An instrumented indentation technique for estimating fracture toughness of ductile materials: A critical indentation energy model based on continuum damage mechanics

We suggest a new instrumented indentation technique for estimating fracture toughness of ductile materials. This technique is based on two key concepts. First, the indentation energy to the characteristic fracture initiation point during indentation may be closely related to a material’s resistance to fracture, i.e., fracture toughness. Second, the characteristic fracture initiation point can be determined by exploiting the basic concepts of continuum damage mechanics. To verify the applicability of the suggested technique, indentation tests and conventional fracture toughness tests were performed on four ductile materials. The estimated fracture toughness values obtained from the indentation technique showed good agreement (within approximately 10% error) with those from conventional fracture toughness tests.