Abstract: The localization of the aerostat envelope has important strategic significance for the engineering application of the stratospheric airship. Because of its harsh service environment, high-performance special fibers are generally used to weave plain cloth as the bearing layer. However, special fibers such as polyarylate and PBO are currently monopolized by foreign countries, with higher prices and the risk of domestic bans. In order to realize the localization of aerostat envelope, this paper uses domestic polyester high-density biaxial warp knitted fabric and polyester film to laminate by TPU to prepare a new type of high-performance low-cost aerostat envelope material. The mechanical properties and failure mechanisms such as tensile, tearing and crack response were experimentally analyzed. The test results show that the polyester-based high-density biaxial warp-knitted skin has excellent mechanical properties (tensile strength> 950 N/cm, tear strength> 600 N), which can meet the requirements of aerostat envelope mechanical properties and can improve the isotropic problem of the envelope material. At the same time, it was found that the high-density warp-knitted skin material has better weft tearing performance than the warp direction, and the existence of cracks causes stress concentration effects in the crack zone, which will aggravate the failure of the envelope. And the loss of strength is determined by the projected length of the crack in the transverse direction.

Key words: high density warp knitted fabric, aerostat envelope, mechanical properties, digital image correlation technology, composites