A sound cavity vibration test adapter device of the present invention comprises a bottom plate part and a supporting part; the bottom plate part is integrated by an isosceles trapezoidal structure located on the upper side and a rectangular structure located on the lower side, the lower bottom side of the trapezoid is equal to the long side of the rectangle, and the two corners of the rectangle away from the trapezoid are chamfered, and a plurality of through holes are processed on the bottom plate; the supporting part comprises a plurality of columns and reinforcing ribs connecting adjacent columns; one end of the column is fixed to the bottom plate part, and the other end is fixedly connected to the reinforcing rib; the sound cavity vibration test adapter device is fixedly connected to the slide table of the 10T electric vibration table through the bottom plate part, and is fixedly connected to the instrument mounting plate of the vibration test piece through the supporting part.

[0034] The bottom plate and the supporting part are both made of hard aluminum. They are cut and then welded into shape. After finite element modeling and simulation optimization, the bottom plate is 20mm thick.

[0035] See also Figure 7 The through holes in the bottom plate portion are arranged in vertical parallel rows along the center line of the bottom plate portion, and the through holes are arranged in rows on multiple horizontal lines perpendicular to the center line, and the row spacing and column spacing are the same.

[0036] The spacing between adjacent through holes in the same row and column is 100 mm.

[0037] See also Figure 8 The columns are arranged along the outer periphery of the bottom plate, and the diameter of the columns is 40 mm.

[0038] The through hole is punched according to the distribution size of the M12 steel sleeve of the 10T electric vibration table slide, and the diameter of the through hole is 14mm; the column is inlaid with an M8 steel sleeve to facilitate docking with the instrument mounting plate.

[0039] See also Figure 9-10 In order to reduce the dead weight and ensure the test strength at the same time, the columns are connected by reinforcing ribs, and the upper ends of the columns are fixedly connected to the reinforcing ribs.

[0040] The acoustic chamber vibration test can provide full-scale vibration testing, including random vibration and sine sweep with a full-scale level of up to 50Grms.

[0041] When performing the axial vibration sinusoidal scanning test, the scanning rate is 4Oct / min, and the first-order frequency range is 20Hz to 1000Hz.

[0042] The first-order resonance frequency of the device measured by the linear vibration sine scanning result is 625.6Hz, which is close to the calculated result of 630.03Hz. After experimental testing, the test device can meet the formal test requirements.

Claims

1. A sound cavity vibration test adapter, characterized in that: It includes a bottom plate part and a supporting part; the bottom plate part is integrated by an isosceles trapezoidal structure located on the upper side and a rectangular structure located on the lower side, the lower bottom side of the trapezoid is equal to the long side of the rectangle, and the two corners of the rectangle away from the trapezoid are chamfered, and a number of through holes are processed on the bottom plate; the supporting part includes a number of columns and reinforcing ribs connecting adjacent columns; one end of the column is fixed to the bottom plate part, and the other end is fixedly connected to the reinforcing rib; the acoustic cavity vibration test adapter is fixedly connected to the 10T electric vibration table slide through the bottom plate part, and is fixedly connected to the instrument mounting plate of the vibration specimen through the supporting part.

2. The acoustic cavity vibration test adapter according to claim 1, characterized in that: The base plate and the support part are both made of hard aluminum. They are cut and then welded into shape, and then modeled and optimized through finite element simulation.

3. The acoustic cavity vibration test adapter device according to claim 2, characterized in that: The thickness of the bottom plate is 20mm.

4. The acoustic cavity vibration test adapter according to claim 1, characterized in that: The through holes in the bottom plate portion are arranged in vertical parallel rows along the center line of the bottom plate portion, and the through holes are arranged in rows on multiple horizontal lines perpendicular to the center line, and the row spacing and column spacing are the same.

5. The acoustic cavity vibration test adapter as claimed in claim 4, characterized in that: The spacing between adjacent through holes in the same row and column is 100 mm.

6. The acoustic cavity vibration test adapter according to claim 1, characterized in that: The columns are arranged along the outer periphery of the bottom plate.

7. The acoustic cavity vibration test adapter according to claim 1, characterized in that: The through hole is punched according to the distribution size of the M12 steel sleeve of the 10T electric vibration table slide, and the diameter of the through hole is 14mm; the column is inlaid with an M8 steel sleeve to facilitate docking with the instrument mounting plate.

8. The acoustic cavity vibration test adapter as claimed in claim 1, characterized in that: In order to reduce the deadweight and ensure the test strength at the same time, the columns are connected by reinforcing ribs, and the upper ends of the columns are fixedly connected to the reinforcing ribs.

9. The acoustic cavity vibration test adapter according to claim 1, characterized in that: The acoustic chamber vibration test can provide full-scale vibration testing, including random vibration and sine sweep with a full-scale level of up to 50Grms.

10. The acoustic cavity vibration test adapter device according to claim 9, characterized in that: When performing the axial vibration sinusoidal scanning test, the scanning rate is 4Oct / min, and the first-order frequency range is 20Hz to 1000Hz.

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