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Peak Acceleration Device (PAD).

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Each year a number of aircraft are involved in incidentsaccidents of varying ground impact severity. The object of this project was to develop a small, passive, low-cost triaxial indicator that in the event of an incidentaccident would record the magnitude of the acceleration experienced at their location in the aircraft. Analysis of this data would would provide an insight into the performance of crashworthy structures and vehicles, thereby contributing to efforts to reduce loss of life, injury and equipment damage. Three basic concepts for the design of the peak acceleration device PAD were examined. Initially, the use of foam that would crush predictably under the action of a metal rod was explored. Unfortunately, this arrangement was found to be impracticable as was a variation of the same concept where metal foils were to be pierced by pointed rods. The drawback in each case being primarily related to material characteristics. The third approach utilized a filament under tensile stress as a g-force indicator. Testing showed that this mechanism provided predictable and repeatable measure of impact levels and therefore it was this conept that was developed into the PAD. The final configuration of the Peak g indicator conforms to the target criteria established for te device. It has the capability to measure impacts of 15-100 g in each of three axes, will fit within a 2-14-in. cube, has a mechanical filter system that isolates the indicators from energy at frequencies above 100 Hz, and is housed in a rugged aluminum casing that provides high resistance to mechanical damage.

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Final rept. 1 Apr 85-19 Dec 86,



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