Sh. Ahn et al., A STUDY ON THE PREDICTION OF FATIGUE LIFE IN AN AXISYMMETRICAL EXTRUSION DIE, Journal of materials processing technology, 71(3), 1997, pp. 343-349
The present paper gives some results of the fatigue behavior of a typi
cal axi-symmetric forward extrusion die. The extrusion process is anal
yzed by the rigid-plastic FEM and deformation analysis of the extrusio
n die is conducted by the elasto-plastic FEM. To approach the crack pr
oblem, LEFM (linear elastic fracture mechanics) is introduced. Using a
special element in order to consider the singularity of stress-strain
in the vicinity of the crack tip, the stress intensity factor and the
effective stress intensity factor are calculated. Applying a proper f
atigue crack propagation criterion such as the Paris-Erdogan fatigue l
aw and maximum principal criterion to these data, the angle and the di
rection of fatigue crack propagation is then simulated. From the resul
ts, it is established that the simulated fatigue crack propagates in t
he zig-zag path along the radial direction and the fatigue life of the
extrusion die is evaluated using the computed crack growth rate. (C)
1997 Elsevier Science S.A.