Combined impact structure for high-G-value half-sine impact test

Abstract

The invention relates to the technical field of half-sine impact tests, in particular to a combined impact structure for a high-G-value half-sine impact test, which comprises a primary impact seat, a waveform generator and a secondary impact seat, and is characterized in that the primary impact seat can impact an impacted seat of a drop impact table or an impacted seat of a pneumatic impact table; the waveform generator is mounted on the top surface of the primary impact seat; the secondary impact seat is arranged above the top surface of the primary impact seat, and the top surface is suitable for mounting a test piece; the ratio of the weight of the primary impact seat to the weight of the secondary impact seat is equal to or larger than 10. When the primary impact seat moves downwards and collides with the collided seat of the falling impact table / pneumatic impact table, the primary impact seat moves upwards and collides with the secondary impact seat moving downwards, so that the speed variation of the secondary impact seat is increased, and the impact magnitude is improved. On the whole, the impact magnitude can reach 20000 g or above, and the pulse width can reach 0.10 ms or above.

Description

Technical Field

[0001] The invention relates to the technical field of half-sine impact test, and in particular to a combined impact structure for high-G value half-sine impact test. Background Art

[0002] When the aircraft's mechanical structure and its electronic components are working, they are often exposed to dynamic environments such as turbulence, explosion, shock and vibration. Among them, shock refers to a high-level input force pulse acting on the equipment in a short period of time, including mechanical shock, explosion separation shock and ballistic shock. Half-sine shock is a common form of shock.

[0003] Usually, electronic components are used as test pieces, and the half-sine shock test adopts the drop shock form or the pneumatic shock form. Both forms use the impact seat to impact the impact seat once, and can only obtain a small impact magnitude, usually below 5000g (g is the acceleration of gravity). The Hopkinson bar can obtain an impact magnitude of about 100000g, and the continuous pulse width is about 0.05ms, which is only suitable for small-sized product shock testing.

[0004] For some slightly larger electronic components on aircraft, the half-sine shock test requires the shock level to reach more than 20,000g and the pulse width to reach more than 0.10ms. Therefore, how to make the shock level reach more than 20,000g and the pulse width reach more than 0.10ms has become a technical problem that needs to be solved urgently by those skilled in the art. Summary of the invention

[0005] The invention provides a combined impact structure for a high G value half-sine impact test, which is used to solve the problem of how to make the impact magnitude reach more than 20000g and the pulse width reach more than 0.10ms.

[0006] The present invention provides a combined impact structure for a high G value half-sine impact test, comprising:

[0007] A primary impact seat capable of impacting a hit seat of a drop impact table or a hit seat of a pneumatic impact table;

[0008] A waveform generator is installed on the top surface of the primary impact seat;

[0009] The secondary impact seat is arranged above the top surface of the primary impact seat, and the top surface is suitable for mounting the test piece; the ratio of the weight of the primary impact seat to the weight of the secondary impact seat is equal to or greater than 10;

[0010] A bracket, mounted on the top surface of the primary impact seat;

[0011] There are two spring ropes, the axes of which are both vertically arranged, the bottom ends of which are respectively installed on the opposite sides of the top surface of the secondary impact seat, and the top ends of which are respectively installed on the top of the bracket.

[0012] In some of these embodiments, the waveform generator is a rubber pad.

[0013] In some of these embodiments, the waveform generator is wool felt.

[0014] In some embodiments, the waveform generator includes:

[0015] Rubber spring;

[0016] Metal spring embedded in rubber spring.

[0017] In some embodiments, it also includes:

[0018] There are two guide rods, both of which have vertically arranged axes, and the bottom ends of which are respectively mounted on the opposite sides of the top surface of the primary impact seat, and the top ends of which are respectively mounted on the top of the bracket;

[0019] The opposite sides of the secondary impact seat are respectively formed with guide holes for the corresponding side guide rods to pass through.

[0020] In some embodiments, the support comprises:

[0021] beam;

[0022] There are two positioning plates, which are respectively installed at the opposite ends of the top surface of the beam;

[0023] There are four vertical rods; the bottom ends of two of them are respectively installed on one side of the top surface of the primary impact seat, and the top end is fixedly connected to one end of the cross beam through one of the positioning plates; the bottom ends of the other two vertical rods are respectively installed on the other side of the top surface of the primary impact seat, and the top end is fixedly connected to the other end of the cross beam through another positioning plate.

[0024] In some embodiments, it also includes:

[0025] The impact panel is installed on the bottom surface of the primary impact seat.

[0026] The beneficial effects of the present invention are as follows: The combined impact structure for high-G value half-sine impact test of the present invention is provided with a primary impact seat. When the primary impact seat moves downward and collides with the impact seat of the drop impact table / pneumatic impact table, it no longer continues to move downward, but turns to move upward, and collides with the secondary impact seat that is moving downward, so that the speed change of the secondary impact seat increases, thereby improving the impact magnitude. With the help of a waveform generator, the secondary impact seat generates a semi-sine waveform. On the whole, with the help of the combined impact structure for high-G value half-sine impact test, the half-sine impact test can reach an impact magnitude of more than 20,000g, and the pulse width can reach more than 0.10ms. It is suitable for some slightly larger electronic components on aircraft for half-sine impact testing. The rising and falling sections of the measured waveform will not be distorted, and the test data meets the expected requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of some specific embodiments of a combined impact structure for a high G value half-sine impact test of the present invention;

[0028] Figure 2 yes Figure 1 Side view of the combined impact structure for high G half-sine impact test shown;

[0029] Figure 3 yes Figure 1 A top view of the combined impact structure for the high G half-sine impact test shown;

[0030] Figure 4 yes Figure 1 A schematic cross-sectional view of a waveform generator in a combined impact structure for a high G half-sine impact test is shown;

[0031] Figure 5 is used Figure 1 The high-G half-sine shock test shown uses a combined impact structure to perform a half-sine shock test.

[0032] In the accompanying drawings, 110, a primary impact seat; 120, a waveform generator; 121, a rubber spring; 122, a metal spring; 130, a secondary impact seat; 140, a bracket; 141, a crossbeam; 142, a positioning plate; 143, a vertical rod; 150, a spring rope; 160, a guide rod; 161, a limiter; 170, an impact panel. DETAILED DESCRIPTION

[0033] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] As described in the background technology, for some slightly larger electronic components on aircraft, when conducting a half-sine shock test, the shock level is required to reach more than 20,000 g and the pulse width is required to reach more than 0.10 ms. Therefore, how to make the shock level reach more than 20,000 g and the pulse width reach more than 0.10 ms has become a technical problem that needs to be solved urgently by those skilled in the art.

[0035] To solve the above problems, refer to Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 On the one hand, the present invention provides a combined impact structure for a high-G value half-sine impact test, including a primary impact seat 110, a waveform generator 120 and a secondary impact seat 130. The primary impact seat 110 can move downward under the traction of the impact cylinder or under the action of its own gravity to impact the impact seat of the drop impact table or the impact seat of the pneumatic impact table. The waveform generator 120 is installed on the top surface of the primary impact seat 110, and can enable the secondary impact seat 130 to generate an impact waveform with a required pulse width. The secondary impact seat 130 is arranged above the top surface of the primary impact seat 110, and the top surface is suitable for installing test pieces such as electronic components of spacecraft.

[0036] The process and principle of conducting a half-sine impact test with a combined impact structure for a high-G half-sine impact test are as follows:

[0037] Under the traction of the impact cylinder or the action of its own gravity, the primary impact seat 110 and the waveform generator 120 move downward. When the primary impact seat 110 collides with the impact seat of the drop impact table / pneumatic impact table, it no longer continues to move downward, but turns to move upward, and collides with the secondary impact seat 130 that is moving downward, so that the speed change of the secondary impact seat 130 increases, thereby increasing the impact magnitude. On the whole, by using the combined impact structure for high-G half-sine impact test to conduct a half-sine impact test, the impact magnitude can reach more than 20,000g, and the pulse width can reach more than 0.10ms, which is suitable for some slightly larger electronic components on the aircraft for half-sine impact testing. The rising and falling sections of the measured waveform will not be distorted, and the test data meets the expected requirements.

[0038] It should be noted that the collision process between the primary impact seat 110 and the impact seat of the drop impact table / pneumatic impact table conforms to the law of conservation of momentum. The collision process between the primary impact seat 110 and the secondary impact seat 130 also conforms to the law of conservation of momentum. Assume that the mass of the primary impact seat 110 is m 1 , the mass of the secondary impact seat 130 is m 2 , assuming that before the primary impact seat 110 collides with the secondary impact seat 130, the speed of the primary impact seat 110 is V 1 , the secondary impact seat 130 speed is V 2 After the primary impact seat 110 collides with the secondary impact seat 130, the speed of the primary impact seat 110 is V 1 ', the secondary impact seat 130 speed is V 2 '.

[0039] According to collision theory:

[0040] m1v1+m21v2=m1v1+m22

[0041] Assuming that the collision time between the primary impact seat 110 and the secondary impact seat 130 is Δt, and the acceleration level generated by the secondary impact seat 130 is G, it can be calculated that:

[0042]

[0043] Through the secondary impact, the secondary impact seat 130 can obtain a larger speed change than the primary impact seat 110. Under the condition of the same collision duration, the ratio of the weight of the primary impact seat 110 to the weight of the secondary impact seat 130 is equal to or greater than 10, so that the secondary impact seat 130 obtains a higher acceleration G value, thereby achieving a larger impact magnitude.

[0044] If a half-sine waveform is to be generated, the stiffness K of the waveform generator 120 should satisfy:

[0045]

[0046] According to the above formula, the peak value and duration of the ideal impact acceleration spectrum can be obtained.

[0047] Preferably, the waveform generator 120 is detachably mounted on the top surface of the primary impact seat 110 by bolts, so that the waveform generator 120 can be easily disassembled, replaced, installed and used.

[0048] Preferably, the primary impact seat 110 and the secondary impact seat 130 are made of aluminum alloy.

[0049] Preferably, the secondary impact seat 130 is an inverted polygonal pyramid structure. The primary impact seat 110 is an inverted polygonal pyramid structure. It should be noted that the structural strength of the secondary impact seat 130 needs to be checked according to the highest test level, and its natural frequency should be greater than 1 / 2Δt. An acceleration sensor is installed on the top surface of the secondary impact seat 130.

[0050] In some of the embodiments, the waveform generator 120 is a rubber pad or wool felt, which is conducive to the secondary impact seat 130 generating a semi-sine waveform with an impact magnitude of more than 20,000 g and a pulse width of more than 0.20 ms.

[0051] In other embodiments, such as Figure 4 As shown, the waveform generator 120 includes a rubber spring 121 and a metal spring 122. The metal spring 122 is embedded in the rubber spring 121, and its cross section is a grid structure, and is integrally formed with the rubber spring 121. In this way, it is beneficial for the secondary impact seat 130 to generate a semi-sine waveform with an impact magnitude of more than 30000g and a pulse width of more than 0.10ms. Assuming that the stiffness of the waveform generator 120 formed by the rubber spring 121 and the metal spring 122 connected in parallel is K 2 , the compressive stiffness of the metal spring 122 is K j , the stiffness of the rubber spring 121 is K x , the elastic modulus of metal material is E j , the section moment of inertia of the metal material is I j , X 2 dA j It is the integral of the product of the area of ​​each microelement of the metal material and the square of the distance from each microelement to a specified axis on the cross section. The material of the rubber spring 121 is rubber material, and the elastic modulus of the rubber material is E a2 , the cross-sectional area of ​​the rubber spring 121 is A x , the axial height of the rubber spring 121 is H 2 , the correction factor of rubber material is β 2 , β 2 Between 0 and 1, then:

[0052]

[0053] Specifically, in the exemplary embodiment, the combined impact structure for the high G value half-sine impact test further includes a bracket 140, two spring ropes 150, two guide rods 160 and an impact panel 170. The bracket 140 is installed on the top surface of the primary impact seat 110. The bracket 140 includes a crossbeam 141, two positioning plates 142 and four vertical rods 143. Figure 3As shown, the two positioning plates 142 are both triangular and are respectively installed at the opposite ends of the top surface of the crossbeam 141, so as to facilitate the positioning and installation of the vertical rod 143 and the guide rod 160. The bottom ends of the two vertical rods 143 are respectively detachably installed on one side of the top surface of the primary impact seat 110 by bolts, and the top ends are respectively fixedly connected to one end of the crossbeam 141 by nuts and one of the positioning plates 142. The bottom ends of the other two vertical rods 143 are respectively detachably installed on the other side of the top surface of the primary impact seat 110 by bolts, and the top ends are respectively fixedly connected to the other end of the crossbeam 141 by nuts and another positioning plate 142. The axes of the two spring ropes 150 are both vertically arranged, and the bottom ends are respectively installed on the opposite sides of the top surface of the secondary impact seat 130, and the top ends are respectively installed on the opposite ends of the crossbeam 141. Before the semi-sine impact test is carried out, the bottom surface of the secondary impact seat 130 can be made higher than the top surface of the waveform generator 120 by means of the two spring ropes 150 to meet the test requirements. At the same time, the two spring ropes 150 can prevent the secondary impact seat 130 from moving up and down too much. The axes of the two guide rods 160 are both vertically arranged, and the bottom ends are detachably mounted on the opposite sides of the top surface of the primary impact seat 110 by bolts, and the top ends are respectively mounted on the top of the bracket 140 by nuts. Guide holes for the corresponding side guide rods 160 to pass through are formed on the opposite sides of the secondary impact seat 130. The two guide rods 160 constrain the moving direction of the secondary impact seat 130, ensuring that the high-speed secondary impact seat 130 moves up and down in the vertical direction. The impact panel 170 is detachably mounted on the bottom surface of the primary impact seat 110 by bolts. When performing an impact test, the impact panel 170 makes the bottom surface of the primary impact seat 110 evenly stressed. When damaged, only the impact panel 170 needs to be replaced, without replacing the more expensive primary impact seat 110, which is conducive to reducing maintenance and repair costs.

[0054] Preferably, the material of the bracket 140 and the guide rod 160 is stainless steel, which has high rigidity and strength. The bracket 140 improves the rigidity and strength of the overall structure formed by the bracket 140, the guide rod 160 and the secondary impact seat 130.

[0055] Preferably, a limiting portion 161 is formed at the lower portion of each guide rod 160 , which increases the contact area when the guide rod 160 is connected to the primary impact seat 110 , thereby eliminating the need for a gasket and ensuring the stability of the connection.

[0056] In some practical applications, the top surface size of the secondary impact seat 130 is 200mm×200mm, the first-order natural frequency is 7500Hz, the weight of the primary impact seat 110 is about 100kg, and the weight of the secondary impact seat 130 is about 10kg. Some slightly larger electronic components are installed on the top surface of the secondary impact seat 130 by bolts. Before the half-sine impact test, the bottom surface of the secondary impact seat 130 is 60mm higher than the top surface of the primary impact seat 110, and the bottom surface of the primary impact seat 110 is 0.85m higher than the top surface of the impacted seat. When the half-sine impact test is carried out, the secondary impact seat 130 and the test piece produce the following Figure 5 The shock level shown is above 30,000 g, and the pulse width is a half-sine waveform above 0.10 ms.

[0057] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0058] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0059] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0060] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0061] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A combined impact structure for high G value half-sine impact test, characterized in that: include: A primary impact seat capable of impacting a hit seat of a drop impact table or a hit seat of a pneumatic impact table; A waveform generator is mounted on the top surface of the primary impact seat; A secondary impact seat is arranged above the top surface of the primary impact seat, and the top surface is suitable for mounting a test piece; the ratio of the weight of the primary impact seat to the weight of the secondary impact seat is equal to or greater than 10; A bracket, mounted on the top surface of the primary impact seat; There are two spring ropes, the axes of which are both vertically arranged, the bottom ends of which are respectively installed on the opposite sides of the top surface of the secondary impact seat, and the top ends of which are respectively installed on the top of the bracket.

2. The combined impact structure for high G value half-sine impact test according to claim 1, characterized in that: The waveform generator is a rubber pad.

3. The combined impact structure for high G value half-sine impact test according to claim 1, characterized in that: The waveform generator is wool felt.

4. The combined impact structure for high G value half-sine impact test according to claim 1, characterized in that: The waveform generator comprises: Rubber spring; The metal spring is embedded in the rubber spring.

5. The combined impact structure for high G value half-sine impact test according to claim 1, characterized in that: Also includes: There are two guide rods, both of which have vertical axes, and the bottom ends are respectively mounted on the opposite sides of the top surface of the primary impact seat, and the top ends are respectively mounted on the top of the bracket; The opposite sides of the secondary impact seat are respectively formed with guide holes for the guide rods on the corresponding sides to pass through.

6. The combined impact structure for high G value half-sine impact test according to claim 1, characterized in that: The support comprises: beam; Two positioning plates are installed at opposite ends of the top surface of the crossbeam respectively; There are four vertical rods; the bottom ends of two of the vertical rods are respectively installed on one side of the top surface of the primary impact seat, and the top ends are fixedly connected to one end of the cross beam through one of the positioning plates; the bottom ends of the other two vertical rods are respectively installed on the other side of the top surface of the primary impact seat, and the top ends are fixedly connected to the other end of the cross beam through another positioning plate.

7. The combined impact structure for high G value half-sine impact test according to claim 1, characterized in that: Also includes: The impact panel is installed on the bottom surface of the primary impact seat.

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