Integrated Digital Reconstruction of Welded Components: Supporting
  Improved Fatigue Life Prediction
Anders Faarbæk Mikkelstrup Morten Kristiansen
In the design of offshore jacket foundations, fatigue life is crucial.
Post-weld treatment has been proposed to enhance the fatigue performance of
welded joints, where particularly high-frequency mechanical impact (HFMI)
treatment has been shown to improve fatigue performance significantly.
Automated HFMI treatment has improved quality assurance and can lead to
cost-effective design when combined with accurate fatigue life prediction.
However, the finite element method (FEM), commonly used for predicting fatigue
life in complex or multi-axial joints, relies on a basic CAD depiction of the
weld, failing to consider the actual weld geometry and defects. Including the
actual weld geometry in the FE model improves fatigue life prediction and
possible crack location prediction but requires a digital reconstruction of the
weld. Current digital reconstruction methods are time-consuming or require
specialised scanning equipment and potential component relocation. The proposed
framework instead uses an industrial manipulator combined with a line scanner
to integrate digital reconstruction as part of the automated HFMI treatment
setup. This approach applies standard image processing, simple filtering
techniques, and non-linear optimisation for aligning and merging overlapping
scans. A screened Poisson surface reconstruction finalises the 3D model to
create a meshed surface. The outcome is a generic, cost-effective, flexible,
and rapid method that enables generic digital reconstruction of welded parts,
aiding in component design, overall quality assurance, and documentation of the
HFMI treatment.