Service life estimation of extrusion dies by numerical simulation of fatigue-crack-growth


Sonsoz A., Tekkaya E.

INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES, cilt.38, ss.527-538, 1996 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: 38 Konu: 5
  • Basım Tarihi: 1996
  • Doi Numarası: 10.1016/0020-7403(95)00064-x
  • Dergi Adı: INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
  • Sayfa Sayıları: ss.527-538

Özet

In this study, fatigue behavior of cold extrusion dies is investigated analytically. Experimental studies and practical experience have shown that fatigue cracks occur at the inlet radius of die shoulders. The highest stress concentration is found also at the same location. For this reason, effective stress intensity factors at different locations of the die-shoulder inlet of a typical axisymmetric extrusion die have been calculated by using the finite element method. The crack growth has been simulated by applying the Paris/Erdogan fatigue law to the computed data. Finally, service life of the extrusion die has been estimated from the crack-growth-rate. Agreement of theoretical estimations with available data is found to be satisfactory within the limits of experimental uncertainties. Furthermore the experimental behavior of the crack growth (stable-unstable-stable growth with final fracture) is simulated correctly. It has been shown that the unexplained behavior is caused by decrease of stress concentration with increasing crack-length.