Large elastic pressurizing structure

Abstract

The invention discloses a large elastic pressurizing structure which comprises a high-strength air spring, a flowerpot-shaped upper cover plate is arranged on the upper boundary of the high-strength air spring, a flowerpot-shaped lower cover plate is arranged on the lower boundary of the high-strength air spring, and a height adjusting rod is arranged. The air spring is fixedly connected with the flowerpot-shaped upper cover plate and the flowerpot-shaped lower cover plate through screws. The large ends of the flowerpot-shaped upper cover plate and the flowerpot-shaped lower cover plate are each provided with a plurality of supporting lugs with mounting holes, the height adjusting rods are connected with the flowerpot-shaped upper cover plate and the flowerpot-shaped lower cover plate through the supporting lugs and the mounting holes in the supporting lugs, and air inlets and outlets are formed in the connecting faces of the flowerpot-shaped upper cover plate and the flowerpot-shaped lower cover plate. The structural rigidity, the boundary strength, the vibration isolation performance, the pressure-resistant stability and the like of the pressurization structure can meet the requirements of testing purposes, the cost is low, the pressurization structure is simple and feasible, corresponding devices can be built according to elastic elements of different sizes and different rated loads, and the pressurization structure has certain universality.

Description

Technical Field

[0001] The invention belongs to the field of aerospace test equipment, and in particular relates to a large-tonnage elastic pressurized structure, which is used for static load loading and vibration isolation of vibration excitation in mechanical environment tests. Background Art

[0002] For aerospace equipment such as launch vehicles that require engines to provide power, in addition to the static load of the engine, the overall structure in the use environment must also withstand the combined loads of engine vibration, filling, and pressurization, which will have a great impact on the dynamic characteristics of the overall structure. Obtaining the load transfer path and possible nonlinear problems through joint tests is of great significance to the design of the structure and environmental reliability analysis. Traditional ground static tests mostly use rigid boundaries as loading boundaries and fixed support boundaries, while vibration tests require that the loading test system be non-rigid.

[0003] In a certain dynamic and static combined test project, it is necessary to build a large-tonnage dynamic and static load combined loading test system. The upper part of the system is a static load loading device, which is fixed on a thousand-ton load-bearing frame, and the lower part is a vibration excitation device and a load-bearing device, which are installed together on the load-bearing platform. The loading test system can realize the longitudinal static load loading of 8500KN and the axial vibration excitation of about 1000KN thrust for the test product, while ensuring that the application of the vibration load will not affect the static load loading system, and prevent the resonance phenomenon of the load-bearing frame at its own natural frequency, so that the entire test system is at risk of damage. At the same time, in order to achieve a real and effective boundary simulation as much as possible, the dynamic characteristics of the product are prevented from changing due to the large gap between the test boundary and the real boundary environment, thereby affecting the load transfer of the test and the dynamic characteristics analysis of the test piece. In this case, the pressurized structure needs to meet the requirements of high-level static load loading and high-thrust vibration load loading, and at the same time needs to maintain low stiffness characteristics, that is, while simulating the real boundary conditions as much as possible, reduce the influence of the static load on the vibration loading, and then realize the vibration isolation function of the product vibration, and ensure the stability and safety of the loading equipment and the load-bearing frame.

[0004] There is an urgent need to design a large-tonnage, low-rigidity pressurized structure to solve the problems of load loading synchronization and test safety in dynamic and static combined tests. Summary of the invention

[0005] The technical problem to be solved by the present invention is to disclose a large-scale elastic pressurized structure to solve the problem of synchronous loading of a large number of static loads and large thrust dynamic loads, and at the same time solve the problem of mutual influence between the static load bearing frame and the test product during vibration loading, so as to prevent the changes in product dynamic characteristics and system risks that may occur during the simultaneous application of a large number of static loads and large thrust dynamic loads.

[0006] The present invention discloses a large elastic pressurized structure, including a large high-strength air spring. The upper and lower surfaces of the air spring are different from the conventional flat plate boundaries. The appearance adopts a disc-shaped structure. While adapting to the connection boundary interface, the overall stiffness of the pressurized structure is further reduced, effectively avoiding the lower limit frequency of the vibration test. In order to enable the pressurized structure to adapt to the test requirements of different spaces, a height adjustment rod is arranged in the pressurized structure to realize the height adjustment function of the pressurized structure.

[0007] As an embodiment of the present invention, a large-scale elastic pressurized structure includes a high-strength air spring, a flowerpot-shaped upper cover plate as the upper boundary of the high-strength air spring, a flowerpot-shaped lower cover plate as the lower boundary of the high-strength air spring, and a height adjustment rod. The high-strength air spring is fixedly connected to the flowerpot-shaped upper cover plate and the flowerpot-shaped lower cover plate by screws respectively; a plurality of ears with mounting holes are provided at the large ends of the flowerpot-shaped upper cover plate and the flowerpot-shaped lower cover plate, the height adjustment rod connects the flowerpot-shaped upper cover plate and the flowerpot-shaped lower cover plate through the mounting holes on the ears, and an air inlet and outlet are provided on the connecting surface of the flowerpot-shaped upper cover plate and the flowerpot-shaped lower cover plate; when the height adjustment rod is locked and fixed, the large-scale elastic pressurized structure is installed and hoisted; during the pressurized loading process of the large-scale elastic pressurized structure, the locking nut between the flowerpot-shaped upper cover plate and the height adjustment rod is loosened to facilitate the extension and retraction of the high-strength air spring; the high-strength air spring bears a pressure of more than 2MPa.

[0008] Preferably, the high-strength air spring actuator adopts Firestone's large constrained membrane air spring Airstroke actuator.

[0009] Preferably, the high-strength air spring model is 348-3 high-strength spring.

[0010] Preferably, the cover plate bodies of the flowerpot-shaped upper cover plate and the flowerpot-shaped lower cover plate are processed by welding, and the material is Q460 steel.

[0011] Preferably, the high-strength air spring stiffness K is calculated as:

[0012]

[0013] K 弹簧 V 弹簧

[0014] Among them, refers to the stiffness of the high-strength air spring, refers to the volume of the high-strength air spring, V 花盆型边界

[0015] Refers to the volume of the flowerpot-shaped upper cover and the flowerpot-shaped lower cover.

[0016] Preferably, three ears with mounting holes are provided at the large ends of the flowerpot-shaped upper cover plate and the flowerpot-shaped lower cover plate.

[0017] Preferably, the large elastic pressurizing structure is provided with three height-adjusting rods, which are screws, and each screw connects the flowerpot-shaped upper cover plate and the flowerpot-shaped lower cover plate through the mounting holes on the support ears. The nut is tightened to adjust the height of the air spring, and a vernier caliper is used to measure to ensure that the height of each point is consistent, so as to ensure that the flowerpot-shaped upper cover plate and the flowerpot-shaped lower cover plate of the pressurizing structure remain in a parallel and stable state during the installation process.

[0018] Preferably, the upper end surface of the flowerpot-shaped upper cover plate is fastened to the load-bearing wall or the load-bearing base, and the lower end surface of the flowerpot-shaped lower cover plate is connected to the pressurized test piece.

[0019] The beneficial effects of the present invention are as follows:

[0020] (1) The large elastic pressure structure disclosed in the present invention can ensure that the application of vibration load will not affect the static load loading system, prevent the bearing frame from resonating at its own natural frequency, and ensure the stability and safety of the loading device and the bearing frame.

[0021] (2) The large elastic pressure structure disclosed in the present invention includes a flowerpot-shaped upper cover plate and a flowerpot-shaped lower cover plate. The unique structure can perform a real and effective boundary simulation, thereby accurately reflecting the load transfer of the test and the dynamic characteristics of the test piece. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Schematic diagram of elastic pressure structure

[0023] Figure 2 Schematic diagram of high-strength air spring

[0024] Figure 3 Schematic diagram of the structure of the flower pot type upper cover plate and the flower pot type lower cover plate, wherein (a) is a schematic diagram of the structure of the flower pot type upper cover plate, and (b) is a schematic diagram of the structure of the flower pot type lower cover plate

[0025] Figure 4 Schematic diagram of the height adjustment rod structure

[0026] Figure 5 The load-pressure-height curve obtained by measurement

[0027] Figure 6 The vibration response simulation experiment curves before and after vibration reduction, where (a) the vibration response simulation experiment curve before vibration reduction, (b) the vibration response simulation experiment curve after vibration reduction

[0028] Description of reference numerals:

[0029] 1-high-strength air spring, 2-flower pot-shaped upper cover, 3-flower pot-shaped lower cover, 4-height adjustment rod, 5-large end support ears of flower pot-shaped upper cover 2 and flower pot-shaped lower cover 3, 6-air inlet and outlet provided on flower pot-shaped upper cover and flower pot-shaped lower cover DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0031] like Figure 1 , Figure 2 , Figure 3 , Figure 4 As shown, a schematic diagram of a large elastic pressurized structure, the large elastic pressurized structure includes a high-strength air spring 1, the upper boundary of the high-strength air spring 1 is a flower pot-shaped upper cover plate 2, the lower boundary of the high-strength air spring 1 is a flower pot-shaped lower cover plate 3, and a height adjustment rod 4. The air spring 1 is fixedly connected to the flower pot-shaped upper cover plate 2 and the flower pot-shaped lower cover plate 3 by screws. The large ends of the flower pot-shaped upper cover plate 2 and the flower pot-shaped lower cover plate 3 are provided with a plurality of ears 5 with mounting holes. The height adjustment rod 4 connects the flower pot-shaped upper cover plate 2 and the flower pot-shaped lower cover plate 3 through the mounting holes on the ears 5. An air inlet and outlet 6 is provided on the connecting surface of the flower pot-shaped upper cover plate 2 and the flower pot-shaped lower cover plate 3. When the height adjustment rod 4 is locked and fixed, the large elastic pressurized structure is installed and hoisted. During the pressurized loading process of the large elastic pressurized structure, the height of the entire flexible system will change because the pressurized structure needs to withstand the combined effect of large internal pressure and high-level load. At this time, loosen the locking nut between the flowerpot-shaped upper cover plate 2 and the height adjustment rod 4, so that the high-strength air spring 1 can be extended and retracted. The total height of the entire elastic pressure structure remains unchanged under the limitation of the thousand-ton load-bearing frame, and no lateral twisting and rotation occur. The high-strength air spring bears a pressure of more than 2MPa.

[0032] Preferably, the high-strength air spring 1 of the present invention adopts the large constrained membrane air spring Airstroke driver of Firestone, which has excellent vibration isolation performance, loads more than 577KN, has a long service life, has a 3-fold safety factor between its nominal maximum pressure and the breaking pressure, and the maximum internal pressure of the high-strength air spring can reach 12bar. The selected air spring model is 348-3 high-strength spring, and its maximum outer diameter can reach 960mm. According to the total load-bearing requirements of the test, when the air pressure of a single spring reaches 10bar, it can bear about 60 tons when the use height is 200mm-220mm. The corresponding number of springs can be increased according to the total load.

[0033] Due to the large total load of the test, the high-strength air spring 1 has a high operating pressure, the overall stiffness is increased, and the natural frequency of the high-strength air spring 1 or the entire pressurized structure is increased. The present invention changes the boundary structure of the high-strength air spring 1, increases the volume of the air chamber, reduces the spring stiffness, and further reduces the natural frequency of the spring group, so that the natural frequency of the test boundary is far away from the lower limit frequency of the vibration environment test, and reduces the impact of the boundary on the structural dynamic characteristics. Under the same height conditions, the flowerpot-shaped cover of the high-strength air spring 1 increases the volume of the pressurized structure cavity by about 1.3 times compared to the traditional flat cover. The air spring system stiffness K is calculated as follows (1).

[0034]

[0035] K 弹簧 V 弹簧 V 花盆边界

[0036] Among them, refers to the stiffness of the air spring, refers to the volume of the air spring, refers to the upper cover,

[0037] According to the equation, the volume and stiffness of the flat plate boundary of the high-strength air spring 1 using the flowerpot-shaped boundary are reduced by about 23% compared with the traditional lower cover plate.

[0038] Preferably, the large ends of the flowerpot-shaped upper cover plate 2 and the flowerpot-shaped lower cover plate 3 are both provided with three ears 5 with mounting holes, the main body of the cover plate is processed by welding, and the material is steel Q460. The optimization simulation experiment results of the flowerpot-shaped upper cover plate 2 and the flowerpot-shaped lower cover plate 3 are as follows: the cover plate is simulated and calculated under the condition of external load of 60 tons, internal pressure of 1MPa, and completely fixed fixing mode, and the structural stress concentration point is optimized, and the maximum stress value is 99.66MPa, and the safety factor is relatively high to meet the use requirements.

[0039] Preferably, each set of large-scale elastic pressurized structure is provided with three height-adjusting rods 4, and the height-adjusting rods 4 are screws. Three 300 mm long screws connect the flowerpot-shaped upper cover plate 2 and the flowerpot-shaped lower cover plate 3 through the mounting holes on the support ears 5. The height of the high-strength air spring 1 is adjusted by tightening the nut, and a vernier caliper is used to measure to ensure that the height of each point is consistent, so as to ensure that the high-strength air spring 1, the flowerpot-shaped upper cover plate 2, and the flowerpot-shaped lower cover plate 3 remain in a parallel and stable state during the installation of the pressurized structure.

[0040] Fix the large elastic pressure structure on a specific test device, loosen the locking nut between the ear 5 on the flowerpot-shaped upper cover plate 2 and the height adjustment rod 4, measure the load-bearing capacity of the air spring at different heights within the specified use height range, observe whether multiple groups of air springs will have structural instability (deflection) as the height increases under large load conditions, and find out the best use height. According to the test data analysis, the best use height is determined to be 200mm~220mm. The test results are shown in Figure 5 .

[0041] The upper end surface of the flowerpot-shaped upper cover plate 2 is fastened to the load-bearing wall or the load-bearing base, and the lower end surface of the flowerpot-shaped lower cover plate 2 is connected to the pressurized test piece.

[0042] The upper end surface of the flowerpot-shaped upper cover plate 2 and the lower end surface of the flowerpot-shaped lower cover plate 3 of the large elastic pressure structure 1 are fastened to the upper and lower force boundaries, the support ears 5 on the flowerpot-shaped upper cover plate 2 and the height adjustment rod 4 are locked with nuts, and longitudinal displacement loads are applied to the flowerpot-shaped upper cover plate 2 and the flowerpot-shaped lower cover plate 3 respectively. The upper and lower boundaries can still constrain the lateral movement of the air spring to maintain the stability of the system.

[0043] During the test, acceleration monitoring points were set at the connection surface between the upper and lower covers and the air spring to monitor the vibration isolation effect of the air spring pressurized structure. The acceleration response results are shown in Figure 6 .

[0044] The large elastic pressurized structure disclosed in the present invention can meet the requirements of the test purpose in terms of its own structural stiffness, boundary strength, vibration isolation performance, pressure resistance stability, etc. It is low in cost, simple and feasible, and can be used to build corresponding devices according to elastic elements of different sizes and different rated loads, and has a certain degree of versatility.

[0045] Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection claimed by the present invention.

Claims

1. A large elastic pressure structure, comprising a high-strength air spring (1), an upper boundary of the high-strength air spring (1) being a flower pot-shaped upper cover plate (2), a lower boundary of the high-strength air spring (1) being a flower pot-shaped lower cover plate (3), and a height adjustment rod (4); the high-strength air spring (1) and the flower pot-shaped upper cover plate (2) and the flower pot-shaped lower cover plate (3) are respectively fixedly connected by screws; a plurality of supporting ears (5) with mounting holes are arranged at the large ends of the flower pot-shaped upper cover plate (2) and the flower pot-shaped lower cover plate (3); the height adjustment rod (4) connects the flower pot-shaped upper cover plate (2) and the flower pot-shaped lower cover plate (3) through the mounting holes on the supporting ears (5); and an air inlet and outlet (6) are arranged on the connecting surface of the flower pot-shaped upper cover plate (2) and the flower pot-shaped lower cover plate (3); When the height adjustment rod (4) is locked and fixed, the large elastic pressurized structure is installed and hoisted; during the pressurized loading process of the large elastic pressurized structure, the locking nut between the flowerpot-shaped upper cover plate (2) and the height adjustment rod (4) is loosened to facilitate the expansion and contraction of the high-strength air spring (1); the high-strength air spring (1) bears a pressure of more than 2MPa.

2. The large elastic pressure structure according to claim 1, characterized in that: The high-strength air spring (1) driver adopts Firestone's large constrained film air spring Airstroke driver.

3. The large elastic pressure structure according to claim 1, characterized in that: The high-strength air spring (1) is a 348-3 high-strength spring.

4. The large elastic pressure structure according to claim 1, characterized in that: The main cover plates of the flowerpot-shaped upper cover plate (2) and the flowerpot-shaped lower cover plate (3) are processed by welding and are made of Q460 steel.

5. The large elastic pressure structure according to any one of claims 1 to 3, characterized in that: The calculation formula of the stiffness K of the high-strength air spring (1) is: K 弹簧 V 弹簧 Wherein, refers to the stiffness of the high-strength air spring (1), refers to the V 花盆型边界 The volume refers to the sum of the volumes of the flowerpot-shaped upper cover plate (2) and the flowerpot-shaped lower cover plate (3).

6. The large elastic pressure structure according to claim 1, characterized in that: The large ends of the flowerpot-shaped upper cover plate (2) and the flowerpot-shaped lower cover plate (3) are both provided with three supporting ears (5) with mounting holes.

7. The large elastic pressure structure according to claim 5, characterized in that: The height adjustment rod (4) is composed of three screws, which are connected to the flowerpot-shaped upper cover plate (2) and the flowerpot-shaped lower cover plate (3) through the mounting holes on the support ears (5). The nuts are tightened to adjust the height of the air spring, and a vernier caliper is used to measure and ensure that the height of each point is consistent, so as to ensure that the flowerpot-shaped upper cover plate (2) and the flowerpot-shaped lower cover plate (3) remain in a parallel and stable state during the installation of the pressurized structure.

8. The large elastic pressure structure according to claim 1, characterized in that: The upper end surface of the flowerpot-shaped upper cover plate (2) is tightly connected to a load-bearing wall or a load-bearing base, and the lower end surface of the flowerpot-shaped lower cover plate (3) is connected to a pressurized test piece.

Images