ANALYSIS OF LIVER IMPACT RESPONSES THROUGH A CHINESE HUMAN BODY FINITE ELEMENT MODEL

2016 ◽  
Vol 16 (08) ◽  
pp. 1640024 ◽  
Author(s):  
TIANYA DU ◽  
JIQING CHEN ◽  
FENGCHONG LAN
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Human Body ◽  
Human Subjects ◽  
Element Model ◽  
Dynamic Responses ◽  
Peak Strain ◽  
Skeleton Model ◽  
Chinese Adult ◽  
Liver Model

Human liver biomechanical responses associated with frontal impacts, lateral impacts were studied using a simplified Chinese human body Finite Element Model (FEM) with more geometrical-accurate liver model for an average Chinese adult male from high resolution CT data. The developed model in this paper was composed by geometrically detailed liver model, simplified models of thoracic-abdominal organs, and the human skeleton model. Then, the whole model was validated at various velocities by comparing simulation outcomes with Post Mortem Human Subjects (PMHS) experimental results in frontal and lateral pendulum impacts. The force–deflection and force–time characteristics were in good agreement with the test results. The validated model was then applied for studying liver dynamic responses and injuries in simulations. Pressure, tensile stress and peak strain that may induce hepatic injuries was computed from model simulations and were analyzed about the correlation with the global parameters, like thoracic deflection, viscous criterion value, contact force. This study demonstrated that the method of developing a simplified finite element thorax-abdomen model with detailed liver model could be effective of hepatic injury assessment in various impacts reported in literature.

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.

Reliability-Based Assessment Method of Buried Pipeline at Fault Crossings

2020 ◽  
Author(s):  
Qian Zheng ◽  
Xiaoben Liu ◽  
Hong Zhang ◽  
Samer Adeeb
Keyword(s):  
Neural Network ◽  
Finite Element ◽  
Finite Element Model ◽  
Limit State ◽  
Element Model ◽  
Normal Operation ◽  
Operating Pressure ◽  
Peak Strain ◽  
Highly Nonlinear ◽  
Fault Displacement

Abstract The tectonic fault, which is one of the most common geohazards in field, poses great threat to buried pipe segments. Pipes will process to buckling or fracture due to large strain induced by continuously increasing ground displacements during earthquakes. Therefore, it is imperative to conduct safety analysis on pipes which are buried in seismic areas for the sake of ensuring normal operation. However, the highly nonlinearity of pipe response restricts the proceeding of reliability assessment. In this study, a hybrid procedure combining finite element method and artificial neural network is proposed for reliability-based assessment. First of all, the finite element model is developed on ABAQUS platform to simulate pipe response to strike-slip fault displacements. Thus, the strain demand value (the peak strain value obtained by finite element model in each design case) can be collected for database establishment, which is the preparation for neural network training. Thoroughness of the strain demand database can be achieved by a fully comprehensive calculation with consideration of influencing factors involving pipe diameter and wall thickness, operating pressure, magnitude of fault displacement, intersection angle between pipeline and fault plane, and characteristic value of backfill mechanics. Sequentially, Back Propagation Neural Network (BPNN) with double hidden layers is trained based on the developed database, and the surrogate strain demand prediction model can be obtained after accuracy verification. Hence, the strain-based limit state function can be respectively determined for tensile and compressive conditions. The strain capacity term is simply assumed based on published papers, the strain demand term is naturally superseded by the surrogate BPNN model, and Monte Carlo Simulation is employed to compute the probability of failure (POF). At last, the workability of the proposed approach is tested by a case study in which basic variables are referred to the Second West-to-East natural gas transmission pipeline project. It indicates that ANN is a good solver for reliability problems with implicit limit state functions especially for highly nonlinear problems. The proposed method is capable of computing POFs, which is an exploratory application for reliability research on pipes withstanding fault displacement loads.

A Comparative Study of the Human Body Finite Element Model Under Blast Loadings

2012 ◽  
Author(s):  
X. G. Tan ◽  
R. Kannan ◽  
Andrzej J. Przekwas
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Human Body ◽  
Material Properties ◽  
Complex Geometry ◽  
Blast Loading ◽  
Element Model ◽  
Stress Wave Propagation ◽  
Brain Response ◽  
Time Step

Until today the modeling of human body biomechanics poses many great challenges because of the complex geometry and the substantial heterogeneity of human body. We developed a detailed human body finite element model in which the human body is represented realistically in both the geometry and the material properties. The model includes the detailed head (face, skull, brain, and spinal cord), the skeleton, and air cavities (including the lung). Hence it can be used to accurately acquire the stress wave propagation in the human body under various loading conditions. The blast loading on the human surface was generated from the simulated C4 blast explosions, via a novel combination of 1-D and 3-D numerical formulations. We used the explicit finite element solver in the multi-physics code CoBi for the human body biomechanics. This is capable of solving the resulting large system containing millions of unknowns in an extremely scalable fashion. The meshes generated for these simulations are of good quality. This enables us to employ relatively large time step sizes, without resorting to the artificial time scaling treatment. In order to study the human body dynamic response under the blast loading, we also developed an interface to apply the blast pressure loading on the external human body surface. These newly developed models were used to conduct parametric simulations to find out the brain biomechanical response when the blasts impact the human body. Under the same blast loading we also show the differences of brain response when having different material properties for the skeleton, the existence of other body parts such as torso.

scholarly journals Analysis of Stationary Random Responses for Non-Parametric Probabilistic Systems

2010 ◽  
Vol 17 (3) ◽  
pp. 305-315 ◽  
Author(s):  
Y. Zhao ◽  
Y.H. Zhang ◽  
J.H. Lin ◽  
W.P. Howson ◽  
F.W. Williams
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Element Model ◽  
Physical Structure ◽  
Dynamic Responses ◽  
Response Analysis ◽  
Random Matrix Model ◽  
Stiffness Matrices ◽  
Element Technique ◽  
Non Parametric

The move from conceptual design, through fabrication to observation and measurement on the resulting physical structure is fraught with uncertainty. This, together with the necessary simplifications inherent when using the finite element technique, makes the development of a predictive model for the physical structure sufficiently approximate that the use of random structural models is often to be preferred. In this paper, the random uncertainties of the mass, damping and stiffness matrices in a finite element model are replaced by random matrices, and a highly efficient pseudo excitation method for the dynamic response analysis of non-parametric probability systems subjected to stationary random loads is developed. A numerical example shows that the dynamic responses calculated using a conventional (mean) finite element model may be quite different from those based on a random matrix model. For precise fabrication, the uncertainties of models cannot be ignored and the proposed method should be useful in the analysis of such problems.

Chest Deflection vs. Chest Acceleration as Injury Indicator in Front Impact Simulations Using Full Human Body Finite Element Model

2009 ◽  
Author(s):  
Raed E. El-Jawahri ◽  
Jesse S. Ruan ◽  
Stephen W. Rouhana ◽  
Saeed D. Barbat
Keyword(s):  
Finite Element ◽  
Plastic Strain ◽  
Finite Element Model ◽  
Human Body ◽  
Element Model ◽  
Von Mises Stress ◽  
Head Acceleration ◽  
Blunt Impact ◽  
Von Mises ◽  
Impact Simulations

The Ford Motor Company Human Body Finite Element Model (FHBM) was validated against rib dynamic tension and 3-point bending tests. The stress-strain and moment-strain data from the tension and bending simulations respectively were compared with human rib specimen test data. The model used represented a 50th percentile adult male. It was used to compare chest deflection and chest acceleration as thoracic injury indicator in blunt impact and belted occupants in front sled impact simulations. A 150 mm diameter of 23.4 kg impactor was used in the blunt impact simulations with impact speeds of 2, 4, and 8 m/s. In the Front sled impact simulations, single-step acceleration pulses with peaks of 10, 20, and 30 g were used. The occupants were restrained by 3-point belt system, however neither pretensioner nor shoulder belt force limiter were used. The external force, head acceleration, chest deflection, chest acceleration, and the maximum values of Von Mises stress and plastic strain were the model outputs. The results showed that the external contact force, head acceleration, chest deflection, and chest acceleration in the blunt impact simulations varied between 1.5–7 kN, 5–28 g, 18–80 mm, and 8–40 g respectively. The same responses varied between 7–24 kN, 13–40 g, 15–50 mm, and 16–46 g respectively in the front sled impact simulations. The maximum Von Mises stress and plastic strain were 50–127 MPa, and 0.04–2% respectively in the blunt impact simulations and 72–134 MPa, and 0.13–3% respectively in the sled impact simulations.

scholarly journals Biomechanics Of Human Lumbar Spine (L3 To L5) With Degenerative Disc Disease Using Finite Element Model

2019 ◽  
Vol 8 (6) ◽  
pp. 4609-4614
Keyword(s):  
Finite Element ◽  
Lumbar Spine ◽  
Finite Element Model ◽  
Disc Degeneration ◽  
Human Body ◽  
Lumbar Disc ◽  
Element Model ◽  
Human Spine ◽  
Human Lumbar Spine ◽  
Normal Human

Human spine is one of the complex structure of the human body. It provides the link between upper and lower extremities of the human body. It is estimated that at least 30% of people in the middle age group from thirty to fifty years have some degree of disc degeneration. Disc degeneration disease can affect the quality of life and in certain individual it can cause severe chronic pain if left untreated. The low back pain associated with lumbar disc degeneration is usually generated from two causes which are abnormal motion instability and inflammation. Abnormal motion instability occurs when the annulus fibrosus are worn down and cannot absorb stress on the human spine effectively resulting in changes in movements along the vertebral segment. To understand lumbar disc problem, a thorough knowledge of the biomechanics of the normal human lumbar spine and a disc degenerated lumbar spine is of great importance. In this study, Computed tomography image of a 33 year old male is used. A three dimensional (3D) human lumbar spine (L3 to L5) is created and validated with literature. The finite element model was modified to degenerated disc and studied the biomechanics of the lumbar spine. Comparison of the biomechanics of normal human lumbar spine is done with the human lumbar spine with disc degeneration for different range of motion and different loads. The result shows that the pressure generated on degenerated disc is greater than normal disc. This work can be implemented and used for designing implants and also for intervertebral disc related analysis

Material Characterization for Dynamic Simulation of Non-Homogeneous Structural Members

2010 ◽  
Vol 449 ◽  
pp. 46-53
Author(s):  
J.A. Quintana-Rodríguez ◽  
J.F. Doyle ◽  
F.J. Carrión-Viramontes ◽  
Didier Samayoa-Ochoa ◽  
J. Alfredo López-López
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Dynamic Simulation ◽  
Structural Parameters ◽  
A Priori ◽  
Element Model ◽  
Dynamic Responses ◽  
Inertia Moment ◽  
Physical Density ◽  
Equivalent Properties

Generally, simulation of non-homogeneous materials requires a homogeneous representation with equivalent properties different from the constitutive elements. Determination of the equivalent properties for dynamic simulation is not always a direct and straightforward calculation, as they have to represent, not only the static reactions, but also the dynamic behavior, which depends on a more complex relation of the geometrical (area, inertia moment), mechanical (elastic modulus) and physical (density) properties. In this context, the Direct Sensitivity Method (DSM) is developed to calibrate structural parameters of a finite element model using a priori information with an inverse parameter identification scheme, where parameters are optimized through an error sensitivity function using experimental data with the dynamic responses of the model. Results demonstrate that parameters of materials can be calibrated efficiently from the DSM and that key aspects for this calibration are noise, sensitivity (structural and sensor), and the finite element model representation.

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