Experimental Study On The Tensile Properties Of Polyarylate Fiber Braided Rope

High-performance fibers have excellent mechanical properties,and braiding technology gives them a flexible and abundant lightweight structure on the premise of maintaining their strength and other properties.It is gradually becoming an important component of lightweight structures in aerospace,because high-performance fiber braided ropes have the characteristics of light-weight,softness,and loading along the rope axis.The stability of mechanical properties along the rope axis is the primary performance requirement for braided ropes to be used as key lightweight structural components.This paper focuses on the application requirements of ropes for the development of communications satellites in China,conducting a series of experimental researches on the tensile properties of Polyarylate fiber braided ropes,which trade named Vectran~?.Firstly,6 kinds of flat ropes and 6 kinds of circular ropes with two different braiding structure(1/1,2/2)and three kinds of braiding angles(15°,30°,45°)were designed and braided.Under the same linear density,four kinds of yarn counts are designed and braided.The tensile testing obtained the optimal structural parameters of the Vectran braided rope.The experimental results show that both flat rope and circular rope has the highest specific strength at 2/2 braided structure and braided angle of 15°(flat rope as 17.82c N/tex,circular rope as 17.19 c N/tex).On the other hand,according to the potential application requirements of circular ropes,two termination methods of rope loops are designed and prepared in which the strength reduction rate of the"O"rope is about 35.2%,and"Q"rope is about 25.3%.Similar to many high-performance fiber braided ropes,in the Vectran braided rope tensile testing,it is difficult to measure both flat and circular ropes deformation by traditional strain measurement systems since the slippage at clamps or joints.This paper based on the strain measurement technology of metal and fabric,combined with the recent common testing methods on flat Vectran rope strain measurement.Comprehensively analyzed the contact electrometric method using the foil strain gauge and conductive paint as the strain acquisition devices,and used the digital image correlation(DIC)technology as a non-contact optical technique for the accuracy of measuring braided rope strain.Under the same tensile conditions compared with the elongation of the marked segment,the results show that the foil strain gauge obtains accuracy strain values in the small deformation region,and the DIC measures exact strain values in the higher strain region.Finally,the tensile properties of both flat and circular Vectran braided ropes were discussed respectively,and the deformation characteristics under tensile load were analyzed.It was found that the initial elongation of the braided rope can be reduced by aking 10 times preloading-unloading steps,due to the internal geometric deformation inside the rope.At the same time,the tensile properties of the two braided ropes under6 kinds of torsion,the tensile properties after abrasion,and the tensile properties after high temperature treatment were tested.The experimental results showed,with the twist increases,the modulus of the braided rope decreases while the elongation increases.When as friction angle of 90°,after 100 times,the special strength of the flat and circular ropes decreased by 21%and 25%,respectively.After 7 times temperature cycles at a high temperature of 150? and a low temperature of-50?,the special strength retention rates of flat and circular ropes were 93%and 83%,respectively.