A COMPUTER-PROGRAM TO AID IN FATIGUE PRECRACKING OF FRACTURE-TOUGHNESS TEST SPECIMENS

Fatigue precracking prior to fracture toughness and fatigue tests ensu res a sharp crack ahead of the notch tip. The precracking procedure is outlined in ASTM Standards E 399-78a (Standard Test Method for Plane- Strain Fracture Toughness of Metallic Materials). E-813-89 (Standard T est Method for J(IC), A Measure of Fracture Toughness), and E-1152-87 (Standard Test Method for Determining J-R Curves). This paper describe s an interactive computer program that accepts material properties and specimen dimensions as program input. The program output when plotted graphically suggests an easy and practical precracking procedure adhe ring to the standards mentioned above. The program is useful in the ab sence of a computer-controlled testing facility. The program listout i s given in the Appendix.