Device for measuring Young modulus of metal wire based on optical principle

Abstract

The utility model discloses a device for measuring the Young modulus of a metal wire based on the optical principle, which relates to the field of physical experiment equipment and comprises an observation screen, a digital height measuring instrument, a cylinder and a helium-neon laser. The air cylinder is connected with an inflating ball and an air storage bottle through air pipes, an air cylinder platform and an electronic scale are installed on the upper portion of the air cylinder, a heavy object is placed on the electronic scale, a steel wire is hung on the heavy object, a linear bearing is arranged on the heavy object, and a fixed reflector is installed on the linear bearing and provided with an adjustable single slit. A spectroscope, a compensating mirror, a movable reflector and a linkage plate are arranged on the upper portion of the adjustable single slit, and a semiconductor laser is installed on the fixed reflector.

Description

Technical Field

[0001] The utility model relates to the field of physical experimental equipment, in particular to a device for measuring the Young's modulus of a metal wire based on an optical principle. Background Art

[0002] "Measuring the Young's modulus of metal wire by stretching method" is a classic mechanical experiment example in university physics experimental teaching. It mainly adopts static stretching method and uses optical lever device to measure small deformation, so as to determine the Young's modulus of metal wire. It is common to use optical lever to measure the Young's modulus of metal wire. The device amplifies the small angle of rotation of the optical lever reflector and reflects it into the linear displacement of the ruler. It is mainly through placing the two front feet of the optical lever on the fixed platform of the experimental device, and the rear foot on the measuring end face of the metal wire to be measured. When the metal wire is slightly stretched by force, the optical lever rotates a small angle around the front foot, thereby driving the optical lever reflector to rotate a corresponding small angle. In this way, the image of the ruler is reflected between the optical lever reflector and the adjustment reflector, which amplifies this small angular displacement into a larger linear displacement. Utility Model Content

[0003] The technical problem mainly solved by the utility model is to provide a Young's modulus device for measuring a metal wire based on optical principles. The Young's modulus measuring instrument is assembled from components such as a pneumatic tension adjustment device, a spectroscope, a compensation mirror, and a single-slit device. The Young's modulus measuring instrument can accurately measure the Young's modulus of the metal wire by using light interference and diffraction methods respectively, with higher measurement accuracy and better repeatability.

[0004] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0005] The Young's modulus device for measuring the metal wire based on optical principles comprises an observation screen, a digital height measuring instrument, a cylinder, and a helium-neon laser. An electron microscope is installed on the digital height measuring instrument. The cylinder is connected to a balloon and a gas storage bottle through a conduit. A cylinder platform and an electronic scale are installed on the upper part of the cylinder. A heavy object is placed on the electronic scale. A steel wire is hung on the heavy object and a linear bearing is provided. A fixed reflector is installed on the linear bearing. The fixed reflector is provided with an adjustable single slit. A beam splitter, a compensation mirror, a movable reflector, and a linkage plate are provided on the upper part of the adjustable single slit. A semiconductor laser is installed on the fixed reflector.

[0006] As a further optimization of the technical solution, the movable reflector is adhered to a linkage plate connected to the metal wire, and moves up and down with a slight deformation of the metal wire.

[0007] The beneficial effects of the above technical solutions are: the experimental measurement data linearity of the Young's modulus device for measuring the wire based on optical principles is very reliable, the instrument performance is very stable, and it can meet the requirements of the experiment. The overall height of the experimental instrument is less than 1m. It can be placed on the optical platform and the entire experimental test process can be completed while sitting. The instrument operation has also become easier, such as the simple operation of moving the semiconductor laser up and down, which is simpler and faster than the adjustment of the traditional Michelson interferometer. After the students repeated the measurement many times using two different methods, the results were basically consistent and the repeatability was very good. Compared with the traditional optical lever method for measuring the Young's modulus of the steel wire of the same material, the measurement accuracy is higher. The experimental phenomenon is clear, and the observation of the pleasing interference fringes and diffraction fringes has increased the students' interest. The use of the modified height measuring instrument to measure the length also allows students to experience the fun of the new length measurement method, especially the pneumatic tension adjustment system makes students curious. The new experience brought by these rich contents has greatly improved the teaching effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The specific implementation of the utility model is further described in detail below with reference to the accompanying drawings.

[0009] Figure 1 is a schematic diagram of the structure of the device for measuring the Young's modulus of a metal wire based on optical principles;

[0010] Figure 2 This is the principle diagram of measuring small length changes using the interference method.

[0011] Among them, 1- observation screen, 2- electron microscope, 3- spectroscope, 4- compensation mirror, 5- movable reflector, 6- linkage plate, 7- digital height measuring instrument, 8- weight, 9- cylinder, 10- balloon, 11- steel wire, 12- semiconductor laser, 13- fixed reflector, 14- adjustable single slit, 15- linear bearing, 16- electronic scale, 17- cylinder platform, 18- gas cylinder, 19- helium-neon laser. DETAILED DESCRIPTION

[0012] The preferred implementation of the device for measuring the Young's modulus of a metal wire based on an optical principle of the present invention is described in detail below in conjunction with the accompanying drawings.

[0013] Figure 1 and Figure 2 The specific implementation of the device for measuring the Young's modulus of a metal wire based on an optical principle is shown below:

[0014] like Figure 1As shown, the Young's modulus device for measuring the metal wire based on optical principles includes an observation screen 1, a digital height measuring instrument 7, a cylinder 9, and a helium-neon laser 19. An electron microscope 2 is installed on the digital height measuring instrument 7. The cylinder 9 is connected to an inflating ball 10 and a gas storage bottle 18 through a conduit. A cylinder platform 17 and an electronic scale 16 are installed on the upper part of the cylinder 9. A heavy object 8 is placed on the electronic scale 16. A steel wire 11 is hung on the heavy object 8 and a linear bearing 15 is provided. A fixed reflector 13 is installed on the linear bearing 15. The fixed reflector 13 is provided with an adjustable single slit 14. A spectrometer 3, a compensation mirror 4, a movable reflector 5, and a linkage plate 6 are provided on the upper part of the adjustable single slit 14. A semiconductor laser 12 is installed on the fixed reflector 13.

[0015] The upper end of the steel wire 11 to be tested is fixed in the wire clamp in the middle of the upper beam, and the lower end of the steel wire 11 is fixed in the wire clamp installed in the linear bearing 15, and is connected to the weight 8 through the linear bearing 15. An electronic scale 16 and a cylinder 9 are placed under the weight 8. The cylinder 9 is inflated and deflated by the balloon 10 to make the cylinder platform 17 rise and fall, driving the weight above to move up and down to change the force on the wire.

[0016] The cylinder 9, the inflating ball 10 and the gas storage bottle 18 form a communication system through a conduit. The pressure in the cylinder 9 is changed by inflating and deflating the inflating ball 10. Selecting a gas storage bottle 18 with a large enough capacity can make the cylinder platform 17 move up and down slowly, steadily and evenly, thereby changing the tension of the weight 8 placed on the cylinder platform 17 on the metal wire. Since the system can control the gas to enter and exit the system very slowly, continuously and evenly, the up and down movement of the cylinder platform 17 becomes slow and even, thereby realizing continuous and even regulation of the tension of the metal wire, that is, stepless regulation. Compared with the method of measuring the Young's modulus of the metal wire by changing the mass of the liquid to change the tension of the metal wire, the tension adjustment system of the device can more accurately and controllably realize the continuous and even adjustment of the force of the metal wire, and compared with other pneumatic Young's modulus measuring instruments, it is easy to operate and the reading of the electronic scale 16 can intuitively and clearly reflect the stress of the metal wire.

[0017] Figure 2 In the figure, S is a semiconductor laser, G1 is a beam splitter, one side of which is coated with a semi-transparent and semi-reflective film, so that half of the light shining on it is reflected and the other half is transmitted. G2 is a compensation mirror, M1 is a fixed reflector, and M2 is a movable reflector attached to a linkage plate connected to a metal wire. It moves a tiny length L as the metal wire stretches under tension. After the laser emitted by the semiconductor laser S enters the G1 mirror, it is divided into two beams on the semi-reflective surface: the light beam (1) is refracted inside the G1 mirror and then directed to the M1 mirror, reflected by M1 and then returned, passing through the G1 mirror again and reaching the observation screen; the light beam (2) passes through the semi-reflective surface, passes through the compensation mirror G2 and then directed to the M2 mirror, reflected by M2, passes through G2 again, and is reflected by the lower surface of G1 and reaches the observation screen. The two beams meet and interfere.

[0018] Interference method to measure Young's modulus:

[0019] (1) Place the entire device on an optical platform, adjust the Young's modulus measuring instrument base and the loading platform to a level level so that the two columns on the base are in a vertical state, straighten the steel wire, and place the cylinder of the pneumatic tension adjustment system in the center of the base to keep it horizontal;

[0020] (2) Place the calibrated electronic scale on the cylinder platform;

[0021] (3) Hang a heavy object on the hook at the lower end of the steel wire and place the heavy object above the center of the electronic scale pan, keeping a distance of 1 to 2 mm from the electronic scale;

[0022] (4) Use an inflating balloon to inflate the pneumatic adjustment device, so that the cylinder platform and the electronic scale move upward synchronously to lift the weight, thereby reducing the tension on the wire;

[0023] (5) Adjust the position of the fixed reflector M1 so that the distances from the beam splitter to M1 and M2 are roughly equal;

[0024] (6) Turn on the switch of semiconductor laser S. From the position of the observation screen, you can see two rows of light spots reflected by M1 and M2 on the screen. Adjust the two screws behind M1 so that the two rows of light spots completely overlap. At this time, M1 and M2 are roughly perpendicular to each other.

[0025] (7) Adjust the focusing lens (beam expander) of the semiconductor laser to expand the laser beam until an interference ring appears on the observation screen, and then adjust the fine-tuning screw M1 so that the interference ring is in the center of the observation screen;

[0026] (8) Turn on the balloon inflator switch to release the gas evenly and slowly. When the interference ring is observed to be evenly "gushing out" or "flooded", record the reading of the electronic scale corresponding to every 40 circles of "gushing out" or "flooding". Measure 10 sets of data in total.

[0027] (9) Use a micrometer to measure the diameter D of the wire in two orthogonal directions at the top, middle, and bottom of the wire, use a steel tape measure to measure the length L of the wire, and use an electronic scale to weigh the mass m0 of the weight.

[0028] Single slit diffraction method to measure Young's modulus:

[0029] (1) Same as interference method (1)-(4);

[0030] (2) Adjust the slit width and the height of the HeNe laser so that the laser is incident from the horizontal direction perpendicular to the slit and forms a clear diffraction pattern on the observation screen;

[0031] (3) Use a digital height meter to measure the line width δ1 of the central bright fringe and record the corresponding reading m1 of the electronic scale;

[0032] (4) Turn on the balloon switch and release a certain amount of gas. Measure the width of the central bright stripe δ2 and the corresponding reading m2 on the electronic scale. Repeat this step and record the width of the central bright stripe δ i and m i A total of 7 sets of data were measured;

[0033] (5) Use a steel tape measure to measure the distance R between the single slit and the observation screen, and use the wire diameter D, length L and weight m0 measured in step (9) of the interference method.

[0034] The above are only preferred implementations of the present invention. It should be pointed out that, for ordinary technicians in this field, several modifications and improvements can be made without departing from the creative concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A device for measuring Young's modulus of metal wire based on optical principle, Features: The Young's modulus device for measuring a metal wire based on an optical principle comprises an observation screen (1), a digital height measuring instrument (7), a cylinder (9), and a helium-neon laser (19). An electron microscope (2) is installed on the digital height measuring instrument (7). The cylinder (9) is connected to a balloon (10) and a gas storage bottle (18) through a conduit. A cylinder platform (17) and an electronic scale (16) are installed on the upper part of the cylinder (9). A weight (8) is placed on the electronic scale (16). A steel wire (11) is suspended on the weight (8) and a linear bearing (15) is provided. A fixed reflector (13) is installed on the linear bearing (15). The fixed reflector (13) is provided with an adjustable single slit (14). A beam splitter (3), a compensation mirror (4), a movable reflector (5), and a linkage plate (6) are provided on the upper part of the adjustable single slit (14). A semiconductor laser (12) is installed on the fixed reflector (13).

2. The device for measuring the Young's modulus of a metal wire based on an optical principle according to claim 1, Features: The movable reflector (5) is adhered to a linkage plate (6) connected to the metal wire, and moves up and down with slight deformation of the metal wire.

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