Experimental and analytical study of anisotropic strength properties of bovine cortical bone
- PDF / 2,404,051 Bytes
- 11 Pages / 595.276 x 790.866 pts Page_size
- 59 Downloads / 196 Views
ORIGINAL PAPER
Experimental and analytical study of anisotropic strength properties of bovine cortical bone H. Mohammadi1 · S. Pietruszczak1 Received: 26 August 2019 / Accepted: 24 February 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract This paper is focused on specification of conditions at failure in bovine cortical bone. Both experimental and analytical studies are conducted. The experimental part includes a series of novel direct shear tests which examine the sensitivity of shear strength to the applied normal stress for different orientations of the sample microstructure. These experiments are supplemented by standard axial compression and tension tests in order to define and quantify a general form of failure criterion. The analytical part examines two different methodologies, viz. critical plane approach and microstructure tensor approach, for defining the anisotropic strength criterion. A procedure for identification of material parameters is outlined which is based on the results of the performed material tests. Keywords Cortical bone · Anisotropic failure criterion · Bone fracture · Critical plane approach · Microstructure tensor
1 Introduction Bone tissues, both cortical and trabecular, have complex heterogeneous microstructure which results in an inherent anisotropy in mechanical properties at a macroscale (cf. Martin et al. 2016). Over the last few decades, extensive experimental testing has been conducted to examine those properties. For the trabecular bone, there are intrinsic difficulties in getting consistent quantitative results (Odgaard and Linde 1991; Keaveny et al. 1997). This stems from the fact that the trabecular tissue has high porosity and its microstructure is very inhomogeneous, i.e. varies significantly with the anatomic location. In view of this, the results strongly depend on the size of the sample as well as its orientation relative to the loading direction. The stiffness and strength properties are typically assessed by conducting uniaxial compression tests. However, more comprehensive testing programs, incorporating torsion and multi-axial compression, have also been carried out (Rincón-Kohli and Zysset 2009). For the cortical bone, the literature on specification of its mechanical properties is more exhaustive, which is due to the fact that this tissue plays a primary role in bearing
* S. Pietruszczak [email protected] 1
McMaster University, Hamilton, ON, Canada
the physiological and other types of loads. The reported experimental programs involved various loading conditions and included both monotonic and cyclic tests (Zdero 2017). The earliest comprehensive work is perhaps that of Reilly and Burstein (1975), who performed a series of uniaxial tension, uniaxial compression and torsion tests on bovine (with both plexiform and Haversian structure), and human bone samples. The main focus there was on examining the anisotropic nature of properties. The nonlinear effects in uniaxial compression and tension, including development of permanent de
Data Loading...
