Experimental device and method for measuring Young modulus by virtue of beam bending method according to resonance principle

Abstract

The invention provides an experimental device and method for measuring Young modulus by virtue of a beam bending method according to a resonance principle and relates to a Young modulus measurement and method. According to the experimental device and the experimental method, the problems that principle of an experiment for measuring the Young modulus by virtue of the beam bending method is single and abstract, and the adjusting difficulty of a telescope is big at present are solved. The experimental device comprises two upright pillars arranged on a base, wherein two ends of a metal beam with a rectangular section are freely bridged above knife edges at the upper ends of the upright pillars, the metal beam is sleeved with a copper framework, a vibration exciter and a metal framework are arranged at the lower end of the metal beam, and the vibration exciter is connected with a signal source; and a measuring device comprises a differential bridge, an alternating voltage source, an amplifier and an oscilloscope, and the differential bridge consists of variable capacitors. According to the experimental method, a sinusoidal signal is converted into mechanical vibration by virtue of the vibration exciter to drive a spring oscillator of the metal beam to do forced vibration, the forced vibration is converted into an electric signal by virtue of the bridge consisting of the variable capacitors, the signal frequency is adjusted, the inherent frequency of the spring oscillator of the metal beam is obtained when the waveform amplitude is maximized, and then the Young modulus is calculated. The experimental device and the experimental method are applicable to the measurement of the Young modulus.

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 based on 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 e...

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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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