Load capacity of twisted CFRP cables: Computational model and FE analysis

Applications of carbon fiber reinforced polymer (CFRP) cables have been expanding from structure strengthening to cable stayed bridge. For the cables with CFRP rods, a twisted arrangement of CFRP rods is required for wound packages of cables for transportation. To evaluate the load capacity of a twisted CFRP cable, in the present paper, a computational model was established theoretically based on mechanical assumptions. Monte Carlo simulation was used to analyze the load capacities for different load specifications. Finite element (FE) simulation and experimental tests were employed to verify the computational model. As found, with more used CFRP rods, the failure mode of the cables shifted from suddenly brittle failure to step by step failure with damage accumulation. The cross-sectional stress distribution of twisted CFRP cables exhibited a “higher in the center and lower at the periphery” pattern, and the stress difference increased with the twisting angle from 2° to 6°. Load capacity followed a normal distribution, and a correction factor was defined to obtain the load capacity design value of twisted CFRP cables for various load specifications and twisting angles. FE simulations were used to analyze the distribution of internal compressive stresses of CFRP cable, confirming radial compressive stress as a key factor and providing stress fields under different conditions. Finally, the test results of two Φ5–61 twisted CFRP cables with a twist angle of 3° were 96.6% and 95.1% of load capacity retention ratio, respectively, exceeded the theoretical value of 94.6%, confirming the accuracy of the computational model.