Evaluation of indentation fracture toughness for brittle materials based on the cohesive zone finite element method

• We examine the effects of material properties and indenter shape on the crack.
• We suggest some formulas to estimate the fracture toughness via indentation test.
• The methods for Vickers indentation can be extended to other pyramidal indenters.
• The fracture toughness can be accurately estimated form pyramidal indentation data.

We propose indentation fracture toughness evaluation methods based on finite element analysis adapting the cohesive zone model. Establishing an appropriate finite element model, we examine the effects of material properties on the size of the cracks formed by Vickers indentation, and then suggest a regression formula for the estimation of the fracture toughness. The formula is extended to other types of pyramidal indenters including variations of the indenter angle and the number of indenter edges. The suggested methods are examined by comparison of the experimental data, and the fracture toughness can be accurately estimated from pyramidal indentation data.