EFFECT OF STRAIGHTENING DISTORTION CAUSED BY RESIDUAL STRESSES ON ULTIMATE COMPRESSIVE STRENGTHS OF U-RIB STIFFENED PLATES

摘要

The residual stresses resulting from a welding process in which plates and stiffeners are joined have a detrimental effect on the ultimate strength of stiffened plates and they have to be carefully analyzed. Therefore, the ultimate compressive strengths of U-rib stiffened plates with various combinations of column and plate slenderness parameters were evaluated using nonlinear Finite Element Analysis (FEA). The effect of straightening the distortion caused by the application of residual stresses on the strength of these plates was investigated. It was found that the straightening process could increase the ultimate strength up to 15% even though the displacements caused by the residual stresses could increase up to three times the initial geometric imperfection. FEA results were also compared with the strength predictions from the Federal Highway Administration (FHWA). For the stiffened plates whose plate slenderness parameters were greater than 0.9, the FHWA predictions were not conservative in the region having relatively low column slenderness parameter values.