Fatigue fracture assessment of 10CrNi3MoV welded load-carrying cruciform
joints considering mismatch effect
Abstract
Fatigue experiments and numerical simulations based on the Linear
Elastic Fracture Mechanics (LEFM) theory were conducted on the
Even-Matched (EM) and Under-Matched (UM) 10CrNi3MoV Load-carrying
Cruciform Welded Joints (LCWJs). The study firstly experimentally
investigated the Fatigue Crack Growth Rate (FCGR) of base metal, EM, and
UM weldments. The corresponding Paris parameters as essential input data
are provided to assess the fatigue crack propagation behavior for weld
toe and weld root failure of LCWJs. On the one hand, the Stress
Intensity Factors (SIFs) at weld toe and weld root were calculated
considering the effects of LCWJ specimen geometries, initial crack
types, and sizes. The comparisons between simulated results and
standards analytical solutions were executed, which exhibit good
accordance. It proved that the fatigue fracture simulation procedure
based on LEFM is appropriate for the fatigue assessment of LCWJs.
Eventually, it conducted the parametric analysis by predicted S-N
curves, which included in the weld length, initial crack shape, initial
crack size, penetration length, and materials fracture parameter, to
explore some safety assessment reference lines for both failure modes of
LCWJ.