The Lanchester Damper—A Design Procedure for Optimizing the Damping Ratio for a Cylindrical Slug Damper Fitted to a Machine Element

The present work shows how the equations of motion for a Lanchester damper can be modified to include the effects of a damper slug rolling inside a cavity within the parent body, and of the kinetic energy of the damping fluid. The effect of the slug rolling is to reduce the performance of the damper below that predicted by the standard theory and to require a different value for damping at the optimum condition. These effects are significant when the build-up of self-excited type of vibrations are to be prevented, and when small forced vibrations are to be controlled. Fluid kinetic energy effects can be neglected when the damping fluid is gaseous, but not necessarily so when it is a liquid.