Analytical and Experimental Studies of Spherical Rigid Ground Radomes: Fid-Bau Portal

Analytical and Experimental Studies of Spherical Rigid Ground Radomes

E. Sevin

This report presents the final results of a two-phase study related to the design of rigid ground radomes. The first phase, an engineering review, was an evaluation of existing methods of structural analysis that have been applied in the design of hemispherical and three-quarter spherical radome shells of space frame, sandwich, and flanged shell constructions. The major findings of this evaluation relate to the apparent lack of applicable solutions to shell bending theory and to the highly approximate methods of stability analysis. The second and major phase of the study was the design and implementation of experiments on a true structural model of a three-quarter spherical radome of a rigid polyurethane foam material subjected to a specified wind loading distribution. As part of the experiment design, a unique and versatile method of wind load simulation was devised. A series of tests were performed on a 38-in.-O.D. shell of nominal radius-to-thickness ratio r/t = 48. Wind loads up to a stagnation pressure of 6 psi were applied without damaging the shell. The measured deflections at this loading were 80% of the shell thickness at the apex and 53% of the thickness at the stagnation point.