Numerical analysis and optimization of CFRP buckle arrestors in subsea pipelines

Abstract

This research investigates the collapse mechanisms and crossover pressure capacity of carbon fiber-reinforced polymer (CFRP) buckle arrestors in subsea pipelines. A nonlinear three-dimensional finite element (FE) model was formulated using ANSYS framework, incorporating a nonlinear geometric algorithm to simulate the collapse and crossover failures. The study underscored a good agreement between the FE model predictions, experimental observations done by the author, and previous research outcomes. Two principal crossover modes; flattening and U-shape modes were identified, though initiated similarly, differ in progression, attributed to the arrestor's attributes. The arrestor thickness ratio (h/t) emerged as a significant determinant of arresting efficiency, particularly impactful when h/t ≥ 1.5. An inverse relationship between σ_yp/σ_uc and P_X/P_P was identified. Furthermore, specific geometric parameters, like h/t and L/D, delineate the predominant crossover mode. Finally, new empirical expressions including the geometric and material parameters are proposed to predict the crossover pressure (P_X) for each crossover mode, separately. Also, the findings suggest that CFRP arrestors, especially those with configurations of L = 1.5D and h = 3t, can offer optimum resilience to external pressure.