光电法受迫振动实验的研究与应用

Research and Application of Forced Vibration Experiment by Photoelectric Method

以常见的玻璃杯为对象,研究通过声波使其受迫振动。利用光杠杆放大法及图形分析法测量反射光斑的振动频率及宽度,即玻璃杯受迫振动的频率及振幅,从而取得不同玻璃杯受迫振动的幅频特性曲线、峰值及对应玻璃杯的共振频率,并依据受迫振动理论模型计算出玻璃杯的固有频率,结果表明实测玻璃杯受迫振动的频率与理论模型计算的固有频率二者相符。将不同体积、不同种类的液体加入玻璃杯后会改变玻璃杯的共振频率,测量得到的玻璃杯共振频率与理论计算结果一致;测量加入不同浓度液体玻璃杯的共振频率,将之与浓度进行拟合,根据拟合方程可以计算该溶液的浓度,结果误差较小。

Sound waves can cause the glass to vibrate under compulsion,and the laser is irradiated on the reflective film of the forced vibrating glass to form a spot on the receiving screen.The light lever amplification method and the graphic analysis method can measure the vibration frequency and width of the reflected light spot,that is,the frequency and amplitude of the forced vibration.In this way,the amplitude-frequency characteristic curves of the forced vibrations of different glasses can be measured.The peak of the amplitude-frequency characteristic curve corresponds to the resonant frequency of the glass,the natural frequency of the glass can be calculated according to the theoretical model of forced vibration,and the experimental measurement results show that the two are consistent.Adding different volumes and different types of liquid to the glass will change the resonance frequency of the glass,and the measured glass resonance frequency is consistent with the theoretical calculation results.If we measure the resonance frequency of the glass with different concentrations of liquid added and fit it to the concentration,according to the fitting equation we can measure the concentration of the solution,the measurement result error is small.