Presented herein are nonobstructive particle damping (NOPD) performance characteristics under forced compaction conditions. NOPD is a new passive vibration damping technique that consists of making small diameter holes (or cavities) at appropriate locations inside the main load-paths of a vibrating structure and filling these holes to appropriate levels with such particles that yield the maximum damping effect. Metallic or nonmetallic particles in powder, spherical, or liquid form (or even mixtures) with different densities, viscosities, and adhesive and cohesive characteristics can be utilized.
In an effort to simulate centrifugal forces on particles placed inside blades of high rotational speed turbomachines, a special test article was made and different particles were tested under various compaction forces and vibration amplitudes. The effectiveness of NOPD was measured and compared with no compaction and no-particle conditions.