DETERMINATION OF THE COMPLEX SHEAR MODULUS OF DAMPING MATERIALS BY THE COMPOSITE BEAM TEST METHOD - (AN EVALUATION OF DETERMINED VALUES IN CONSIDERATION OF EFFECT OF BONDING ADHESIVE LAYER)

A method for determination of the complex shear modulus of damping mat erials is presented, which involves a torsional vibration test of an e lastic rectangular rod bonded to layered damping materials on both sid es. The value determined by means of this method must take into accoun t the effect of the thin adhesive layers bonding the elastic and the d amping material. This effect is evaluated by means of the five-layer t heory accounting for the adhesive layers. The reliability of the deter mined values is considered in conjunction with the adhesive layer thic kness and the material properties of both the adhesive and the damping material. Furthermore, instability of the determined values in the hi gh-temperature range is discussed.