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

Abstract

The experimental device and method for measuring Young's modulus by the beam bending method based on the principle of resonance relates to a Young's modulus measuring device and method. Difficult question. The device of the present invention includes setting two columns on the base, the two ends of the metal beam with rectangular cross-section are freely straddled on the knife edge of the upper end of the column, a copper frame is placed on the metal beam, and a vibration exciter and a metal frame are arranged at the lower end, and the vibration exciter Connected with the signal source, the measuring device is composed of a differential bridge made of variable capacitors, an AC voltage source, an amplifier and an oscilloscope; the method of the invention uses a vibrator to convert a sinusoidal signal into a mechanical vibration, so that the metal beam spring vibrator is subjected to Forced vibration, the bridge composed of variable capacitors is converted into an electrical signal, and the frequency of the signal is adjusted. When the waveform amplitude is the largest, the natural frequency of the metal beam spring vibrator is obtained, and the Young's modulus is calculated. The invention is applicable to the measurement of Young's 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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