Numerical and Experimental Analysis of the Tensile and Bending Behaviour of CFRP Cables

Abstract

Due to their high fatigue life, specific strength and specific stiffness in comparison with steel, carbon-fibre reinforced polymer (CFRP) cables have attracted the infrastructure industry interest in recent years, primarily for use as structural tendons. Particularly the oil and gas industry showed interest for application in offshore platform anchorage systems, because of their exceptional corrosion and creep/relaxation behaviour. In such applications, the cables need to be tensioned in service and to be bent around relatively small-diameter spools for transportation and maintenance. Therefore, their tensile and bending behaviour is a subject of great concern. The aim of this work was to perform a test program on 1 × 19 CFRP cables in two different situations: tensile loading and four-point bending loading. Finite element models were developed to simulate both conditions, including frictional contact between the cable wires. A simplified analytical model was also used to predict the cable behaviour in tension. Numerical predictions were compared to experimental data showing relatively good accuracy, unlike the verified analytical model. CFRP cables presented outstanding tensile behaviour, but bending over small radius spools could not reach the performance of steel wire ropes. Furthermore, simulation could only fairly predict bending below strains of μ1,000 μe for the external rods, beyond which the cable presented highly non-linear behaviour that could not be simulated by the numerical model.