Design of a Mortar-Deployed Video Imager

Abstract

As part of a US Army Research Laboratory (Aberdeen Proving Ground, MD) project to provide electromechanical packaging support for a developmental gun-hardened, munition-deployed, parachute-deployed video imager, a dynamic FEA structural analysis was performed on the imager’s aluminum housing. This imager can provide real-time, telemetered, digitally-encrypted and encoded video imaging of the battlefield. The housing was designed as a carrier for the power distribution electronics; video encoding electronics; telemetry transmitter and wrap-around antenna; rechargeable NiCad batteries; and CCD camera module, and provided for direct replacement of an existing illumination canister within a modified US Army 120mm mortar system. The imager assembly, once inserted within the mortar body, is first exposed to a launch ‘setback’ acceleration load upon firing and then is exposed to an explosively-generated internal pressure and impact loading upon in-flight fuze initiation, mortar body separation and subsequent imager submunition expulsion. The dynamic analysis entailed verification of the structural integrity and deflections of the imager housing and adjacent impacting steel ‘pusher’ plate under launching, pressure, and impact loadings. A 2-D axi-symmetric, quadrilateral-only, finite element model of the housing and pusher plate was constructed. Contact elements, birth & death displacement constraints and simplified mortar body elements were added to simulate the boundary conditions. Analysis predictions were validated by inspection of the recovered imager hardware following flight testing.