Nastran Analysis of Nuclear Effects on Helicopter Transparencies,
GOODYEAR AEROSPACE CORP LITCHFIELD PARK AZ
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This paper deals with the linear and geometric nonlinear analysis of the gunners window on the AH-1S Cobra helicopter in response to a nuclear overpressure environment. The work was sponsored by the Applied Technology Laboratory, U.S. Army Research and Technology Laboratories AVRADCOM, Fort Eustis, Virginia. Both monolithic stretched acrylic and multilayered transparency configurations are considered in this report. Comparison analyses using both the NASTRAN finite element program and classical Timoshenko plate theory show good agreement. Comparison of the analytical results with experimental observations made by other sources indicates that the geometric nonlinear mathematical models, rather than the linear models, are the more realistic and appropriate representation of transparency response to nuclear overpressure loading in the range considered. It is shown that the classical analysis of a simplified equivalent configuration serves as a useful checkpoint, while finite element programs, such as MSCNASTRAN, are the necessary analytical tools to examine the complicated configurations and loading conditions.