Investigations of the Mechanical Behavior of Naturally Weathered Envelopes Based on a Long-Term Service Airship

Abstract

Manufactured with a multilayer functional composite fabric envelope, lighter-than-air (LTA) airships offer a cost-effective approach for payload platforms. Considering the long-term service of LTA airships and their severe operating environments, the weathering degradation of the envelope materials is of extreme importance. However, few researchers have focused on the mechanical degradation of envelope materials from authentic LTA airships. In this study, URETEK3216LV, a typical weathered airship envelope, was sampled from a decommissioned authentic airship structure. A series of tests, including monouniaxial tensile tests, uniaxial cyclic tensile tests, and biaxial cyclic tensile tests, were performed to determine different specimen specifications. It was found that the strength reduction in warp reached more than 40%, and the breaking strain decreased. The elastic constants were calculated using the stress-strain curve fitting and the minimal residual strain method. According to the results, the degradation of the biaxial tensile elastic moduli was more severe than that of the uniaxial parameters, as the Poisson’s ratio remained almost unchanged. In future research, the results can be applied to the long-term analyses of airship structures, such as durable evaluation and deformation calculation.