Loss factor identification to evaluate damping performances of metallic alloys

Abstract

Several standards or manuals are available for the test methods of damping capacity of damping materials such as composites or laminated damping steel sheets, however, there are little documents focusing on lightly damped materials like metallic alloys. This study intends to provide a simple method for loss factor identification for metallic materials using common vibration measurement setups. Using slender beam shaped specimens, vibration measurement and data processing procedures are investigated in order to obtain loss factors with high reliability. It has been shown that applying a 6 dB bandwidth method together with spline interpolation technique to measured mechanical impedance, rather than commonly used half-power bandwidth method, leads to good results.