The combined effect of impact load-corrosion causes great damage to offshore pipelines, which has not been sufficiently considered in structural analysis and safety design, raising potential risks. Addressing this point, the failure mechanism of pipelines with corrosion defects under transient impact loads is explored: first, a finite element analysis model is developed. Through a systematical verification, including the performance in describing the mechanical elastic-plastic behaviours of pipelines under impact loads, pipe-soil interactions, and structural failure behaviours influenced by corrosion defects, the model's fidelity is demonstrated. Then, structural responses corresponding to multiple influential factors are investigated, including the corrosion dimensions, pipe-soil interactions, internal pressures and pipeline geometrical parameters. Furthermore, surrogate models are derived to predict pipeline damage. Results show that: with the deterioration in corrosion defects, pipeline dent damage becomes severe, and multiple mechanical behaviours are triggered and coupled, including deformation compatibility, stress-strain concentrations, bending and bulging buckling, which consequently causes various deformation configurations of structures. The pipe-soil interaction can alleviate the impact damage, which is insensitive to soil strengths owing to the strain rate and strain softening effect. The dent damage on pressurized pipelines tends to be localized, but the stress is increased. Increasing wall thickness and pipeline diameter reduce the local dent damage with a gradually weakened effect, owing to the energy dissipation from global responses. With a coefficient of determination over 0.987, the surrogate model of multiple layer perceptron demonstrates promising feasibilities in damage prediction and safety assessment. The developed models and analysis results provide theoretical and technical reserve for pipeline safety design and maintenance.

来源平台：OCEAN ENGINEERING