Investigation of Foam Plastic Techniques for Hardening Ground Radomes

摘要

The investigation reported here was directed toward the determination of the feasibility of hardening above ground antenna installations, at the 75 psi free-field overpressure range for a one megaton nuclear burst, by means of psuedo-encapsulation with a foam plastic radome. Conclusions from the investigation of the effects of a nuclear detonation on the selected foam plastics are summarized as follows: (1) The nuclear radiation will have a negligible effect on the dielectric and mechanical properties. (2) Thermal radiation produces considerable physical changes in all foam plastic materials through ablation, burning and melting. The electrical properties of most foam plastics are affected as a result of charred composites on the residual surface. However, polyethylene foam was observed in thermal ablation tests to leave no charry residue. A thermal protection system using a polyehtylene foam laminate was concluded feasible. (3) Mechanical shock effects due to the blast overpressure wave were inconclusive due to inadequate test data on the stress-strain response of foams to dynamic loading. Conditional feasibility can be assumed on the basis of anticipated foam plastic nonlinear viscoelastic response.