scholarly journals The mechanical response of the lumbar spine to different combinations of disc degenerative changes investigated using randomized poroelastic finite element models

2010 ◽  
Vol 20 (4) ◽  
pp. 563-571 ◽  
Author(s):  
Fabio Galbusera ◽  
Hendrik Schmidt ◽  
Cornelia Neidlinger-Wilke ◽  
Andreas Gottschalk ◽  
Hans-Joachim Wilke
Keyword(s):  
Finite Element ◽  
Lumbar Spine ◽  
Mechanical Response ◽  
Degenerative Changes ◽  
Finite Element Models

scholarly journals Can finite element models of ballooning procedures yield mechanical response of the cardiovascular site to overexpansion?

2016 ◽  
Vol 49 (13) ◽  
pp. 2778-2784 ◽  
Author(s):  
Giorgia M. Bosi ◽  
Benedetta Biffi ◽  
Giovanni Biglino ◽  
Valentina Lintas ◽  
Rod Jones ◽  
...  
Keyword(s):  
Finite Element ◽  
Mechanical Response ◽  
Finite Element Models

scholarly journals Investigation of the effect of raster angle, build orientation, and infill density on the elastic response of 3D printed parts using finite element microstructural modeling and homogenization techniques

2021 ◽  
Author(s):  
Hassan Gonabadi ◽  
Yao Chen ◽  
Arti Yadav ◽  
Steve Bull
Keyword(s):  
Finite Element ◽  
Computational Models ◽  
Mechanical Response ◽  
Elastic Response ◽  
Scale Model ◽  
Finite Element Models ◽  
Fused Filament Fabrication ◽  
Homogenization Technique ◽  
Macro Scale ◽  
3D Printed

AbstractAlthough the literature is abundant with the experimental methods to characterize mechanical behavior of parts made by fused filament fabrication 3D printing, less attention has been paid in using computational models to predict the mechanical properties of these parts. In the present paper, a numerical homogenization technique is developed to predict the effect of printing process parameters on the elastic response of 3D printed parts with cellular lattice structures. The development of finite element computational models of printed parts is based on a multi scale approach. Initially, at the micro scale level, the analysis of micro-mechanical models of a representative volume element is used to calculate the effective orthotropic properties. The finite element models include different infill densities and building/raster orientation maintaining the bonded region between the adjacent fibers and layers. The elastic constants obtained by this method are then used as an input for the creation of macro scale finite element models enabling the simulation of the mechanical response of printed samples subjected to the bending, shear, and tensile loads. Finally, the results obtained by the homogenization technique are validated against more realistic finite element explicit microstructural models and experimental measurements. The results show that, providing an accurate characterization of the properties to be fed into the macro scale model, the use of the homogenization technique is a reliable tool to predict the elastic response of 3D printed parts. The outlined approach provides faster iterative design of 3D printed parts, contributing to reducing the number of experimental replicates and fabrication costs.

scholarly journals Lumbar Spine Response of Computational Finite Element Models in Multidirectional Spaceflight Landing Conditions

2020 ◽  
Vol 142 (5) ◽  
Author(s):  
Xin Ye ◽  
Derek A. Jones ◽  
James P. Gaewsky ◽  
Bharath Koya ◽  
Kyle P. McNamara ◽  
...  
Keyword(s):  
Finite Element ◽  
Lumbar Spine ◽  
Environmental Variables ◽  
Loading Condition ◽  
Spine Injury ◽  
Finite Element Models ◽  
Latin Hypercube Design ◽  
Hybrid Iii ◽  
Human Body Models ◽  
Lumbar Extension

Abstract The goals of this study are to compare the lumbar spine response variance between the hybrid III, test device for human occupant restraint (THOR), and global human body models consortium simplified 50th percentile (GHBMC M50-OS) finite element models and evaluate the sensitivity of lumbar spine injury metrics to multidirectional acceleration pulses for spaceflight landing conditions. The hybrid III, THOR, and GHBMC models were positioned in a baseline posture within a generic seat with side guards and a five-point restraint system. Thirteen boundary conditions, which were categorized as loading condition variables and environmental variables, were included in the parametric study using a Latin hypercube design of experiments. Each of the three models underwent 455 simulations for a total of 1365 simulations. The hybrid III and THOR models exhibited similar lumbar compression forces. The average lumbar compression force was 45% higher for hybrid III (2.2 ± 1.5 kN) and 51% higher for THOR (2.0 ± 1.6 kN) compared to GHBMC (1.3 ± 0.9 kN). Compared to hybrid III, THOR sustained an average 64% higher lumbar flexion moment and an average 436% higher lumbar extension moment. The GHBMC model sustained much lower bending moments compared to hybrid III and THOR. Regressions revealed that lumbar spine responses were more sensitive to loading condition variables than environmental variables across all models. This study quantified the intermodel lumbar spine response variations and sensitivity between hybrid III, THOR, and GHBMC. Results improve the understanding of lumbar spine response in spaceflight landings.

Validation of an In Vivo Medical Image-Based Young Human Lumbar Spine Finite Element Model

2019 ◽  
Vol 141 (3) ◽  
Author(s):  
Matthew J. Mills ◽  
Nesrin Sarigul-Klijn
Keyword(s):  
Finite Element ◽  
Lumbar Spine ◽  
Finite Element Model ◽  
Medical Image ◽  
Female Subject ◽  
Element Model ◽  
Young Female ◽  
Lumbosacral Spine ◽  
Finite Element Models ◽  
The Finite Element Model

Mathematical models of the human spine can be used to investigate spinal biomechanics without the difficulties, limitations, and ethical concerns associated with physical experimentation. Validation of such models is necessary to ensure that the modeled system behavior accurately represents the physics of the actual system. The goal of this work was to validate a medical image-based nonlinear lumbosacral spine finite element model of a healthy 20-yr-old female subject under physiological moments. Range of motion (ROM), facet joint forces (FJF), and intradiscal pressure (IDP) were compared with experimental values and validated finite element models from the literature. The finite element model presented in this work was in good agreement with published experimental studies and finite element models under pure moments. For applied moments of 7.5 N·m, the ROM in flexion–extension, axial rotation, and lateral bending were 39 deg, 16 deg, and 28 deg, respectively. Excellent agreement was observed between the finite element model and experimental data for IDP under pure compressive loading. The predicted FJFs were lower than those of the experimental results and validated finite element models for extension and torsion, likely due to the nondegenerate properties chosen for the intervertebral disks and morphology of the young female spine. This work is the first to validate a computational lumbar spine model of a young female subject. This model will serve as a valuable tool for predicting orthopedic spinal injuries, studying the effect of intervertebral disk replacements using advanced biomaterials, and investigating soft tissue degeneration.

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