Experimental device and method for measuring Young's modulus of metal wire based on resonance principle

Abstract

The invention relates to a Young's modulus measuring device and method, in particular, an experimental device and method for measuring the Young's modulus of a metal wire based on the resonance principle. The objective of the invention is to solve problems caused by a situation that experimental principles adopted to measure the Young's modulus of a metal wire in existing university physics experiments are monotonous and abstract, and the problem of high difficulty in telescope adjustment. According to the experimental device of the invention, the upper end of a bracket is provided with a cross beam; the middle of the cross beam is provided with an upper chuck and a vibration exciter; two ends of the metal wire are respectively connected with the vibration exciter and a metal frame; and the vibration exciter is connected with a signal source. The measuring device is composed of a differential bridge composed of variable capacitors, an alternating current voltage source, an amplifying device and an oscilloscope. According to the experimental device and method of the invention, the vibration exciter is utilized to convert sine signals into mechanical vibration, so that a metal wire spring oscillator can be forced to vibrate, and the mechanical vibration is converted into electric signals through the differential bridge composed of the variable capacitors; signal frequency is adjusted; when waveform amplitude is maximum, the natural frequency of the metal wire spring oscillator can be obtained; and the natural frequency is introduced into a formula, so that the Young's modulus of the metal wire can be calculated. The experimental device and method of the invention are suitable for the measurement of the Young's modulus of a metal wire.

Description

technical field [0001] The invention relates to a university physics experiment device, in particular to an experiment device and method for measuring the Young's modulus of a metal wire according to the resonance principle. Background technique [0002] The change in shape of a solid under the action of an external force is called deformation. It can be divided into elastic deformation and normative deformation. The deformation that an object can completely return to its original shape after the external force is removed is called elastic deformation. If the external force applied to the object is too large, so that after the external force is removed, the object cannot completely return to its original shape, leaving residual deformation, which is called normative deformation. In this experiment, only elastic deformation is studied. Therefore, the magnitude of the external force should be controlled to ensure that the object can return to its original shape after the ex...

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Problems solved by technology

[0005] First, the Young's modulus of metal wire is usually measured by static stretching method, and the principle is relatively simple

[0006] Second, according to the optical lever amplification principle, the tiny elongation of the metal wire is measured through the amplification system composed of optical levers, telescopes and rulers. Although the method is ingenious, the principle is abstract and difficult to understand. The adjustment of the telescope is relatively difficult. Notes There are many, and it is very easy to get tired and make mistakes in the data, which will affect the accuracy of the measurement results.

[0007] Third, weights are generally used to apply tension to the wire, and the nominal mass of the weights is used to calculate the tension inaccurately, thus affecting the accuracy of the experimental results

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