Quality assurance for fracture mechanical finite element analyses

A program system for automated fracture mechanical analyses with three-dimensional (3D) finite element (FE) models has been developed. The main application has been safety analyses of pressurized components of nuclear power stations such as pipes and pipe bends containing surface cracks. The system is being extended to surface cracks in reactor pressure vessel (RPV) nozzle area. A large matrix of varying surface crack sizes in a plate under tension has been analysed and the automatically generated mesh is shown to give good accuracy. Such tests cannot guarantee the same accuracy for general loading conditions and geometries. Methods are being developed for the accuracy assessment of the results and for directing the mesh refinement. Results of a test series with plane models are promising. In the mesh refinement element sub-division was used. The same accuracy assessment approach is applied also to 3D models.