Abstract
Deepwater sandwich pipes (SPs) offer high collapse resistance and thermal insulation, making them promising for hydrocarbon transport under high-pressure and low-temperature conditions. However, mechanical damage such as local dents increases cross-sectional ovality and can substantially degrade their external pressure capacity. This study develops a numerical model using ABAQUS to assess the collapse pressure of dented deepwater SPs under hydrostatic loading. The model is validated against existing reference data. A total of 2316 FE models are constructed to investigate the effects of material properties, geometric configurations, and dent characteristics on collapse performance. Results show that the collapse pressure decreases significantly with increasing dent depth, and spherical dents have a more pronounced effect than planar dents. Enhanced collapse resistance is observed as both the thickness ratio and the core thickness of the sandwich structure increase. The use of higher-strength materials in the core layer and the internal and external layers also improves compressive capacity. Drawing on these results, a simplified formula for estimating the collapse pressure of dented sandwich pipes is proposed.