Macrodamage Accumulation Model for a Human Femur

Abstract

The objective of this study was to more fully understand the mechanical behavior of bone tissue that is important to find an alternative material to be used as an implant and to develop an accurate model to predict the fracture of the bone. Predicting and preventing bone failure is an important area in orthopaedics. In this paper, the macrodamage accumulation models in the bone tissue have been investigated. Phenomenological models for bone damage have been discussed in detail. In addition, 3D finite element model of the femur prepared from imaging data with both cortical and trabecular structures is delineated using MIMICS and ANSYS® and simulated as a composite structure. The damage accumulation occurring during cyclic loading was analyzed for fatigue scenario. We found that the damage accumulates sooner in the multiaxial than in the uniaxial loading condition for the same number of cycles, and the failure starts in the cortical bone. The damage accumulation behavior seems to follow a three-stage growth: a primary phase, a secondary phase of damage growth marked by linear damage growth, and a tertiary phase that leads to failure. Finally, the stiffness of the composite bone comprising the cortical and trabecular bone was significantly different as expected.

Biomechanical Behavior of a Variable Angle Locked Tibiotalocalcaneal Construct

“…The walking gait cycle of the knee joint was obtained from the Orthoload website [20]. The material properties of the bone were obtained from [21], as an anisotropic representation of bone tissue was performed by calculating the elastic constants (Modulus of elasticity E, Poisson's ratio ν, and shear modulus G) of cortical and trabecular parts with respect to radial, circumferential, and longitudinal directions.…”

“…The following orthotropic relationships were used to calculate the elastic constants of the cortical part where the density ( ) is equal to 1.071 g/cm 3 [21]: radial = 2314ρ 1.57 circumferential = 2314 1.57 longitudinal = 2065 3.09…”

“…The following orthotropic relationships were used to calculate the elastic constants of the cortical part where the density ( ) is equal to 1.071 g/cm 3 [21]: radial = 2314ρ 1.57 circumferential = 2314 1.57 longitudinal = 2065 3.09 Figure 4. X-ray images of the PHILOS construct after two years showing the different types of screws used in fixation (cannulated and talonavicular screws were excluded from this study) (left and middle).…”

“…The following orthotropic relationships were used to calculate the elastic constants of the cortical part where the density (ρ) is equal to 1.071 g/cm 3 [21]: 3.09 While the following orthotropic relationships were used to calculate the elastic constants of the trabecular part where the density (ρ) is equal to 0.997 g/cm 3 [21]: 1.64 The elastic constants and elasticity tensor components were calculated (Table 1) and imported into the Ansys program for cortical and trabecular parts. While the following orthotropic relationships were used to calculate the elastic constants of the trabecular part where the density ( ) is equal to 0.997 g/cm 3 [21]: radial = 1157 1.78 circumferential = 1157 1.78 longitudinal = 1904 1.64 The elastic constants and elasticity tensor components were calculated (Table 1) and imported into the Ansys program for cortical and trabecular parts. [22] was compared with the proposed model, Figure 6.…”

Failure Analysis of PHILOS Plate Construct Used for Pantalar Arthrodesis Paper II—Screws and FEM Simulations

“…Additionally, the material properties of stainless steel 316L were assigned according to the ASTM standard [22], shown in Table 4. The cortical and cancellous components were modeled with a 12.7 GPa and a 0.9 GPa modulus of elasticity and a 0.3 and a 0.2 Poisson's ratio, respectively [25]. Materials were treated as homogeneous, isotropic, and a linear elastic analysis was carried out.…”