Energy in random vibration - reduce, resist, recycle

Random vibration of a structure dissipates energy at a rate proportional to the Power Spectral Density of the vibration and the mass of the structure. This energy must be directed away from damaging processes, especially fatigue, into non-damaging damping mechanisms. A portion of the available energy can be extracted as useful work, for example to power a condition monitoring system. Perpetuum manufacture just such a system. The issues raised by this approach are the extraction of the highest proportion of the available energy, and the overall durability of the system in its environment. This paper reports efficiency measurements of an energy harvesting condition monitoring system applied to a rail vehicle, along with a design rule and figures of merit for operation in harsh environments.