Method for measuring slight extension amount of Young modulus based on grating diffraction

Abstract

The invention discloses a method for measuring slight extension amount of Young modulus based on grating diffraction. The method has the advantages that the slight extension of the Young modulus is measured by a grating diffraction principle; the smaller the deflection angle of the incident ray is, the larger the angle magnification times is, so that the method is especially suitable for measuring the related slight extension and angle; the distance between a telescope and a steel wire is greatly reduced, and the operation difficulty of experiment is decreased; under the same conditions, the extension amount of a sample is proportional to the original length; because of larger magnification times of the slight angle based on the grating, the larger angle reading can be realized by the shorter steel wire original length, the original length of the measured steel wire can be further reduced, and the measuring error caused by natural bending of the steel wire is obviously reduced.

Description

technical field [0001] The invention belongs to the technical field of Young's modulus measurement, in particular to a method for measuring the small elongation of Young's modulus based on grating diffraction. Background technique [0002] When a metal wire with a length L and a cross-sectional area S is elongated by ΔL under the action of a force F, F / S is called stress, and its physical meaning is the force on the metal wire per unit cross-sectional area; ΔL / L is called strain, and its physical meaning It is the elongation corresponding to the unit length of the wire. The ratio of stress to strain is called Young's modulus of elasticity. [0003] Measuring Young's modulus is an important experiment in university physics experiments. University physics laboratories usually use the static tension method to measure the Young's modulus of metal wires. Most colleges and universities use the optical lever method to measure a small amount of ΔL in the experiment. The optical le...

AI Technical Summary

Problems solved by technology

Most colleges and universities use the optical lever method to measure a small amount of ΔL in the experiment. The optical lever measurement has the following disadvantages: (1) The distance between the optical lever and the telescope is about 1m, which makes the measurement process inconvenient. On the one hand, it is necessary to load / unload the weight in front of the steel wire, and on the other hand, it is necessary to read the indication behind the telescope

(2) Low magnification: the magnification of the optical lever is usually on the order of 30 to 40 times, that is, 10 -4 The small elongation of m order is enlarged to measurable mm order

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