CN112179761A

CN112179761A - Young modulus of metal wire measured by laser guide light path

Info

Publication number: CN112179761A
Application number: CN202010142477.9A
Authority: CN
Inventors: 张为印; 王庆武; 罗倩; 刘云龙; 袁琳; 孙洁; 胡玲玲; 张为斌
Original assignee: Chengdu Ditai Technology Co ltd
Current assignee: Chengdu Ditai Technology Co ltd
Priority date: 2020-03-05
Filing date: 2020-03-05
Publication date: 2021-01-05

Abstract

Young's modulus of a material is measured by observing the relationship of the positive strain of an object as a function of a controllable external force. Common methods are stretching and bending. For linear materials such as wire, the drawing method is most convenient. The equipment appearing on the market is either expensive or inconvenient to adjust, and the project aims to design a simple device for measuring the Young modulus of the metal wire by a stretching method through matching an optical lever with the reading of a telescope. The project shortens the preparation process time of observing the scale reading in the early stage, so that the preparation process is simpler and easier. In order to achieve the purpose, the technical scheme is as follows: the device is schematically shown in figure 1. An arc-shaped groove is introduced at the optical lever of the bracket platform, so that the optical lever can rotate horizontally and is stable; the light path adjustment is conducted through the laser, the near end adjustment is changed into the far end adjustment, the laser is introduced, and the position of the optical lever is adjusted in an auxiliary mode; a horizontally movable scale is introduced to make it easier to move the scale to the center of the telescope field of view.

Description

Young modulus of metal wire measured by laser guide light path

Technical Field

The invention relates to the technical field of experiments, in particular to a method for measuring the Young modulus of a steel wire by a stretching method.

Background

Young's modulus of a material is measured by observing the relationship of positive strain of an object with the change of a controllable external force, and the Young's modulus reflects the basic property of deformation of the material. Common methods are stretching and bending. For linear materials such as wire, the drawing method is most convenient. One section of the wire is fixed, the other end is stretched, the change in length of the wire is observed, and the Young's modulus of the material can be calculated. At present, various devices for measuring the Young modulus of the metal wire by a pulling method are available on the market. For example, the device which can directly read the Young modulus by utilizing a tension sensor and electronic extension counting is expensive although an optical lever and a reading telescope are omitted, and the demonstration effect is not intuitive if the device is used as teaching equipment; in addition, a reading scale is designed on the wire, but is introduced into the reading microscope. Another common device is that the metal wire is slightly contacted with the optical lever to cause the light sensing rod to rotate, the elongation of the metal wire is amplified, and the deformation of the metal wire after the external force is changed is measured by reading the change of the reading of the scale integrated with the reading telescope through the reading telescope. However, in the method, the reading telescope is required to sense the scale beside the reading telescope through the reflective mirror with limited size on the optical lever, a series of adjusting steps are required, time is consumed, and if the method is used as teaching equipment, the main purpose of the experiment is deviated.

At present, in a college physical laboratory, steel wires are generally used as wire rods. Hanging the weight under the steel wire and being as the counter weight, the optical lever passes through the fulcrum connection on the steel wire. To optically measure the scale reading through the reading telescope, firstly, the height of the reading telescope is adjusted to be equal to that of the optical lever, and then the optical sensor reflector with the visual field is adjusted to fill the visual field. Because the reflector has two rotational degrees of freedom, namely, up, down, left and right, the reading of the scale cannot be seen at once under general conditions. If one person operates, it is not possible to adjust the mirror simultaneously while viewing through the reading telescope. If the reading telescope is always on one side, the position of the telescope and the angle of the telescope are continuously adjusted, so that the light rays reflected by the mirror surface of the scale can enter the telescope. Meanwhile, during the movement, the objective lens is continuously adjusted to observe whether the reflector is in the visual field of the telescope. It was found in teaching that this process was not easy to master and was often erroneous. Some or all of the mirrors are not in the field of view of the telescope. This results in an unclear reading of the scale being observed, an opposite object image appearing in the field of view, or an observation of the scale of the opposite operating device being mistaken for the sensing of its own scale. Therefore, the teaching significance of the Young modulus test measured by a stretching method is greatly reduced due to the fact that time is consumed and errors are prone to occurring.

Disclosure of Invention

The device for measuring the Young modulus of the metal wire by the stretching method is designed to shorten the preparation process time of observing the scale reading in the early stage, so that the preparation process is simpler and easier.

In order to achieve the purpose, the technical scheme is as follows:

the device is schematically shown in figure 1.

The telescope does not need to horizontally fine adjust rhythm, and the horizontal position is adjusted by moving the support rod up and down;

the light path adjustment is conducted through the laser, the near end adjustment is changed into the far end adjustment, the laser is introduced, and the position of the optical lever is adjusted in an auxiliary mode;

the laser is connected with the telescope, and the connection part can freely stretch and rotate;

an arc-shaped groove is introduced at the optical lever of the bracket platform, so that the optical lever can rotate horizontally and is stable;

a horizontally movable scale is introduced to make it easier to move the scale to the center of the telescope field of view.

Drawings

FIG. 1 is a schematic view of a Young's modulus measuring apparatus.

FIG. 2 is a top view of the groove design of the support platform

In the figure: 1. support, 2 metal wires, 3 metal wire accessories, 4 balance weights, 5 optical levers and 6 support platforms

7. Telescope, 8 telescope collimation center, 9 objective knob, 10 telescope support, 11 scale, 12 scale hook,

13. connecting rod, 14 laser, 15 laser collimation center, 16 arc groove.

Detailed description of the invention

The method of use of the corresponding component to be measured mounting and viewing device is described below with reference to the device schematic diagram:

(1) position of each equipment

Observer remote: the metal wire (2) is hung on the bracket (1). In order to enable the metal wire to be in a stretching state, a counterweight (4) such as a weight with a certain weight is firstly matched according to different materials. The fulcrum of the light sensing lever (5) is lightly placed on the metal wire accessory (3) but does not contact the metal wire, the two fulcrums at the other end are symmetrically placed on the arc-shaped groove (16), the mirror surface is vertical, and the mirror surface is perpendicular to the horizontal plane.

Observer-proximal end: the reading telescope (7) is placed right opposite to the optical lever, the height is adjusted through the telescope centering (8), the eyepiece is adjusted, clear cross hairs are observed, the reflector of the optical lever can be observed through the cooperation of the eyepiece and the objective knob (9), and the reflector is full of the visual field of the eyepiece. The laser is rotated on a connecting rod (13) combined with the telescope to drive a laser (14) to rotate, so that the laser is aligned with a center (15) on a connecting line of the reading telescope and the reflector, and the laser is started

(2) Debugging light path

The first step is mirror angle adjustment.

First, the mirror (5) of the optical lever is rotated up and down. So that the reflected laser spot and the reading telescope are on the same horizontal line. Then, the optical lever is horizontally rotated so that the laser spot enters the horizontally movable range of the scale. If a visible light path laser is adopted, the effect is better. And turning off the laser after the adjustment is completed. Rotating the laser causes the laser to move out of view.

The second step is as follows: and (5) observing a scale.

The scale (11) which is connected to the telescope column (10) through the hook (12) is transversely and slowly moved, and the scale is observed through a telescope, so that the scale appears in the center of the visual field. By blocking the scale by hand, it is confirmed again that the scale appearing in the field of view is the own device component.

And finally, increasing or decreasing the balance weight of the metal wire, reading the change of the scale in the reading telescope relative to the reading of the cross wire, measuring the length and the diameter of the metal wire, and calculating the Young modulus.

Claims

1. An apparatus for measuring Young's modulus of a metal wire by drawing has a laser (14) connected to a telescope.

2. A method according to claim 1, characterized in that the laser is provided with an alignment center (15).

3. A method according to claim 1, characterized in that the laser is connected to the front end of the telescope by means of a connecting rod (13).

4. According to claim 3, the link is free to telescope on the telescope.

5. An arc-shaped groove (6) is arranged on the platform of the steel wire bracket to facilitate the horizontal rotation of the optical lever (5) on the platform.

6. There is a horizontally laterally displaceable scale (11) directly connected to the telescope.

7. According to claim 6, the scale is provided with a hook (12).