Characterization Of Ductile Crack Growth Resistance Behaviour Of Interstitial-Free Steel Sheet Using Energy Dissipation Rate Parameter

The present study aims at charactering the crack growth resistance parameter in an 1 mm thick interstitial-free (IF) steel sheet using the energy dissipation rate parameter, R. The R-Delta a plots of single-edge and double-edge notched tension specimens have been determined with only additional computations of mechanical and optical test data already generated in the course of determining the variation of crack tip opening angle with Delta a following the optical method of ASTM E 2472. A new method has been adopted for determining the stationary value of energy dissipation rate, R infinity, This has been done by analyzing mechanical test data generated in the course of essential work fracture (EWF) testing, with additional inputs on crack initiation points identified in those EWF tests. An attempt has been made to normalize the R-Delta a plots in order to reduce the specimen geometry dependence of the energy dissipation results.