Mechanical characteristic and damage mechanism of carbon/glass composites in offshore oil exploration

Carbon/glass hybrid rods exhibit superior tensile strength, low weight, and exceptional corrosion resistance. However, rod splitting presents a considerable challenge to their practical applications, impeding widespread acceptance. A strength prediction model for carbon/glass hybrid rods was created utilizing a multi-mode damage constitutive material model. Tensile experiments were conducted to validate the simulation model, elucidating stress distribution patterns and creating progressive damage evolution laws to clarify failure causes, thus offering theoretical support for the construction of high-strength rods. The results indicated that: (1) Experimental data indicated an average tensile load of 452.4 kN, with failure resulting from brittle fracture and interface debonding; (2) The simulated ultimate tensile load was 439.2 kN, deviating by 3% from experimental values within acceptable engineering accuracy limits; (3) As displacement increased from 0.3 mm to 0.7 mm, von Mises stresses in the coating layer, –40°winding layer, 40°winding layer, and core layer rose from 96.4 MPa, 45.2 MPa, 38.8 MPa, and 199.2 MPa to 229.6 MPa, 141.6 MPa, 111.1 MPa, and 472.4 MPa, respectively; (4) The primary forms of damage were interface debonding, matrix cracking, matrix extrusion, fiber extrusion and fiber fracture. The weak interface strength and asynchronous deformation between the carbon-fiber core layer and the glass-fiber cladding layer facilitated interface slip, leading to the premature failure of the winding layer due to a rapid decline in interface load transfer, ultimately resulting in interlayer splitting failure of the rod.