Affiliations: CTVR, Stokes Institute, University of Limerick,
Limerick, Ireland | Bell Labs Ireland, Alcatel-Lucent, Blanchardstown
Industrial Park, Blanchardstown, Dublin, Ireland
Abstract: This theme of this paper is the design and characterisation of a
velocity amplifier (VAMP) machine for high-acceleration shock testing of
micro-scale devices. The VAMP applies multiple sequential impacts to amplify
velocity through a system of three progressively smaller masses constrained to
move in the vertical axis. Repeatable, controlled, mechanical shock pulses are
created through the metal-on-metal impact between pulse shaping test rods,
which form part of the penultimate and ultimate masses. The objectives are to
investigate the controllable parameters that affect the shock pulses induced on
collision, namely; striker and incident test rod material; test rod length;
pulse shaping mechanisms; and impact velocity. The optimum VAMP configuration was established as a 60 mm long
titanium striker test rod and a 120 mm long titanium incident rod. This
configuration exhibited an acceleration magnitude and a primary pulse duration
range of 5,800–23,400 g and 28.0–44.0 μs respectively. It was
illustrated that the acceleration spectral content can be manipulated through
control of the test rod material and length. This is critical in the context of
practical applications, where it is postulated that the acceleration signal can
be controlled to effectively excite specific components in a multi-component
assembly affixed to the VAMP incident test rod.
