インピーダンス解析による可聴領域粘弾性測定装置の試作

抄録

A new viscoelastic spectrometer for measurements of complex moduli of solid samples in the audiofrequency range from 10² to 10³ Hz was designed based on the mechanical impedance method. The feature of this instrument is to measure mechanical impedance of a rod-shaped specimen at its driving end : one end of the specimen was glued to a mass served as the fixed end; longitudinal vibrations were applied from the other end by an electromechanical driver through an impedance head at various frequencies. The mechanical impedances, forces and accelerations were detected through the impedance head. The measured impedance of the specimen with a dimension comparable to the wavelength was a hyperbolic function of the complex modulus, the dimension, the density of the specimen and the frequency. Here, we used a computer method to seek the particular value of dynamic modulus with which the calculated and observed values of the mecha nical impedance matched with each other. Preliminary tests for this method were demonstrated with poly (vinylidene fluoride), poly (ethylene terephthalates) and plasticised poly (vinyl chloride) samples. For all these samples, the present method gave reasonably good results. The results at low frequencies agreed with the data obtained by conventional Rheovibron.