Transverse Static and Low-Velocity Impact Behavior of CFRP Wires under Pretension

The transverse static performance and low-velocity impact response of individual carbon fiber-reinforced polymer (CFRP) wires were investigated experimentally in this study. First, the axial tensile properties of CFRP wires with a nominal diameter of 4.17 mm were obtained through axial tensile tests. Then transverse static tests and low-velocity impact tests were conducted on 15 and 12 preloaded wire specimens, respectively, using a custom-designed device and a drop-weight impact test system. The results show that the maximum wire tension, maximum contact force, and transverse deflection at fracture of the specimens in the impact tests were 89%, 72%, and 82%, respectively, of those in the transverse static tests. In a pretension ratio range of 0 to 0.34, the average transverse static load resistance and average impact resistance of the wire were approximately 4.65 and 3.38 kN, respectively, and were slightly affected by the pretension ratio. Because of the shear effect and contact damage, a wire subjected to a transverse static load and impact load absorbed a total energy of 17.8 and 12.4 J, respectively, which is lower than the absorbed energy under an axial tensile load. Based on the experimental results, the dynamic reduction factor for CFRP wires under impact was determined to be 0.85. Combined with an analytical model, the prediction formulas for transverse static load resistance and corresponding impact resistance of CFRP wires were proposed. Compared with an individual CFRP wire, the axial tensile properties and transverse impact resistance of a twisted seven-wire CFRP strand were only 86% and 70%, respectively, of those of a single wire.