Young modulus measuring instrument based on single slit diffraction and buoyancy dynamic adjustment tensile method

Abstract

A Young modulus measuring instrument based on a single-slit diffraction and buoyancy dynamic adjustment tensile method comprises a diffraction generating device and a receiving device, the diffraction generating device comprises a base 13, a stand column 1 vertically installed on the base 13, an upper cross beam 2 installed on the stand column 1 in a sliding mode, and a single-slit platform 7 located in the middle of the stand column 1; the semiconductor laser 8 is fixed on the diffraction single-slit platform 7, and the digital display tension meter 9 is connected with the diffraction single-slit platform. The light diffraction receiving device comprises a diffraction observation screen 14 and a diffraction observation screen base 16. The diffraction observation screen is placed on a laser light path away from the single slit by one meter. A buoyancy dynamic adjusting device is designed at the lower end of a to-be-measured wire 4 to indirectly measure the tensile force borne by the to-be-measured wire, the to-be-measured wire drives a single-slit lower knife edge to move after the length of the to-be-measured wire is expanded and contracted, the width of a single slit is changed, a 1: 10 lever 6 is connected with a single-slit upper knife edge and a digital microscope head 5, and the upper knife edge can move up and down under the action of the 1: 10 lever 6. And the digital display micrometer head 5 can accurately read the change of the slit width. The device is based on a single slit diffraction principle and buoyancy dynamic bidirectional stepless adjustment tension, and has the advantages of simple process, low manufacturing cost, small error and the like.

Description

Technical Field

[0001] The present invention relates to the field of Young's modulus measurement, and in particular to a measuring instrument that uses a digital differential head to read a single slit width, indirectly measures the material's expansion and contraction length and buoyancy dynamic bidirectional stepless adjustment tension, and realizes Young's modulus measurement. Background Art

[0002] Young's modulus is a parameter used to describe the ability of solid materials to resist longitudinal deformation. There are many methods to measure the Young's modulus of solid materials, such as tensile method, bending method, vibration method, internal friction method, etc. The tensile method is often used to measure the Young's modulus of solid materials in physical experiments in colleges and universities. The measurement principle and process of the tensile method for measuring the Young's modulus of solid materials are as follows: , the length is The uniform steel wire is subjected to external force in the longitudinal direction After that, the elongation is The vertical force per unit cross-sectional area It is called normal stress, the relative elongation of the wire Defined as linear strain. Within the elastic limit, stress is proportional to strain, and its proportionality coefficient is , is called the Young's modulus of the wire. The diameter of the metal wire is expressed in If , then Young's modulus can be expressed as . The existing diffraction method for measuring Young's modulus has shortcomings such as large errors in slit width variation and diffraction fringe readings, large errors in measuring the tension on the material, and the inability to continuously and steplessly add and subtract. Based on the existing basis, the present invention uses the high-precision measurement technology of single-slit diffraction and the buoyancy dynamic adjustment stretching method to propose a new method for measuring Young's modulus, aiming to improve measurement accuracy, simplify operation steps, and broaden the scope of application. Summary of the Invention

[0003] The present invention aims to solve the above-mentioned deficiencies in the prior art and proposes a device with a simple structure and ingenious design, which uses a more direct method than traditional measurement methods to measure the Young's modulus of filaments of various different materials. The device is based on the principle of single-slit diffraction and dynamic bidirectional stepless adjustment of buoyancy tension, and has the advantages of simple process, low manufacturing cost and small error.

[0004] The present invention is primarily characterized by comprising an upper crossbeam, a column, a base, a test wire, a test wire fastening screw, a single-slit platform, a side surface of a receiving plate, upper and lower single-slit cutting edges, a digital micrometer, a 1:10 lever, a locking screw, a semiconductor laser, a buoyancy dynamic adjustment device, and a diffraction observation screen. The two columns are secured by the upper crossbeam and the base; the test wire is secured to the upper crossbeam by the test wire fastening screw; the single-slit platform is secured to the center of the column; the upper single-slit cutting edge and the semiconductor laser are secured to the single-slit platform; the lower single-slit cutting edge is locked to the test wire by the locking screw; the semiconductor laser beam is directed directly into the gap between the upper and lower single-slit cutting edges (this gap is often referred to as a single slit); and the diffraction observation screen is placed in the laser beam path one meter away from the single slit. After a laser beam passes through a single slit formed by upper and lower cutting edges, its diffraction spot appears on a diffraction observation screen. The width of the diffraction spot on the diffraction observation screen varies by the amount of expansion and contraction of the wire being measured. Furthermore, the device of the present invention incorporates a dynamic buoyancy adjustment device at the lower end of the wire being measured. This device indirectly measures the tension on the wire being measured by varying the buoyancy of the weight attached to the wire. As the buoyancy changes, the tension on the wire being measured changes accordingly. This causes the length of the wire to expand and contract, driving the lower cutting edge of the single slit to move, resulting in a change in the width of the single slit and, consequently, a change in the width of the diffraction stripes on the diffraction observation screen. A 1:10 lever is designed in the device of the present invention to connect the upper cutting edge of the single slit and the digital micrometer. The tip of the upper cutting edge of the 1:10 lever is 10.0 mm from the lever's cylindrical pin, while the tip of the micrometer head is 100.0 mm from the lever's cylindrical pin. The upper cutting edge can move up and down under the action of the 1:10 lever, and the digital micrometer head precisely adjusts the slit width by controlling the displacement of the upper cutting edge via the 1:10 lever. The lower cutting edge of the single seam is fixed on the side of the receiving plate and connected with the locking screw. The tested wire is stretched under the force and drives the receiving plate to move downward, causing the position of the lower cutting edge of the single seam to change, so that the seam width is changed from Increase to , while the width of the diffraction central bright fringe is Shorten to At this time, adjust the digital micrometer head to control the upper blade to move downward, and change the width of the central bright stripe from Restore to , the single slit width is also given by Restore to At this time, one tenth of the change in the reading of the digital micrometer head is the slight change in the length of the wire to be measured. ,Right now The tension on the wire to be tested can be directly read by the buoyancy dynamic adjustment device, which consists of an outer barrel, an inner barrel, a digital tension gauge, an infusion tube, a speed control valve, and a water tank. One end of the digital tension gauge is connected to the wire to be tested through a locking screw, and the other end is connected to the inner barrel. Equal to the gravity of the inner barrel and buoyancy In the experiment, water was added to the outer barrel to make Reduce, that is Increases, the tension on the wire to be tested Increase. Change in the reading of the digital dynamometer The tensile force on the wire The wavelength of the laser is known, and the distance from the single slit to the diffraction observation screen is easy to measure. ,diameter and tension change , substitute into the formula , the Young's modulus of the corresponding wire to be tested can be calculated.

[0005] The present invention combines the high-precision measurement technology of single-slit diffraction with the buoyancy dynamic adjustment stretching method, and has the following advantages: 1. High-precision measurement: Utilizing the principle of single-slit diffraction, it is possible to accurately measure the tiny elongation of the sample and improve the measurement accuracy of Young's modulus.

[0006] 2. Dynamic stretching: Through the dynamic adjustment of buoyancy stretching method, continuous and stepless tension adjustment is achieved, avoiding the instability and error of manual stretching in traditional methods.

[0007] 3. Simplified operation: The experimental device has a simple structure and is easy to operate, which reduces the difficulty and cost of the experiment.

[0008] 4. Broaden the scope of application: This method is suitable for measuring the Young's modulus of a variety of materials and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 This is a schematic diagram of the working principle structure of the single-slit diffraction Young's modulus measuring instrument.

[0010] Figure 2 yes Figure 1 Schematic diagram of the single-slit platform structure of the Young's modulus measuring instrument Figure 3 yes Figure 1 Schematic diagram of the buoyancy dynamic adjustment structure of the Young's modulus measuring instrument In the figure, 1. column, 2. upper crossbeam, 3. fastening screw of the wire to be measured, 4. wire to be measured, 5. digital micrometer, 6. 1:10 lever, 7. single-slit platform, 8. semiconductor laser, 9. digital dynamometer, 10. buoyancy adjustment inner barrel, 11. buoyancy adjustment outer barrel, 12. base, 13. level adjustment knob, 14. diffraction observation screen, 15. buoyancy adjustment water tank, 16. diffraction observation screen base, 17. stool, 18. infusion tube, 19. speed control valve, 20. single-slit upper blade, 21. single-slit lower blade, 22. locking screw, 23. receiving plate, 24. digital micrometer, 25. 1:10 lever. DETAILED DESCRIPTION

[0011] The following is combined with Figure 1 , Attachment Figure 2 , Attachment Figure 3 The present invention is further described.

[0012] In the figure, two columns (1) are fixed by an upper crossbeam (2) and a base (12), a wire to be measured (4) is fixed to the upper crossbeam by a wire fastening screw (3), a single-slit platform (7) is fixed to the middle of the column (1), a single-slit upper blade (20) and a semiconductor laser (8) are fixed to the single-slit platform, a single-slit lower blade is connected to a receiving plate (23) and is locked to the wire to be measured by a locking screw (22), a laser beam of the semiconductor laser is directed to the gap between the upper and lower blades of the single-slit (called a single-slit), and a diffraction observation screen (14) together with a diffraction screen holder (16) is placed on the laser light path one meter away from the single-slit.

[0013] Place the entire device on the ground, adjust the horizontal adjustment knob (13) of the base of the Young's modulus measuring instrument and the loading platform to make the two columns in a vertical state, straighten the metal wire to be measured, and place the outer barrel (11) of the buoyancy dynamic adjustment system in the center of the base, keeping it horizontal, then place the inner barrel (10) in the outer barrel, hang the digital display tensile gauge (9) on the hook at the lower end of the metal wire, and hang the inner barrel (10) in the center of the outer barrel (11), ensuring that there is a gap of 5-10mm with the bottom of the outer barrel; place the buoyancy adjustment tank (15) on the stool (17), ensuring that the top of the inner barrel is higher than the outer barrel, connect the outer barrel and the tank with an infusion tube (18) equipped with a speed control valve (19) in the middle, and inject an appropriate amount of saturated salt water into the outer barrel (11); adjust the slit width and the position of the semiconductor laser so that the laser is incident from the horizontal direction perpendicular to the slit and forms a clear diffraction pattern on the diffraction observation screen.

[0014] Mark the initial position of the central bright stripe on the diffraction screen and set the reading of the digital differential head (24) to zero; open the speed control valve to control the salt water to flow evenly from the outer barrel into the water tank, and observe that the line width of the central bright stripe becomes narrower. Whenever the reading of the dynamometer increases by 3N, stop the water flow, adjust the digital differential head to control the upper blade to move downward, and reduce the line width of the central bright stripe from Restore to , the single slit width is also given by Restore to , so that the central bright stripe is reset to its initial position. At this time, one tenth of the change in the reading of the digital micrometer head is the slight length change of the measured wire. ,Right now , record the reading of the digital micrometer head and the corresponding dynamometer readings Measure multiple sets of data; change the direction of water flow, conduct reverse experiment, re-record multiple sets of data, and calculate the change in tension on the wire to be measured based on the change in the reading of the digital dynamometer A more accurate value. The single slit width is obtained from the Fraunhofer single slit diffraction principle Width of central bright fringe The relationship is . (Where is the distance from the slit to the screen, is the wavelength.) Under experimental conditions, the wavelength of light and the distance from the slit to the screen Therefore, the line width of the diffraction central bright fringe is Will strictly depend on the width of the single slit The change of the width of the central bright stripe Always reflect the changes of the bidirectionally adjustable single slit width , that is, the small length change .

[0015] In the present invention, the top of the upper blade of the 1:10 lever is 10.0 mm from the lever shaft, and the top of the digital micrometer is 100.0 mm from the lever shaft. The upper blade of the single slit can move up and down under the action of the 1:10 lever. The digital micrometer controls the movement of the upper blade of the single slit through the 1:10 lever to cause the central bright stripe to return to its initial position. Therefore, the slit width can be precisely adjusted by adjusting the digital micrometer. The change in the digital micrometer reading can be used to obtain the minute length change of the measured wire. , substitute into the formula , the Young's modulus of the corresponding wire to be tested can be calculated.

Claims

1. A Young's modulus measuring instrument based on single-slit diffraction and buoyancy dynamic adjustment tensile method, characterized by: The device comprises (1) a column, (2) an upper crossbeam, (3) a fastening screw for the wire to be measured, (4) the wire to be measured, (5) a digital micrometer, (6) a 1:10 lever, (7) a single-slit platform, (8) a semiconductor laser, (9) a digital force gauge, (10) an inner buoyancy adjustment barrel, (11) an outer buoyancy adjustment barrel, (12) a base, (13) a level adjustment knob, (14) a diffraction observation screen, (15) a buoyancy adjustment water tank, (16) a base for the diffraction observation screen, (17) a stool, (18) an infusion tube, (19) a speed control valve, (20) an upper single-slit blade, (21) a lower single-slit blade, (22) a locking screw, (23) a receiving plate, (24) a digital micrometer, and (25) a 1:10 lever.

2. A measuring instrument for measuring the Young's modulus of a filament using the device according to claim 1, characterized in that: The device consists of an upper crossbeam, a column, a base, a test wire, a thread fastening screw, a single-slit platform, the side of a receiving plate, upper and lower single-slit cutting edges, a digital micrometer, a 1:10 lever, a locking screw, a semiconductor laser, a buoyancy dynamic adjustment device, and a diffraction observation screen. The two columns are secured by the upper crossbeam and the base. The test wire is secured to the upper crossbeam with the thread fastening screw. The single-slit platform is fixed to the center of the column. The upper single-slit cutting edge and the semiconductor laser are fixed to the single-slit platform. The lower single-slit cutting edge is locked to the test wire with a locking screw. The semiconductor laser beam is directed directly into the gap between the upper and lower single-slit cutting edges (this gap is often called a single slit). The diffraction observation screen is placed in the laser beam path one meter away from the single slit.

3. The device for measuring the Young's modulus of a filament according to claim 1, characterized in that: This device is designed with a buoyancy dynamic adjustment device at the lower end of the measured wire to indirectly measure the tension on the measured wire. When the length of the measured wire expands or contracts, it drives the lower blade of the single slit to move, resulting in a change in the width of the single slit. A 1:10 lever connects the upper blade of the single slit and the digital micrometer. The upper blade can move up and down under the action of the 1:10 lever, and the digital micrometer can accurately read the change in the slit width.

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