Research on strength model for combined fabric tether of Kevlar fiber

The application demand for tethered system has been increasingly widespread in space technologies. The higher standard of the mechanical properties and the textile technology is put forward because of the special environment in space. Kevlar fiber, which features high tensile strength, far working temperature limits and excellent flexibility, is one of the most preferred materials used for tethered system. The Spinning crafts of tether could be stated as follows; At first, the non-twist bunchy Kevlar fiber is twisted, and then several twisted fiber bundle are combined and twisted to high strength tether. The tether mechanical properties depend largely on the spinning crafts. At present, some scholars have studied mainly in the strength model of single fiber, non-twisted and twisted fiber. In this paper, in consideration of the entire process of the Spinning crafts, the strength model of combined fabric tether is derived. The paper also analyzes the relationship between the tether strength properties and the Spinning crafts. Then this strength model is verified by tensile strength experiment. The result shows that the relationship between the tether strength properties and the spinning crafts can be reflected by the strength model. The strength of the initial twisted fiber bundle, the count of the strand and the twisted times during spinning are the main factors to decide the strength value of the tether.