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Fracture Toughness

Fracture Toughness



  • 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 

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