13th International Conference on Fracture June 16–21, 2013, Beijing, China -6- Figure 4. Stiffened panel specimen 4.2. Modeling of welding residual stresses in a stiffened panel by using FEM In this study the distribution of welding residual stresses in a stiffened panel is taken into account in a similar manner as in the model developed by Dexter at. al. [22], and is shown in Figure 5. Dexter suggested the implementation of a rectangular shape of the residual stresses, which proved to give good results for the simulated fatigue life for such a type of welded stiffened panels. Figure 5. Welding residual stress distribution To evaluate the SIF value contributed by the residual stresses, Kres, it is important to input correct initial stress conditions in the numerical model. In ANSYS software package the command INISTATE can be used to define initial stress conditions [26]. These initial stresses are equilibrated in the first analysis step. Due to the symmetry of specimen’s geometry and loading conditions it was sufficient to model only one quarter of the specimen. Figure 6 shows welding residual stresses in the stiffened panel specimen obtained for the implemented stress distribution as given in Figure 5.
RkJQdWJsaXNoZXIy MjM0NDE=