Full-envelope modular vibration test fixture based on interface boundary simulation

Abstract

The invention relates to the field of vibration test fixtures, and discloses a full-envelope modular vibration test fixture based on interface boundary simulation, which comprises a fixture base and a top cover which are detachably connected and jointly form a mounting inner cavity, the elastic bag system is arranged in the mounting inner cavity and used for wrapping and being attached to the side surface of the product after being filled with fluid, and the pressure of the fluid in the elastic bag system is adjustable so as to dynamically simulate the distribution boundary pressure acting on the side surface of the product; the front baffle ring and the rear baffle ring are adjustably connected to the clamp base and / or the top cover and used for covering and pressing the front end face and the rear end face of the product so as to simulate boundary pressure acting on the end faces of the product. The method has the beneficial effect that the equivalence of a ground vibration test and a real flight environment in load transmission paths and structural excitation characteristics is improved.

Description

Technical Field

[0001] This invention relates to the technical field of vibration test fixtures, and specifically to a fully enveloped modular vibration test fixture based on interface boundary simulation. Background Technology

[0002] During flight, an aircraft's outer shell is subjected to unevenly distributed, dynamically changing aerodynamic turbulent loads. These loads induce shell vibrations, which are then transmitted to the internal components. To assess the reliability of a product in a real flight environment, these loads must be simulated in ground vibration tests. Traditional ground vibration tests use fixtures to connect the product to a vibration table to simulate the transmission of vibration.

[0003] Currently, test fixtures transfer loads by connecting to high-rigidity parts of the aircraft, allowing concentrated loads to be transferred only through a limited number of local mounting points on the product. This transfer method differs fundamentally from the boundary conditions under which the entire surface of the aircraft's outer shell experiences distributed aerodynamic loads in actual flight, and cannot simulate the spatial distribution, dynamic changes, and frequency dependence of aerodynamic loads. Therefore, tests using traditional fixtures struggle to accurately reproduce the structural vibration response during real flight, easily leading to overtesting or undertesting, reducing the equivalence of ground simulation tests and the accuracy of product evaluation. Summary of the Invention

[0004] To address the aforementioned technical issues, the aim is to provide a fully enveloped modular vibration test fixture based on interface boundary simulation, which significantly improves the equivalence between ground vibration tests and real flight environments in terms of load transfer paths and structural excitation characteristics.

[0005] A fully enclosed modular vibration test fixture based on interface boundary simulation includes a fixture base and a top cover, which are detachably connected and together form an installation cavity. An elastic bladder system is disposed in the installation cavity to cover and conform to the side surface of the product after being filled with fluid. The pressure of the fluid in the elastic bladder system is adjustable to dynamically simulate the distributed boundary pressure acting on the side surface of the product. A front retaining ring and a rear retaining ring are adjustablely connected to the fixture base and / or the top cover, respectively, to cover and press the front and rear end faces of the product to simulate the boundary pressure acting on the end faces of the product.

[0006] The beneficial effects of this invention are that, by employing an installation cavity consisting of a detachably connected fixture base and a top cover, an elastic bladder system that can be filled with pressure-regulating fluid to cover the side surface of the product, and front and rear retaining rings that are adjustablely connected to the base and / or top cover to press the front and rear end faces of the product, the fixture can be transformed from transmitting concentrated loads at traditional local mounting points to transmitting loads through full-surface envelope contact with the product shell. This transforms the load applied to the product surface during the test from discrete concentrated forces to continuous surface pressure that can be spatially distributed and dynamically adjusted. Thus, it physically achieves a high-fidelity simulation of the unevenly distributed and dynamically changing aerodynamic turbulent load boundary conditions experienced by aircraft in actual flight, significantly improving the equivalence between ground vibration tests and real flight environments in terms of load transmission paths and structural excitation characteristics.

[0007] In some embodiments, the elastic bladder system includes a bladder made of elastic material and at least one inlet pipe and one outlet pipe communicating with the internal cavity of the bladder. The fluid is a shear-thickening fluid that is filled and regulated through the inlet and outlet pipes. Due to the use of a bladder structure made of elastic material and filled and regulated with shear-thickening fluid through the inlet and outlet pipes, the elastic bladder system transcends the function of ordinary flexible contact. It cleverly utilizes the characteristic that the apparent viscosity of the shear-thickening fluid increases significantly and nonlinearly with increasing external shear rate, giving the entire clamping system frequency-adaptive dynamic stiffness. Under high-frequency vibration, the fluid hardens due to the high shear rate, effectively transmitting the excitation from the vibration table to the product. Under low-frequency vibration, the fluid maintains low stiffness, avoiding over-constraint. This achieves a physical simulation of the key characteristic of load transmission path variation with frequency in the actual environment of the product, solving the core defect of frequency-independent load transmission characteristics in traditional rigid clamps.

[0008] In some embodiments, the elastic bladder system includes multiple bladders, each bladder having an independent fluid cavity and an inlet and outlet pipe communicating with the fluid cavity, to independently adjust the fluid pressure within each bladder. By designing the elastic bladder system as multiple bladder structures with independent fluid cavities and pipes, the fixture can implement independent and precise pressure control on different areas of the product's side surface. This allows testers to set different initial pressures or dynamic pressure spectra for different areas of the bladders based on the actual aerodynamic load distribution of the product (such as the pressure difference between the windward and leeward sides) or the local stiffness differences of the product's structure. This achieves high-fidelity simulation of the non-uniformly distributed pressure field in space experienced by the aircraft's outer shell, overcoming the limitations of traditional single-cavity or integral fixtures that can only apply uniform pressure, and significantly improving the realism of simulations of complex load environments.

[0009] In some embodiments, a pressure sensor is provided at the inlet or outlet pipe of at least one of the bladders. The pressure sensor is communicatively connected to the control system and is used to dynamically adjust the fluid pressure or trigger a safety protection action based on the monitored pressure data. By integrating a pressure sensor into the bladder piping and communicating with the control system, the actual pressure distribution on the product surface can be sensed and fed back in real time, and the fluid pressure of each bladder can be dynamically adjusted accordingly. This achieves active tracking and simulation of dynamically changing boundary pressures. Simultaneously, this structure also establishes an important safety redundancy: when an abnormal pressure is detected (such as a sudden pressure drop due to bladder leakage or a sudden pressure rise due to blockage), the control system can immediately trigger a safety protection action (such as adjusting the pressure or shutting down), effectively avoiding product overload damage or test accidents that may occur due to fixture failure, thus improving the reliability and safety of the test.

[0010] In some embodiments, a stiffness compensation device is further included to compensate for insufficient stiffness of the shear-thickening fluid under low-frequency vibration. The stiffness compensation device is selected from at least one of the following: a pressurization unit for increasing the initial fluid pressure inside the elastic bladder system; an adjustable locking mechanism for adjusting the preload force of the front and / or rear retaining rings on the product end face; and a micro-actuator integrated inside the elastic bladder system for actively stimulating the fluid's rigid response. By employing various optional stiffness compensation devices, including pressurization units, adjustable locking mechanisms, and micro-actuators, the static stiffness is increased through initial pressurization, basic constraints are provided through mechanical preload, or the fluid is actively stimulated through internal actuators. These compensation mechanisms, based on different physical principles, ensure that the clamp can transmit sufficient mechanical impedance to the product across the entire frequency range (especially the low-frequency range). This achieves continuous, uninterrupted, and accurate simulation of the full-frequency vibration environment during actual flight, filling the gap in low-frequency performance of intelligent fluid-based clamps.

[0011] In some embodiments, the micro-actuator is disposed within the fluid cavity of the capsule and configured to apply active periodic pressure excitation to the shear-thickening fluid to compensate for insufficient shear rate under low-frequency vibration. Due to the specific structure of directly disposing the micro-actuator within the fluid cavity of the capsule and configuring it to apply active periodic pressure excitation, low-frequency stiffness compensation achieves endogenous, high-response active control. The micro-actuator does not depend on the external vibration environment but acts directly on the fluid interior, artificially increasing the local shear rate of the fluid by generating high-frequency, low-amplitude pulses or vibrations, thereby stimulating the fluid's shear-thickening properties and enabling it to exhibit the required stiffness even under low-frequency external excitation.

[0012] In some embodiments, both the inlet and outlet pipes are metal pipes. A reinforcing transition section is provided at one end of the inlet and outlet pipes within the inner cavity of the capsule. This reinforcing transition section is annular in shape. The connections between the inlet and outlet pipes and the capsule body are fixed with high-strength adhesive, and adjacent capsule bodies are also fixed together with high-strength adhesive. Due to the use of a composite structure combining metal pipes with annular reinforcing transition sections and high-strength adhesive for pipe connection and capsule fixation, the metal pipes provide a reliable fluid channel; the annular reinforcing plate effectively disperses stress concentration at the pipe openings, preventing the elastic capsule from tearing under alternating pressure; and the high-strength adhesive ensures the integrity of the connection interface, ensuring the test fixture can operate stably for a long time and maintain pressure control accuracy.

[0013] In some embodiments, an elastic element is provided between the end face of the rear retaining ring and the corresponding end face of the clamp base and the top cover, and an elastic element is provided between the end face of the front retaining ring and the corresponding end face of the clamp base and the top cover. The rear and front retaining rings are connected to the corresponding end faces of the clamp base and the top cover by connecting bolts. Adjusting the tightening torque of the corresponding connecting bolts changes the clamping force of the front and rear retaining rings on the product end face. Because of the structure that uses elastic elements between the front and rear retaining rings and the clamp body, and adjusts the clamping force through connecting bolts, the boundary constraints on the front and rear end faces of the product achieve quantifiable and adjustable flexible loading. The presence of elastic elements (such as rubber pads or disc springs) avoids purely rigid contact, making the end face pressure distribution more uniform and absorbing some vibration energy, thus more closely approximating the actual installation boundary. By adjusting the bolt torque, the magnitude of the end face preload can be precisely controlled, thereby flexibly simulating different degrees of mechanical constraints or pneumatic pressures on the end face during actual installation, thus improving the adjustability and realism of the end face boundary conditions in full-envelope simulation.

[0014] In some embodiments, the fixture base is provided with a first cooling channel for circulating cooling liquid. The first cooling channel includes a first lateral channel on both sides of the fixture base, and a bottom channel and a first top channel at the end of the fixture base. The fixture base is provided with a first lateral channel inlet pipe and a first lateral channel outlet pipe communicating with the first lateral channel, and a bottom channel inlet pipe and a bottom channel outlet pipe communicating with the bottom channel and the first top channel. Due to the complex cooling channel structure integrating the first lateral channel, bottom channel, and first top channel inside the fixture base, and equipped with independent inlet and outlet pipes, the coolant flowing through these channels surrounding the mounting cavity can effectively remove the heat generated by the internal fluid shear heat or environmental conduction in the elastic bladder system, ensuring that the shear-thickening fluid in this region remains within its optimal operating temperature range, thereby guaranteeing the stability and repeatability of its rheological properties (especially shear-thickening properties).

[0015] In some embodiments, the top cover is provided with a second cooling channel for circulating cooling liquid. The second cooling channel includes second lateral channels on both sides of the top cover, and a second and third top channels on the top of the top cover. The top cover is provided with a second lateral channel inlet pipe and a second lateral channel outlet pipe communicating with the second lateral channel, and a top channel inlet pipe and a top channel outlet pipe communicating with the second and third top channels. By integrating a cooling channel structure with a second lateral channel, a second and a third top channel, and independent inlet and outlet pipes inside the top cover, symmetrical and independent temperature control is achieved for the upper part of the fixture. This prevents uneven fluid characteristics or changes in the performance of the capsule material caused by temperature gradients, further ensuring the consistency of the full-surface pressure boundary simulation. This allows the test conditions to remain highly stable during long-term operation or under different ambient temperatures, improving the accuracy and comparability of the test data.

[0016] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0017] 1. The fixture can transform the traditional local mounting point to transfer concentrated loads to the full surface envelope contact of the product shell, so that the load applied to the product surface in the test is transformed from discrete concentrated force to continuous surface pressure that can be spatially distributed and dynamically adjusted. This enables a high-fidelity simulation of the unevenly distributed and dynamically changing aerodynamic turbulent load boundary conditions that the aircraft experiences in actual flight, and significantly improves the equivalence between ground vibration test and real flight environment in terms of load transfer path and structural excitation characteristics.

[0018] 2. The capsule structure, made of elastic material and filled with shear-thickening fluid through inlet and outlet pipes, allows the elastic capsule system to surpass the function of ordinary flexible contact. It cleverly utilizes the characteristic that the apparent viscosity of the shear-thickening fluid increases significantly and nonlinearly with the increase of the external shear rate, giving the entire clamping system frequency-adaptive dynamic stiffness. Under high-frequency vibration, the fluid hardens due to the high shear rate, effectively transmitting the excitation of the vibration table to the product. Under low-frequency vibration, the fluid maintains low stiffness, avoiding over-constraint, and realizing the physical simulation of the key characteristic of load transmission path changing with frequency in the actual environment of the product, thus solving the core defect of frequency-independent load transmission characteristics of traditional rigid clamps.

[0019] 3. The structure integrates pressure sensors at the bladder tubing and communicates with the control system, enabling it to sense and provide feedback on the actual pressure distribution on the product surface in real time, and dynamically adjust the fluid pressure in each bladder accordingly, thereby achieving active tracking and simulation of dynamically changing boundary pressure. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings:

[0021] Figure 1 This is an exploded view of the present invention;

[0022] Figure 2 This is a structural diagram of the elastic capsule system in this invention;

[0023] Figure 3 This is a schematic diagram showing the installation relationship between the metal tube and the bladder in this invention;

[0024] Figure 4 This is a cross-sectional view of the water-cooling circulation system in this invention;

[0025] Figure 5 This is a schematic diagram of the inlet and outlet of the water-cooled circulation system in this invention.

[0026] The attached diagram shows the markings and corresponding component names:

[0027] 1. Fixture base, 1-1. First side flow channel, 1-2. Bottom flow channel, 1-3. First top flow channel, 2. Front retaining ring, 3. Elastic bladder system, 3-1. Bladder body, 3-2. Inlet pipe, 3-3. Outlet pipe, 4. Top cover, 4-1. Second side flow channel, 4-2. Third top flow channel, 4-3. Top cover mounting screw, 5. Product, 6. Rear retaining ring, 7. Front and rear retaining ring mounting screw, 8. Inlet pipe of first side flow channel, 9. Inlet pipe of second side flow channel, 13. Outlet pipe of first side flow channel, 10. Outlet pipe of second side flow channel, 14. Inlet pipe of bottom flow channel, 11. Outlet pipe of bottom flow channel, 12. Inlet pipe of top flow channel, 15. Outlet pipe of top flow channel, 16. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0029] Throughout this specification, references to "an embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in connection with that embodiment or example is included in at least one embodiment of the invention. Therefore, the phrases "an embodiment," "an example," "an example," or "an example" appearing in various places throughout the specification do not necessarily refer to the same embodiment or example. Furthermore, specific features, structures, or characteristics can be combined in one or more embodiments or examples in any suitable combination and / or sub-combination. Moreover, those skilled in the art will understand that the illustrations provided herein are for illustrative purposes and are not necessarily drawn to scale. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0030] In the description of this invention, the terms "front", "rear", "left", "right", "up", "down", "vertical", "horizontal", "high", "low", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of this invention.

[0031] The terms "first," "second," etc., used in this invention are merely for clarity of description and are not intended to limit any order or emphasize importance. Furthermore, the term "connection" as used herein, unless otherwise specified, can refer to a direct connection or an indirect connection via other components.

[0032] Example

[0033] like Figures 1-5 As shown, this embodiment provides a fully enclosed modular vibration test fixture based on interface boundary simulation, including a fixture base 1 and a top cover 4, which are detachably connected by top cover mounting screws 5 and together form an installation cavity; an elastic bladder system 3 is disposed in the installation cavity, used to cover and fit the side surface of the product 6 after being filled with fluid, the pressure of the fluid in the elastic bladder system 3 is adjustable to dynamically simulate the distributed boundary pressure acting on the side surface of the product 6; a front retaining ring 2 and a rear retaining ring 7 are respectively adjustablely connected to the fixture base 1 and / or the top cover 4, used to cover and press the front and rear end faces of the product 6 to simulate the boundary pressure acting on the end faces of the product 6.

[0034] Figures 1-4The elastic bladder system 3 includes a bladder 3-1 made of elastic material, and at least one inlet pipe 3-2 and an outlet pipe 3-3 communicating with the internal cavity of the bladder 3-1. The fluid is a shear-thickening fluid that is filled and regulated through the inlet pipe 3-2 and the outlet pipe 3-3. Because the bladder 3-1 is made of elastic material and filled and regulated with shear-thickening fluid through the inlet pipe 3-2 and the outlet pipe 3-3, the elastic bladder system 3 transcends the function of ordinary flexible contact. It cleverly utilizes the core characteristic of shear-thickening fluid—its apparent viscosity increases significantly and nonlinearly with increasing external shear rate—to give the entire clamping system frequency-adaptive dynamic stiffness. Under high-frequency vibration, the fluid hardens due to the high shear rate, effectively transmitting the excitation from the vibration table to the product 6. Under low-frequency vibration, the fluid maintains low stiffness, avoiding over-constraint. This achieves a physical simulation of the key characteristic of load transmission path variation with frequency in the actual environment of the product 6, solving the core defect of frequency-independent load transmission characteristics in traditional rigid clamps.

[0035] Specifically, in order to achieve the frequency-adaptive dynamic stiffness, the fluid filled in the elastic capsule system (3) is a shear-thickening fluid. Its core characteristic is that there is a critical shear rate: when the shear rate that the fluid is subjected to is lower than this critical value, it behaves like a viscous fluid; when the shear rate exceeds this critical value, its apparent viscosity will rise sharply, exhibiting solid-like behavior.

[0036] In this invention, the critical shear rate range of the shear-thickening fluid should be designed and matched according to the typical frequency range of the vibration test and the gap size between the capsule and the product surface to ensure that it can reliably enter the shear-thickening state under the target high-frequency vibration excitation.

[0037] As non-limiting examples, the following shear-thickening fluid formulations can be used: Formulation A (High-Performance Standard): By weight percentage, it is prepared by high-speed dispersion and vacuum degassing of 70%-80% polyethylene glycol 400 and 20%-30% fumed silica nanoparticles (particle size approximately 12 nm). This system exhibits significant shear-thickening effect and good stability. Formulation B (Wide Temperature Range): Using polypropylene glycol 2000 instead of polyethylene glycol as the dispersion medium, the nanoparticle silica content is 22%-28%. This system has better flowability at low temperatures. Formulation C (Economic Demonstration): A suspension of corn starch and deionized water, with a starch volume fraction of approximately 40%-50%. Attention should be paid to its sedimentation stability during use; suitable for short-term or proof-of-concept experiments. To optimize performance, 0.1%-1% by weight of a dispersant (such as a silane coupling agent) can be added to the above basic formulations to improve particle dispersion stability; or an anti-settling agent; and a preservative (for water-based systems).

[0038] See Figures 1-4 The elastic bladder system 3 includes multiple bladders 3-1, each of which has an independent fluid cavity and an inlet pipe 3-2 and an outlet pipe 3-3 connected to the fluid cavity, allowing for independent adjustment of the fluid pressure within each bladder 3-1. By designing the elastic bladder system 3 as multiple bladders 3-1 with independent fluid cavities and pipelines, the fixture can implement independent and precise pressure control on different areas of the product 6's side surface. This allows testers to set different initial pressures or dynamic pressure spectra for different areas of the bladders 3-1 based on the actual aerodynamic load distribution of the product 6 (such as the pressure difference between the windward and leeward sides) or the local stiffness differences of the product 6's structure. This achieves high-fidelity simulation of the non-uniformly distributed pressure field in space experienced by the aircraft's outer shell, overcoming the limitations of traditional single-cavity or integral fixtures that can only apply uniform pressure, and significantly improving the realism of complex load environment simulations.

[0039] Specifically, the capsule 3-1 is made of an elastic material with high elasticity, high tear strength, good fatigue resistance, and compatibility with the shear-thickening fluid. The elastic material must be able to withstand repeated tensile, compressive, and shear deformations over a wide frequency range and acceleration range of vibration tests without permanent deformation or rupture, and maintain reliable sealing performance over a long period. Fluororubber, silicone rubber, polyurethane elastomers, and nitrile rubber can be used.

[0040] See Figure 2 and Figure 3 A pressure sensor is installed at the inlet pipe 3-2 or outlet pipe 3-3 of at least one of the bladders 3-1. The pressure sensor is communicatively connected to the control system and is used to dynamically adjust the fluid pressure or trigger safety protection actions based on the monitored pressure data. Because of the structure that integrates pressure sensors at the bladder 3-1 pipelines and communicates with the control system, the actual pressure distribution on the surface of the product 6 can be sensed and fed back in real time, and the fluid pressure of each bladder 3-1 can be dynamically adjusted accordingly. This achieves active tracking and simulation of dynamically changing boundary pressures. Simultaneously, this structure also constructs an important safety redundancy: when an abnormal pressure is detected (such as a sudden pressure drop due to leakage in the bladder 3-1 or a sudden pressure rise due to blockage), the control system can immediately trigger safety protection actions (such as adjusting the pressure or stopping the machine), effectively avoiding overload damage to the product 6 or test accidents that may occur due to fixture failure, thus improving the reliability and safety of the test.

[0041] Specifically, the pressure sensor is a miniature piezoresistive or thin-film pressure sensor, whose sensing diaphragm is flush with the inner wall of the inlet pipe 3-2 of the capsule 3-1 or a dedicated pressure measuring interface through a sealing structure (e.g., an O-ring) to accurately measure fluid pressure.

[0042] See Figure 1To address the issue of low stiffness in the shear-thickening fluid at low frequencies, a stiffness compensation device is provided to compensate for the insufficient stiffness of the shear-thickening fluid under low-frequency vibration. The stiffness compensation device is selected from at least one of the following: a pressurization unit for increasing the initial fluid pressure inside the elastic bladder system 3; an adjustable locking mechanism for adjusting the preload of the front retaining ring 2 and / or the rear retaining ring 7 on the end face of the product 6; and a miniature actuator integrated inside the elastic bladder system 3 for actively stimulating the fluid's rigidity response. By employing various optional stiffness compensation devices, including a pressurization unit, an adjustable locking mechanism, and a micro-actuator, the static stiffness is increased through initial pressurization, basic constraints are provided through mechanical pre-tightening (by adjusting the tightening torque of the front retaining ring 2 and / or rear retaining ring 7 to the top cover 4 and the front and rear retaining ring mounting screws 8 of the clamp base 1), or the fluid is actively stimulated by the internal actuator. These compensation mechanisms, based on different physical principles, ensure that the clamp can transmit sufficient mechanical impedance to the product 6 in the entire frequency band (especially the low frequency band), thereby achieving a continuous and uninterrupted accurate simulation of the full-frequency vibration environment of the product 6 in actual flight.

[0043] See Figure 2 and Figure 3 The micro-actuator is disposed within the fluid cavity of the capsule 3-1 and configured to apply active periodic pressure excitation to the shear-thickening fluid to compensate for insufficient shear rate under low-frequency vibration. Due to the specific structure of directly placing the micro-actuator within the fluid cavity of the capsule 3-1 and configuring it to apply active periodic pressure excitation, low-frequency stiffness compensation achieves endogenous, high-response-speed active control. The micro-actuator does not depend on the external vibration environment but acts directly on the fluid interior, artificially increasing the local shear rate of the fluid by generating high-frequency, micro-amplitude pulses or vibrations, thereby stimulating the fluid's shear-thickening properties and enabling it to exhibit the required stiffness even under low-frequency external excitation.

[0044] See Figure 1 The micro actuator is connected to the vibration test controller, and its excitation frequency and amplitude can be adjusted according to the real-time vibration spectrum or a preset program to ensure that the compensation of fluid stiffness in the low-frequency test section is synchronized with or optimally matched with the external excitation.

[0045] Specifically, the micro-actuator is connected to the capsule 3-1 via a sealing connector, which is a high-strength, flexible adhesive sealant, such as oil-resistant, fatigue-resistant polyurethane sealant or silicone rubber. After insulating and sealing the lead portion of the piezoelectric ceramic actuator, the adhesive sealant is used to circumferentially wrap its shell and bond it to the reserved mounting position on the inner wall of the capsule 3-1, forming an integrated sealed and fixed structure. The sealing connector can also be achieved by integrally embedding the piezoelectric ceramic actuator during the vulcanization molding process of the capsule 3-1. Specifically, the actuator is first positioned in the mold of the capsule 3-1, and then unvulcanized rubber material is injected for compression molding. During vulcanization, the rubber tightly bonds with the actuator shell and lead wires, forming a seamless, inherently sealed connection structure that combines excellent sealing and fatigue resistance.

[0046] See Figure 2 and Figure 4 Both the inlet pipe 3-2 and the outlet pipe 3-3 are metal pipes. A reinforcing transition section is provided at one end of the inlet pipe 3-2 and the outlet pipe 3-3 within the inner cavity of the capsule 3-1. This reinforcing transition section is annular in shape. The connections between the inlet pipe 3-2 and the outlet pipe 3-3 and the capsule 3-1 are fixed with high-strength adhesive. Adjacent capsules 3-1 are also fixed with high-strength adhesive. Due to the use of a composite structure combining metal pipes with annular reinforcing transition sections and high-strength adhesive for pipe connection and capsule 3-1 fixation, the metal pipes provide a reliable fluid channel; the annular reinforcing plate effectively disperses stress concentration at the pipe openings, preventing the elastic capsule 3-1 from tearing under alternating pressure; and the high-strength adhesive ensures the integrity of the connection interface, ensuring long-term stable operation of the test fixture and maintaining pressure control accuracy.

[0047] See Figure 1 and Figure 5An elastic element is provided between the end face of the rear retaining ring 7 and the corresponding end faces of the clamp base 1 and the top cover 4. An elastic element is also provided between the end face of the front retaining ring 2 and the corresponding end faces of the clamp base 1 and the top cover 4. The rear retaining ring 7 and the front retaining ring 2 are connected to the corresponding end faces of the clamp base 1 and the top cover 4 by connecting bolts. Adjusting the tightening torque of the corresponding connecting bolts changes the clamping force of the front retaining ring 2 and the rear retaining ring 7 on the end face of the product 6. Because of the structure that uses elastic elements between the front and rear retaining rings 7 and the clamp body, and adjusts the clamping force through connecting bolts, the boundary constraints on the front and rear end faces of the product 6 achieve quantifiable and adjustable flexible loading. The presence of the elastic elements (such as rubber pads or disc springs) avoids purely rigid contact, making the end face pressure distribution more uniform and absorbing some vibration energy, thus more closely approximating the actual installation boundary. By adjusting the bolt torque, the magnitude of the end face preload can be precisely controlled, thereby flexibly simulating the different degrees of mechanical constraints or pneumatic pressures that the end face of Product 6 is subjected to during actual installation, thus improving the adjustability and realism of the end face boundary conditions in the full-envelope simulation.

[0048] See Figure 4 The fixture base 1 is provided with a first cooling channel for circulating cooling liquid. The first cooling channel includes a first lateral channel 1-1 provided on both sides of the fixture base 1, and a bottom channel 1-2 and a first top channel 1-3 provided at the end of the fixture base 1. The fixture base 1 is provided with a first lateral channel inlet pipe 9 and a first lateral channel outlet pipe 10 communicating with the first lateral channel 1-1, and a bottom channel inlet pipe 11 and a bottom channel outlet pipe 12 communicating with the bottom channel 1-2 and the first top channel 1-3. Because of the complex cooling channel structure that integrates a first lateral flow channel 1-1, a bottom flow channel 1-2, and a first top flow channel 1-3 inside the fixture base 1, and is equipped with independent inlet and outlet pipes 3-3, the coolant flows through these channels surrounding the mounting cavity, which can effectively remove the heat generated by the internal fluid shear heat or environmental conduction in the elastic bladder system 3, ensuring that the shear thickening fluid in this area is maintained in its optimal operating temperature range, thereby ensuring the stability and repeatability of its rheological properties (especially shear thickening properties).

[0049] See Figure 4The top cover 4 has a second cooling channel for circulating cooling liquid inside. The second cooling channel includes a second lateral channel 4-1 disposed on both sides of the top cover 4, and a second top channel 4-2 and a third top channel 4-3 disposed on the top of the top cover 4. The top cover 4 is provided with a second lateral channel inlet pipe 13 and a second lateral channel outlet pipe 14 communicating with the second lateral channel 4-1, and a top channel inlet pipe 15 and a top channel outlet pipe 16 communicating with the second top channel 4-2 and the third top channel 4-3. By adopting a cooling channel structure that integrates a second lateral flow channel 4-1, a second and a third top flow channel 4-3, and independent inlet and outlet pipes 3-3 inside the top cover 4, a symmetrical and independent temperature control capability is formed for the upper part of the fixture. This ensures that the temperature of the capsule remains within the set threshold range, preventing uneven fluid characteristics or changes in the material properties of the capsule 3-1 caused by temperature gradients. This further ensures the consistency of the full surface pressure boundary simulation, allowing the test conditions to remain highly stable during long-term operation or under different ambient temperatures, thereby improving the accuracy and comparability of the test data.

[0050] During the operation of the fixture, firstly, modules such as the elastic bladder system 3 and front and rear retaining rings 7 are selected and assembled according to the shape of product 6, and product 6 is installed in the fixture; then, shear-thickening fluid is filled into the bladder 3-1 through pipelines and the initial pressure is adjusted, while the cooling circulation system integrated in the fixture base 1 and top cover 4 is started to maintain the working temperature of the fluid; during the test, the excitation of the vibration table is transmitted to the entire surface of product 6 through the fluid medium that is rigidified by high-frequency shear, simulating high-frequency aerodynamic loads, while the micro actuators integrated in the bladder 3-1 actively stimulate fluid rigidity in the low-frequency stage to compensate for its insufficient rigidity; during this process, the pressure sensor monitors the contact pressure in real time and feeds it back to the control system to realize dynamic closed-loop adjustment of pressure distribution and safety protection for abnormal states, thereby completely simulating the complex aerodynamic load boundary of product 6 in actual flight, which is full-surface, dynamically distributed and frequency-dependent.

[0051] The system highly integrates subsystems such as full-envelope mechanical constraints, zoned independent pressure control, embedded active stiffness compensation, real-time pressure sensing feedback, and global precise temperature control. These subsystems are not simply superimposed, but rather work in deep collaboration around the goal of high-fidelity simulation of dynamically distributed pressure boundaries. Mechanical constraints establish the basic envelope; intelligent fluid provides the adaptive kernel; independent multi-capsules and sensors enable spatial and dynamic reconstruction of the pressure field; micro-actuators actively compensate for low-frequency limits; and the cooling system ensures the stability of core material performance. This achieves a realistic simulation effect that cannot be achieved by a single technology. Specifically, based on computational fluid dynamics (CFD) simulations or actual flight test data, a dynamic pressure distribution map of the product surface under specific operating conditions can be obtained; this map is then converted into a time-varying pressure control spectrum for each independent capsule; during testing, through real-time feedback from the pressure sensor network and closed-loop adjustment of the control system, precise tracking and reproduction of this preset dynamic boundary can be achieved. This allows vibration testing to move from traditional standard excitation to personalized, high-fidelity reproduction of the product's actual service boundary conditions.

[0052] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A fully enveloped modular vibration test fixture based on interface boundary simulation, characterized in that, include: The clamp base and top cover are detachably connected and together form the mounting cavity; An elastic bladder system, disposed within the mounting cavity, is used to cover and conform to the side surface of the product after fluid is injected. The pressure of the fluid within the elastic bladder system is adjustable to dynamically simulate the distributed boundary pressure acting on the side surface of the product. The front and rear retaining rings are adjustablely connected to the clamp base and / or top cover, respectively, to cover and press the front and rear end faces of the product to simulate the boundary pressure acting on the end faces of the product.

2. The fully enclosed modular vibration test fixture based on interface boundary simulation according to claim 1, characterized in that, The elastic capsule system includes a capsule made of elastic material, and at least one inlet pipe and an outlet pipe communicating with an internal cavity of the capsule, wherein the fluid is a shear-thickening fluid that is filled and regulated through the inlet pipe and the outlet pipe.

3. The fully envelope modular vibration test fixture based on interface boundary simulation according to claim 2, characterized in that, The elastic bladder system includes multiple bladders, each of which has an independent fluid cavity and an inlet pipe and an outlet pipe connected to the fluid cavity, so as to independently adjust the fluid pressure in each bladder.

4. The fully enclosed modular vibration test fixture based on interface boundary simulation according to claim 3, characterized in that, A pressure sensor is provided at at least one of the inlet or outlet pipes of the bladder. The pressure sensor is communicatively connected to the control system and is used to dynamically adjust the fluid pressure or trigger a safety protection action based on the monitored pressure data.

5. The fully envelope modular vibration test fixture based on interface boundary simulation according to claim 2, characterized in that, It also includes a stiffness compensation device for compensating for insufficient stiffness of the shear-thickening fluid under low-frequency vibration, the stiffness compensation device being selected from at least one of the following: a pressurization unit for increasing the initial fluid pressure inside the elastic bladder system, an adjustable locking mechanism for adjusting the preload of the front and / or rear retaining rings on the product end face, and a miniature actuator integrated inside the elastic bladder system for actively stimulating the fluid rigidity response.

6. The fully enveloping modular vibration test fixture based on interface boundary simulation according to claim 5, characterized in that, The micro-actuator is disposed within the fluid cavity of the capsule and is configured to apply active periodic pressure excitation to the shear-thickening fluid to compensate for insufficient shear rate under low-frequency vibration.

7. The fully envelope modular vibration test fixture based on interface boundary simulation according to claim 2, characterized in that, Both the inlet and outlet pipes are metal pipes. A reinforced transition section is provided at one end of the inlet and outlet pipes located in the inner cavity of the bladder. The reinforced transition section is in the shape of a circular plate. The connection between the inlet and outlet pipes and the bladder body is fixed by high-strength adhesive. Adjacent bladder bodies are also fixed by high-strength adhesive.

8. The fully enclosed modular vibration test fixture based on interface boundary simulation according to claim 1, characterized in that, An elastic element is provided between the end face of the rear retaining ring and the corresponding end face of the clamp base and the top cover. An elastic element is provided between the end face of the front retaining ring and the corresponding end face of the clamp base and the top cover. The rear retaining ring and the front retaining ring are connected to the corresponding end faces of the clamp base and the top cover by connecting bolts. Adjusting the tightening torque of the corresponding connecting bolts changes the clamping force of the front retaining ring and the rear retaining ring on the end face of the product.

9. The fully enclosed modular vibration test fixture based on interface boundary simulation according to claim 1, characterized in that, The fixture base is provided with a first cooling channel for circulating cooling liquid. The first cooling channel includes a first lateral channel on both sides of the fixture base, a bottom channel and a first top channel at the end of the fixture base. The fixture base is provided with a first lateral channel inlet pipe and a first lateral channel outlet pipe communicating with the first lateral channel, and a bottom channel inlet pipe and a bottom channel outlet pipe communicating with the bottom channel and the first top channel.

10. The fully enveloping modular vibration test fixture based on interface boundary simulation according to claim 1, characterized in that, The top cover is provided with a second cooling channel for circulating cooling liquid. The second cooling channel includes a second lateral channel on both sides of the top cover, and a second top channel and a third top channel on the top of the top cover. The top cover is provided with a second lateral channel inlet pipe and a second lateral channel outlet pipe communicating with the second lateral channel, and a top channel inlet pipe and a top channel outlet pipe communicating with the second top channel and the third top channel.

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