Processing Residual Stress Analysis Based On Structural Safety Of The Ship

As complex welding steel structure, ships and marine structures will inevitably produce residual stress with complex distribution because of shaping, connecting, welding and assembly process of heating and cooling cycle in the construction process. During running the ships and marine structures, applied load such as the goods loading pressure and wave bending moment superimposed with residual stress. If residual stress reaches a certain value, the structure will reach the material yield stress in advance that will reduce the ship's structural strength and safety to a certain extent. In order to protect the safety and reliability of hull structural strength, to prompt the ship specification development and vessel inspection agencies to pay attention and consider the residual stress on strength of ship structure during strength checking process, it has very important practical significance to accurately analyze residual stress distribution and the superposition between residual stress and applied load. For this research goal, based on previous studies, combined with numerical methods, and by using ANSYS finite element analysis software, this paper studied hull strength checking method adding processing residual stress, summed up the influence rules of residual stress on the hull.This paper first pointed out meaning and purpose to research the influence of processing residual stress on strength of ship structure, summed up briefly correlational research at home and abroad, and brought forward the contents of this research. For the most important welding residual stress of process, this paper summarized residual stress distribution of plate butt welds and T-fillet weld which are the common structure of the ship, and analyzed the influence of the welding sequence, component size, thickness and other factors on the residual stress distribution. By referencing relevant CCS ship structural strength checking norms, the paper discussed selection of the hold model scope, modeling, given the calculating method of applied loading, and studied a key technology in depth about how to load the residual stress field in the ANSYS software.Based on this theory, and by ANSYS analysis software, this paper established a half-wide model of an FPSO oil storage platform's cargo hold area, and checked structure strength under the various load cases through joining different size residual stress as the initial stress load. By comparing and analyzing the checking results of with and without residual stress, we obtained not only influence rules of residual stress on different parts of the hull, but also allowed values range and harmful determine standards to guide the control and elimination work of residual stress better.