Transfer function method for investigating the complex modulus of acoustic materials: Spring-like specimen

摘要: Abstract The complex modulus of acoustic materials has to be known as a function frequency. Among many methods for investigating the modulus, it is advantageous use transfer method detailed frequency analysis. In this method, cylindrical or prismatic specimen excited into longitudinal vibration at one end, other end being loaded by mass. can calculated after having measured function: i.e., amplitudes ends and phase angle between them. paper its measurability are investigated theoretically experimentally in that range where essentially modelled lumped parameter mechanical elements. role measurement errors analyzed shown smaller loss factor higher accuracy needed. Furthermore, disregarding wave motion frequencies leads an apparent increase dynamic decreases factor. This effect may compensated up certain lateral specimen. Experimental results supporting theoretical predictions presented.