A sample surface temperature regulating device and regulating method

Abstract

The application discloses a kind of sample surface temperature regulating device and regulating method, regulating device includes cold air supply box, cold air conveying component, nozzle and ultrasonic wave fatigue loading module, sample is connected with ultrasonic wave fatigue loading module, the inside of nozzle is provided with first passage and second passage through its height direction, sample is through first passage and the gauge length section of sample is below nozzle, second passage is used to supply cold air, one end of cold air conveying component is connected with cold air supply box, the other end of cold air conveying component is connected with the top of second passage;The outer periphery of gauge length section is equipped with the measuring end of thermocouple.The sample surface temperature regulating device and regulating method of the application can produce high-speed gas jet along the axial direction of sample around sample, blow cold air to sample, generate negative pressure to take away air around sample, cool gauge length section of sample, reduce the stress influence on gauge length section of sample, and ensure the accuracy of test result.

Description

Technical Field

[0001] This invention belongs to the field of sample surface temperature control technology, specifically relating to a sample surface temperature control device and a method for controlling the sample surface temperature using the control device. Background Technology

[0002] Fatigue loading is a high-frequency load borne by major components in many engineering fields. During fatigue fracture, the initiation and propagation of fatigue cracks are somewhat insidious, and components often do not undergo obvious plastic deformation during fatigue fracture, which can easily lead to catastrophic accidents, endanger people's lives, and cause property damage. Therefore, research on fatigue fracture has always been a hot topic in academia.

[0003] Traditional fatigue fracture studies typically categorize fatigue into low-cycle fatigue and high-cycle fatigue based on the number of load cycles the material experiences. Due to limitations in testing conditions and equipment, the number of test cycles for high-cycle fatigue is generally limited to 10. 7 Below that. However, with the continuous development of materials research and the increasing knowledge of materials fatigue fracture behavior in academia, it has been found that many materials face higher cycle counts (10). 9 (More than 10 cycles). To study fatigue fracture behavior at higher cycles, the academic community has proposed the ultrasonic fatigue testing method. This testing method can generate loading frequencies of tens of kHz, achieving ultra-high frequency fatigue, greatly shortening the test time, and enabling 10... 9 The fatigue test can be completed in a dozen hours.

[0004] However, a technical problem with ultra-high frequency fatigue testing is that the temperature of the gauge length of the specimen continuously rises due to the influence of high-frequency vibrations. Without cooling, the temperature can reach several hundred degrees Celsius, affecting the accuracy of the test results. Currently, the industry often uses direct cold air blowing to dissipate heat from the gauge length of the specimen. This involves directing a cold air nozzle at the gauge length to remove the heat generated during ultra-high frequency fatigue, thus cooling the specimen. However, this cooling method has a problem: the impact of direct cold air blowing can generate stress in the gauge length, thereby altering the stress state of the gauge length during ultra-high frequency fatigue and affecting the accuracy of the test results. Furthermore, the impact of this direct cold air blowing is more pronounced on small-sized specimens. Summary of the Invention

[0005] In view of this, in order to overcome the shortcomings of the prior art, the purpose of this invention is to provide a device and method for regulating the surface temperature of a sample, which can generate a high-speed gas jet along the axial direction of the sample around the gauge length, thereby cooling the gauge length while reducing the stress on the gauge length.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] One object of the present invention is to provide a device for regulating the surface temperature of a sample. The sample includes a gauge length, a cold air supply box, a cold air delivery assembly, a nozzle, and an ultrasonic fatigue loading module. The sample is connected to the ultrasonic fatigue loading module. The nozzle has a first channel and a second channel extending through its height. The sample passes through the first channel, and the gauge length is located below the nozzle. The second channel is used for cold air to pass through. One end of the cold air delivery assembly is connected to the cold air supply box, and the other end is connected to the top of the second channel. The nozzle is used to blow the cold air delivered by the cold air delivery assembly to the second channel along the axial direction of the sample toward the gauge length. The outer periphery of the gauge length is fitted with the measuring end of a thermocouple. The design of the first channel on the nozzle facilitates the passage of the sample. In addition, the ultrasonic fatigue loading module is used to perform fatigue loading on the sample. The ultrasonic fatigue loading module includes an amplitude transformer, and the top of the sample is connected to the bottom of the amplitude transformer. Both the amplitude transformer and the sample can pass through the first channel of the nozzle, and the sample is located below the nozzle.

[0008] By setting a nozzle, cold air flows out through a second channel within the nozzle, generating a high-speed gas jet along the specimen's axial direction around the gauge length. This creates a negative pressure around the gauge length, carrying away air near it and cooling the gauge length. This avoids the stress effects of directly blowing cold air onto the specimen during cooling. The control device of this invention can maintain the temperature of the gauge length within the range of room temperature to 100°C, preventing the temperature of the gauge length from continuously rising due to high-frequency vibrations and affecting the test results.

[0009] According to some preferred embodiments of the present invention, the cold air delivery assembly includes a supply duct and an inlet. One end of the supply duct is connected to the cold air supply box, and the other end of the supply duct is connected to the inlet. The end of the inlet away from the supply duct is connected to the top of the second channel. The end of the thermocouple away from the sample is connected to the cold air supply box. The cold air supply box directs cold air to the supply duct, then from the supply duct to the inlet, and from the inlet into the second channel of the nozzle, finally being sprayed onto the sample from the bottom of the nozzle.

[0010] According to some preferred embodiments of the present invention, multiple air supply ducts are arranged in parallel, each air supply duct is further provided with a regulating valve, and the number of air inlets is equal to the number of air supply ducts; the air inlets are evenly spaced along the circumference of the top end of the second channel, and the shape of each air inlet is frustum-shaped, with its inner diameter gradually increasing from the top end to the bottom end. The regulating valve is used to adjust the air volume flowing through the air supply ducts to ensure that the air volume flowing to the nozzles from each air supply duct is the same.

[0011] According to some preferred embodiments of the present invention, the nozzle includes an inner tube and a shell, the shell being located outside the inner tube, the center of the inner tube and the center of the shell being on the same vertical line; the shell is frustum-shaped, the inner diameter of the shell gradually decreasing from its top end to its bottom end; the inner tube is cylindrical, the inner diameter of the inner tube being smaller than the inner diameter of the bottom end of the shell.

[0012] According to some preferred embodiments of the present invention, the heights of both the first and second channels are equal to the height of the nozzle, the diameter of the first channel is equal to the inner diameter of the inner tube, the second channel is formed by the outer wall of the inner tube and the inner wall of the shell, and the cross-sectional area of ​​the second channel gradually decreases from its top to its bottom. The frustum-shaped shell, with its inner diameter gradually decreasing from its top to its bottom, ensures that the cross-sectional area of ​​the second channel gradually decreases from its top to its bottom. This allows the cold air flowing through the second channel to generate a high-speed gas jet when it reaches the bottom of the second channel, resulting in high pressure at the bottom of the second channel. This ensures that the atmospheric pressure air around the gauge length of the sample is carried away to cool the sample.

[0013] According to some preferred embodiments of the invention, the distance between the top of the gauge section and the bottom of the nozzle is 5-10 mm, and the center of the sample and the center of the nozzle are located on the same vertical line. Ensuring a suitable distance between the sample and the bottom of the nozzle allows the high-speed gas jet to carry away the air surrounding the sample.

[0014] According to some preferred embodiments of the invention, a frame and a flow guide are further included. The top of the ultrasonic fatigue loading module is fixedly connected to the top of the frame, and the bottom surface of the flow guide is fixedly connected to the bottom of the frame. The flow guide is located below the gauge length section. The frame provides support for the ultrasonic fatigue loading module, i.e., the flow guide. The flow guide is located directly below the nozzle. When the axial high-speed gas jet reaches the flow guide, the gas is guided to flow outwards under the flow guide's influence, preventing it from stagnating near the sample.

[0015] According to some preferred embodiments of the present invention, the distance from the bottom end of the gauge section to the top end of the guide section is 5 to 20 mm, and the center of the guide section and the center of the nozzle are located on the same vertical line.

[0016] According to some preferred embodiments of the invention, the area of ​​the top surface of the guide portion is larger than the area of ​​the bottom surface, and the generatrix of the guide portion is a concave arc. The sides of the guide portion are streamlined, which can better guide the gas flow.

[0017] Another object of the present invention is to provide a method for controlling the surface temperature of a sample, using the control device described above, the control method comprising the following steps:

[0018] After the specimen is mounted on the ultrasonic fatigue loading module, the ultra-high frequency fatigue test begins. Then, the cold air supply box is activated. Based on the specimen temperature at the gauge length as fed back by the thermocouple, the temperature and / or wind speed of the cold air supplied by the cold air delivery assembly are adjusted to maintain the specimen gauge length temperature between room temperature and 100°C. In some embodiments of the present invention, the specific method for controlling the specimen surface temperature using this control device is as follows:

[0019] Step 1: Mount the sample onto the ultrasonic fatigue loading module.

[0020] Step 2: Start the ultrasonic fatigue loading module to begin the ultra-high frequency fatigue test on the sample.

[0021] Step 3: Start the cold air supply box and turn the regulating valve to make the airflow of cold air in the multiple air supply pipes consistent.

[0022] Step 4: Based on the real-time monitoring of the sample temperature fed back to the cold air supply box by the thermocouple, adjust the temperature and / or wind speed of the cold air to control the sample temperature within the range of room temperature to 100℃.

[0023] Step 5: After the sample has failed due to fatigue, turn off the cold air supply box and the ultrasonic fatigue loading module in sequence, and then remove the sample.

[0024] By adopting the above technical solutions, compared with the prior art, the sample surface temperature control device and control method of the present invention can generate a high-speed gas jet along the axial direction of the sample around the gauge length section, blow cold air towards the sample, generate negative pressure to remove the air around the sample, thereby achieving cooling of the sample gauge length section while reducing the stress influence on the sample gauge length section, thus ensuring the accuracy of the test results. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a three-dimensional structural diagram of the control device in Embodiment 1 of the present invention;

[0027] Figure 2 This is a schematic diagram of the main structure of the control device in Embodiment 1 of the present invention;

[0028] Figure 3 for Figure 2 A magnified view of a portion of section A in the middle;

[0029] Figure 4 This is a three-dimensional structural diagram of the nozzle of the control device in Embodiment 1 of the present invention;

[0030] Figure 5 This is a cross-sectional view of the nozzle of the control device in Embodiment 1 of the present invention;

[0031] The attached figures are labeled as follows: frame-1, ultrasonic fatigue loading module-2, nozzle-3, first channel-31, second channel-32, inner pipe-33, shell-34, cold air supply box-4, cold air delivery assembly-5, air supply pipe-51, air inlet-52, regulating valve-53, thermocouple-6, flow guide-7, sample-8, gauge length section-81. Detailed Implementation

[0032] To enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0033] Example 1: Device for controlling the surface temperature of the sample

[0034] Reference Figures 1 to 5This embodiment provides a device for controlling the surface temperature of a sample, including a frame 1, an ultrasonic fatigue loading module 2, a nozzle 3, a cold air supply box 4, a cold air delivery assembly 5, a thermocouple 6, and a flow guide 7. The top of the ultrasonic fatigue loading module 2 is fixedly connected to the top of the frame 1, and the bottom surface of the flow guide 7 is fixedly connected to the bottom of the frame 1. The sample 8 includes a gauge length 81. The sample 8 is connected to the amplitude transformer of the ultrasonic fatigue loading module 2 so that the ultrasonic fatigue loading module 2 performs a fatigue loading test on the sample 8. One end of the cold air delivery assembly 5 is connected to the cold air supply box 4, and the other end of the cold air delivery assembly 5 is connected to the nozzle 3. The sample 8 and the amplitude transformer both pass through the interior of the nozzle 3 and are located below the nozzle 3. The flow guide 7 is located below the sample 8. The measuring end of the thermocouple 6 is fitted around the outer periphery of the gauge length 81 of the sample 8 to measure the real-time temperature of the sample 8 during the test. The end of the thermocouple 6 away from the sample 8 is connected to the cold air supply box 4 to feed back the temperature of the gauge length 81 of the sample 8 to the cold air supply box 4.

[0035] Furthermore, such as Figure 4 and Figure 5 As shown, the nozzle 3 has a first channel 31 and a second channel 32 extending through its height. The heights of both channels 31 and 32 are equal to the height of the nozzle 3. The first channel 31 is used for the sample 8 and its connected amplitude transformer to pass through, while the second channel 32 is used for the passage of cold air. Furthermore, the nozzle 3 includes an inner tube 33 and a shell 34. The shell 34 is located outside the inner tube 33, and the center of the inner tube 33 and the center of the shell 34 are on the same vertical line. The shell 34 is frustum-shaped, and its inner diameter gradually decreases from its top to its bottom. The inner tube 33 is cylindrical, and its inner diameter is smaller than the inner diameter of the bottom of the shell 34.

[0036] The diameter of the first channel 31 is equal to the inner diameter of the inner tube 33. The second channel 32 is formed by the outer wall of the inner tube 33 and the inner wall of the shell 34. The cross-sectional area of ​​the second channel 32 gradually decreases from the top to the bottom. This allows the cold air flowing from the top to the bottom of the second channel 32 to generate a high-speed gas jet along the axial direction of the sample 8. The pressure at the bottom of the second channel 32 is high, thus ensuring that the atmospheric pressure air around the gauge section 81 of the sample 8 is carried away to cool the sample 8. The center of the sample 8 and the center of the nozzle 3 are located on the same vertical line. After the sample 8 passes through the first channel 31, the distance between the top of its gauge section 81 and the bottom of the nozzle 3 is 5-10 mm. Ensuring that the distance between the sample 8 and the bottom of the nozzle 3 is appropriate is necessary for the high-speed gas jet to carry away the air around the sample 8.

[0037] Furthermore, such as Figure 1 and Figure 2As shown, in this embodiment, the cold air delivery assembly 5 includes four air supply pipes 51 and four air inlets 52. The four air inlets 52 are evenly spaced along the circumference of the top of the second channel 32. One end of the air supply pipe 51 is connected to and communicates with the cold air supply box 4, and the other end of the air supply pipe 51 is connected to and communicates with the air inlets 52. The bottom surface of the end of the air inlet 52 away from the air supply pipe 51 corresponds to the top surface of the second channel 32 and is connected to the top of the housing 34 and inner pipe 33 of the nozzle 3. The air inlet 52 is shaped like a frustum, and its inner diameter gradually increases from the top to the bottom. The cold air supply box 4 directs cold air to the air supply pipes 51, then from the air supply pipes 51 to the air inlets 52, and from the air inlets 52 into the second channel 32 of the nozzle 3, finally spraying it onto the sample 8 from the bottom of the nozzle 3. Each air supply duct 51 is also equipped with a regulating valve 53 for adjusting the air volume of cold air to ensure that the air volume flowing from each air supply duct 51 to the nozzle 3 is the same.

[0038] like Figures 1 to 3 As shown, the distance from the bottom of the gauge length section 81 to the top of the guide section 7 below is 5-20 mm, and the center of the guide section 7 and the center of the nozzle 3 are also located on the same vertical line. In order to direct the gas flowing around the sample 8 to flow out in all directions and avoid stagnation near the sample, the side of the guide section 7 is designed to be streamlined. Specifically, the area of ​​the top surface of the guide section 7 is larger than the area of ​​the bottom surface, and the generatrix of the guide section 7 is a concave arc to achieve better flow guidance.

[0039] Example 2 describes a method for controlling the surface temperature of a sample using the control device described in Example 1, which mainly includes the following steps:

[0040] Step 1: Install the sample 8 onto the ultrasonic fatigue loading module 2.

[0041] Step 2: Start the ultrasonic fatigue loading module 2 to begin the ultra-high frequency fatigue test on the sample 8.

[0042] Step 3: Start the cold air supply box 4, and rotate the regulating valve 53 to adjust the air volume of the cold air flowing in each air supply pipe 51, so that the air volume of the cold air flowing from each air supply pipe 51 to the nozzle 3 is consistent.

[0043] Step 4: Based on the real-time monitoring of the sample 8 temperature fed back to the cold air supply box 4 by the thermocouple 6, adjust the temperature and / or wind speed of the cold air to control the temperature of the sample 8 within the range of room temperature to 100℃.

[0044] Step 5: After the sample 8 has failed due to fatigue, turn off the cold air supply box 4 and the ultrasonic fatigue loading module 2 in sequence, and then remove the sample 8.

[0045] The sample surface temperature control device and method of the present invention can generate a high-speed gas jet along the axial direction of the sample around the gauge length, blow cold air toward the sample, generate negative pressure to remove the air around the sample, thereby cooling the gauge length of the sample while reducing the stress influence on the gauge length of the sample, thus ensuring the accuracy of the test results.

[0046] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A device for controlling the surface temperature of a sample, wherein the sample includes a gauge length section, characterized in that, The device includes a cold air supply box, a cold air delivery assembly, a nozzle, and an ultrasonic fatigue loading module. The sample is connected to the ultrasonic fatigue loading module. The nozzle has a first channel and a second channel extending through its height. The sample passes through the first channel, and the gauge length is located below the nozzle. The second channel is used for cold air to pass through. One end of the cold air delivery assembly is connected to the cold air supply box, and the other end is connected to the top of the second channel. The nozzle is used to blow the cold air delivered by the cold air delivery assembly to the second channel along the axial direction of the sample toward the gauge length. The outer periphery of the gauge length is fitted with the measuring end of a thermocouple. The cold air delivery assembly includes an air supply pipe and an air inlet. The air inlets are evenly spaced along the circumference of the top of the second channel. The air inlets are truncated cone-shaped, and their inner diameter gradually increases from the top to the bottom. The center of the sample and the center of the nozzle are on the same vertical line. The nozzle includes an inner tube and a shell. The height of the first channel and the second channel are both equal to the height of the nozzle. The diameter of the first channel is equal to the inner diameter of the inner tube. The second channel is formed by the outer wall of the inner tube and the inner wall of the shell. The cross-sectional area of ​​the second channel gradually decreases from its top to its bottom.

2. The control device according to claim 1, characterized in that, One end of the air supply pipe is connected to the cold air supply box, and the other end of the air supply pipe is connected to the air inlet. The end of the air inlet away from the air supply pipe is connected to the top of the second channel. The end of the thermocouple away from the sample is connected to the cold air supply box.

3. The control device according to claim 2, characterized in that, Multiple air supply pipes are arranged in parallel, and each air supply pipe is also equipped with a regulating valve. The number of air inlets is equal to the number of air supply pipes.

4. The control device according to claim 1, characterized in that, The shell is located outside the inner tube, and the center of the inner tube and the center of the shell are on the same vertical line; the shell is shaped like a frustum, and the inner diameter of the shell gradually decreases from its top to its bottom; the inner tube is shaped like a cylinder, and the inner diameter of the inner tube is smaller than the inner diameter of the bottom of the shell.

5. The control device according to claim 1, characterized in that, The distance between the top of the gauge section and the bottom of the nozzle is 5~10mm.

6. The control device according to claim 1, characterized in that, It also includes a frame and a flow guide. The top of the ultrasonic fatigue loading module is fixedly connected to the top of the frame, and the bottom surface of the flow guide is fixedly connected to the bottom of the frame. The flow guide is located below the gauge length section.

7. The control device according to claim 6, characterized in that, The distance from the bottom of the gauge section to the top of the guide section is 5~20mm, and the center of the guide section and the center of the nozzle are located on the same vertical line.

8. The control device according to claim 6, characterized in that, The area of ​​the top surface of the guide section is larger than the area of ​​the bottom surface, and the generatrix of the guide section is a concave arc.

9. A method for controlling the surface temperature of a sample, characterized in that, The surface temperature of the sample is controlled using the control device as described in any one of claims 1 to 8, and the control method includes the following steps: After the specimen is installed on the ultrasonic fatigue loading module, the ultra-high frequency fatigue test is started. Then the cold air supply box is turned on. According to the specimen temperature in the gauge section fed back by the thermocouple, the temperature and / or wind speed of the cold air delivered by the cold air delivery component are adjusted so that the temperature of the specimen gauge section is room temperature to 100℃.

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