Experiments with particle damping

High cycle fatigue in jet engines is a current military concern. The vibratory stresses that cause fatigue can be reduced by adding damping. However, the high temperatures that occur in the gas turbine greatly hinder the application of mature damping technologies. One technology which may perform in the harsh environment is particle damping. Particle damping involves placing metallic or ceramic particles inside structural cavities. As the cavity vibrates, energy is dissipated through particle collisions. Performance is influenced by many parameters including the type, shape, and size of the particles; the amount of free volume for the particles to move in; density of the particles; and the level of vibration. This pager presents results from a series of experiments designed to gain an appreciation of the important parameters. The experimental setup consists of a cantilever beam with drilled holes. These holes are partially filled with particles. The types of particles, location of the particles, fill level, and other parameters are varied. Damping is estimated for each configuration. Trends in the results are studied to determine the influence of the varied parameter.