Analyzing the effect of hydration on the wedge indentation fracture behavior of cortical bone.
Hydration directly affects the mechanical properties of bone. An initial and basic procedure shows both wedge indentation fracture experiments under plane strain conditions in cortical bone and numerical simulation with finite elements agree that dry bone fractures much more easily than fully hydrated bone submerged in an aqueous environment, such as in the body of an animal. The wedge indentation experiments were performed with high speed video microscopy, under dry and fully hydrated (submerged) conditions. The numerical simulation, specifically finite element analysis using cohesive elements to simulate fracture, was utilized to capture plasticity, fracture initiation and propagation, and to study the applicability of brittle material based indentation fracture theory. Experiment and theory give similar results for the dependence of depth of fracture initiation, and size of plastic zone, on hydration state. Comparison of fracture propagation characteristics between wet and dry bone are examined and discussed. This research demonstrates the ability to quantitatively assess the effect of hydration on the fracture initiation, propagation, and plastic zone size of cortical bone, through an approach using simple wedge indentation, with important implications for efforts in developing methods to understand clinical diagnostic testing and general fracture behavior of living bone in the ultimate interest of health care purposes.
Department of Mechanical Engineering, University of California Santa Barbara, Santa Barbara, CA 93106, USA. Electronic address: kevhoffseth@engineering.ucsb.edu.
Kevin
K
Hoffseth
Department of Mechanical Engineering, University of California Santa Barbara, Santa Barbara, CA 93106, USA; Department of Physics, University of California Santa Barbara, Santa Barbara, CA 93106, USA.
Connor
C
Randall
Center for Materials Processing and Tribology, School of Industrial Engineering, Purdue University, West Lafayette, IN 47907, USA.
Srinivasan
S
Chandrasekar
Department of Physics, University of California Santa Barbara, Santa Barbara, CA 93106, USA.
Paul
P
Hansma
Department of Mechanical Engineering, University of California Santa Barbara, Santa Barbara, CA 93106, USA.
Henry T Y
HTY
Yang
D000818:Animals; D001696:Biomechanical Phenomena; D002417:Cattle; D000071538:Cortical Bone / Q000473:pathology*; D020342:Finite Element Analysis; D050723:Fractures, Bone; D013314:Stress, Mechanical