Effect of pre-strain on the indentation fracture toughness of high strength low alloy steel by means of continuum damage mechanics

The effect of pre-strain on indentation fracture toughness of copper strengthened high strength low alloy structural steel has been studied with the help of a model based on continuum damage mechanics developed by J.-S. Lee et al. To examine the basic assumption of the model, finite element simulation of ball indentation has been done and which feasibility has been checked by comparing the load depth curve with the experimental data. With pre-straining, continuous decrement of indentation fracture toughness values of the materials has been observed which showed good agreement with the ‘J’ initiation fracture toughness values from the conventional test technique.