Modeling microdamage behavior of cortical bone

Abstract

Bone is a complex material which exhibits several hierarchical levels of structural organization. At the submicron-scale, the local tissue porosity gives rise to discontinuities in the bone matrix which have been shown to influence damage behavior. Computational tools to model the damage behavior of bone at different length scales are mostly based on finite element (FE) analysis, with a range of algorithms developed for this purpose. Although the local mechanical behavior of bone tissue is influenced by microstructural features such as bone canals and osteocyte lacunae, they are often not considered in FE damage models due to the high computational cost required to simulate across several length scales, i.e., from the loads applied at the organ level down to the stresses and strains around bone canals and osteocyte lacunae. Hence, the aim of the current study was twofold: First, a multilevel FE framework was developed to compute, starting from the loads applied at the whole bone scale, the local mechanical forces acting at the micrometer and submicrometer level. Second, three simple microdamage simulation procedures based on element removal were developed and applied to bone samples at the submicrometer-scale, where cortical microporosity is included. The present microdamage algorithm produced a qualitatively analogous behavior to previous experimental tests based on stepwise mechanical compression combined with in situ synchrotron radiation computed tomography. Our results demonstrate the feasibility of simulating microdamage at a physiologically relevant scale using an image-based meshing technique and multilevel FE analysis; this allows relating microdamage behavior to intracortical bone microstructure.

Micro computed tomography based finite element models for elastic and strength properties of 3D printed glass scaffolds

“…The proposed computational strategy features the typical limitations of simulations carried out using linear kinematic relationships (small strains and small displacements) in damaging elastic solids. Element annihilation as that used with voxel-like finite element models [29] implies that stress and strain fields in the annihilated elements are not reliable as large strains may locally occur as material undergoes the damage process. As the amount of incremental fracture surface is controlled (through a predetermined number of annihilated elements) and, as displacement is re-scaled at each step so to reduce stress within the strength limit, the stress and strain fields in the vicinity of the damaged elements can still be considered to be as accurate as those occurring in the original μ − CT based finite element models.…”

Microdamage as a Bone Quality Component: Practical Guidelines for the Two‐Dimensional Analysis of Linear Microcracks in Human Cortical Bone

“…Linear microcracks typically occur in compression, appearing as ellipsoidal shaped planes of separation particularly in interstitial, extra‐osteonal areas of high mineralization within the cortex . Rising in both incidence and length with increasing age, previous research attributes these changes to increased collagen cross‐linking, greater bone mineralization, and increased intracortical porosity and remodeling events, indicating that altered material properties influence a bone's structural response. Inherent repair mechanisms that target these linear microcracks (ie, targeted remodeling) are essential to maintaining skeletal integrity, principally by keeping microcrack propagation in check .…”

Inverse Finite Element Modeling for Characterization of Local Elastic Properties in Image-Guided Failure Assessment of Human Trabecular Bone

“…Local mechanical stress and strain in bone plays a crucial role for failure initiation and propagation [1][2][3][4], Linear and nonlinear pFE simulations using local failure criterions have been imple mented in order to predict specimen failure [5][6][7][8][9][10][11][12][13] and organ frac ture risk of bones [14][15][16][17][18][19][20][21][22][23]. On the other side, it is also well known that bone remodeling is related to the mechanical environment [24][25][26][27][28][29].…”