Identification of Damping Characteristic of a Structural Adhesive by Extended Modal Based Direct Model Updating Method

In order to identify damping characteristics (loss factors in bending and shear modes versus frequency) of an adhesive material, modal based direct model updating method used in previous paper (Jahani and Nobari, Exp Mech, 48:2008) is modified here. Two approaches adopted in the identification process. In the first one, the pre identified moduli from undamped model were used in identification of loss factors and in the second approach loss factors and moduli are identified simultaneously. The loss factors of a typical adhesive were identified using both approaches leading to acceptable results in both cases. The results show that loss factors and Young’s and shear moduli of adhesive are frequency dependent. All experiments and subsequent identifications are conducted both in bending and shear modes. The repeatability and consistency of method is proved by repeating the identification process for several times.