부산대학교 도서관

To explore the mechanical behavior of circular steel tube components strengthened with welded casings, two groups of six specimens are designed, and two working conditions of zero-load reinforcement and load reinforcement are defi ned. Typical failure modes, ultimate bearing capacity, defl ection curves, and strain data of measuring points are obtained. The FE modeling method considering the thermal eff ect of the welding process is proposed and verifi ed. A total of 446 fi nite element models are established to explore the eff ects of the initial defects, the slenderness ratio, the boundary conditions, and the area ratio of the welded casing to the circular steel tube on the ultimate bearing capacity of the strengthened components. In addition, the ultimate bearing capacity equations for zero-load strengthened components is proposed using regression fi tting and considering the adverse eff ects of the residual stresses due to the rolling and welding processes. Moreover, equations for calculating the deformation and the ultimate bearing capacity of the load-strengthened components considering the eff ect of the welding heat are also derived. Finally, the experimental, numerical, and theoretical analyses results were consistent in high calculation validity and effi ciency.