Particle Impact Damping in the Horizontal Plane

Abstract

Particle impact damping is measured for a cantilevered beam vibrating freely in the horizontal plane. Several particle configurations are investigated beginning with a single particle and progressing to multiple layers of particles. The effects of clearance between the particles and enclosure, initial displacement of the primary system, repeatability of damping, and damping efficiency per unit mass added are evaluated for each particle configuration. The investigation shows that the particle configuration significantly affects damping. Configurations with the fewest particles per cavity demonstrate higher damping efficiency per unit mass. Generally, for configurations with a definable clearance between the particles and enclosure, damping is shown to be a function of the clearance and initial system displacement. For configurations with multiple layers of particles, for which horizontal clearance between the particles and enclosure has no meaning, a new dimensionless parameter which captures the geometry of the particle arrangement is proposed.