Abstract: A self-tuning impact damper is disclosed that absorbs and dissipates vibration energy in the blades of rotors in compressors and/or turbines thereby dramatically extending their service life and operational readiness. The self-tuning impact damper uses the rotor speed to tune the resonant frequency of a rattling mass to an engine order excitation frequency. The rattling mass dissipates energy through collisions between the rattling mass and the walls of a cavity of the self-tuning impact damper, as well as through friction between the rattling mass and the base of the cavity. In one embodiment, the self-tuning impact damper has a ball-in-trough configuration with tire ball serving as the rattling mass.

Abstract: A new apparatus and method for dynamically absorbing resonant vibration in jet engine blades and other rotating turbomachine components over all engine speeds is disclosed. A distributed pendulum (a pendulum having its axis of motion inside its body instead of at an end) is mounted inside a jet engine blade to function as a centrifugal pendulum. A centrifugal pendulum can be tuned so that its natural frequency linearly tracks the rotational speed of the engine or other turbomachine in which it is mounted and can absorb resonant vibrations from turbomachine components whenever the frequency of a source of vibratory excitation from a so-called speed line of the turbomachine coincides with a resonant frequency of the component. The equations of motion of a distributed pendulum are derived to show that a distributed pendulum small enough to fit inside a turbomachine component can be tuned to track a turbomachine speed line by adjusting its mass distribution about its axis of motion.