model, respectively. Predicted axial and hoop residual stresses,
measured along axial path started from the plane of symmetry at
the pipe inner surface at angle q ¼ 180 from the weld start point,
are compared with Um and Yoo test data [28] in Figs. 7c and 8c,
respectively. The FE results for both models are in good agreement
with reported test data and hence verify the adopted procedures
for use in further analyses.
4. Results and discussions
4.1. Effect of pipe length on residual stresses
Residual stresses developed during welding process depend
upon many parameters including the stiffness of the parts being
welded. In the present study, the selection of the pipe length (i.e.
pipe stiffness) will affect the resulting residual stresses after inservice
sleeve repair welding. To obtain reliable results that are
not dependent on the considered pipe length, four axisymmetric
models are developed here for the in-service sleeve repair welding
of a pipe (D ¼ 234 mm, t ¼ 6.5 mm) with total length ranging from
300 mm to 450 mm. The axial and hoop residual stresses are found
to be independent of pipe length when length exceeds 400 mm, as