CN116380305A - Magnetorheological liquid metal pressure sensing device and manufacturing method thereof - Google Patents
Magnetorheological liquid metal pressure sensing device and manufacturing method thereof Download PDFInfo
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L1/00—Measuring force or stress, in general
- G01L1/20—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress
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Abstract
The invention discloses a magnetorheological liquid metal pressure sensing device and a manufacturing method thereof, wherein the sensing device comprises a first magnetic field excitation device, a flexible pressure inductor, a second magnetic field excitation device, an external current regulator and a resistance data acquisition instrument, wherein the first magnetic field excitation device, the flexible pressure inductor, the second magnetic field excitation device, the external current regulator and the resistance data acquisition instrument are sequentially overlapped from top to bottom, a Helmholtz coil is formed by the first magnetic field excitation device and the second magnetic field excitation device, glass fiber reinforced polyoxymethylene is selected as a shell substrate, a communicated double-line planar spiral micro-channel is formed in the flexible pressure inductor, and magnetorheological liquid metal is filled in the micro-channel. The invention overcomes the defects of fixed detection limit and sensitivity of the existing pressure sensor, improves the adjustability and controllability of the sensing device, and can realize intelligent pressure detection.
Description
Technical Field
The invention relates to a pressure sensing device, in particular to an intelligent magnetorheological liquid metal pressure sensing device with adjustable detection limit and sensitivity and a manufacturing method of the pressure sensing device.
Background
The pressure sensor has wide application range in the fields of industrial production and scientific research test, besides the traditional rigid pressure sensor, in the prior art, chinese patent CN 113091988A discloses a flexible pressure sensor based on liquid metal, which adopts elastic materials as a liquid metal pressure sensor formed by a surface covering; CN 115507216a discloses a magnetic fluid pressure control valve and a regulating method, which adopts magnetorheological fluid as a regulating matrix, and stepless regulates the shutoff area of a resistance gap, thereby changing the valve device of pressure. However, the following problems exist with these pressure sensors made of liquid metal:
1. the pressure detection range is fixed, the upper limit and the lower limit of the pressure detection are not adjustable, the lower detection lower limit and the higher detection upper limit cannot be simultaneously considered, and the range is small;
2. the pressure detection sensitivity is low, and the method cannot be suitable for different pressure detection scenes;
3. the durability of the pressure sensor is poor, the arrangement of the micro flow channels and the positions of the wiring ports are unreasonable, so that local stress concentration and uneven stress are caused;
4. the current and the magnetic field strength cannot be intelligently regulated and controlled according to the pressure change, and the intelligent detection of the pressure cannot be realized;
5. the magnetorheological fluid used for the valve device has poor conductivity, and has a large magnetoresistance effect, so that regular resistance value changes cannot be obtained. The magnetoresistance effect is a phenomenon in which the resistance value of some metals or semiconductors changes with the change of an applied magnetic field, and in the conventional non-conductive magnetorheological fluid or the magnetorheological fluid with weak conductivity (including the magnetorheological fluid disclosed in CN 115507216 a), the carbonyl iron particles are loosely aligned from no magnetic field to oriented alignment when magnetized, and a large change in resistance value occurs.
Disclosure of Invention
Aiming at the problems existing in the prior art, the technical problem to be solved by the invention is to provide the magnetorheological liquid metal pressure sensing device which can improve the upper limit, the lower limit, the sensitivity and the measuring range of the pressure sensor, enlarge the application range of the sensor, improve the controllability and the durability during use and realize the intelligent detection of the pressure. The invention also provides a manufacturing method of the magnetorheological liquid metal pressure sensing device.
In order to solve the technical problems, the technical scheme of the invention is as follows:
the invention provides a magnetorheological liquid metal pressure sensing device which comprises a first magnetic field excitation device, a flexible pressure sensor and a second magnetic field excitation device which are sequentially overlapped from top to bottom, wherein a current regulator is connected to an external power supply line of the first magnetic field excitation device and the second magnetic field excitation device, a resistance data acquisition instrument is connected to an extraction detection end of the flexible pressure sensor, and an output signal end of the resistance data acquisition instrument is connected to a control signal input end of the current regulator. Real-time resistance data is transmitted to the current regulator.
Preferably, the flexible pressure sensing body is internally provided with a communicated double-line plane spiral micro-channel, and the micro-channel is filled with magnetorheological liquid metal.
The invention provides a preparation method of a magnetorheological liquid metal pressure sensing device, which comprises the following steps:
step 1, manufacturing an injection mold of a magnetic field excitation device by using a photoetching technology and a flexible pressure sensor mold comprising a double-line planar spiral micro-channel;
step 4, bonding the 2 PDMS sheets manufactured in the step 3; the bonding is to adhere the 2 layers manufactured above to form a whole with micro-channels inside;
and 6, placing the flexible pressure sensor filled with the magnetorheological liquid metal between the upper disc and the lower disc of the magnetic field excitation device by the center of the flexible pressure sensor, and connecting the resistance data acquisition instrument with the current regulator.
The basic working principle of the magnetorheological liquid metal pressure sensing device is as follows:
the method is characterized in that a magnetorheological liquid metal is prepared by adding a high-permeability insoluble medium into the liquid metal by utilizing the magnetorheological effect and the variable stiffness principle of a magnetorheological elastomer, a uniform magnetic field is generated in a space by utilizing a Helmholtz coil as a magnetic field excitation device, so that magnetic particles in the magnetorheological liquid metal are magnetized, at the moment, the rheological property of the magnetorheological liquid metal is suddenly changed, the magnetorheological liquid metal is quickly solidified and loses fluidity, and the rigidity of a flexible pressure sensor containing the magnetorheological liquid metal is further changed. The rigidity change in the process is a transient process, can be completed in milliseconds, is reversible, and recovers fluidity after the external magnetic field is removed. In addition, the resistance data acquisition instrument is connected with the current regulator, real-time resistance data are transmitted to the current regulator, the current regulator automatically regulates and controls current after the resistance threshold is reached by using the set resistance threshold as a current regulation signal, so that the upper limit and the lower limit of pressure detection are intelligently regulated, and detected pressure data are obtained from an output signal of the resistance data acquisition instrument.
The invention has the technical effects that: the upper limit, the lower limit and the sensitivity of the pressure detection can be adjusted and controlled, the resistance signal is fed back in real time through the resistance data acquisition instrument, and the current regulator is used for regulating and controlling the current connected to the magnetic field excitation device, so that the intelligent detection of the pressure is realized.
Drawings
The drawings of the present invention are described as follows:
FIG. 1 is a schematic diagram of the structure of the present invention;
FIG. 2 is a schematic diagram of the structure of the first and second magnetic field excitation devices;
FIG. 3 is a schematic diagram of a flexible pressure sensor;
FIG. 4 is a schematic diagram of the principle of detection limit and sensitivity adjustment of a flexible pressure sensor;
fig. 5 is a diagram showing the deformation of the flexible pressure sensor under pressure.
In the figure, 1, a first magnetic field excitation device; 2. a flexible pressure sensor; 3. a second magnetic field excitation device; 4. a current regulator; 5. a resistance data acquisition instrument; 6. a non-magnetically permeable rigid housing; 7. a helmholtz coil; 8. a double-line planar spiral; 9. magnetorheological liquid metal; 10. carbonyl iron particles.
Detailed Description
The invention is further illustrated by the following examples in conjunction with the accompanying drawings:
for the sake of clarity of description of the invention, the present application uses the azimuth terms "upper" and "lower" to distinguish, where the "upper" and "lower" are determined according to the layout azimuth of the above drawings, and the directions of the present application are changed along with the actual directions of use of the present application, and the terms of azimuth are not to be considered as limiting the scope of patent protection.
As shown in fig. 1, the invention comprises a first magnetic field excitation device 1, a flexible pressure sensor 2 and a second magnetic field excitation device 3 which are sequentially overlapped from top to bottom, wherein an external power supply circuit of the first magnetic field excitation device 1 and the external power supply circuit of the second magnetic field excitation device 3 are connected with a current regulator 4, a resistance data acquisition instrument 5 is connected with a leading-out detection end of the flexible pressure sensor 2, and an output signal end of the resistance data acquisition instrument 5 is connected with a control signal input end of the current regulator. The current regulator receives the regulation and control signal, adjusts the current of the magnetic field excitation device according to a preset resistance threshold gear, controls the excitation magnetic field intensity generated by the magnetic field excitation device, and realizes intelligent pressure detection and adjustable upper and lower detection limits and sensitivity of the flexible pressure sensor.
As shown in fig. 2, the first magnetic field excitation device 1 and the second magnetic field excitation device 3 have the same specifications, and form a helmholtz coil 7, and the coil is covered with a non-magnetically conductive rigid housing 6. The non-magnetic conductive rigid housing 6 is made of glass fiber reinforced polyformaldehyde, and a helmholtz coil is utilized to generate a uniform magnetic field.
As shown in fig. 3, a micro-channel is engraved in the flexible pressure sensor 2, the micro-channel is a communicated double-line planar spiral 8, and magnetorheological liquid metal 9 is filled in the micro-channel. The flexible pressure sensor 2 is made of Polydimethylsiloxane (PDMS).
The magnetorheological liquid metal 9 is a mixed liquid of gallium indium alloy liquid metal and carbonyl iron particles 10. According to the use requirement, the carbonyl iron particles 10 and the gallium indium alloy liquid metal are mixed according to the mass ratio of 0.1-1:2.
The resistance data acquisition instrument feeds back signals, the current regulator is regulated and controlled, the Helmholtz coil is controlled to feed in current, the strength of an excitation magnetic field is further controlled, the pressure detection range and the detection sensitivity of the sensing device are regulated, the detection end led out by the flexible pressure sensor 2 is connected with the resistance data acquisition instrument, the resistance change of magnetorheological liquid metal in the communicated double-wire planar spiral micro-channel is detected, the regulation signals are fed back to the current regulator in real time, the regulation signals are resistance signals, the resistance data acquisition instrument singly feeds in alternating current, the alternating current does not share a power supply with the magnetic field excitation device and the current regulator, and the stable resistance value obtained by the last resistance data acquisition instrument and the current value fed in by the excitation magnetic field are transmitted to the computer processing module, so that the pressure on the flexible pressure sensor is obtained.
The working principle of the invention is as follows:
magneto-rheological effect: the magnetorheological liquid metal is EGaIn liquid metal mixed with a certain proportion of carbonyl iron particles, the carbonyl iron particles 10 are uniformly and randomly dispersed in gallium-based liquid metal, and the difference of magnetic permeability between the liquid metal matrix and the carbonyl iron particles is the root cause for causing the magnetorheological effect of the invention.
As shown in fig. 4, the carbonyl iron particles 10 have the characteristic of magnetic field polarization, and under the action of an external magnetic field, the carbonyl iron particles 10 in the magnetorheological liquid metal, which are originally loosely arranged in the liquid state, form a chain structure along the direction of the magnetic field, so that regular directional arrangement is generated, and the carbonyl iron particles are converted from a fluid state to a quasi-solid state, thereby causing the rigidity of the flexible pressure sensor 2 to be changed as a whole. Since the carbonyl iron particles are soft magnetic materials, there is no residual magnetism of solidification. The magnetorheological fluid metal has high saturation magnetization, and after the external magnetic field is removed, the magnetorheological fluid metal is quickly restored under the action of an external elastomer, so that the magnetorheological fluid metal can repeatedly operate.
In addition, the liquid metal can be regarded as a mixture composed of positive ion fluid and free electron gas, the liquid metal has high conductivity, the liquid metal has fouling property, the fouling property means that the liquid metal can leave marks on a flowing path, the marks are continuous and continuous, the main component is ultrathin lamellar liquid metal and oxides thereof, even if a double-line planar spiral micro-channel in the flexible pressure sensor is compressed to be flat, the integrity of a conductive channel can be ensured, the pressure sensor has extremely strong conductivity stability, in addition, the conductivity of the liquid metal in the magnetorheological liquid metal is far stronger than the conductivity of carbonyl iron particles, the liquid metal plays a main conductive role, so that the movement of the carbonyl iron particles does not influence the conductivity of the whole conductive channel, the reluctance effect of the traditional magnetorheological fluid and the unstable conductivity of the magnetorheological fluid are overcome, the resistance value of the magnetorheological fluid is ensured to be changed only along with the geometric shape of the micro-channel according to the law of resistance, and the change function formula of the bearing pressure of the flexible pressure sensor and the resistance of the liquid metal can be established.
The magnetization of carbonyl iron particles in a uniform electromagnetic field can be deduced according to the langevin classical paramagnetic theory, in which the langevin equation introduces a random potential for the movement of the magnetic particles under the action of the electromagnetic field, and the force of the electromagnetic field acting on the carbonyl iron particles can be replaced by a random force according to the random potential introduced by the langevin equation, although the force cannot be specifically calculated, so that the magnetization of carbonyl iron particles under the action of the electromagnetic field can be deduced. The derivation process is as follows:
firstly deducing the number of carbonyl iron particles in the magnetorheological liquid metal, wherein the number of carbonyl iron particles contained in the whole magnetorheological liquid metal is controlled by the following two factors, namely the volume fraction of carbonyl iron particles contained in the liquid metal and the particle size of carbonyl iron particles, and the carbonyl iron particles adopted in the invention are custom-made for uniform production, and the particle sizes are the same, so that the number of carbonyl iron particles contained in the magnetorheological liquid metal is as follows:
in the formula (1), phi v The volume fraction of carbonyl iron particles in the magnetorheological liquid metal; d is the particle size of the carbonyl iron particles.
The magnetic moment of the single carbonyl iron particle is:
in the formula (2), M S Is the saturation magnetization of carbonyl iron particles.
The expression of the introduced langevin function is:
in formula (3), coth is the hyperbolic cotangent in the hyperbolic function, α is the parameter of the langevin function, and the magnitude of this parameter is determined by the external environmental factors including the magnetic field strength and the magnetic field temperature and the characteristics of the magnetic particle itself including the vacuum permeability and the magnetic moment, so the parameter of the langevin function can be expressed as:
in the formula (4), mu 0 Vacuum permeability of carbonyl iron particles; m is the magnetic moment of a single carbonyl iron particle; h is the intensity of the externally applied magnetic field; k is Boltzmann constant; t is absolute temperature.
According to the langevin theory, the relationship of the magnetization intensity of the magnetorheological liquid metal after the random potential is introduced is as follows:
M＝nmL(α) (5)
calculating the total magnetization of the magnetorheological liquid metal inner carbonyl iron particles obtained by the formula (5) as follows:
the magnetization formula of the magnetorheological liquid metal obtained by finishing in the formula (6) is as follows:
in the formula (7): n is the number of carbonyl iron particles;
m is the magnetic moment of a single carbonyl iron particle;
Φ v the volume fraction of carbonyl iron particles in the magnetorheological liquid metal;
d is the particle size of carbonyl iron particles;
M S saturation magnetization intensity of carbonyl iron particles;
alpha is a parameter of a langevin function;
μ 0 vacuum permeability of carbonyl iron particles;
h is the intensity of the externally applied magnetic field;
k is Boltzmann constant;
t is absolute temperature.
The magnetic field excitation device in the magnetorheological liquid metal flexible pressure sensing device is a glass fiber reinforced polyformaldehyde coated Helmholtz coil, the glass fiber reinforced polyformaldehyde is also known as Sai steel, and has the advantages of high strength, no magnetic conduction, heat resistance, acid resistance, good stability and the like, the magnetic field excitation device can be regarded as a non-deformable rigid body in the pressure range of the flexible pressure sensing body, the Helmholtz coil can generate a uniform magnetic field in a space, and further, carbonyl iron particles in the magnetorheological liquid metal in the micro-flow channel of the flexible pressure sensing body are ensured to be uniformly magnetized.
As shown in fig. 1, the flexible pressure sensor 2 is led out and detected to be connected with a resistance data acquisition instrument 5, the output signal end of the resistance data acquisition instrument 5 is connected with the control signal input end of a current regulator, the current regulator receives a regulating signal, the regulating signal is a resistance signal, different resistance thresholds are set according to a calibration experiment of the flexible pressure sensor, after the current regulator stores the resistance thresholds, the current of the magnetic field excitation device is regulated to a preset size according to a preset threshold gear, and then the excitation magnetic field intensity generated by the magnetic field excitation device is controlled, so that the pressure sensing device can realize an intelligent control process.
The resistance change of the magnetorheological liquid metal in the pressure sensor micro-channel can be measured by a resistance data acquisition instrument, and the resistance data acquisition instrument can be a high-precision LCR tester (HG 2810). The current regulator can be a thyristor-adjustable direct-current power controller produced by Shanghai energy industry of domestic brands.
As shown in fig. 4, applying direct currents of different magnitudes to the magnetic field excitation device causes carbonyl iron particles in the micro flow channel of the pressure sensor to have different magnetization intensities, thereby affecting the overall rigidity of the pressure sensor. When the magnetic field excitation device is not electrified, the rigidity of the pressure sensing body is minimum, the sensitivity of the sensing device is highest, and the micro pressure can be detected, but the upper limit of pressure monitoring is lower; when the magnetic field excitation device is electrified, the rigidity of the pressure sensing body is increased, the detection lower limit of the sensing device is gradually increased, the pressure detection upper limit is also gradually increased, and the larger pressure detection requirement can be met. This is the basic principle of pressure sensing device detection limit and sensitivity adjustment.
As shown in fig. 4, after the magnetic field excitation device is adjusted to an external current with a predetermined magnitude, the magnetic field excitation device generates a uniformly distributed magnetic field, and carbonyl iron particles in the pressure sensor micro-channel are uniformly magnetized. When the pressure sensor receives external pressure, the micro-flow channel in the pressure sensor is compressed and deformed, so that the resistance value of the micro-flow channel in the pressure sensor is influenced, the external pressure has a functional relation with the resistance value of the pressure sensor, and the external pressure is represented by measuring the resistance change. This is the basic principle by which a pressure sensing device is able to detect pressure.
As shown in fig. 5, fig. 5 (a) shows that the filling diameter of the magnetorheological liquid metal in the microchannel is d when no pressure is applied in the present embodiment. FIG. 5 (b) shows the deformation of the flexible pressure sensor 2 when the pressure is applied to the present embodiment, wherein the filling diameter of the magnetorheological liquid metal in the microchannel is d'; the change of the diameter of a micro-channel in the pressure sensing body inevitably causes the resistance value change of magnetorheological liquid metal in the communicated double-line planar spiral coil according to the principle of detecting pressure by the pressure sensing device; therefore, the resistance change value of the magnetorheological liquid metal in the communicated double-line planar spiral coil can reflect the pressure P.
The magnetic field excitation device is controlled to be connected with current, so that magnetic fields with different strengths can be generated, the magnetic fields with different strengths can influence the magnetization intensity of carbonyl iron particles in the pressure sensing body, the deformation rigidity of the pressure sensing body with different magnetization intensity is different, the change of resistance, the change of external current and the magnitude of pressure are measured, the stepless continuous adjustment of the pressure detection limit can be theoretically realized, but in actual use, different pressure detection gears can be arranged, such as high, middle, low, three gears are arranged, and the pressure of large, middle, small, three types is respectively detected for simplifying experiment calibration times. And determining different external currents to select different detection gears, wherein the work can be completed by the cooperation of the resistance data acquisition instrument and the current regulator. And feeding back real-time resistance value data to the current regulator through the resistance data acquisition instrument, and automatically adjusting gears after the set resistance value threshold is reached. And determining the pressure applied to the flexible pressure sensor according to the final stable resistance value output by the resistance data acquisition instrument, and converting the electrical signal measured by the resistance into a pressure value.
The manufacturing method of the pressure sensing device provided by the invention comprises the following steps:
step 1, manufacturing an injection mold of a magnetic field excitation device by using a photoetching technology and a flexible pressure sensor mold comprising a double-line planar spiral micro-channel;
step 4, bonding the 2 PDMS sheets manufactured in the step 3; the bonding is to adhere the 2 layers manufactured above to form a whole with micro-channels inside;
and 6, placing the flexible pressure sensor filled with the magnetorheological liquid metal in the middle of the upper disc and the lower disc of the magnetic field excitation device by the center of the flexible pressure sensor, and connecting the resistance data acquisition instrument with the current regulator.
In actual use, the flexible pressure sensing body is aligned with the center lamination between the upper disc and the lower disc of the magnetic field excitation device, and bonding is not needed, so that the flexible pressure sensing body can be fully deformed after being stressed, and the sensitivity of pressure detection is improved.
The magnetic field excitation device is connected with the current regulator, controls the magnitude of input current, and a resistance data acquisition instrument is connected to the detection end led out by the flexible pressure sensor and feeds back a regulating signal to the current regulator in real time. And finally, transmitting the current value output by the current regulator and a final stable resistance signal obtained by the resistance data acquisition instrument to a calculation processing module, namely measuring the final stable resistance value of the magnetorheological liquid metal and measuring the external pressure.
Claims (7)
1. A magnetorheological liquid metal pressure sensing device is characterized in that: the flexible pressure sensor comprises a first magnetic field excitation device (1), a flexible pressure sensor (2) and a second magnetic field excitation device (3) which are sequentially overlapped from top to bottom, wherein a current regulator (4) is connected on an external power supply line of the first magnetic field excitation device (1) and the second magnetic field excitation device (3), a resistance data acquisition instrument (5) is connected at an extraction detection end of the flexible pressure sensor (2), and an output signal end of the resistance data acquisition instrument (5) is connected with a control signal input end of the current regulator (4).
2. The magnetorheological liquid metal pressure sensing device of claim 1, wherein: the first magnetic field excitation device (1) and the second magnetic field excitation device (3) are identical in specification, a Helmholtz coil (7) is formed, and the coil is wrapped by a non-magnetic conductive rigid shell (6).
3. The magnetorheological liquid metal pressure sensing device of claim 2, wherein: micro-channels are engraved in the flexible pressure sensing body (2), the micro-channels are communicated double-line plane spirals (8), and magnetorheological liquid metal (9) is filled in the micro-channels.
4. The magnetorheological liquid metal pressure sensing device of claim 3, wherein: the magnetorheological liquid metal (9) is a mixed liquid of gallium-indium alloy liquid metal and carbonyl iron particles (10).
5. The magnetorheological liquid metal pressure sensing device of claim 4, wherein: the carbonyl iron particles (10) and gallium indium alloy liquid metal are mixed according to the mass ratio of 0.1-1:2.
6. The magnetorheological liquid metal pressure sensing device according to any one of claims 2 to 5, wherein: the non-magnetic conductive rigid shell (6) is made of glass fiber reinforced polyformaldehyde; the flexible pressure sensor (2) is made of PDMS.
7. The preparation method of the magnetorheological liquid metal pressure sensing device is characterized by comprising the following steps of:
step 1, manufacturing an injection mold of a magnetic field excitation device by using a photoetching technology and a flexible pressure sensor mold comprising a double-line planar spiral micro-channel;
step 2, selecting glass fiber reinforced polyformaldehyde, adopting an injection molding process to manufacture a circular cake-shaped magnetic field excitation device disc coated with a copper coil, wherein each specification of an upper disc and a lower disc of the magnetic field excitation device is completely consistent, and the magnetic field excitation device is connected with a current regulator on an external circuit;
step 3, mixing the organic silicon rubber and the curing agent in proportion, uniformly stirring, and placing the liquid PDMS into a deaerating machine for more than 30 minutes to remove internal bubbles; then pouring the material into a flexible pressure sensor mould containing a double-line plane spiral micro-channel, placing the material into an incubator, maintaining at 60-80 ℃ for more than 50 minutes, taking out the mould after PDMS is solidified to obtain a first sheet, and manufacturing a second sheet by the same method;
step 4, bonding the 2 PDMS sheets manufactured in the step 3; the bonding is to adhere the 2 layers manufactured above to form a whole with micro-channels inside;
step 5, mixing liquid metal with carbonyl iron particles, uniformly stirring to obtain magnetorheological liquid metal, putting the magnetorheological liquid metal into a deaerating machine for more than 30 minutes, removing internal bubbles, punching at a preset through hole by using a puncher, injecting the magnetorheological liquid metal by using an injector, sealing by using glue to obtain a flexible pressure sensor, and connecting an extraction detection end of the flexible pressure sensor with a resistance data acquisition instrument;
and 6, placing the flexible pressure sensor filled with the magnetorheological liquid metal between the upper disc and the lower disc of the magnetic field excitation device by the center of the flexible pressure sensor, and connecting the resistance data acquisition instrument with the current regulator.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN202310356277.7A CN116380305A (en) | 2023-04-06 | 2023-04-06 | Magnetorheological liquid metal pressure sensing device and manufacturing method thereof |
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| CN202310356277.7A CN116380305A (en) | 2023-04-06 | 2023-04-06 | Magnetorheological liquid metal pressure sensing device and manufacturing method thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117470418A (en) * | 2023-10-30 | 2024-01-30 | 浙江大学 | Flange gasket for monitoring structural health of underground pipeline system |
| CN117988908A (en) * | 2024-04-03 | 2024-05-07 | 武汉大学 | Graded early warning anchor rod based on liquid metal and early warning method |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117470418A (en) * | 2023-10-30 | 2024-01-30 | 浙江大学 | Flange gasket for monitoring structural health of underground pipeline system |
| CN117988908A (en) * | 2024-04-03 | 2024-05-07 | 武汉大学 | Graded early warning anchor rod based on liquid metal and early warning method |
| CN117988908B (en) * | 2024-04-03 | 2024-06-11 | 武汉大学 | Graded early warning anchor rod based on liquid metal and early warning method |
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