<p>A carcass is the innermost layer of a deep-sea unbonded flexible pipe, which is in direct contact with the gas/liquidsolid multi-phase flow. Considering that stress-accelerated erosion is common for carcasses, this study proposes a general model and simulation method for stress-accelerated erosion (SE) of carcasses under external water pressure. First, an SE model suitable for 316 stainless steel was developed, which was then used for stress-erosion simulation for an external pressurized carcass, and the solid domain, fluid domain and rough inner surface of the carcass were carefully considered. Moreover, a simplified model (equivalent smooth pipe) was also established on the basis of the main geometric characteristics of the carcass, and the stress-erosion characteristics under different operating conditions, including the effects of the elastic stress level, flow velocity, particle diameter and concentration, were carefully compared, and the key factors governing the elastic stress-erosion of the carcass were discussed. Finally, a modified geometry factor (GF) for carcasses was proposed considering the stress acceleration effect.</p>