Assessment of Factors Influencing Finite Element Vertebral Model Predictions

2007 ◽  
Vol 129 (6) ◽  
pp. 898-903 ◽  
Author(s):  
Alison C. Jones ◽  
Ruth K. Wilcox
Keyword(s):  
Finite Element ◽  
Boundary Conditions ◽  
Material Property ◽  
Material Properties ◽  
Property Values ◽  
Sensitivity Study ◽  
Element Analysis ◽  
Homogeneous Models ◽  
Specific Material ◽  
Similar Accuracy

This study aimed to establish model construction and configuration procedures for future vertebral finite element analysis by studying convergence, sensitivity, and accuracy behaviors of semiautomatically generated models and comparing the results with manually generated models. During a previous study, six porcine vertebral bodies were imaged using a microcomputed tomography scanner and tested in axial compression to establish their stiffness and failure strength. Finite element models were built using a manual meshing method. In this study, the experimental agreement of those models was compared with that of semiautomatically generated models of the same six vertebrae. Both manually and semiautomatically generated models were assigned gray-scale-based, element-specific material properties. The convergence of the semiautomatically generated models was analyzed for the complete models along with material property and architecture control cases. A sensitivity study was also undertaken to test the reaction of the models to changes in material property values, architecture, and boundary conditions. In control cases, the element-specific material properties reduce the convergence of the models in comparison to homogeneous models. However, the full vertebral models showed strong convergence characteristics. The sensitivity study revealed a significant reaction to changes in architecture, boundary conditions, and load position, while the sensitivity to changes in material property values was proportional. The semiautomatically generated models produced stiffness and strength predictions of similar accuracy to the manually generated models with much shorter image segmentation and meshing times. Semiautomatic methods can provide a more rapid alternative to manual mesh generation techniques and produce vertebral models of similar accuracy. The representation of the boundary conditions, load position, and surrounding environment is crucial to the accurate prediction of the vertebral response. At present, an element size of 2×2×2mm3 appears sufficient since the error at this size is dominated by factors, such as the load position, which will not be improved by increasing the mesh resolution. Higher resolution meshes may be appropriate in the future as models are made more sophisticated and computational processing time is reduced.

Finite element analysis and dentistry

2015 ◽  
Vol 6 (3) ◽  
pp. 134-139
Author(s):  
Douglas Hammond ◽  
Justin Whitty
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Product Design ◽  
Material Properties ◽  
Manufacturing Process ◽  
New Products ◽  
Element Analysis ◽  
Specific Material

Finite element analysis (FEA) uses a computerised model to enable a material or model to be artificially stressed or analysed for specific material properties. FEA has been used in industry but is now being used more frequently in medicine and dentistry. It enables the design of new products and also allows for product refinement. This process makes it possible to verify a proposed design prior to what may be an expensive manufacturing process. It may also be able to determine why an existing product design has failed.

A REVIEW OF FINITE ELEMENT APPLICATIONS IN ORAL AND MAXILLOFACIAL BIOMECHANICS

2018 ◽  
Vol 18 (02) ◽  
pp. 1830002 ◽  
Author(s):  
SUZAN CANSEL DOGRU ◽  
EROL CANSIZ ◽  
YUNUS ZIYA ARSLAN
Keyword(s):  
Finite Element ◽  
Boundary Conditions ◽  
Material Properties ◽  
Dental Materials ◽  
Numerical Approach ◽  
Patient Specific ◽  
Element Analysis ◽  
Biomechanical Models ◽  
Dental Instruments ◽  
Wide Range

Finite element method (FEM) is preferred to carry out mechanical analyses for many complex biomechanical structures. For most of the biomechanical models such as oral and maxillofacial structures or patient-specific dental instruments, including nonlinearities, complicated geometries, complex material properties, or loading/boundary conditions, it is not possible to accomplish an analytical solution. The FEM is the most widely used numerical approach for such cases and found a wide range of application fields for investigating the biomechanical characteristics of oral and maxillofacial structures that are exposed to external forces or torques. The numerical results such as stress or strain distributions obtained from finite element analysis (FEA) enable dental researchers to evaluate the bone tissues subjected to the implant or prosthesis fixation from the viewpoint of (i) mechanical strength, (ii) material properties, (iii) geometry and dimensions, (iv) structural properties, (v) loading or boundary conditions, and (vi) quantity of implants or prostheses. This review paper evaluates the process of the FEA of the oral and maxillofacial structures step by step as followings: (i) a general perspective on the techniques for creating oral and maxillofacial models, (ii) definitions of material properties assigned to oral and maxillofacial tissues and related dental materials, (iii) definitions of contact types between tissue and dental instruments, (iv) details on loading and boundary conditions, and (v) meshing process.

scholarly journals A Three-Dimensional Inverse Finite Element Analysis of the Heel Pad

2012 ◽  
Vol 134 (3) ◽  
Author(s):  
Snehal Chokhandre ◽  
Jason P. Halloran ◽  
Antonie J. van den Bogert ◽  
Ahmet Erdemir
Keyword(s):  
Experimental Data ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Material Properties ◽  
Three Dimensional ◽  
Element Analysis ◽  
Heel Pad ◽  
Tool Force ◽  
Specific Material ◽  
Inverse Finite Element Analysis

Quantification of plantar tissue behavior of the heel pad is essential in developing computational models for predictive analysis of preventive treatment options such as footwear for patients with diabetes. Simulation based studies in the past have generally adopted heel pad properties from the literature, in return using heel-specific geometry with material properties of a different heel. In exceptional cases, patient-specific material characterization was performed with simplified two-dimensional models, without further evaluation of a heel-specific response under different loading conditions. The aim of this study was to conduct an inverse finite element analysis of the heel in order to calculate heel-specific material properties in situ. Multidimensional experimental data available from a previous cadaver study by Erdemir et al. (“An Elaborate Data Set Characterizing the Mechanical Response of the Foot,” ASME J. Biomech. Eng., 131(9), pp. 094502) was used for model development, optimization, and evaluation of material properties. A specimen-specific three-dimensional finite element representation was developed. Heel pad material properties were determined using inverse finite element analysis by fitting the model behavior to the experimental data. Compression dominant loading, applied using a spherical indenter, was used for optimization of the material properties. The optimized material properties were evaluated through simulations representative of a combined loading scenario (compression and anterior-posterior shear) with a spherical indenter and also of a compression dominant loading applied using an elevated platform. Optimized heel pad material coefficients were 0.001084 MPa (μ), 9.780 (α) (with an effective Poisson’s ratio (ν) of 0.475), for a first-order nearly incompressible Ogden material model. The model predicted structural response of the heel pad was in good agreement for both the optimization (<1.05% maximum tool force, 0.9% maximum tool displacement) and validation cases (6.5% maximum tool force, 15% maximum tool displacement). The inverse analysis successfully predicted the material properties for the given specimen-specific heel pad using the experimental data for the specimen. The modeling framework and results can be used for accurate predictions of the three-dimensional interaction of the heel pad with its surroundings.

Role of Material Properties in the Finite Element Solution for Three-Dimensional Composites—A Sensitivity Study

1995 ◽  
Vol 209 (2) ◽  
pp. 157-160
Author(s):  
H-B Hellweg ◽  
M A Crisfield
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Material Properties ◽  
Three Dimensional ◽  
Transversely Isotropic ◽  
Sensitivity Study ◽  
Two Dimensional ◽  
Element Analysis ◽  
The Impact

Three-dimensional material test data for orthotropic laminae are difficult to obtain. Consequently, various simplifications are made for the material properties of individual layers in a finite element analysis, ranging from the assumption of transversely isotropic layers to applying two-dimensional material data in a three-dimensional analysis. In order to investigate the impact and validity of such simplifications, the sensitivity of the stresses and deformations in a finite element analysis on the material properties was investigated.

scholarly journals Foam Density Sensitivity Study for the 9977 Package

2008 ◽  
Author(s):  
Jennifer L. Gorczyca ◽  
Tsu-Te Wu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Polyurethane Foam ◽  
Material Properties ◽  
Functional Performance ◽  
Sensitivity Study ◽  
Foam Density ◽  
Element Analysis ◽  
Hypothetical Accident ◽  
Accident Conditions

Two layers of insulation fill the volume of the 9977 package between the drum liner and the shell. One of these layers is composed of General Plastics FR-3716 polyurethane foam (also known as Last-A-Foam®), poured through fill holes in the drum bottom and foamed in place. There was concern that the density of the foam insulating layer may vary due to the manufacturing process and that variations in foam density would compromise the safety basis of the package. Thus, a structural finite element analysis was performed to investigate this concern. The investigation examined the effect of replacing the material properties for the FR-3716 polyurethane foam, which has a density equal to 16 lbm/ft3, with material properties of similar foam with varying densities through finite element analysis of hypothetical accident conditions (HAC) pertaining to impact conditions. The results showed that the functional performance of the containment vessel (CV) was not compromised under the conditions investigated.

scholarly journals Shape Sensing of a Complex Aeronautical Structure with Inverse Finite Element Method

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1388
Author(s):  
Daniele Oboe ◽  
Luca Colombo ◽  
Claudio Sbarufatti ◽  
Marco Giglio
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Boundary Conditions ◽  
Strain Field ◽  
Element Analysis ◽  
Inverse Finite Element Method ◽  
Shape Sensing ◽  
Definition Of ◽  
High Level ◽  
Element Method

The inverse Finite Element Method (iFEM) is receiving more attention for shape sensing due to its independence from the material properties and the external load. However, a proper definition of the model geometry with its boundary conditions is required, together with the acquisition of the structure’s strain field with optimized sensor networks. The iFEM model definition is not trivial in the case of complex structures, in particular, if sensors are not applied on the whole structure allowing just a partial definition of the input strain field. To overcome this issue, this research proposes a simplified iFEM model in which the geometrical complexity is reduced and boundary conditions are tuned with the superimposition of the effects to behave as the real structure. The procedure is assessed for a complex aeronautical structure, where the reference displacement field is first computed in a numerical framework with input strains coming from a direct finite element analysis, confirming the effectiveness of the iFEM based on a simplified geometry. Finally, the model is fed with experimentally acquired strain measurements and the performance of the method is assessed in presence of a high level of uncertainty.

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