Experiment device and method for measuring Young modulus by beam bending method via resonance principle

Abstract

The invention provides an experiment device and method for measuring Young modulus by a beam bending method via resonance principle, and relates to a Young modulus measuring device and method. The device and the method solve the problems that in the prior art, when the beam bending method is used for measuring the Young modulus, the experiment principle is simple and abstract, and the regulation difficulty of a telescope is high. The experiment device comprises two upright posts arranged on a base, wherein two ends of a rectangular cross section metal beam freely step across cutter openings formed in the upper ends of the upright posts; a copper framework sleeves the metal beam; a vibration exciter and a metal framework are arranged at the lower end; the vibration exciter is connected with a signal source; a measuring device consists of an oscilloscope, an amplifying device, an alternating voltage source and a differential electric bridge formed by four magnetosensitive resistors. The method has the advantages that the vibration exciter is used for converting a sinusoidal signal into mechanical vibration, so that a metal beam spring oscillator does forced vibration; the vibration is converted into an electric signal by the electric bridge formed by the magnetosensitive resistors; the signal frequency is regulated; when the waveform amplitude is the maximum, the inherent frequency of the metal beam spring oscillator is obtained; the Young modulus is calculated out. The device and the method are applicable to Young modulus measurement.

Description

technical field [0001] The invention relates to a university physics experiment device, in particular to an experiment device and method for measuring Young's modulus by a beam bending method using 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 exte...

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Problems solved by technology

[0005] First, the static tensile method is usually used to measure the Young's modulus of metal materials, and the principle is relatively simple

[0006] Second, according to the optical lever amplification principle, the sag of the midpoint of the rectangular cross-section metal beam is measured through the amplification system composed of the optical lever, the telescope and the ruler. Although the method is ingenious, the principle is abstract and difficult to understand, and the adjustment of the telescope is relatively difficult. It is large, and there are many precautions, 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 metal beams, and the calculation of tension with the nominal mass of weights is inaccurate, thus affecting the accuracy of experimental results

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