Journal Club 08 January 2012 Simin Li

The structure and mechanics of bone -anniversary review John D Currey Department of Biology, University of York Journal of Materials Science JAN 2012 DOI 10.1007/s10853-011-5914-9

World wide research Groups in bone community ● UK: 2; ●USA: 6; ● Irland: 1; ●Japan: 1 Others: to be added …

Prof. John. D. Currey: Department of biology, University of York, UK Publication: 1959-now; 117 publication hits in web of knowledge Research group: Biochemistry and Biophysics Research interest: specialist in bone tissue The mechanical properties of mineralised tissues, at the moment, deer antler. The role of microdamage in determining the toughness of bone Books: The mechanical adaptations of bones; Bones: structure and mechanics 2002, The effect of porosity and mineral-content on the youngs modulus of elasticity of compact-bone (360 cites) Changes in the stiffness, strength, and toughness of human cortical bone with age Prediction of mechanical properties of the human calcaneus by broadband ultrasonic attenuation

Dr Peter Zioupos : Department of Engineering and Applied Science, Cranfield University, UK Publication: 1992-now, 70 publication hits in web of knowledge (with Currey, Rho) Research interest: biomaterial hard tissues (simulation and exp) Biomechanics of Materials research group (strain rate, simulation etc) The effect of strain rate on fracture toughness of human cortical bone: a finite element study. Simulation of Creep in non-homogeneous samples of human cortical bone The Effect of Strain Rate on the Mechanical Properties of Human Cortical Bone The importance of the elastic and plastic components of strain in tensile and compressive fatigue of human cortical bone in relation to orthopaedic biomechanics

Prof. Stephen C. Cowin :Department of Mechanical Engineering The City College, NY USA Publication: 1972-now; 87 publication hits in web of knowledge Research group: Musculoskeletal Biomechanics research centers Research Interests: (bone theory, test) His current publications are in orthopedic biomechanics and anisotropic elasticity. Books: Bone Mechanics Handbook; Mechanical Properties of Bone; Tissue Mechanics A model for the excitation of osteocytes by mechanical loading-induced bone fluid shear stresses (502) On the dependence of the elasticity and strength of cancellous bone on apparent density A continuous wave technique for the measurement of the elastic properties of cortical bone Bone poroelasticity

A.Prof. Q. D. Yang: Mechanical and Aerospace Engineering Department University of Michigan, USA; Brian N Cox: Rockwell Scientific Co., LLC With Ritchie and Nalla Publication: 1990-now; 128 publication hits in web of knowledge Group: Materials Research Group Research interests: (FEA, CZ element, A-FEM) Mixed-mode fracture analyses of plastically-deforming adhesive joints (96) High-Fidelity Simulations of Multiple Fracture Processes in Laminated Composites in Tension Cohesive models for damage evolution in laminated composites An augmented finite element method for modeling arbitrary discontinuities in composite materials

Prof. Robert O. Ritchie; Ravi Kiran Nalla (RA): Department of Materials Science & Engineering, University of California, Berkeley USA; Materials Sciences Division, Lawrence Berkeley National Laboratory Publication: 1986-now; 102 publication hits in web of knowledge Research interest: (fracture mechanics) Structure material; fracture mechanics and fatigue-crack propagation Book: Small fatigue cracks Ritchie: On the relationship between critical tensile stress and fracture toughness in mild steel (927 in Google scholar) Propagation of short fatigue cracks Fracture toughness and fatigue-crack propagation in a Zr–Ti–Ni–Cu–Be bulk metallic glass Nalla: 32 hits Mechanistic fracture criteria for the failure of human cortical bone (187) Mechanistic aspects of fracture and R-curve behavior in human cortical bone On the origin of the toughness of mineralized tissue: microcracking or crack bridging?

A. Prof. Elisa budyn: Department of Mechanical and Industrial Engineering University of Illinois at Chicago USA Publication: 2003-now; 8 publication hits in web of knowledge Laboratory Computational Mechanics Laboratory Research interest: (Multi-scale, XFEM) An extended finite element method with higher-order elements for curved cracks (66) A method for multiple crack growth in brittle materials without Remeshing Fracture strength assessment and aging signs detection in human cortical bone using an X-FEM multiple scale approach Bovine Cortical Bone Stiffness and Local Strain are Affected by Mineralization and Morphology

Rho J Y: Department of Biomedical Engineering, University of Memphis, Memphis USA Publication: 1997-2011 51 publication hits in web of knowledge Research interest: ultrasonic characterization of biomaterials; Nanoindentation Mechanical properties and the hierarchical structure of bone (407) The characterization of broadband ultrasound attenuation and fractal analysis by biomechanical properties Elastic properties of human cortical and trabecular lamellar bone measured by nanoindentation Youngs modulus of trabecular and cortical bone material - ultrasonic and microtensile measurements

Surgeon group: Dr. ALBERT H. BURSTEIN; Dr. Donald T Reilly Dr. Donald T Reilly: publication from 1972-2010; 64 publication hits in web of knowledge ALBERT H. BURSTEIN publication from 1968-2008; 145 publication hits in web of knowledge Most from 1970s (early research of mechanical properties) Elastic and ultimate properties of compact bone tissue (577) Review article - mechanical-properties of cortical bone (289) Aging of bone tissue - mechanical-properties Ultimate properties of bone tissue - effects of yielding

Prof. D. Taylor: Department of Mechanical Engineering, Trinity Centre for Bioengineering, Trinity College Dublin, Ireland Publication: 1990-now; 78 publication hits in web of knowledge on ‘bone’ 231 in total Research group: Trinity Centre for Bioengineering Research interest: (The Theory of Critical Distances-TCOD, Bone Mechanics) Development of new approaches in fracture mechanics, using theoretical analysis and experimental testing; Investigations into the strength and fracture of bone, including repair and adaptation; Theoretical modelling and experimental studies PREDICTION OF BONE ADAPTATION USING DAMAGE ACCUMULATION (122) Micro-damage and mechanical behaviour: predicting failure and remodeling in compact bone The Cellular Transducer in Damage-Stimulated Bone Remodelling Micro-crack accumulation at different intervals during fatigue testing of compact bone

Japan group: Prof. Mamoru Mitsuishi: Department of Mechanical Engineering, School of Engineering, The University of Tokyo, JP Publication: 27 hits in web of knowledge in ‘bone’ Research interests: bone cutting -experimental based newest on bone publication 2010 Relationship between anisotropic tissue and cutting stress characteristics in pig cortical bone New cutting method for bone based on its crack propagation characteristics A study of bone micro-cutting characteristics using a newly developed advanced bone cutting machine tool for total knee arthroplasty Fluoroscopic bone fragment tracking for surgical navigation in femur fracture reduction by incorporating optical tracking of hip joint rotation center

The structure and mechanics of bone Catigrized hierarchical structure into 4 levels Nano, micro, meso, whole bone Different levels of simplification Fracture mechanics Size effect The role of genetics and external forces

Elastic behaviour

Fracture behaviour Mineral-collagen interaction in bone through either ions or hydrogen bonds: Ionic interactions Sliding of layered water films Sacrificial bonds and hidden lengths Virtual internal bonds Bone becomes insensitive to flaws or cracks at sub-micro level Counter-arguments: flaw weaken strength of nanotube compare with flawless one

Stiffness v.s. toughness Stiffness and toughness go against each other Increase stiffness with increasing mineralization. – mineral stiffer

Increase mineral decrease toughness Denser crystal inhibit collagen from deformation Reduce post-yield deformation Less micro-damage, means lease total work to be done for breakage.

Micro scale level

Plexiform bone=fibrolamellar bone=laminar Compact bone Woven bone Osteonal bone Plexiform bone=fibrolamellar bone=laminar Primary Secondary Lamellar bone

Woven bone Primary bone Secondary and plexiform bone

Woven bone: found in infant or fractue callus; randomly arranged collagen fibers; pool mechanical properties, quick grow Osteonal bone: primary (no haversian system): are likely formed by mineralization of cartilage, less lamellae than secondary, small vascular channels (no haversian), may be stronger than secondary Secondary osteon (haversian system, cement line): always younger then the bone replaced, so, less mineral, low E(stiffness) than interstitial; cement line: discontinuity between inter and secondary, so cracks are likely initiate there or divert from Plexiform bone=fibrolamellar bone=laminar Rapid grow, offer increased mechanical support for longer periods of time. more surface area then osteonal, This increases the amount of bone which can be formed in a given time frame and provided a way to more rapidly increase bone stiffness and strength in a short period of time. greater stiffness than primary or secondary cortical bone

Lamellae Osteoclasts Lacunae Canaliculi

Fracture mechanics in micro-scale Micro-structure interface, discontinuity cause cracks are likely to initiate or divert from here Uncrack bridges R-curve Old people low KC and low R-curve (brittle) Young people High KC and high R-curve (tough)

Low mineral content 48% High mineral content85% Work of fracture 6200J m-2 work of fracture 20 J m-2

Size effect remain puzzling Bone shape is determined by gene