Development of a computational model for creep crack growth

Sammanfattning

This thesis presents the theory, process, and results of creating a computational model for creep crackgrowth calculations. The model aims to enable industry customers to better plan their productions byestimating the remaining life affected by creep crack growth. The creep crack growth is modeledusing existing theories based on fracture mechanics, such as stress intensity factors 𝐾𝐼, and the 𝐶∗parameter. Replica testing was explored as the assumed method for identifying creep defects. Thedifficulty of where to place the replicas due to creep phenomena changing the critical locationscompared to elastic analyses is also discussed. The model was developed using Python, the model allows users to input parameters such as geometry,material properties, load data, and settings. These settings include calculating creep crack growth forvarying depth-to-length ratios, applying different stress states at different points of the crack frontand whether R6 defect assessment analysis should be performed. The model is heavily based on theSwedish handbook SSM2018:18 but also relies on the British standard BS7910 and has been partiallyvalidated by comparing its results with those from commercially available software. Additionally, thesensitivity of the input parameters is analysed and presented.