Sharif Digital Repository

In this research the behavior of Circular Steel Tubes (CSTs) with corrosion under axial force and bending have been studied. There are several factors leading to corrosion in steel structures, especially marine structures that results in strength reduction of whole structure. Steel tubes are widely used in construction of on-shore and off-shore structures such as, oil rigs and platforms, oil and gas transmission lines. Current study focus on strength reduction of steel tubes with “pitting corrosion”. To this end numerical analyses using finite element software, Abaqus, have been performed. Therefore, utilizing verified models, the simultaneous effect of bending, axial load and corrosion on... 

This study proposes a sustainable multi-objective portfolio optimization model that simultaneously integrates financial performance, sustainability, and market uncertainty through the framework of intuitionistic trapezoidal fuzzy sets. By allowing continuous degrees of membership and non-membership, the framework offers greater flexibility for financial problems and thus better captures uncertainty, investor preferences, and asset performance under ambiguous, incomplete and linguistic information. The proposed “Sustainability–Mean–Variance–Entropy” model jointly optimizes expected return, risk, and uncertainty, linking entropy-based risk assessment with stock sustainability within a single...