Portable internal friction measuring device and internal friction measuring method

Abstract

The portable internal friction measurement device includes a cavity (10), a sample fixture (20), a fixing plate (30), a heating plate (40), a thermal barrier (50), an excitation module (60), and a vibration sensor (70). The excitation module (60) includes a rotatable vibration impeller (61), and at least one protrusion is provided on the outer wall of the vibration impeller (61), so that the protrusion can intermittently push the lower edge of the sample (80) when the vibration impeller (61) is rotated. In addition, an optical sensor is used as the vibration sensor (70), and the vibration amplitude of the sample (80) is determined from the difference in angle between an emitted light beam and a reflected light beam from the sample (80). This achieves the technical effect of exciting the vibration of the sample (80) by mechanical pushing and measuring the vibration of the sample (80) without contact. In addition, since the device can be integrated into a small cavity (10), it is convenient to carry around. The internal friction measurement method uses mechanical pressing vibration excitation and non-contact measurement, which has a simple structure, excellent reliability, wide application range, high measurement accuracy and wide operating frequency, making it suitable for on-site measurement of irradiation defect characteristics.

Description

[Technical Field]

[0001] The present invention relates to the technical field of measurement, and more particularly to a portable internal friction measurement device and method. [Background technology]

[0002] Internal friction is a basic attribute that reflects the inherent physical properties of a material, and like parameters such as density, conductivity, magnetic permeability, and elastic modulus, it is not affected by the shape, weight, or volume of the material, but is determined solely by the state of microscopic defects within the material itself.

[0003] When a material is deformed by an external force under conditions isolated from the outside, if the material is defect-free, the stress will cause lattice distortion, which can form strain energy accumulation. When the stress is released, the stored energy is released as kinetic energy with lattice recovery, so no energy is lost. On the other hand, in materials with internal defects, even if lattice distortion occurs due to deformation of the material, not all of it is converted into stored energy; instead, a certain amount of energy is dissipated by the action of defect absorption, so when the stored energy is released to the outside, some of the kinetic energy is lost.

[0004] Therefore, by measuring the changes in the internal friction and elastic modulus of a material under certain external conditions (e.g., temperature, frequency, amplitude, etc.), it is possible to reflect the micro-defect information of the material and obtain micro-defect parameters such as the concentration and distribution of defects, the activation energy of defect diffusion, and phase transition dynamics. Internal friction technology is often referred to as internal friction spectroscopy or mechanical spectroscopy.

[0005] Internal friction is currently one of the most effective non-destructive testing tools for studying the relaxation process of defects and changes in microstructure. There are many methods for measuring internal friction, but all of them require the application of dynamic force to a macroscopic sample.

[0006] The method of measuring the stress-strain curve while applying a periodic force to a sample within a fixed time is called the forced vibration method. The method of applying a linear force to a sample within a fixed time, releasing the force after a fixed deformation, and measuring the strain-decay curve is called the free decay method. The method of applying a periodic force with a constantly changing frequency to a sample within a fixed time and measuring the curve of the strain amplitude with the change in frequency is called the resonance peak method. These measurement methods can be selected depending on the micro-defect characteristics of the material.

[0007] Internal friction is extremely sensitive to changes in microscopic defects in metallic materials, and therefore can play an important role in the study of radiation defect damage mechanisms in nuclear structural materials and in non-destructive testing of material degradation processes.

[0008] Internal friction measurement differs from other non-destructive testing methods in the following respects: the frequency range of internal friction measurement completely covers the natural frequency range of the slow transition process of defects; the applied stimulus signal is an alternating stress (the amplitude is much smaller than the yield stress of the material), and the response signal is a strain. Therefore, it is suitable for any object that can propagate elastic stress waves, and has proven to be one of the most effective means for studying the relaxation process of defects and changes in microstructure.

[0009] After decades of development, internal friction measurement methods have been constantly improved and improved, among which the forced vibration method, free decay method, and resonance peak method have been widely used. Generally, the internal friction test devices designed and manufactured are large in volume, heavy in mass, and have high inertia due to the adverse effects of external vibrations on the measurement. Although these devices are not affected when used in scientific research institutions or universities, they are not portable, limiting their use in project sites.

[0010] In detecting radiation-damaged surface defects in nuclear power materials, the conventional internal friction measurement structure and technology still have some problems as follows:

[0011] (1) The excitation structure is complex. To achieve excitation with an effective strain amplitude, conventional electrostatic excitation systems vibrate the sample by adding an AC signal to a DC or high voltage. This requires a dedicated boost circuit, signal synthesis circuit, and high-frequency carrier circuit, which makes the circuit structure complex and increases the requirements for electrical shielding and high-voltage insulation of the equipment.

[0012] (2) Poor reliability. The sample deforms as it heats up during the test. When using electrical excitation and collection, the sample must maintain a certain distance from the excitation or collection electrode. However, in actual testing, the sample must be close to both electrodes to obtain a valid signal. Therefore, if the sample becomes distorted, it may come into contact with the excitation or collection electrode, making measurement impossible. This will prevent the device from operating normally and reduce reliability.

[0013] (3) It is difficult to achieve variable temperature measurement. Current high-precision displacement sensors used in internal friction measurement devices often use sensors based on the capacitance method, eddy current method, or voltage-variable dynamic transformer (LVDT) method. These sensors must be very close to the sample (at the millimeter level) or must be in contact with the sample. Therefore, in situations where the temperature changes, the temperature of the sample itself and its surroundings can become too high, making the sensor unusable. In severe cases, this can cause irreversible damage to the electronic components inside the sensor, making it difficult to achieve variable temperature measurement.

[0014] The above problems not only affect the accuracy of quantitative data on the physical parameters of internal friction, but also make it difficult to meet the requirements for on-site measurement of materials such as the fuel cladding of nuclear reactors, making it impossible to measure the elastic modulus, temperature coefficient of elastic modulus, and attenuation of the oxide film on the surface of the fuel cladding or the ion-irradiated material. It is also difficult to detect defects in the material, making it impossible to research the type, concentration, and progression mechanism of the defects. Summary of the Invention [Problem to be solved by the invention]

[0015] The present invention aims to overcome the drawbacks of the prior art by providing a portable internal friction measurement device that has a simple structure, excellent reliability, a wide range of applications, high measurement accuracy, a wide operating frequency range, is suitable for measuring irradiation defect characteristics, and is easy to carry. The present invention also provides an internal friction measurement method that has excellent reliability, high measurement accuracy, a wide range of applications, and a wide operating frequency range. [Means for solving the problem]

[0016] To achieve the above objectives, the technical solution provided by the present invention is a portable internal friction measurement device, which includes a sealed cavity having an upper cover with a handle connected to its upper end and a bottom base connected to its lower end, a sample fixture connected to the upper cover and extending downward for clamping the upper end of a sheet-like sample, a fixing plate connected to the bottom base and extending vertically upward, a heating plate connected to the fixing plate and located behind the sample for heating the lower end of the sample, a thermal barrier connected to the fixing plate for enclosing the heating plate and the lower end of the sample and for forming a localized high-temperature region within the cavity, and an excitation module and a vibration sensor installed within the cavity.

[0017] The excitation module generates vibrations at the lower end of the sample by mechanically pushing. The excitation module includes a vibration impeller rotatably mounted directly below the sample. The rotation axis of the vibration impeller is parallel to the plane of the sample when suspended vertically. The rotation axis of the vibration impeller is also parallel to the horizontal plane. The outer wall of the vibration impeller is provided with at least one protrusion. When the vibration impeller rotates, the protrusion intermittently pushes against the lower edge of the sample, generating vibrations at the lower end of the sample. The vibration sensor is an optical sensor. The vibration sensor is used to emit a light beam to illuminate the sample and receive the light beam reflected from the sample. The portable internal friction measurement device measures the internal friction by measuring the difference in angle between the emitted light beam and the reflected light beam to determine the vibration amplitude of the sample.

[0018] Preferably, the outer wall of the vibration impeller is provided with four teeth protruding outward, the heights of the four teeth increasing sequentially in a clockwise direction.

[0019] Preferably, the front surface of the thermal barrier has an observation hole for passing the emitted and reflected light.

[0020] More preferably, the vibration sensor is fixed to the bottom base via a side mounting plate, and the detection port of the vibration sensor faces directly toward the observation hole.

[0021] More preferably, the angle between the plane of the detection opening and the plane of the sample varies within a range of ±15°.The detection opening is higher than the lower edge of the sample.

[0022] More preferably, the axis of the observation hole is perpendicular to the plane of the sample when it is suspended vertically.

[0023] Preferably, the cavity is provided with an observation window, an electrical and vacuum flange interface, the observation window being located at the lower end of the cavity and facing the sample and the oscillating impeller, and the electrical and vacuum flange interface being located on the opposite side of the observation window.

[0024] Preferably, the sample fixing device includes a support rod, a slide chuck, and a pressing member. The support rod is cylindrical. The upper end of the support rod is connected to the upper cover and is provided coaxially with the upper cover. The slide chuck is connected to the lower end of the support rod so as to be slidable up and down. The pressing member is used to press the upper end of the sample against the slide chuck.

[0025] Preferably, the thermal barrier comprises a multi-layered metal case fitted together, with openings in the top and bottom surfaces for inserting the sample therethrough.

[0026] More preferably, the adjacent metal cases are locked with bolts, and the distance between the adjacent metal cases and the distance between the metal cases and the sample can be changed by adjusting the bolts.

[0027] Preferably, the excitation module further includes an excitation motor for rotating the vibration impeller, the excitation motor being provided on the bottom base.

[0028] To achieve the above object, the technical solution provided in the present invention is as follows: The internal friction measurement method includes the following steps:

[0029] S1. A sheet-like sample is placed in a vacuum environment, the upper end of the sheet-like sample is fixed, and the lower end of the sheet-like sample is stretched vertically downward.

[0030] S2. The lower end of the sample is heated to a set temperature.

[0031] S3. Vibration is generated at the lower end of the sample at a set frequency by mechanical pressing.

[0032] S4. An optical sensor is used to emit a light beam to the bottom end of the sample and receive the light beam reflected from the sample, and the difference in angle between the emitted and reflected light beams is then detected to calculate the amplitude of the sample, thereby achieving internal friction measurement.

[0033] Preferably, the direction of the driving force applied to the sample during the mechanical pushing in step S3 is perpendicular to the plane of the sample in the vertically suspended state.

[0034] Preferably, the heating in step S2 is radiative heating, and the heating range is limited to the region where the lower end of the sample is located.

[0035] Preferably, in the internal friction measurement method, the measurement is carried out using any one of the above portable internal friction measurement devices. [Effects of the Invention]

[0036] By utilizing the above technical solutions, the present invention has the following advantages over the prior art:

[0037] The portable internal friction measurement device provided by the present invention includes a cavity, a sample fixture, a fixing plate, a heating plate, a thermal barrier, an excitation module, and a vibration sensor. The excitation module includes a rotatable vibration impeller, and at least one protrusion is provided on the outer wall of the vibration impeller, allowing the protrusion to intermittently press against the lower edge of the sample as the vibration impeller rotates. An optical sensor is used as the vibration sensor, and the vibration amplitude of the sample is determined from the difference in angle between the emitted light beam and the light beam reflected from the sample. This achieves the technical effects of vibrating the sample by mechanical pressing and measuring the sample vibration without contact. The structure is simple, reliable, has a wide range of applications, high measurement accuracy, and a wide operating frequency. Furthermore, since the internal friction measurement device can be integrated into a small cavity, it is highly portable and suitable for measuring irradiation defect characteristics in situ. The internal friction measurement method provided by the present invention uses vibration excitation by mechanical pressing and non-contact measurement. Therefore, it has high reliability, high measurement accuracy, a wide range of applications, and a wide operating frequency. [Brief explanation of the drawings]

[0038] [Figure 1] FIG. 1 is a schematic front view of a preferred embodiment of the portable internal friction measuring device of the present invention. [Figure 2] FIG. 2 is a schematic left side view of FIG. [Figure 3] FIG. 3 is a schematic cross-sectional view taken along the line AA in FIG. [Figure 4] FIG. 4 is a schematic perspective view of FIG. [Figure 5] FIG. 5 is a schematic perspective view of FIG. 1, with the cavity omitted for clarity. [Figure 6] FIG. 6 is a schematic perspective view of FIG. 1, with the cavity omitted for clarity. [Figure 7] FIG. 7 is an analysis of the force applied to the sample when it is bent. [Figure 8] Figure 8 shows the internal friction-temperature spectra of samples with different lengths. [Figure 9]FIG. 9 shows the internal friction-temperature spectrum and modulus-temperature spectrum of the sample. DETAILED DESCRIPTION OF THE INVENTION

[0039] In the following, preferred embodiments of the present invention will be described in detail in combination with drawings, in order to make the advantages and features of the present invention more easily understood by those skilled in the art, and also to define the scope of protection of the present invention more clearly and distinctly.

[0040] The up-down direction in this invention is the up-down direction in FIG. 1, the left-right direction in this invention is the left-right direction in FIG. 1, and the front-rear direction in this invention is the right-left direction in FIG.

[0041] As shown in FIGS. 1 to 6 , the portable internal friction measurement device provided by the present invention includes a cavity 10, a sample fixture 20, a fixture plate 30, a heating plate 40, a thermal barrier 50, an excitation module 60, and a vibration sensor 70. The cavity 10 extends vertically. An upper cover 11 with a handle 111 is hermetically connected to the upper end of the cavity 10 to seal the interior of the cavity 10, and a bottom base 12 is hermetically connected to the lower end of the cavity 10. An observation window 13, an electrical flange interface 14, and a vacuum flange interface 15 are provided on the outer wall of the lower end of the cavity 10. The electrical flange interface 14 and the vacuum flange interface 15 are located on opposite sides of the observation window 13 and are symmetrically distributed. The sample fixture 20, the fixture plate 30, the heating plate 40, the thermal barrier 50, the excitation module 60, and the vibration sensor 70 are all provided within the cavity 10. The electrical flange interface 14 allows the heating plate 40, excitation module 60, and vibration sensor 70 in the cavity to be easily connected to an external circuit. The vacuum flange interface 15 also allows the cavity 10 to be easily evacuated, isolating the sample from the external environment. The sample fixture 20 is connected to the upper cover 11 and extends downward. The sample fixture 20 is used to clamp the upper end of a sheet-like sample 80. Specifically, the sample fixture 20 includes a support rod 21, a slide chuck 22, and a pressing member 23. The support rod 21 is cylindrical. The upper end of the support rod 21 is fixed to the center of the back surface of the upper cover 11 by welding or screws. The support rod 21 is coaxially attached to the upper cover 11. This facilitates installation of the sample 80 and ensures sufficient sturdiness of the sample fixture 20. The slide chuck 22 is connected to the lower end of the support rod 21 so that it can slide up and down. A bolt is provided between the slide chuck 22 and the support rod 21 to lock the relative positions of the slide chuck 22 and the support rod 21. The center of the slide chuck 22 has a slide groove structure.The pressing member 23 presses the upper end of the sample 80 into the slide groove structure. The pressing member 23 and the slide chuck 22 are locked with bolts. The position of the lower end (free end) of the sample 80 can be changed by adjusting the vertical position of the slide chuck 22. The fixing plate 30 is connected to the bottom base 12 and extends vertically upward. The fixing plate 30 is used to support the heating plate 40 and the thermal barrier 50. Specifically, the heating plate 40 is locked to the fixing plate 30 with bolts. The heating plate 40 has a flat shape and is located below the slide chuck 22 and the pressing member 23 and directly behind the sample 80. It is used to heat the lower end of the sample 80. This allows the temperature of the sample 80 to rise more rapidly and uniformly. The thermal barrier 50 is connected to the fixing plate 30 and encloses the lower end of the heating plate 40 and the sample 80. The thermal barrier 50 is used to create a localized high-temperature region within the cavity 10. Heating the lower end of the sample 80 in a vacuum environment is radiative heating, but after being reflected by the thermal barrier 50, it does not generally affect other components within the cavity 10. The excitation module 60 generates vibrations at the lower end of the sample 80 by mechanical pushing. Specifically, the excitation module 60 includes a vibration impeller 61 and an excitation motor 62 that rotates the vibration impeller 61. The excitation motor 62 is fixed to the bottom base 12 via a motor fixing plate 621. The vibration impeller 61 is located directly below the sample 80 and is fixed to the transmission shaft of the excitation motor 62. The rotation axis of the vibration impeller 61 is parallel to the plane of the sample 80 when it is suspended vertically. The rotation axis of the vibration impeller 61 is also parallel to the horizontal plane. The vibration impeller 61 has at least one protrusion on its outer wall. When the vibration impeller 61 rotates, the protrusion intermittently pushes against the lower edge of the sample 80, generating vibrations at the lower end of the sample 80. In this embodiment, four teeth 611 protruding outward are provided on the outer wall of the vibration impeller 61. The teeth 611 constitute the protrusion. The four teeth 611 are provided with intervals between them. The height of the four teeth 611 increases sequentially in a clockwise direction.Furthermore, adjacent teeth 611 are connected by a smooth arc surface. The vibrating impeller 61 is made of metal. When the vibrating impeller 61 rotates, the teeth 611 push against the lower end of the sample 80, generating vibrations at the lower end of the sample 80. The observation window 13 directly faces the sample 80 and the vibrating impeller 61, allowing the user to conveniently observe the measurement process. The vibration sensor 70 is an optical sensor. The vibration sensor 70 is fixed to the bottom base 12 via a side mounting plate 71. The vibration sensor 70 emits a light beam to illuminate the sample 80 and receives the light beam reflected from the sample 80. This portable internal friction measurement device measures the internal friction by measuring the difference in angle between the emitted light beam and the reflected light beam to determine the vibration amplitude of the sample 80.

[0042] This configuration has the advantage of achieving the technical effect of vibrating the sample by mechanical pressing and measuring the sample vibration without contact. This structure is simple, reliable, has a wide range of application, high measurement accuracy, and a wide operating frequency. In addition, since the internal friction measurement device can be integrated into a small cavity, it is easy to carry and is suitable for measuring irradiation defect characteristics in situ.

[0043] In this embodiment, the thermal barrier 50 includes a multi-layer metal case 52 fitted together. The metal case 52 is made of a metal sheet. Openings 53 are provided on the top and bottom surfaces of the metal case 52 for inserting the sample 80. Adjacent metal cases 52 are locked together with bolts, and adjusting the bolts allows the distance between adjacent metal cases 52 and between the metal case 52 and the sample 80 to be changed. This allows the size of the opening 53 to be adjusted according to the thickness of the sample 80 and also makes it possible to avoid contact with the sample 80 so as not to affect its vibration. An observation hole 51 is also provided on the front surface of the thermal barrier 50 to allow the emitted and reflected light rays to pass through. The axis of the observation hole 51 is perpendicular to the plane of the sample 80 when it is suspended vertically. The detection port 72 of the vibration sensor 70 faces the observation hole 51. The detection aperture 72 is used to emit light rays to illuminate the sample 80 and to receive light rays reflected from the sample 80. To prevent the reflected light rays from exceeding the detection aperture 72, the included angle between the plane on which the detection aperture 72 exists and the plane of the sample 80 varies within a range of ±15°. The detection aperture 72 is also higher than the lower edge of the sample 80.

[0044] The excitation motor 62 rotates the vibration impeller 61, and the teeth 611 on the vibration impeller 61 are used to vibrate the sample 80 at a certain frequency, amplitude, and temperature. The vibration sensor 70 then collects the vibration signal of the sample 80, and obtains the time spectrum of the vibration displacement of the sample 80. From this, parameters such as damping and modulus of the sample material are calculated, and by combining data on the internal friction, the temperature spectrum of the modulus, the frequency spectrum, and the amplitude spectrum, information such as the type, activation energy, and concentration of microscopic defects in the material is obtained.

[0045] The vibration sensor 70 uses an optical sensor that optically illuminates the surface of the sample 80 without contact and collects the light reflected from the sample 80. This allows for measurement accuracy of submicron level, and even nano-level resolution, by measuring slight changes in the angle of the reflected light. Furthermore, its small size makes it very suitable for manufacturing portable internal friction measurement devices and for on-site measurement of internal friction, modulus measurement, and defect detection of materials. In use, the emitted light passes through the observation hole 51 at the bottom of the thermal barrier 50 and illuminates the lower surface of the sample 80, allowing the vibration process of the sample 80 to be clearly measured.

[0046] The portable internal friction measurement device in this embodiment can be carried to a nuclear reactor site to perform on-site measurements of elastic modulus, temperature coefficient of elastic modulus, damping, etc. of materials that are difficult to transport due to their danger, such as fuel cladding materials that are exposed to a certain amount of irradiation dose. This is convenient for providing clear and reliable equipment to support the research process of radiation defect damage and dynamics in materials.

[0047] Next, the use process of the portable internal friction measuring device will be described. The use process includes the following:

[0048] 1. Open the cavity: Loosen the fastening screw between the flange of the upper cover and the cavity, lift up the flange of the upper cover, and place it horizontally on the holder on the laboratory bench.

[0049] 2. Mounting the sample: Loosen the screw on the pressing member, push one end of the sample to be tested into the gap between the pressing member and the slide chuck, then tighten the screw on the chuck to clamp the sample. If you want to change the excitation amplitude or frequency, simply adjust the clamping length of the sample and the clamping position of the slide chuck.

[0050] 3. Close the cavity: Insert the flange of the upper cover with the sample attached into the cavity slowly, using the positioning pins to fit the flange of the upper cover and the flange of the cavity tightly. Then, observe through the observation window whether the free end of the sample is in contact with the thermal barrier. If not, tighten the screws on the flange of the upper cover.

[0051] 4. Evacuation: If you want to test in a vacuum environment, connect the vacuum flange interface at the bottom of the cavity to a group of vacuum pumps and evacuate. The group of vacuum pumps and vacuum gauge are externally installed.

[0052] 5. Connect the electrical wires: Connect the electrical connectors for heating, measurement, excitation, etc. to the electrical flange interface at the bottom of the cavity.

[0053] 6: Setting parameters: Turn on the power supply and the test software on the computer, and set parameters such as test temperature, excitation frequency, amplitude, test time, etc. Then, perform test vibration on the sample to obtain the parameters of the modulus and elastic modulus of the material in advance.

[0054] 7. Auto Test: Click the Auto Test button to send an excitation signal, collect vibration signals, and calculate the internal friction and elastic modulus values, then obtain the results for analysis.

[0055] 8. Turn off the system: When the test is finished, stop the test program and turn off the test software and power.

[0056] The principle of the test is as follows: A program drives the excitation motor, causing the teeth on the vibration impeller to displace the free end of the sample. After the teeth separate from the free end of the sample, the sample undergoes free decay motion. Alternatively, the vibration impeller is rotated at high speed using high frequency to forcibly vibrate the sample. Then, a vibration sensor collects the sample's vibration curve or amplitude signal to obtain the sample's amplitude-time curve and amplitude-frequency curve. This allows for the calculation of material parameters such as damping and elastic modulus, and the acquisition of characteristic information such as the type, concentration, and activation energy of microscopic defects in the material based on the sample's damping and elastic modulus curves as the temperature, frequency, and amplitude change.

[0057] The internal friction measurement method provided in the present invention includes the following steps:

[0058] S1. A sheet-like sample is placed in a vacuum environment, the upper end of the sheet-like sample is fixed, and the lower end of the sheet-like sample is stretched vertically downward.

[0059] S2. The lower end of the sample is heated to a set temperature.

[0060] S3. Vibration is generated at the lower end of the sample at a set frequency by mechanical pressing.

[0061] S4. An optical sensor is used to emit a light beam to the bottom end of the sample and receive the light beam reflected from the sample, and the difference in angle between the emitted and reflected light beams is then detected to calculate the amplitude of the sample, thereby achieving internal friction measurement.

[0062] Preferably, the direction of the driving force applied to the sample during the mechanical pushing in step S3 is perpendicular to the plane of the sample in the vertically suspended state.

[0063] Preferably, the heating in step S2 is radiative heating, and the heating range is limited to the region where the lower end of the sample is located.

[0064] Preferably, in the internal friction measurement method, the measurement is carried out using the above-mentioned portable internal friction measurement device.

[0065] This method eliminates the electrostatic excitation and electrode measurement methods, and therefore has excellent reliability, high measurement accuracy, a wide range of application, and a wide operating frequency.

[0066] Next, a specific sample test will be described.

[0067] The test uses a sheet-like sample with a thickness between 20 and 250 μm, a width between 2 and 6 mm, and a length between 15 and 70 mm. The sample is clamped at its upper end. When the lower end of the sample is pressed by the teeth on the vibrating impeller, a perpendicular force acts in the thickness direction of the sample, causing the sample to elastically deform and bend. As the vibrating impeller rotates to a certain angle, the tips of the teeth separate from the deformed sample. The sample then dynamically vibrates due to its own elasticity until it returns to its original equilibrium state of being suspended vertically. As shown in Figure 7, when a sheet-shaped sample material is subjected to a point or area force in the thickness direction, the material on the surface in contact with the force stretches, while the material on the back side is compressed. Therefore, if the thickness direction is taken as a cross section, there is almost no deformation in the plane represented by the centerline in the thickness direction. A formula for calculating the Young's modulus of a sheet-shaped sample can be obtained by solving the equation based on Hooke's law of elasticity and the continuity equation.

[0068]

number

[0069] l is the vibration length of the sample, d is the thickness of the sample, f is the vibration frequency of the sample (usually the first resonance frequency is used), and Mn is a characteristic constant.

[0070] The formula for calculating the attenuation value is as follows:

[0071]

number

[0072] The value of δ is the logarithmic decay rate of the amplitude.

[0073] E is an inherent property of the material and does not change with the length, thickness, or outer shape of the sample. Changing the length l also changes the measurement frequency. As shown in Figure 8, the longer the length of the free end, the lower the resonant frequency. Furthermore, by measuring the material at different frequencies and temperatures, the internal friction curves obtained can be used to further study the microscopic mechanisms and dynamics processes reflected by the corresponding internal friction peaks, as shown in Figure 9. This has important application value in the field of evaluating the radiation degradation resistance of materials in nuclear reactors.

[0074] The above examples are merely for illustrating the technical ideas and characteristics of the present invention, and are intended to enable those skilled in the art to understand and practice the contents of the present invention. Therefore, they should not limit the scope of protection of the present invention. Any equivalent modifications or alterations made based on the essence of the spirit of the present invention shall be included in the scope of protection of the present invention. [Explanation of symbols]

[0075] 10 cavities 11 Top cover 111 Handle 12 Bottom Base 13 Observation window 14 Electrical flange interface 15 Vacuum flange interface 20 Sample Fixture 21 Support rod 211 Mounting surface 22 Slide chuck 23 Pressing member 30 Fixing plate 40 Heating Plate 50 Heat Barrier 51 Observation hole 52 Metal Case 53 Aperture 60 Excitation Module 61 Vibrating impeller 611 teeth 62 Excitation motor 621 Motor fixing plate 70 Vibration Sensor 71 Side mounting plate 72 Detection port 80 samples

Claims

1. A portable internal friction measurement device comprising: a sealed cavity extending in a vertical direction, the cavity being provided with a sample fixture, a heating plate, a thermal barrier, an excitation module and a vibration sensor, the sample fixture being used to clamp an upper end of a sheet-like sample, the heating plate being used to heat a lower end of the sample, and the thermal barrier enclosing the heating plate and the lower end of the sample such that a localized high temperature area is formed in the cavity, The excitation module generates vibrations at the lower end of the sample by mechanical pushing, the excitation module includes a vibrating impeller whose rotation axis is parallel to the plane and horizontal plane of the sample when it is suspended vertically, the outer wall of the vibrating impeller is provided with at least one protrusion, and when the vibrating impeller rotates, the protrusion intermittently pushes the lower edge of the sample to generate vibrations at the lower end of the sample, and the vibration sensor emits a light beam to irradiate the sample and receives the light beam reflected from the sample, and measures the difference in angle between the emitted light beam and the reflected light beam to determine the vibration amplitude of the sample, thereby realizing internal friction measurement.

2. 2. The portable internal friction measuring device according to claim 1, wherein the outer wall of the vibrating impeller is provided with four teeth protruding outward, and the heights of the four teeth increase sequentially in a clockwise direction.

3. 2. The portable internal friction measuring device according to claim 1, wherein the thermal barrier has an observation hole for passing the emitted light and the reflected light, and the observation hole and the heating plate are located on the front and rear sides of the sample, respectively.

4. 4. The portable internal friction measuring device according to claim 3, wherein the axis of the observation hole is perpendicular to a plane on which the sample is suspended vertically.

5. 5. The portable internal friction measuring device according to claim 4, wherein the vibration sensor is provided with a detection port facing directly to the observation hole, the detection port being higher than a lower edge of the sample, and the variation range of the included angle between a plane on which the detection port is present and a plane of the sample is ±15°.

6. 4. The portable internal friction measuring device according to claim 3, wherein the thermal barrier comprises a metal case having a plurality of layers fitted together, and the upper and lower surfaces of the metal case have openings for inserting the sample therethrough.

7. The portable internal friction measuring device according to claim 6, characterized in that the adjacent metal cases are locked with bolts, and the distance between the adjacent metal cases and between the metal case and the sample can be changed by adjusting the bolts.

8. 2. The portable internal friction measuring device according to claim 1, wherein an upper cover having a handle is connected to an upper end of the cavity, and a sample fixing tool is connected to the upper cover and extends downward.

9. 9. The portable internal friction measurement device according to claim 8, wherein the sample fixing device includes a support rod, a slide chuck, and a pressing member, the support rod being cylindrical, the upper end of the support rod being connected to the upper cover and being arranged coaxially with the upper cover, the slide chuck being connected to the lower end of the support rod so as to be slidable up and down, and the pressing member being used to press the upper end of the sample against the slide chuck.

10. The portable internal friction measuring device of claim 1, characterized in that a bottom base is connected to the lower end of the cavity, and a fixed plate and a side mounting plate are connected to the bottom base, extending vertically upward, the fixed plate is used to mount the heating plate and the thermal barrier, the side mounting plate is used to mount the vibration sensor, and the bottom base is further provided with an excitation motor for rotating the vibration impeller.

11. 2. The portable internal friction measuring device according to claim 1, wherein the cavity is provided with an observation window and an electrical and vacuum flange interface, the observation window is located at a lower end of the cavity and faces the sample and the vibrating impeller, and the electrical and vacuum flange interface is located on the opposite side of the observation window.

12. A method for measuring internal friction, comprising the steps of: S1. Place a sheet-like sample in a vacuum environment, fix the upper end of the sheet-like sample, and stretch the lower end of the sheet-like sample vertically downward; S2. Heat the lower end of the sample to a set temperature; S3. Vibration is generated at the lower end of the sample at a set frequency by mechanical pressing. S4. Using an optical sensor, emit a light beam to the lower end of the sample and receive the light beam reflected from the sample, and calculate the amplitude of the sample by detecting the difference in angle between the emitted light beam and the reflected light beam, thereby achieving internal friction measurement; A method comprising the steps of:

13. 13. The method for measuring internal friction according to claim 12, wherein the direction of the driving force applied to the sample during the mechanical pressing in step S3 is perpendicular to a plane in which the sample is suspended vertically.

14. The method for measuring internal friction according to claim 12, characterized in that the heating in step S2 is radiative heating, and the heating range is limited to a region where the lower end of the sample is located.

15. The internal friction measuring method according to claim 12, wherein the internal friction measuring method uses a portable internal friction measuring device according to any one of claims 1 to 11 to perform the measurement.

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