Fracture toughness is a measure of the energy required to extend a crack and is a crucial parameter required in hydraulic fracturing design.
Most commercial fracture modeling software require fracture toughness as an input parameter.
Mode I fracture toughness is measured in the laboratory using the ISRM recommended Cracked Chevron Notch Brazilian Disc (CCNBD) test.
Anisotropy in fracture toughness can be captured by notching sample in different orientations with respect to bedding.
Material requirements for CCNBD based fracture toughness are more economic than other recommended methods.
Sample dimensions can be scaled while meeting the requisite geometrical considerations for optimal material utilization.
Recommended Sample Dimensions:
Diameter – 2 inches or 1.5 inches
Length – 0.8 inch or 0.6 inches