National Aerospace Laboratory Advanced Composite Evaluation Technology Center
National Aerospace Laboratory Structures and Materials Research Center
National Aerospace Laboratory Stratospheric Platforms Project Center
Materials ideal for use in pressurized non-rigid airship envelopes would have the following properties: 1) High strength to weight ratio, 2) Resistance to environmental degradation, 3) High tear resistance, 4) Low helium permeability, and 5) Strong, reliable joints not subject to creep. For the stratospheric airship platform, the temperature environment is estimated to be from - 80 deg to 80 deg (maximum under solar cell layer). There has been a need therefore for basic strength data recorded under these conditions. In this report, the validity of the video extensometer was evaluated by comparing it with the strain-gage method for the use of envelope material tests at high temperature. Tensile strength and overlap joint strength tests were then conducted at 20 (RT), 40, 50, 60, and 80 deg. The stress-strain relationship and fracture properties for envelope materials were investigated.