A pneumatic cylinder driven integrated pressure sensitive throttling device for SHPB

Abstract

The application discloses a kind of SHPB integrated pressure-sensitive throttle devices driven by inflatable cylinder, belong to material mechanics performance test technical field, pneumatic clamping unit includes double-acting ring cylinder and coaxial piston rod, the inner ring of double-acting ring cylinder is shrunk-on with SHPB absorption rod, double-acting ring cylinder is used to drive piston to move along the axial direction by air pressure, to drive coaxial piston rod and SHPB absorption rod coaxial movement clamping sample.The application is synergized by pneumatic clamping and pressure-sensitive throttle, integrates two major functions of traditional separation in single detachable module, reduces component quantity by more than 30%, and experimental operation efficiency is improved by 50%.

Description

Technical Field

[0001] This invention belongs to the field of material mechanical property testing technology, and specifically relates to an SHPB integrated pressure-sensitive throttling device driven by an air cylinder. Background Technology

[0002] Currently, in split Hopkinson bar (SHPB) experimental setups, sample clamping and transmitted wave damping absorption are typically achieved using independent devices. Regarding clamping, existing technologies mostly employ mechanical screw clamps or ordinary pneumatic clamps, which only fix the sample and lack damping absorption capabilities. Furthermore, the clamping force control accuracy is low, easily introducing lateral shear forces that can cause the bar system to bend. For damping absorption, traditional solutions primarily use passive damping materials such as foam and rubber, or employ multi-hole pneumatic regulating valve structures. The core throttling component releases pressure through multiple small orifices, but this only absorbs energy in a single way and cannot simultaneously meet the sample clamping requirements.

[0003] Existing technologies suffer from three major limitations: First, functional separation, with clamping and damping devices set up independently, increasing system complexity and experimental difficulty; second, lag in response, as traditional damping devices cannot dynamically adjust energy absorption efficiency according to impact loads, easily leading to stress wave reflections interfering with experimental data; and third, poor versatility, with most devices adapting to specific diameter SHPB rod systems, cumbersome assembly and disassembly, and unable to meet the needs of multi-specification experiments. Although some technologies attempt to optimize a single function (such as patent CN118565971A optimizing the clamping structure and patent CN202320914478 optimizing the damping effect), none have achieved the integration of the two core functions and lack a pressure-sensitive intelligent response mechanism. Summary of the Invention

[0004] To solve the above problems, the present invention adopts the following technical solution: A pneumatic cylinder-driven SHPB integrated pressure-sensitive throttling device includes: A pneumatic clamping unit includes a double-acting annular cylinder and a coaxial piston rod. The inner ring of the double-acting annular cylinder is interference-fitted with the SHPB absorption rod. The double-acting annular cylinder contains a piston that can reciprocate axially. The rear end of the coaxial piston rod is fixedly connected to the piston, and the front end of the coaxial piston rod protrudes from the front end cover of the double-acting annular cylinder and has a connecting portion. The coaxial piston rod is coaxially and fixedly connected to the front end of the SHPB absorption rod through the connecting portion. The double-acting annular cylinder is used to drive the piston axially via pneumatic pressure, thereby causing the coaxial piston rod and the SHPB absorption rod to move coaxially to clamp the sample. A pressure-sensitive throttle valve unit is disposed on the outer wall of the cylinder body of the double-acting annular cylinder; A quick-release adapter unit is disposed between the double-acting annular cylinder and the SHPB absorber rod to enable quick assembly and disassembly of the device and the SHPB absorber rod.

[0005] Furthermore, the pneumatic clamping unit also includes a miniature force sensor, which is located at the connection between the coaxial piston rod and the SHPB absorption rod. The miniature force sensor is used to detect the clamping force in real time and feed it back to the pneumatic control system to achieve closed-loop adjustment of the clamping force.

[0006] Furthermore, the pressure-sensitive throttle valve unit includes a valve body, a valve seat, a valve core, a spring, and an adjusting nut; The valve body is connected to the internal cavity of the double-acting annular cylinder; the valve seat is fixed in the valve body, and a throttling orifice is provided on the valve seat; the valve core and the valve seat are sealed with a conical seal to block the throttling orifice; the spring is disposed in the valve body and sleeved on the outside of the valve core, one end of the spring abuts against the valve body or the adjusting nut, and the other end abuts against the valve core, for applying a preload force to the valve core to press the valve core against the valve seat; the adjusting nut is threadedly connected to the valve body, for adjusting the preload of the spring to set a preset threshold for opening; when the pressure in the double-acting annular cylinder exceeds the preset threshold, the gas in the double-acting annular cylinder overcomes the preload force of the spring and pushes the valve core away from the valve seat, so that the gas is discharged through the throttling orifice.

[0007] Furthermore, the throttling orifice is a multi-stage adjustable flow orifice, with a quantity of 3 to 4 and an orifice diameter of 0.8 to 1.5 mm; and the throttling orifice is located on the valve seat side of the valve core and is evenly distributed along the circumferential direction of the valve seat, so that the gas flows through the conical sealing structure of the valve core and the valve seat.

[0008] Furthermore, the quick-release adapter unit includes a variable diameter bushing, a spring clip, and a positioning pin; The variable diameter bushing is sleeved on the outer wall of the SHPB absorber rod and embedded in the inner ring of the double-acting annular cylinder to eliminate gaps. The spring clip is radially inserted through the outer wall of the housing of the double-acting annular cylinder, and is used to lock the double-acting annular cylinder and the variable diameter bushing onto the SHPB absorber rod. The locating pin is located on the front end cover of the double-acting annular cylinder and is used to cooperate with the locating groove on the SHPB absorber rod to restrict circumferential rotation.

[0009] Furthermore, the variable diameter bushing is made of polyurethane and has multiple inner diameter specifications. The spring clips are in three sets and are evenly distributed along the circumference of the variable diameter bushing to enable quick replacement and positioning of rod systems of different specifications.

[0010] The clamping-damping coupling control method for the SHPB integrated pressure-sensitive throttling device driven by the pneumatic cylinder described above includes the following steps: S1. Assembly and Fitting: Select the corresponding polyurethane variable diameter bushing according to the diameter of the SHPB absorber rod, and fix the device to the front end of the absorber rod through the quick-release buckle to ensure that the positioning pin is accurately locked and to eliminate assembly gaps. S2. Parameter setting and pre-clamping: Start the air pressure control system and charge high-pressure gas into the pneumatic clamping unit through the pressure regulating valve. The piston rod pushes the absorption rod to move forward axially and clamps the sample together with the transmission rod. The force sensor provides real-time feedback on the clamping force. After the set value is reached, the air charging valve is closed to maintain the pressure holding state. S3. Impact Response and Damping Absorption: When the stress wave generated by the impact of the incident rod propagates to the absorption rod, it drives the piston rod to vibrate instantaneously, causing the pressure inside the cylinder to rise sharply. When the pressure exceeds the preset threshold of the pressure-sensitive throttle valve, the valve core is pushed open, and the gas is discharged through the multi-stage adjustable flow orifice, using the viscous damping effect to dissipate the stress wave energy. S4. Automatic Reset and Cyclic Use: After the stress wave energy dissipates, the pressure inside the cylinder drops back to the working pressure, the spring drives the valve core to reset and seal the throttle orifice, and the device returns to the pressure holding state; after the experiment, open the exhaust valve to release the gas, loosen the buckle to disassemble the device, and replace the parts to adapt to the next experiment.

[0011] The beneficial effects of this invention are: 1. Highly integrated functions: Through the synergistic effect of pneumatic clamping and pressure-sensitive throttling, the two traditionally separate functions are integrated into a single detachable module, reducing the number of parts by more than 30% and improving experimental operation efficiency by 50%.

[0012] 2. Intelligent response and precise energy absorption: By setting a preset pressure threshold, the device can automatically adjust the exhaust volume according to the magnitude of the impact load, with an energy dissipation rate of up to 88%, and the damping coefficient can be adjusted within the range of 0.5 to 2.0 N·s / mm, effectively preventing stress wave reflection.

[0013] 3. Stable and interference-free clamping: The closed-loop control of the force sensor combined with the coaxial piston rod design avoids the introduction of lateral shear force, ensuring the one-dimensional propagation conditions of stress waves, and the sample slip rate is less than 1%.

[0014] 4. High versatility and low cost: The variable diameter bushing and quick-release buckle enable rapid adaptation of multiple specifications of rod systems, and the manufacturing cost is controlled at 20,000 to 30,000 yuan, which is more than 50% lower than that of imported equipment. Attached Figure Description

[0015] Figure 1 A side view of an SHPB integrated pressure-sensitive throttling device driven by an inflatable cylinder provided by the present invention; In the diagram: 1. SHPB absorber rod; 2. Double-acting annular cylinder; 3. Pressure-sensitive throttle valve unit. Detailed Implementation

[0016] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0017] Example 1

[0018] refer to Figure 1 A pneumatic cylinder-driven SHPB integrated pressure-sensitive throttling device, comprising: The pneumatic clamping unit includes a double-acting annular cylinder 2 and a coaxial piston rod. The inner ring of the double-acting annular cylinder 2 is interference-fitted with the SHPB absorption rod 1. The double-acting annular cylinder 2 is equipped with a piston that can slide back and forth along the axial direction. The rear end of the coaxial piston rod is fixedly connected to the piston, and the front end of the coaxial piston rod protrudes through the front end cover of the double-acting annular cylinder and is provided with a connecting part. The coaxial piston rod is coaxially fixedly connected to the front end of the SHPB absorption rod 1 through the connecting part. The double-acting annular cylinder 2 is used to drive the piston to move axially by air pressure, so as to drive the coaxial piston rod and the SHPB absorption rod 1 to move coaxially to clamp the sample. Pressure-sensitive throttle valve unit 3 is installed on the outer wall of the cylinder body of the double-acting annular cylinder; A quick-release adapter unit is located between the double-acting annular cylinder and the SHPB absorber rod to enable quick assembly and disassembly of the device and the SHPB absorber rod.

[0019] Preferably, the pneumatic clamping unit also includes a miniature force sensor, which is located at the connection between the coaxial piston rod and the SHPB absorption rod. The miniature force sensor is used to detect the clamping force in real time and feed it back to the pneumatic control system to achieve closed-loop adjustment of the clamping force.

[0020] Preferably, the pressure-sensitive throttle valve unit 3 includes a valve body, a valve seat, a valve core, a spring, and an adjusting nut; The valve body is connected to the internal cavity of the double-acting annular cylinder; the valve seat is fixed in the valve body and has a throttling orifice; the valve core and the valve seat are sealed with a conical seal to block the throttling orifice; the spring is located in the valve body and sleeved on the outside of the valve core, one end of the spring abuts against the valve body or adjusting nut, and the other end abuts against the valve core, which is used to apply a preload force to the valve core to press the valve core against the valve seat; the adjusting nut is threaded to the valve body and is used to adjust the preload of the spring to set the preset threshold for opening; when the pressure in the double-acting annular cylinder exceeds the preset threshold, the gas in the double-acting annular cylinder overcomes the preload force of the spring and pushes the valve core away from the valve seat, so that the gas is discharged through the throttling orifice.

[0021] In this embodiment, the adjusting nut is used to adjust the pre-compression of the spring to set the opening pressure range of the preset threshold from 1.2MPa to 1.5MPa.

[0022] Preferably, the throttling orifice is a multi-stage adjustable flow orifice, with a quantity of 3 to 4 orifices and a diameter of 0.8 to 1.5 mm; and the throttling orifice is located on the side of the valve seat of the valve core and is evenly distributed along the circumferential direction of the valve seat, so that the gas flows through the conical sealing structure between the valve core and the valve seat.

[0023] Preferably, the quick-release adapter unit includes a variable diameter bushing, a spring clip, and a locating pin; The variable diameter bushing is fitted on the outer wall of the SHPB absorber rod and embedded in the inner ring of the double-acting annular cylinder to eliminate clearance. The spring clip is radially inserted into the outer wall of the housing of the double-acting annular cylinder to lock the double-acting annular cylinder and the variable diameter bushing onto the SHPB absorber rod. The locating pin is located on the front end cap of the double-acting annular cylinder and is used to engage with the locating groove on the SHPB absorber rod to limit circumferential rotation.

[0024] Preferably, the variable diameter bushing is made of polyurethane and has multiple inner diameter specifications. There are three sets of spring clips, which are evenly distributed along the circumference of the variable diameter bushing to enable quick replacement and positioning of different specifications of rod systems.

[0025] In this embodiment, the inner diameter of the variable diameter bushing is Φ50mm, Φ75mm, or Φ100mm.

[0026] In this embodiment, the clamping force is calculated as follows: F = p × A (where p is the working pressure and A is the effective area of ​​the piston).

[0027] Damping force calculation (turbulent state): ΔP∝Q²×ρ / d 5 (Q is the flow rate, ρ is the gas density, and d is the orifice diameter)

[0028] Energy dissipation rate: η = Dissipated energy / Input energy × 100% (Design target η ≥ 85%)

[0029] Example 2

[0030] This embodiment is based on the clamping-damping coupling control method of the SHPB integrated pressure-sensitive throttling device driven by the pneumatic cylinder in Embodiment 1. The clamping-damping coupling control method includes the following steps: S1. Assembly and Fitting of Device: Select a polyurethane variable diameter bushing of the corresponding specification according to the diameter of SHPB absorber rod 1. Fix the device to the front end of the absorber rod with quick-release buckles to ensure that the positioning pin is accurately locked and to eliminate assembly gaps. In this embodiment, the diameter of the SHPB absorption rod is Φ50 / 75 / 100mm.

[0031] S2. Parameter setting and pre-clamping: Start the pneumatic control system and charge high-pressure gas into the pneumatic clamping unit through the pressure regulating valve. The piston rod pushes the absorption rod to move forward axially and clamps the sample together with the transmission rod. The force sensor provides real-time feedback of the clamping force (2-8kN). After the set value is reached, the gas charging valve is closed to maintain the pressure holding state. In this embodiment, the high-pressure gas is 0.3 to 1.0 MPa.

[0032] S3. Impact Response and Damping Absorption: When the stress wave generated by the impact of the incident rod propagates to the absorption rod, it drives the piston rod to vibrate instantaneously, causing the pressure inside the cylinder to rise sharply. When the pressure exceeds the preset threshold (1.2MPa) of the pressure-sensitive throttle valve, the valve core is pushed open, and the gas is discharged through the multi-stage adjustable flow orifice, using the viscous damping effect to dissipate the stress wave energy. S4. Automatic Reset and Cyclic Use: After the stress wave energy dissipates, the pressure inside the cylinder drops back to the working pressure, the spring drives the valve core to reset and seal the throttle orifice, and the device returns to the pressure holding state; after the experiment, open the exhaust valve to release the gas, loosen the buckle to disassemble the device, and replace the parts to adapt to the next experiment.

[0033] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. A pneumatic cylinder-driven SHPB integrated pressure-sensitive throttling device, characterized in that, include: A pneumatic clamping unit includes a double-acting annular cylinder and a coaxial piston rod. The inner ring of the double-acting annular cylinder is interference-fitted with the SHPB absorption rod. The double-acting annular cylinder contains a piston that can reciprocate axially. The rear end of the coaxial piston rod is fixedly connected to the piston, and the front end of the coaxial piston rod protrudes from the front end cover of the double-acting annular cylinder and has a connecting portion. The coaxial piston rod is coaxially and fixedly connected to the front end of the SHPB absorption rod through the connecting portion. The double-acting annular cylinder is used to drive the piston axially via pneumatic pressure, thereby causing the coaxial piston rod and the SHPB absorption rod to move coaxially to clamp the sample. A pressure-sensitive throttle valve unit is disposed on the outer wall of the cylinder body of the double-acting annular cylinder; A quick-release adapter unit is disposed between the double-acting annular cylinder and the SHPB absorber rod to enable quick assembly and disassembly of the device and the SHPB absorber rod.

2. The SHPB integrated pressure-sensitive throttling device driven by an inflatable cylinder according to claim 1, characterized in that, The pneumatic clamping unit also includes a miniature force sensor, which is located at the connection between the coaxial piston rod and the SHPB absorption rod. The miniature force sensor is used to detect the clamping force in real time and feed it back to the pneumatic control system to achieve closed-loop adjustment of the clamping force.

3. The SHPB integrated pressure-sensitive throttling device driven by an air cylinder according to claim 1, characterized in that, The pressure-sensitive throttle valve unit includes a valve body, a valve seat, a valve core, a spring, and an adjusting nut; The valve body is connected to the internal cavity of the double-acting annular cylinder; the valve seat is fixed in the valve body, and a throttling orifice is provided on the valve seat; the valve core and the valve seat are sealed with a conical seal to block the throttling orifice; the spring is disposed in the valve body and sleeved on the outside of the valve core, one end of the spring abuts against the valve body or the adjusting nut, and the other end abuts against the valve core, for applying a preload force to the valve core to press the valve core against the valve seat; the adjusting nut is threadedly connected to the valve body, for adjusting the preload of the spring to set a preset threshold for opening; when the pressure in the double-acting annular cylinder exceeds the preset threshold, the gas in the double-acting annular cylinder overcomes the preload force of the spring and pushes the valve core away from the valve seat, so that the gas is discharged through the throttling orifice.

4. The SHPB integrated pressure-sensitive throttling device driven by an air cylinder according to claim 3, characterized in that, The throttling orifice is a multi-stage adjustable flow orifice, with a quantity of 3 to 4 orifices and a diameter of 0.8 to 1.5 mm; and the throttling orifice is located on the side of the valve seat of the valve core and is evenly distributed along the circumferential direction of the valve seat, and the gas flows through the conical sealing structure of the valve core and the valve seat.

5. The SHPB integrated pressure-sensitive throttling device driven by an air cylinder according to claim 1, characterized in that, The quick-release adapter unit includes a variable diameter bushing, a spring clip, and a positioning pin; The variable diameter bushing is sleeved on the outer wall of the SHPB absorber rod and embedded in the inner ring of the double-acting annular cylinder to eliminate gaps; The spring clip is radially inserted through the outer wall of the housing of the double-acting annular cylinder, and is used to lock the double-acting annular cylinder and the variable diameter bushing onto the SHPB absorber rod. The locating pin is located on the front end cover of the double-acting annular cylinder and is used to cooperate with the locating groove on the SHPB absorber rod to restrict circumferential rotation.

6. The SHPB integrated pressure-sensitive throttling device driven by an inflatable cylinder according to claim 5, characterized in that, The variable diameter bushing is made of polyurethane and has multiple inner diameter specifications. The spring clips are in three sets and are evenly distributed along the circumference of the variable diameter bushing to enable quick replacement and positioning of rod systems of different specifications.

7. A clamping-damping coupling control method for a pneumatically operated SHPB integrated pressure-sensitive throttling device driven by an air cylinder, characterized in that, The clamping-damping coupling control method for the SHPB integrated pressure-sensitive throttling device driven by an inflatable cylinder according to any one of claims 1-6 includes the following steps: S1. Assembly and Fitting: Select the corresponding polyurethane variable diameter bushing according to the diameter of the SHPB absorber rod, and fix the device to the front end of the absorber rod through the quick-release buckle to ensure that the positioning pin is accurately locked and to eliminate assembly gaps. S2. Parameter setting and pre-clamping: Start the air pressure control system and charge high-pressure gas into the pneumatic clamping unit through the pressure regulating valve. The piston rod pushes the absorption rod to move forward axially and clamps the sample together with the transmission rod. The force sensor provides real-time feedback on the clamping force. After the set value is reached, the air charging valve is closed to maintain the pressure holding state. S3. Impact Response and Damping Absorption: When the stress wave generated by the impact of the incident rod propagates to the absorption rod, it drives the piston rod to vibrate instantaneously, causing the pressure inside the cylinder to rise sharply. When the pressure exceeds the preset threshold of the pressure-sensitive throttle valve, the valve core is pushed open, and the gas is discharged through the multi-stage adjustable flow orifice, using the viscous damping effect to dissipate the stress wave energy. S4. Automatic Reset and Cyclic Use: After the stress wave energy dissipates, the pressure inside the cylinder drops back to the working pressure, the spring drives the valve core to reset and seal the throttle orifice, and the device returns to the pressure holding state; after the experiment, open the exhaust valve to release the gas, loosen the buckle to disassemble the device, and replace the parts to adapt to the next experiment.

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