A device for measuring Young's modulus of metal wire based on gas injection method and torsion balance principle

Abstract

The invention discloses a device for measuring the Young's modulus of a metal wire based on an air injection method and a torsion balance principle, comprising an air injection chamber, an air cylinder fixedly provided in one side wall of the air injection chamber, a torsion balance device provided on the side of the air cylinder away from the air injection chamber, a fine-tuning air injection cylinder and an air pump fixedly provided inside the air injection chamber, a metal base provided at one end of the air cylinder close to the air injection chamber, a connecting plate provided on the metal base, two one-way ventilation air nozzles provided on the lower side of the connecting plate, the fine-tuning air injection cylinder and the air pump are connected to the air nozzle through an air pipe, and the air cylinder comprises a cylindrical glass air cover. The invention has high integration, simple operation, and convenient use, uses cheap and not easy-to-damage materials, and the main part is easy to disassemble and assemble. It rationally uses a variety of physical ideas and is highly innovative. The readings are stable and accurate during use, which greatly reduces the reading errors caused by structural defects of existing devices.

Description

Technical Field

[0001] The invention relates to the technical field of experimental devices, and in particular to a device for measuring the Young's modulus of a metal wire based on a gas injection method and a torsion balance principle. Background Art

[0002] Assume that the original length of the metal wire of uniform thickness is , the cross-sectional area is , force applied along the length direction After that, its length changes , then the vertical force per unit area of ​​the wire is It is called normal stress, the relative elongation of the wire It is called linear strain. Experimental results show that within the elastic range, Hooke's law shows that the normal stress of an object is proportional to the linear strain, that is,

[0003]

[0004] Proportional coefficient Young's modulus of elasticity, referred to as Young's modulus. It characterizes the properties of the material itself. The larger the material, the greater the force per unit cross-sectional area required to cause it to undergo a certain relative deformation. The SI unit of mass is Pascal, denoted as Pa (1 Pa = 1 N / m 2 ).

[0005] and is a small length change (in this experiment, when ≈1m, For every 1kg change, the corresponding Therefore, this experiment uses the optical amplification effect of the optical lever to achieve the micro elongation of the steel wire. indirect measurement of .

[0006] is the length of the short arm of the mirror, is the distance from the smooth rod plane mirror to the ruler. When adding or subtracting weights, The right end of the side falls and rises as the measured wire stretches and shrinks, thus changing the direction of the normal line of the optical lever mirror, making an adjusted telescope on the left side of the figure see The reading of the ruler image in the mirror changes , using geometric relationships, you can derive the wire Elongation , to achieve the measurement purpose.

[0007] However, during actual measurement, the wire and the groove code underneath it are difficult to maintain stability, causing the projected cursor to fluctuate up and down, left and right, making it difficult to obtain accurate readings and resulting in experimental errors. Therefore, a more accurate, effective, and stable method for measuring wire elongation is needed. Summary of the Invention

[0008] In order to overcome the defects in the above-mentioned prior art, the present invention provides a device for measuring the Young's modulus of a metal wire based on the gas injection method and the torsion balance principle. The device is simple to operate, easy to use, uses inexpensive and non-damageable materials, is easy to disassemble and assemble, and rationally applies a variety of physical ideas. The device is easy to understand and has high accuracy.

[0009] Technical Solution

[0010] A device for measuring the Young's modulus of a metal wire based on an air injection method and a torsion balance principle, comprising an air injection chamber, an air cylinder fixedly provided in one side wall of the air injection chamber, a torsion balance device provided on the side of the air cylinder away from the air injection chamber, a fine-tuning air injection cylinder and an air pump fixedly provided inside the air injection chamber, a metal base provided at one end of the air cylinder close to the air injection chamber, a connecting plate provided on the metal base, two one-way ventilation air nozzles provided on the lower side of the connecting plate, the fine-tuning air injection cylinder and the air pump connected to the air nozzle through an air pipe, The gas cylinder includes a cylindrical glass gas cover, a piston is slidably arranged inside the glass gas cover, a metal wire located inside the gas cylinder is fixedly connected between the piston and the metal base, the torsion balance device includes a torsion balance glass cover, an electromagnetic torsion balance mechanism is arranged inside the torsion balance glass cover, a plane mirror is arranged on the upper side of the electromagnetic torsion balance mechanism, a laser emitting device fixed to the glass gas cover is arranged on one side of the plane mirror, and a fixed scale parallel to the plane mirror is arranged on the side of the laser emitting device close to the plane mirror.

[0011] Furthermore, the air cylinder is also connected to a pressure gauge.

[0012] Furthermore, a first adjustable bracket for adjusting the height of the gas cylinder is provided on the lower side of the gas cylinder.

[0013] Furthermore, a second adjustable bracket for adjusting the height of the torsion balance device is provided on the lower side of the torsion balance device.

[0014] Furthermore, the electromagnetic torsion balance mechanism includes a vertical suspension wire and a light rod connected to the suspension wire in a front-to-back direction, one end of the light rod is connected to a charged metal ball, and the other end of the light rod is connected to an uncharged metal ball, and the direction of the light rod is perpendicular to the horizontal central axis of the gas cylinder.

[0015] Furthermore, the height and angle of the first adjustable bracket and the second adjustable bracket can be fine-tuned. Using the existing technical structure, it can be adjusted so that the laser emitted by the laser emitting device hits the coordinate origin position engraved on the fixed scale through the plane mirror to ensure that the entire device is in a horizontal state in the initial state.

[0016] Furthermore, an insulating rod that is not easy to bend is provided at the center of one side of the piston close to the torsion balance device, and a charged lightweight metal ball is provided at the other end of the insulating rod.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1. Compared with existing devices, the experimental equipment of the present invention has a higher degree of integration, is simple to operate, easy to use, and uses cheap materials that are not easily damaged;

[0019] 2. Easy to disassemble and assemble, it rationally applies a variety of physical concepts and is highly innovative;

[0020] 3. The experimental results of the present invention are highly accurate, greatly reducing the reading errors caused by structural defects of existing devices;

[0021] 4. The present invention has high automation and integration, is easy to understand and has high accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The present invention is a structural schematic diagram of a device for measuring the Young's modulus of a metal wire based on the gas injection method and the torsion balance principle.

[0023] Figure numerals: gas injection chamber 1, gas cylinder 2, torsion balance device 3, fine-tuning gas injection cylinder 4, air pump 5, air pressure gauge 6, connecting plate 7, metal base 8, piston 9, fixed scale 10, glass gas cover 11, first adjustable bracket 12, electromagnetic force torsion balance mechanism 13, second adjustable bracket 14, torsion balance glass cover 15, laser emitting device 16, plane mirror 17, gas nozzle 18, air tube 19. DETAILED DESCRIPTION

[0024] To better illustrate the present invention, the following is a detailed description with reference to the accompanying drawings and implementation examples:

[0025] have Figure 1As shown, the present invention discloses a device for measuring the Young's modulus of a metal wire based on an air injection method and a torsion balance principle, comprising an air injection chamber 1, an air cylinder 2 is fixedly provided in one side wall of the air injection chamber 1, a torsion balance device 3 is provided on the side of the air cylinder 2 away from the air injection chamber 1, a fine-tuning air injection cylinder 4 and an air pump 5 are fixedly provided inside the air injection chamber 1, a metal base 8 is provided at one end of the air cylinder 2 close to the air injection chamber 1, a connecting plate 7 is provided on the metal base 8, two one-way ventilation air nozzles 18 are provided on the lower side of the connecting plate 7, the fine-tuning air injection cylinder 4 and the air pump 5 are connected to the air nozzle 18 through an air pipe 19, The gas cylinder 2 includes a cylindrical glass gas cover 11, a piston 9 is slidably arranged inside the glass gas cover 11, and a metal wire located inside the gas cylinder 2 is fixedly connected between the piston 9 and the metal base 8. The torsion balance device 3 includes a torsion balance glass cover 15, an electromagnetic torsion balance mechanism 13 is arranged inside the torsion balance glass cover 15, a plane mirror 17 is arranged on the upper side of the electromagnetic torsion balance mechanism 13, a laser emitting device 6 fixed to the glass gas cover 11 is arranged on one side of the plane mirror 17, and a fixed scale 10 parallel to the plane mirror 17 is provided on the side of the laser emitting device 6 close to the plane mirror 17.

[0026] Furthermore, the gas cylinder 2 is also connected to a pressure gauge 6.

[0027] Furthermore, a first adjustable bracket 12 for adjusting the height of the gas cylinder 2 is provided on the lower side of the gas cylinder 2 .

[0028] Furthermore, a second adjustable bracket 14 for adjusting the height of the torsion balance device 3 is provided on the lower side of the torsion balance device 3 .

[0029] Furthermore, the electromagnetic torsion balance mechanism 13 includes a vertical suspension wire and a light rod connected to the suspension wire in a front-to-back direction, one end of the light rod is connected to a charged metal ball, and the other end of the light rod is connected to an uncharged metal ball, and the direction of the light rod is perpendicular to the horizontal central axis of the gas cylinder 2.

[0030] Furthermore, the height and angle of the first adjustable bracket 12 and the second adjustable bracket 14 can be fine-tuned. Using the existing technical structure, it can be adjusted so that the laser emitted by the laser emitting device 16 hits the coordinate origin position engraved on the fixed scale 10 through the plane mirror 17 to ensure that the entire device is in a horizontal state in the initial state.

[0031] Furthermore, an insulating rod that is not easily bent is provided at the center of the piston 9 on one side close to the torsion balance device 3 , and a charged lightweight metal ball is provided at the other end of the insulating rod.

[0032] Specifically, let the inner wall radius of the cylinder 2 be R室 , which is filled with air at standard atmospheric pressure. The bottom of the air cylinder 2 is connected to the metal base 8, which is connected to the pressure gauge 6 and the fine-tuning air injection cylinder 4. The center of the metal base 8 is connected to an embedded airtight screw, and the airtight screw is connected to a chuck to fix the horizontal metal wire. The metal wire is connected to the chuck embedded in the center of the piston 9, and the air cylinder 2 is also connected to the air pump 5 through the metal base 8;

[0033] Start the air pump 5 and inject air pressure p. When the pressure gauge approaches the specified reading, stop. Use the fine-tuning air injection cylinder 4 to fine-tune it to the specified reading. The horizontal metal wire in the air cylinder 2 is stretched to the right by a distance △L under the force of the piston 9 generated by the pressure change, so that the charged light metal ball moves to the right by a distance △L. Assume that the charged metal ball end of the electromagnetic torsion balance mechanism 13 is initially at a distance X0 from the charged light metal ball on the piston 9. At this time, the torsion balance 13 is rotated by an angle θ due to the electromagnetic force. The electromagnetic force is F 电 .

[0034] Formula derivation:

[0035] Assume that the radius of cylinder 2 is R 室 The initial pressure of the cylinder 2 is the same as the external atmospheric pressure, which is P0. The initial length of the wire in the cylinder 2 is L0, which is fixed horizontally by the metal base 8 at the bottom of the cylinder 2 and the clamp at the piston 9. The piston 9 is initially subjected to the average force F0 of the air pressure. The radius of the piston 9 is R. 塞 ≈R 室 The initial reading of the barometer 6 is P0, and the filling pressure of the air pump 5 is P 充 , fine-tune the air pressure P injected into the air cylinder 4 微 , the air pressure display number changes to P1, the change in the number of the pressure gauge 6 is △P, at this time the average force F1 exerted by the air pressure on the piston 9, at this time the change in the average force F exerted by the air pressure on the piston 9 is 气 , the wire is subjected to a tensile force T1, and the change in tensile force is T 丝 , the length of the wire under the pulling force of the piston chuck becomes L1, and the elongation length of the wire is △L

[0036] For cylinder 2: P 示 =P 充 +P 微 (1)

[0037] Against the Pistons 9: S 塞 =πR² 塞 , F 气 =F1-F0, F 气 =(P1-P0)S 室 (2)

[0038] Analysis of the interaction force between the piston 9 and the metal wire: T1=F1, T0=F0 (3)

[0039] For wire: T丝 =T1-T O =F1-F0;△L=L1-L0(4)

[0040] From (2) and (4) we can get:

[0041] T 丝 =F 气

[0042] = (P1-P0)S 塞

[0043] = (P1-P0)πR² 塞

[0044] =△PπR² 塞

[0045] Therefore, △P and T wire are in a linear relationship.

[0046] Assume that the charge of the charged metal ball of the electromagnetic torsion balance mechanism 13 is q1 and the charge of the charged lightweight metal ball of the piston 9 is q2, the initial distance is X0, the electrostatic force constant k=9.0×10^9N·m^2 / C^2, the torque length of the electromagnetic torsion balance mechanism 13 is l, the diameter of the suspension wire of the electromagnetic torsion balance mechanism 13 is d, and the suspension wire length is l 丝 , piston 9 is subjected to the inrush pressure △P and T 丝 After the force is applied, the distance between the charged metal ball of the electromagnetic torsion balance mechanism 13 becomes X1, and the charged metal ball of the electromagnetic torsion balance mechanism 13 and the charged light metal ball of the piston 9 are subjected to the electromagnetic force F 电 , repelling each other, the light rod of the electromagnetic torsion balance mechanism 13 is forced to rotate by an angle θ.

[0047] For two charged balls: X1=X0-△L (5)

[0049] Torsion balance system: M 库 =M 扭

[0050] M 库 =F 电 ∙l⇒F 电 =

[0051] M 扭 =F 扭 ∙l

[0052] =k 扭 ∙θ∙l

[0053] (6)

[0054] From (5) (6) we get

[0055]

[0056] Further deformation gives ⇓

[0057] (7)

[0059] Therefore and

[0060] It is a linear relationship, and the tensile length of the wire can be indirectly measured by θ .

[0061] and

[0062] In a linear relationship,

[0063] is the magnification factor.

[0064] Substituting the Young's modulus formula into equation (7) yields

[0065] Among them, △L in the above formula can be replaced by taking the average value in combination with the successive difference method to reduce the experimental error.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A device for measuring the Young's modulus of a metal wire based on the gas injection method and the torsion balance principle, characterized in that: The invention comprises an air injection chamber (1), wherein an air cylinder (2) is fixedly provided in one side wall of the air injection chamber (1), a torsion balance device (3) is provided on the side of the air cylinder (2) away from the air injection chamber (1), a fine-tuning air injection cylinder (4) and an air pump (5) are fixedly provided inside the air injection chamber (1), a metal base (8) is provided at one end of the air cylinder (2) close to the air injection chamber (1), a connecting plate (7) is provided on the metal base (8), two one-way ventilation nozzles (18) are provided on the lower side of the connecting plate (7), the fine-tuning air injection cylinder (4) and the air pump (5) are connected to the nozzles (18) through air pipes (19), and the air cylinder (2) comprises a cylindrical glass air cover (1 1), a piston (9) is slidably provided in the glass gas cover (11), a metal wire located inside the gas cylinder (2) is fixedly connected between the piston (9) and the metal base (8), the torsion balance device (3) comprises a torsion balance glass cover (15), an electromagnetic force torsion balance mechanism (13) is provided inside the torsion balance glass cover (15), a plane mirror (17) is provided on the upper side of the electromagnetic force torsion balance mechanism (13), a laser emitting device (16) fixedly provided on the glass gas cover (11) is provided on one side of the plane mirror (17), and a fixed scale (10) parallel to the plane mirror (17) is provided on the side of the laser emitting device (16) close to the plane mirror (17); A first adjustable bracket (12) for adjusting the height of the gas cylinder (2) is provided on the lower side of the gas cylinder (2); A second adjustable bracket (14) for adjusting the height of the torsion balance device (3) is provided on the lower side of the torsion balance device (3); The electromagnetic force torsion balance mechanism (13) comprises a vertical suspension wire and a light rod connected to the suspension wire in a front-to-back direction. One end of the light rod is connected to a charged metal ball, and the other end of the light rod is connected to a non-charged metal ball, and the direction of the light rod is perpendicular to the horizontal center axis of the gas cylinder (2); The height and angle of the first adjustable bracket (12) and the second adjustable bracket (14) can be finely adjusted, and can be adjusted so that the laser emitted by the laser emitting device (16) hits the coordinate origin position engraved on the fixed scale (10) through the plane mirror (17) to ensure that the entire device is in a horizontal state in the initial state; An insulating rod that is not easily bent is provided at the center of one side of the piston (9) close to the torsion balance device (3), and a charged lightweight metal ball is provided at the other end of the insulating rod.

2. The device for measuring the Young's modulus of a metal wire based on the gas injection method and the torsion balance principle according to claim 1, characterized in that: The air cylinder (2) is also connected to a pressure gauge (6).

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