Abstract:
A three-dimensional finite-element method computer program was developed to
establish the elastic–plastic, residual, and service stress distributions in cylinders with flush
and non-protruding optimal-chamfered cross-bores under internal pressure. Eight-noded
brick and four-noded tetrahedral isoparametric elements and the displacement formulation
were used. The incremental theory of plasticity with a 5 per cent yield condition and von
Mises yield criterion were assumed. The incipient and 5 per cent overstrain (ov) pressures
were established for various thickness ratios and cross-bore to main bore radius ratios. For
the optimum chamfer angle geometrical configuration, the stresses were determined for varying
ov. The maximum and minimum effective stresses were located 7.58 from the meridional and
transverse planes, respectively. Meridional plane through thickness yielding occurred at an ov
of 41 per cent. The service stress gradients at the cross-bore chamfer end increased with ov
for ovs .30 per cent. Stress reversals were eliminated for overstrain .27 per cent. Alternative
autofrettage and yield condition procedures were proposed.
