Optimization and validation of braid-reinforced thermosetting pipe processing parameters for oil & gas applications using response surface methodology

Braid-reinforced thermosetting pipes (BRTPs) are rapidly displacing metallic and filament-wound composite pipelines, but their mechanical performance is highly sensitive to manufacturing variables. Here, Response Surface Methodology (RSM) was used to map and optimize the processing parameters–mechanical performance space defined by braiding angle (55°, 65°, 75°), reinforcement layer count (1–3), and matrix system (epoxy, vinyl ester, polyester). BRTPs were fabricated for all factor combinations and tested to relevant ASTM standards for axial tensile strength/modulus, hoop tensile strength/modulus, and pipe stiffness at 5% and 10% diametral distortion. Analysis of variance identified braiding angle and layer count as the primary drivers of stiffness and strength, with matrix type governing deformation resistance and load transfer efficiency. Quadratic RSM models demonstrated high predictive accuracy, with coefficients of determination (R 2 ) of 0.9944, 0.8969, 0.9981, 0.7422, 0.9993, and 0.9994 for the respective responses, and enabled multi-objective optimization. The optimum configuration (epoxy matrix, three layers, 75° braiding angle; desirability = 0.822) yielded experimentally validated values of 80 MPa hoop tensile strength, 0.66 GPa hoop tensile modulus, 18.5 MPa axial tensile strength, 0.643 GPa axial tensile modulus, 11.86 MPa pipe stiffness at 5%, and 15.46 MPa at 10% deflection, all within <5% prediction error. This provides an actionable processing window for high-reliability BRTPs in harsh oil-and-gas service.