Damping of Structural Vibration Using Lightweight Granular Materials

An investigation of the vibration damping capability of granular treatments is presented. Cavities in aluminum and sandwich beams were filled with the lightweight particles made of polyimide. For analysis of vibration damping, the complex stiffness of structures before and after damping treatment was measured. Particles of different sizes, weights and polymer composition were used in the damping treatments. Large, frequency-dependent variations in structural loss factor depending on the types of particles were observed. This behavior was predicted by the Rayleigh-Ritz method. The frame wave propagation characteristics of the particles were measured and used in the numerical simulation. The acoustic-structure interaction between particles and structures enhances the dissipation of vibration energy.