Development and Validation of an In-Vivo Finite Element Pelvis Model With Cortical Thickness Mapped From a Cadaver

2011 ◽  
Author(s):  
Young Ho Kim ◽  
Jong-Eun Kim ◽  
Alan W. Eberhardt
Keyword(s):  
Finite Element ◽  
Motor Vehicle ◽  
Human Subjects ◽  
Model Development ◽  
Biomechanical Properties ◽  
Fe Model ◽  
Lateral Impact ◽  
Vehicle Accidents ◽  
Pelvis Fracture

Pelvis fracture and associated injuries from motor vehicle accidents or falls are often life threatening [1]. Cadaveric experiments and finite element (FE) models have been widely used to investigate biomechanical properties, structural responses, and injury tolerances of the pelvis. In FE model development, the geometry of the bone structures is commonly constructed from computed tomography (CT) scans of cadavers. The use of live human subjects, however, has been limited due to low CT resolution resulting from mandatory low radiation doses and involuntary movements of the subject. The Global Human Body Models Consortium (GHBMC) elected to use a living 50th percentile male for its full body FE model development; however, cortical bone thickness was not accurately imaged for the pelvis, where it is believed to play an important role in absorbing strain energy during lateral impact [2].

Development and Validation of a Finite Element Model of the Lower Limb

2004 ◽  
Author(s):  
Costin Untaroiu ◽  
Kurosh Darvish ◽  
Jeff Crandall ◽  
Bing Deng ◽  
J. T. Wang
Keyword(s):  
Finite Element ◽  
Lower Limb ◽  
Model Development ◽  
Fe Model ◽  
Lateral Impact ◽  
Hexahedral Elements ◽  
Limb Injuries ◽  
Bend Tests ◽  
Point Bend ◽  
Validation Tests

Pedestrians struck by a vehicle frequently sustain lower limb injuries. Moreover, the biomechanics of the lower limb under lateral impact influences the trajectory of the pedestrian and subsequent injuries to the pelvis, thorax, and head. In order to increase the understanding of injury mechanisms in the lower limb, a finite element (FE) model of the lower limb was developed. The geometry of the bones and flesh was originally obtained from the Visible Human Project Database and was scaled to a 50th percentile male. The geometry of the knee ligaments was originally obtained from the 3D-CAD-Browser Database and was scaled according to the published anatomical data to align with the bones and the corresponding insertion sites. The FE mesh consists mostly of hexahedral elements which was developed using a structural mesh generator. The material and failure properties were initially selected from the literature and were later tuned based on the validation tests. The FE model was validated using the literature data and several cadaveric component tests performed specifically for model development and evaluation. The validation tests included quasi-static and dynamic lateral three-point-bend tests of the femur and the leg with flesh, and lateral four-point-bend tests of the knee joint.

Development and Verification of a Dynamic TKR Model

2002 ◽  
Author(s):  
Jason P. Halloran ◽  
Anthony J. Petrella ◽  
Paul J. Rullkoetter
Keyword(s):  
Finite Element ◽  
Contact Mechanics ◽  
Dynamic Loading ◽  
Soft Tissues ◽  
Dynamic Models ◽  
Total Joint Replacement ◽  
Fe Model ◽  
Loading Conditions ◽  
Dynamic Loading Conditions

The success of current total knee replacement (TKR) devices is contingent on the kinematics and contact mechanics during in vivo activity. Indicators of potential clinical performance of total joint replacement devices include contact stress and area due to articulations, and tibio-femoral and patello-femoral kinematics. An effective way of evaluating these parameters during the design phase or before clinical use is via computationally efficient computer models. Previous finite element (FE) knee models have generally been used to determine contact stresses and/or areas during static or quasi-static loading conditions. The majority of knee models intended to predict relative kinematics have not been able to determine contact mechanics simultaneously. Recently, however, explicit dynamic finite element methods have been used to develop dynamic models of TKR able to efficiently determine joint and contact mechanics during dynamic loading conditions [1,2]. The objective of this research was to develop and validate an explicit FE model of a TKR which includes tibio-femoral and patello-femoral articulations and surrounding soft tissues. The six degree-of-freedom kinematics, kinetics and polyethylene contact mechanics during dynamic loading conditions were then predicted during gait simulation.

scholarly journals Factors Affecting the Severity of Placental Abruption in Pregnant Vehicle Drivers: Analysis with a Novel Finite Element Model

Healthcare ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 27
Author(s):  
Katsunori Tanaka ◽  
Yasuki Motozawa ◽  
Kentaro Takahashi ◽  
Tetsuo Maki ◽  
Masahito Hitosugi
Keyword(s):  
Finite Element ◽  
Pregnant Woman ◽  
Finite Element Model ◽  
Placental Abruption ◽  
Motor Vehicle ◽  
Human Subjects ◽  
Element Model ◽  
Collision Velocity ◽  
Vehicle Collisions ◽  
Factors Affecting

We clarified factors affecting the severity of placental abruption in motor vehicle collisions by quantitively analyzing the area of placental abruption in a numerical simulation of an unrestrained pregnant vehicle driver at collision velocities of 3 and 6 m/s. For the simulation, we constructed a novel finite element model of a small 30-week pregnant woman, which was validated anthropometrically using computed tomography data and biomechanically using previous examinations of post-mortem human subjects. In the simulation, stress in the elements of the utero–placental interface was computed, and those elements exceeding a failure criterion were considered to be abrupted. It was found that a doubling of the collision velocity increased the area of placental abruption 10-fold, and the abruption area was approximately 20% for a collision velocity of 6 m/s, which is lower than the speed limit for general roads. This result implies that even low-speed vehicle collisions have negative maternal and fetal outcomes owing to placental abruption without a seatbelt restraint. Additionally, contact to the abdomen, 30 mm below the umbilicus, led to a larger placental abruption area than contact at the umbilicus level when the placenta was located at the uterus fundus. The results support that a reduction in the collision speed and seatbelt restraint at a suitable position are important to decrease the placental abruption area and therefore protect a pregnant woman and her fetus in a motor vehicle collision.

Effect of a Degenerated C5-C6 Disc on the Biomechanics of Adjacent Levels: A Poroelastic Finite Element Investigation

2007 ◽  
Author(s):  
Mozammil Hussain ◽  
Raghu N. Natarajan ◽  
Gunnar B. J. Andersson ◽  
Howard S. An
Keyword(s):  
Finite Element ◽  
Cervical Spine ◽  
Morphological Changes ◽  
Axial Strain ◽  
Fe Model ◽  
Fe Method ◽  
Regional Effect ◽  
In Vitro Techniques

Degenerative changes in the cervical spine due to aging are very common causes of neck pain in general population. Although many investigators have quantified the gross morphological changes in the disc with progressive degeneration, the biomechanical changes due to degenerative pathologies of the disc and its effect on the adjacent levels are not well understood. Despite many in vivo and in vitro techniques used to study such complex phenomena, the finite element (FE) method is still a powerful tool to investigate the internal mechanics and complex clinical situations under various physiological loadings particularly when large numbers of parameters are involved. The objective of the present study was to develop and validate a poroelastic FE model of a healthy C3-T1 segment of the cervical spine under physiologic moment loads. The model included the regional effect of change in the fixed charged density of proteoglycan concentration and change in the permeability and porosity due to change in the axial strain of disc tissues. The model was further modified to include various degrees of disc degeneration at the C5-C6 level. Outcomes of this study provided a better understanding on the progression of degeneration along the cervical spine by investigating the biomechanical response of the adjacent segments with an intermediate degenerated C5-C6 level.

Automated Segmentation of Swine Skulls for Finite Element Model Creation Using High Resolution μ-CT Images

2019 ◽  
Vol 16 (03) ◽  
pp. 1842012 ◽  
Author(s):  
Zimo Zhu ◽  
Donna C. Jones ◽  
G. R. Liu ◽  
Sajjad Soleimani ◽  
Xu Huang ◽  
...  
Keyword(s):  
Finite Element ◽  
Material Properties ◽  
Complex Structure ◽  
Model Development ◽  
Element Model ◽  
Fe Model ◽  
Micro Computed Tomography ◽  
Mineral Density ◽  
Detailed Model ◽  
Bone Mineral Density Loss

Finite element (FE) analysis has been widely used to investigate bone responses to mechanical loading. Research in long bones has been straight forward because modeling of these bones requires only two material properties. Such an FE model may provide an adequate approximation of the anatomy for many cases. However, a more detailed model of skull bones is needed to accurately capture its complex structure of multiple bone pieces and the various mineral densities distributed throughout these bone pieces. Unfortunately, FE model development incorporating both complex geometries and anatomically accurate material properties is both computationally and labor intensive. In this study, a method is proposed to automatically segment micro-computed tomography ([Formula: see text]-CT) scan images of bone pieces to build an FE model of a full swine hemi-skull. Using the Digital Imaging and Communications in Medicine (DICOM) files from scanned bones, the complete geometry of each bone piece is recreated through seven customized processing algorithms. After assembling the bone pieces to form the skull, experimentally derived Young’s modulus values are correlated to grayscale values to produce a detailed FE model for accurate simulation. This detailed skull model can be used to predict strain/stress patterns in response to various loading regimes to facilitate research questions in fracture healing and growth, as well as bone tissue engineering and bone mineral density loss (e.g., osteoporosis).

Toward a Functional Tolerance Criterion for the Hippocampus Developed From Organotypic Slice Cultures

2010 ◽  
Author(s):  
Zhe Yu ◽  
Woo Hyeun Kang ◽  
Barclay Morrison
Keyword(s):  
Finite Element ◽  
Brain Injuries ◽  
Motor Vehicle ◽  
Biological Response ◽  
Finite Element Models ◽  
Permanent Disability ◽  
Injury Biomechanics ◽  
Current Form ◽  
Vehicle Accidents ◽  
Brain Deformation

Approximately 1.5 million traumatic brain injuries (TBI) occur each year which result in 50,000 deaths, and about 80,000 people are left with a permanent disability. The annual cost associated with these injures is estimated to be $60 billion. Because there is no pharmacological treatment for TBI, engineering strategies to prevent these injuries enabled through an improved understanding of injury biomechanics is crucial. To this end, finite element models play a central role for predicting brain deformation induced by various loading scenarios such as falls or motor vehicle accidents. Novel protection strategies can then be tested in silico before the start of physical testing. However, in their current form, finite element models predict only mechanical responses and cannot predict the biological response of the brain tissue to the imposed deformation.

Numerical and Experimental Analysis of Articular Chondrocyte Deformation: Calibration of a Multiscale Finite Element Model

2007 ◽  
Author(s):  
Scott L. Bevill ◽  
Paul L. Briant ◽  
Thomas P. Andriacchi
Keyword(s):  
Finite Element ◽  
Load Transfer ◽  
Numerical Models ◽  
Experimental Studies ◽  
Element Model ◽  
Cartilage Explants ◽  
Fe Model ◽  
Articular Chondrocyte ◽  
Superficial Zone

Mechanical loading of chondrocytes in isolation [1] and of articular cartilage in culture [2] has been reported to be a potent regulator of chondrocyte metabolism. Experimental studies have related tissue-level and cell-level strains in mechanically loaded cartilage explants [3], but cannot be readily extended to address more physiologic loading cases. Numerical models, which might address this need, have primarily been axisymmetric [4, 5] or two-dimensional [6] and have idealized chondrocyte geometry. Given the complexity of the mechanism of the load transfer between the tissue and cell, however, there remains a lack of information regarding the in vivo level of cell stresses and strains. Thus, the purpose of this study was to develop a multiscale experimental/numerical approach to calibrate a three-dimensional finite element (FE) model of a chondrocyte based on experimentally derived chondrocyte morphology and deformation data. The method was than applied to determine the modulus of a chondrocyte located in the superficial zone.

scholarly journals Bio-Compatible Processing of LENSTM DepositedCo-Cr-W alloy for Medical Applications

2018 ◽  
Vol 7 (2.20) ◽  
pp. 362 ◽  
Author(s):  
Ganzi Suresh ◽  
K L Narayana ◽  
M Kedar Mallik
Keyword(s):  
Chronic Toxicity ◽  
Motor Vehicle ◽  
Experimental Period ◽  
Layer By Layer ◽  
Medical Implants ◽  
Osteoblast Cells ◽  
Acceptable Result ◽  
Vehicle Accidents

Developing a Medicinal implants or devices is a challenging task for the researchers, right from the selection of materials, design, bio-compatibility and implantation to the host tissue. At every stage it requires proper care in processing of medical implants. In recent years the demand for medical implants had grown rapidly due to the awareness in the society. Major share of implants is used by younger people as they are active in sports, motor vehicle accidents leads to facture. Even older people also preferring to implants for ease of living. The commonly used implants are, prosthetic joints, knee replacement, dental, maxillofacial reconstructions etc.There is huge demand for the medical implants in coming years, presently a few bio-materials available for implant devices such as Ti-alloys, Stainless steel and Co-Cr-Mo alloys. There a scope to the researchers to develop a new alloy that are bio-compatible in nature and bring down the cost of the implant procedure to the needed patients. In this context additive manufacturing (AM) is an advanced manufacturing technology emerging as prominent technique in medical fields. Laser Engineered Net ShapingTM (LENS) is one such metal additive technique which provides fabrication of parts with the help of laser power, melts the powder alloy completely and builds parts layer by layer directly from the CAD model.In the present study, samples are fabricated from LENS process and carried the In-Vitro and In -Vivo bio-compatible tests as cytotoxicity and sub chronic toxicity to verify the toxicants release and their sustainability as the medical implants by the LENS deposited Co-Cr-W alloy samples. From the studies it is observed that the alloy samples show acceptable result. MTT assay demonstrate that cell viability is better in Osteoblast cells compared to the Fibroblast cells. Osteoblast cells show slightly more viable to the cell treatment on the samples during the experimental period. Sub chronic toxicity conclude that LENS deposited Co-Cr-W alloy is not toxic in all the rats studied herein and did not produce any toxic signs or evident symptoms. LENS deposited Co-Cr-W alloy did not cause any lethality or produce any relative body organs weight and haematological studies didn’t show adverse effects.  

scholarly journals Multi-layered bird beaks: a finite-element approach towards the role of keratin in stress dissipation

2012 ◽  
Vol 9 (73) ◽  
pp. 1787-1796 ◽  
Author(s):  
Joris Soons ◽  
Anthony Herrel ◽  
Annelies Genbrugge ◽  
Dominique Adriaens ◽  
Peter Aerts ◽  
...  
Keyword(s):  
Finite Element ◽  
Material Properties ◽  
Speckle Pattern ◽  
Young Modulus ◽  
Von Mises Stress ◽  
Fe Model ◽  
Element Approach ◽  
Von Mises ◽  
The Impact

Bird beaks are layered structures, which contain a bony core and an outer keratin layer. The elastic moduli of this bone and keratin were obtained in a previous study. However, the mechanical role and interaction of both materials in stress dissipation during seed crushing remain unknown. In this paper, a multi-layered finite-element (FE) model of the Java finch's upper beak ( Padda oryzivora ) is established. Validation measurements are conducted using in vivo bite forces and by comparing the displacements with those obtained by digital speckle pattern interferometry. Next, the Young modulus of bone and keratin in this FE model was optimized in order to obtain the smallest peak von Mises stress in the upper beak. To do so, we created a surrogate model, which also allows us to study the impact of changing material properties of both tissues on the peak stresses. The theoretically best values for both moduli in the Java finch are retrieved and correspond well with previous experimentally obtained values, suggesting that material properties are tuned to the mechanical demands imposed during seed crushing.

Subject-Specific Finite Element Models of the Tibia With Realistic Boundary Conditions Predict Bending Deformations Consistent With In Vivo Measurement

2019 ◽  
Vol 142 (2) ◽  
Author(s):  
Ifaz T. Haider ◽  
Michael Baggaley ◽  
W. Brent Edwards
Keyword(s):  
Finite Element ◽  
Boundary Conditions ◽  
Internal Rotation ◽  
Stress Fracture ◽  
Contact Forces ◽  
Female Participant ◽  
Fe Model ◽  
In Vivo Measurements ◽  
Subject Specific

Abstract Understanding the structural response of bone during locomotion may help understand the etiology of stress fracture. This can be done in a subject-specific manner using finite element (FE) modeling, but care is needed to ensure that modeling assumptions reflect the in vivo environment. Here, we explored the influence of loading and boundary conditions (BC), and compared predictions to previous in vivo measurements. Data were collected from a female participant who walked/ran on an instrumented treadmill while motion data were captured. Inverse dynamics of the leg (foot, shank, and thigh segments) was combined with a musculoskeletal (MSK) model to estimate muscle and joint contact forces. These forces were applied to an FE model of the tibia, generated from computed tomography (CT). Eight conditions varying loading/BCs were investigated. We found that modeling the fibula was necessary to predict realistic tibia bending. Applying joint moments from the MSK model to the FE model was also needed to predict torsional deformation. During walking, the most complex model predicted deformation of 0.5 deg posterior, 0.8 deg medial, and 1.4 deg internal rotation, comparable to in vivo measurements of 0.5–1 deg, 0.15–0.7 deg, and 0.75–2.2 deg, respectively. During running, predicted deformations of 0.3 deg posterior, 0.3 deg medial, and 0.5 deg internal rotation somewhat underestimated in vivo measures of 0.85–1.9 deg, 0.3–0.9 deg, 0.65–1.72 deg, respectively. Overall, these models may be sufficiently realistic to be used in future investigations of tibial stress fracture.

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