Isolation from Mechanical Shock with a Mounting System Having Nonlinear Dual-Phase Damping.

摘要

This investigation demonstrates that, when the foundation of a simple mounting system is transiently displaced, the use of a shock mount having non-linear dual-phase damping can simultaneously reduce or minimize the resulting acceleration and displacement of the mounted item. Normally, such reductions pose conflicting requirements that cannot be satisfied at the same time by a conventional viscously damped linear shock mount. The dashpot of the non-linear system considered here exerts a dual-phase damping force that is relatively small when the system undergoes abrupt transients, but is significantly larger (1) during the relatively slow decay of motion that follows this abrupt loading, and (2) when the system is subjected to less abrupt transients. The response of the mounted item has been either calculated from closed-form expressions derived for the linear mounting system considered, or obtained by numerical integration of a differential equation of motion that incorporates the dual-phase damping characteristic of the nonlinear mounting system considered. The steplike and pulselike input transients examined are realistic in that they describe how the foundation of each mounting system is displaced through a finite distance in a finite time with finite acceleration and deceleration. The rise times and durations of the transients are chosen to be much larger than, of the same order as, and much shorter than the half-period of natural vibration of the mounting systems. (Author)