And it can be turned into surface circumferential crack and surface axial crack.

Through the 3-D elastic-plastic FEM analysis, the plastic collapse failure of the circumferentially part-through wall cracked pipes used in the petrochemical industry was studied in this paper, and it was concluded that the local collapse of ligament always occurred before the net section collapse.

Finite element analysis for stress intensity factor of semi-elliptical surface crack in circular tube under torsion and bending;

In order to determine the stress intensity factors (SIFs) for a semi-elliptical surface crack at the T-root groove of a turbine disc under centrifugal forces, three-dimensional finite element method was employed to solve the displacement field of the cracked disc.

The major researches as follows:(1) The surface fracture was studied for Zirconia / Ni-Cr alloy FGMs strip with a semi-elliptical surface crack subjected to the thermal shock load, and studied the influence of crack depth, aspect ratios and thermal boundary conditions on the normalized stress-intensity factors along a crack-front.

A practical procedure, which is referred to as elementary modes method, was proposed for evaluating stress intensity factors (SIF) along fronts of semi elliptical surface cracks at weld toes in complex stress fields.