3 032 Mechanical Behavior of Materials Fall 2007 Fatigue fracture failure case study Human bone Images removed due to copyright restrictions Please see http www lbl gov Ritchie Programs Tissue image002 gif Image source Naza Krulick Kinney and Ritchie Biomaterials 26 2005 217 226 Lecture 36 12 10 07 3 032 Mechanical Behavior of Materials Fall 2007 How to test bone fracture Double cantilevered beam Courtesy of R O Ritchie Used with permission Image source Nallaa Kinney and Ritchie Nature Materials 2 2003 Lecture 36 12 10 07 K f a 1 2 optical micrograph of crack tip 3D tomography of osteons and cracks Courtesy of Elsevier Inc http www sciencedirect com Used with permission Image source Naza Krulick Kinney and Ritchie Biomaterials 26 2005 217 226 Lecture 36 12 10 07 Cracks follow cement line or mineralized surface surrounding osteons 3D tomographic reconstruction Image source Naza Krulick Kinney and Ritchie Biomaterials 26 2005 217 226 Courtesy Elsevier Inc http www sciencedirect com Used with permission Lecture 36 12 10 07 Crack growth follows a Paris law relation based in time Courtesy of Elsevier Inc http www sciencedirect com Used with permission Conclusion Fig 8 and Table 3 in Nalla R K et al Mechanistic aspects of fracture and R curve behavior in human cortical bone Biomaterials 26 2005 217 231 Image source Naza Krulick Kinney and Ritchie Biomaterials 26 2005 217 226 Lecture 36 12 10 07 Stress concentrations generate new cracks ahead of old cracks bridging Figure and table removed due to copyright restrictions Please see Fig 7 and Table 2 in Nalla R K et al Mechanistic Aspects of Fracture and R curve Behavior in Human Cortical Bone Biomaterials 26 2005 217 231 Image source Naza Krulick Kinney and Ritchie Biomaterials 26 2005 217 226 Lecture 36 12 10 07 How bone breaks Courtesy of R O Ritchie Used with permission Image source Nallaa Kinney and Ritchie Nature Materials 2 2003 Lecture 36 12 10 07
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