Application of Optimization Methodology and Specimen-Specific Finite Element Models for Investigating Material Properties of Rat Skull

Abstract

Finite element (FE) models of rat skull bone samples were developed by reconstructing the three-dimensional geometry of microCT images and voxel-based hexahedral meshes. An optimization-based material identification method was developed to obtain the most favorable material property parameters by minimizing differences in three-point bending test responses between experimental and simulation results. An anisotropic Kriging model and sequential quadratic programming, in conjunction with Latin Hypercube Sampling (LHS), are utilized to minimize the disparity between the experimental and FE model predicted force-deflection curves. A selected number of material parameters, namely Young's modulus, yield stress, tangent modulus, and failure strain, are varied iteratively using the proposed optimization scheme until the assessment index 'F', the objective function comparing simulation and experimental force-deflection curves through least squares, is minimized. Results show that through the application of this method, the optimized models' force-deflection curves are closely in accordance with the measured data. The average differences between the experimental and simulation data are around 0.378 N (which was 3.3% of the force peak value) and 0.227 N (which was 2.7% of the force peak value) for two different test modes, respectively. The proposed optimization methodology is a potentially useful tool to effectively help establish material parameters. This study represents a preliminary effort in the development and validation of FE models for the rat skull, which may ultimately serve to develop a more biofidelic rat head FE model.

High-Pressure Compression-Molded Porous Resorbable Polymer/Hydroxyapatite Composite Scaffold for Cranial Bone Regeneration

“…The highest compressive performance was achieved when the scaffold was molded at 1000 MPa and 180 °C for 45 min, after which the compressive yield strength and modulus were 0.91 and 6.84 MPa, respectively. The compressive modulus here is comparable with that of the cranial bone of a 43-day-old adult rat (∼6 MPa at 25 °C), 18 which highlights its great potential for repairing cranial bone. The porous composite scaffold reported below, i.e., the HPCM scaffold, was fabricated under such optimal processing conditions, and the LPCM specimen (5 MPa/180 °C/45 min) was determined for comparison.…”

Evaluation of the effects of miniscrew incorporation in palatal expanders for young adults using finite element analysis

“…Because this study was designed to investigate the initial reaction to an orthopedic expansion force, the teeth, alveolar bone, periodontal ligament, suture, and supporting wire were assumed to be homogeneous, isotropic, and linearly elastic. The mechanical properties of the components of the model were obtained from experimental data reported in previous studies 18 19 ( Table 1 ).…”

The mechanical and morphological properties of 6 year-old cranial bone

“…These properties drive the overall mechanical response of the head including skull fracture and brain response. Other methods, including inverse finite element optimization, couples experimentally observed force-deflection curves with computational models to reverse engineer the material properties of a given material (Guan et al, 2011).…”