Fatigue reliability assessment of load-carrying cruciform welded joints
with undercuts and misalignments
Abstract
Due to the additional local stress concentration caused by undercut and
misaligned defects, welded joints own less fatigue strength. This work
uses probabilistic technique and fracture mechanics theory to
quantitatively investigate the impacts of undercuts and misalignments on
fatigue performance and reliability of Load-carrying Cruciform Welded
Joint (LCWJ). Firstly, the geometrical characteristics summary of the
size and type of undercuts and misalignments are provided from
researches and experiments. Subsequently. Evaluations of the stress
levels are combined with the nominal loadings in LCWJs, probabilistic
distributions of material fracture properties, and various
configurations of geometries and flaws. Meanwhile, the estimations of
fatigue strengths are conducted by the probabilistic reliability theory
by taking into account the distributions of the actual fatigue data. The
findings reveal a clear disparity between the base metal and weldment
test results. Different reliability levels for various defect types and
sizes and in LCWJs are caused by the tolerance limits.