Identification of damping mechanism in layered and welded structures

Welded joints are often used to fabricate assembled structures in machine tools, automotive and many such industries requiring high damping. Vibration attenuation in these structures can enhance the dynamic stability significantly. It has been observed that friction damping at interfaces in built up structures provides a beneficial role in reducing the adverse effects of vibrations thereby enhancing their life. A little amount of work has been reported till date on the damping capacity of welded structures. The present work outlines the basic formulation for the slip damping mechanism in layered and welded structures. The numerical stability of the method and its applicability to actual working conditions have been investigated in case of a tack welded cantilever beam structure with multiple interfaces. The developed damping model of the structure is found to be in fairly good agreement with measured data. In the present work damping model has been developed for multilayered structures that have been overlooked by earlier researchers. It is observed that there are a number of vital parameters such as; pressure distribution characteristics, relative slip and kinematic coefficient of friction at the interfaces, initial amplitude of excitation, length and thickness of the beam specimen and number of layers govern the damping capacity of the welded structures.

► Welded joints are used to fabricate assembled structure in machine tools, automotive & many industries require high damping.
► Slip damping is predominant in layered and welded structures.
► Onset of slip is delayed in the structures with multiple interfaces.
► Pressure distribution, relative slip and co-efficient of friction at the interfaces, length, thickness.
► And initial amplitude of excitation are the vital parameters that govern damping capacity of layered and welded structures.