Flexible riser is a critical transportation device for offshore oil and gas development, and its innermost structure is the carcass layer, which is built from flat steel plates through multiple passes of roll bending and winding lock forming processes. Due to the complex structural characteristics and numerous geometric parameters of the carcass layer, as well as the longitudinal and transverse deformations of the steel plate during forming process, the influence of key processing parameters on its deformation characteristics during roll bending shaping is not clear. In this paper, based on dimensional analysis principles, dimensionless expressions for the relationship between key processing parameters and the deformation characteristics (bending angle) of the carcass layer in multi-pass roll bending are established. Using polynomial regression and symbolic regression methods, the expanded forms of dimensionless expressions are obtained to clarify the effects of processing parameters (elastic modulus, steel plate thickness, roller radius, roller spacing) on the bending angle of the carcass layer. Conclusion shows that the steel plate thickness has a significant impact on the bending angle and that when the thickness increases from 1 mm to 2 mm, the bending angle decreases by 27.74%.

flexible pipes  /  carcass layer  /  rolling forming  /  bending angle  /  dimensional analysis