Summary of Aging Effects on 25-Year Old Nylon Parachutes.

摘要

The results of structural evaluations on several parachute systems were examined to determine if any trends could be found that would indicate significant aging in the materials. All of the parachutes were more than 20 years old. Five 64 ft diameter parachutes were evaluated along with three 16.5 ft diameter ribbon parachutes and one 4 ft diameter guide surface parachute. Another group included six 48 ft diameter ribbon parachutes, two 4 ft diameter guide surface parachutes, and two 16.5 ft diameter extraction ribbon parachutes. The parachute systems used in the study were all fabricated from nylon materials. Data were obtained for several material properties such as tensile strength, air permeability and melting point. Military specifications were used as zero-time data base due to lack of raw material data. Generally speaking, after 25 years the material properties of the 64 ft parachutes were within specifications. The same generalization cannot be made for the 48 ft parachutes which were about 23 years old. The explanation for their differences may lie in their respective histories. 10 refs., 2 figs., 5 tabs. (ERA citation 14:022602)