A corrosion assessment methodology based on triangular intuitionistic fuzzy comprehensive evaluation (TIFCE) with analytic network process (TIFANP): An application to external corrosion of the storage tank floor

The increasing demand for oil, natural gas, and green energy has led to massive construction of storage and transportation infrastructure, and the resulting corrosion problems have attracted increasing attention. The complexity of the factors influencing corrosion and the uniqueness of infrastructure pose great challenges to the inspection, assessment, and prediction of corrosion. This challenge is reflected in the large number of influencing factors and the intricate interrelationships between them, which often require the involvement of experts in the assessment. However, due to reasons such as incomplete data and the complexity of corrosion mechanisms, there is uncertainty in the expert's judgment. To address this problem, this work proposes a multilevel, multi-index framework for corrosion evaluation. This framework integrates both analytic network process and comprehensive evaluation method under an intuitionistic fuzzy environment. It uses the triangular intuitionistic fuzzy numbers-based analytic network process (TIFANP) to establish and analyze the weights of the interactive and employed triangular intuitionistic fuzzy comprehensive evaluation (TIFCE) to address the subjective judgment and uncertainty issues in corrosion evaluation. The introduction of the intuitionistic fuzzy concept effectively handles the uncertainty in corrosion assessment. To verify the feasibility and practicability of the framework, it was applied to external corrosion assessment of the floor of a crude oil storage tank. Soil corrosion, cathodic protection, coating protection, and stray current interference were considered the main factors influencing the external corrosion of the storage tank floor. The assessment results were consistent with the open-tank inspection. This work can provide valuable information for storage tank operation, corrosion protection, and maintenance to reduce economic losses and safety accidents caused by the corrosion of crude oil tank floors.