Young modulus measuring method achieved through metal wire drawing method

Abstract

The invention provides a Young modulus measuring method achieved through a metal wire drawing method, and relates to physical parameter measuring. According to the technical scheme for simplifying Young modulus measuring, the upper end of a metal wire is fixed, and a tray is fixed to the lower end of the metal wire; one end of a lever is clamped on the metal wire, a support point of the lever is fixed to the upper end of a support, and the lever can rotate around the support point; a cylindrical scale is hung at the tail end of the lever; a horizontal slender rod stretches out of a fixing platform, and the tail end of the right side of the horizontal slender rod is in a cylindrical shape and is used as a reading pointer; the diameter d of the metal wire is measured, the distance L between the fixing point of the lever on the metal wire and the upper end fixing point of the metal wire is measured, the magnification times n of the lever is measured, the reading number x1 of the scale is read through the position where the slender rod points, a weight with the mass of m is added on the tray, the scale reading number x2 of the position where the slender rod points is read again, and then the Young modulus Y=4 m*g*n*L / (pi*d<2>*|x2-x1|) is obtained, wherein g is the gravity acceleration, and pi is the circumference ratio. The method has the advantages that the cost is reduced, and regulation is convenient.

Description

technical field [0001] The invention relates to the field of measurement of physical parameters, especially the measurement of Young's modulus of materials. Background technique [0002] The measurement of Young's modulus of metal wire is a common experiment in university physics experiments. It mainly uses the principle of optical lever amplification to measure the elongation of steel wire, so as to calculate the Young's modulus of steel wire. The parameters that must be measured are: the length of the wire, the diameter of the wire, the elongation of the wire, the mass of the added weight (use weights, the mass of 1 weight is 1 kg, generally use 8-9 Weights), the shortcomings of which are: [0003] The length measurement of the metal wire is inaccurate: because the upper end and the lower end of the metal wire are clamped by the clamp, the upper end clamp is fixed on the support plate of a support frame, and the lower end clamp is located in the center hole of the support...

AI Technical Summary

Problems solved by technology

[0003] The length measurement of the metal wire is inaccurate: because the upper end and the lower end of the metal wire are clamped by the clamp, the upper end clamp is fixed on the support plate of a support frame, and the lower end clamp is located in the center hole of the support plate in the middle of the support frame. The effective length of the root wire (the distance between the fixed point of the upper clamp and the fixed point of the lower clamp) is different. When measuring the length of the wire, the tape measure used to measure the wire is affected by the angle between the surface of the wire clamp and the wire at approximately 90 degrees. If the tape is close to the steel wire, the tape will bend and cannot be close to the fixed point between the steel wire and the fixture, resulting in large errors in measurement

[0004] Measuring the elongation of the metal wire with a polished rod is more complicated: a vertical ruler is fixed next to the telescope, the upper surface of the lower end fixture of the steel wire fixes the rear feet of the polished rod, and the fulcrum (two front legs) of the polished rod is located in the middle of the support frame. On the support plate, there is a rotatable plane mirror above the two front feet of the light lever. The scale of the scale is diffusely reflected to the plane mirror of the light lever, reflected from the plane mirror to the telescope, and from the horizontal reference line of the telescope reticle (called the reading reference). Line) to read the scale of the scale, with the increase or decrease of the weight, the scale of the telescope field of view is located on the scale of the reading reference line, so as to measure the relationship between the elongation of the steel wire and the weight of the weight

It is necessary to adjust the verticality of the plane mirror, observe the ruler above the telescope, and find the ruler in the field of view of the telescope; there is an error in measuring the distance from the mirror surface of the polished rod to the rear foot, because the mirror is generally located in the middle of the frame, so it is generally simplified to measure the front and rear feet of the polished rod The distance between the two front feet is not necessarily within the mirror surface in mathematics; the distance between the mirror surface and the ruler needs to be measured at the same height, and the vertical distance cannot be tilted. These are difficult to be accurate experimentally.

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