Experimental device and method for measuring Young modulus with beam bending method based on resonance principle

Abstract

An experimental device and method for measuring Young's modulus by the beam bending method based on the resonance principle relates to a Young's modulus measuring device and method. Difficult question. The device of the present invention includes 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 movable armature are arranged at the lower end. Connected with the signal source, the measuring device is composed of a differential bridge composed of two inductance coils and two resistors, an AC voltage source, an amplifying device and an oscilloscope; the method of the present invention converts a sinusoidal signal into a mechanical vibration by using an exciter to make the metal The beam spring vibrator is forced to vibrate, and the electric bridge composed of variable inductance is converted into an electrical signal, and the frequency of the signal is adjusted. When the waveform amplitude is maximum, 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 college physics experiment device, in particular to an experiment device and method for measuring Young's modulus by using the beam bending method of resonance principle. Background technique [0002] Under the action of external force, the shape change of a solid is called deformation. It can be divided into two types: elastic deformation and normal deformation. The deformation in which the object can completely return to its original shape after the external force is removed is called elastic deformation. If the external force applied to an object is too large, so that after the external force is removed, the object cannot be completely restored to its original state, leaving residual deformation, which is called normal deformation. In this experiment, only elastic deformation is studied. For this reason, the size 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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