Determination of Mode I Fracture Toughness of Cortical Human Bone using the DCB Test

Abstract

The fracture behaviour of human cortical bone was analysed considering a miniaturized version of theDouble Cantilever Beam (DCB) test. A specific data reduction scheme based on crack equivalentconcept was used to obtain the resistance curves. The definition of the cohesive laws mimicking thefracture process was performed measuring the crack tip opening displacement by digital imagecorrelation during the test. The differentiation of the relation between the strain energy release rate andcrack tip opening displacement allows to define the experimental cohesive law. In order to validate theprocedure, trapezoidal cohesive laws with bilinear softening were adjusted to the experimental ones.The DCB tests were simulated by finite element analysis including cohesive zone modelling with theadjusted laws. The resulting numerical load-displacement and resistance curves were compared withthe numerical ones. Good agreement was obtained which validates the proposed procedure.