高密经编浮空器蒙皮材料的制备与力学行为研究

STUDY ON PREPARATION AND MECHANICAL BEHAVIOR OF HIGH-DENSITY WARP KNITTED AEROSTAT ENVELOPE MATERIAL

柔性蒙皮的国产化对于实现平流层飞艇等浮空器的工程化应用有着重要的战略意义,由于其服役环境严苛,一般采用高性能特种纤维织成平纹布作为承力层。然而,聚芳酯、PBO等特种纤维目前由国外垄断,价格较高且有对国内禁售的风险。为实现浮空器蒙皮的国产化,本文采用国产的涤纶高密双轴向经编织物与聚酯薄膜通过TPU层压复合,制备了一种新型的高性能低成本飞艇蒙皮材料,并对其拉伸、撕裂以及裂纹响应等力学性能与失效机理进行了试验探讨分析。试验结果表明:涤纶基高密双轴向经编蒙皮力学性能优异(拉伸强度>950 N/cm,撕裂强度>600 N),能够满足浮空器蒙皮力学性能要求,并且可以良好地改善蒙皮材料各向同性的问题,同时发现高密经编蒙皮材料纬向撕裂性能优于经向,并且裂纹的存在使得裂纹区发生应力集中效应,会加剧蒙皮的失效,其强力损失率主要取决于裂纹在横向方向上的投影长度。

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.