Microfabricated sequential-leaf time-delay mechanisms

Arrays of micromechanical sequential-leaf time-delay mechanisms based on SOI/DRIE technology have been designed, fabricated, and characterized. The devices were designed as elements of a larger fuzing system for rifled munitions, in which a passive timing mechanism triggers at a predetermined rotational speed, followed by a desired delay time before the next element of the munition fuzing train is activated. Analytical models for the micromechanical timing mechanisms have been developed, and a variety of designs were simulated from the linear and nonlinear models, and using dynamics simulation software. Fabricated mechanism arrays designed to initiate switching at centrifugal accelerations from 44 to 263 g were characterized using a high-speed camera, with delay times of between 0.67 and 0.95 ms achieved for single elements within the arrays. Measured delay times and switching accelerations follow predicted trends based on analytical and numerical models.