Tissue necrosis and passage of fluid due to cold stress from the thermally damaged human body peripherals: A mathematical model

2015 ◽  
Vol 04 (02) ◽  
pp. 1550012
Author(s):  
M. A. Khanday ◽  
Fida Hussain ◽  
Khalid Nazir
Keyword(s):  
Mathematical Model ◽  
Finite Element ◽  
Heat Equation ◽  
Cold Stress ◽  
Human Body ◽  
Human Subjects ◽  
Diffusion Equations ◽  
Tissue Necrosis ◽  
Cold Temperatures ◽  
Element Technique

The development of cold injury takes place in the human subjects by means of crystallization of tissues in the exposed regions at severe cold temperatures. The process together with the evaluation of the passage of fluid discharge from the necrotic regions with respect to various degrees of frostbites has been carried out by using variational finite element technique. The model is based on the Pennes' bio-heat equation and mass diffusion equations together with suitable initial and boundary conditions. The results are analyzed in relation with atmospheric temperatures and other parameters of the tissue medium.

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.

MATHEMATICAL MODEL FOR THE TRANSPORT OF OXYGEN IN THE LIVING TISSUE THROUGH CAPILLARY BED

2015 ◽  
Vol 15 (04) ◽  
pp. 1550055 ◽  
Author(s):  
M. A. KHANDAY ◽  
AIJAZ NAJAR
Keyword(s):  
Mathematical Model ◽  
Finite Element Method ◽  
Finite Element ◽  
Diffusion Equation ◽  
Oxygen Transport ◽  
Human Body ◽  
Oxygen Supply ◽  
Living Tissue ◽  
Capillary Bed ◽  
Living Tissues

Oxygen is essential for the survival of living tissues in the human body. The mechanism of oxygen transport in the human body is a subject of great concern. In the conditions like hypoxia and hypothermia, the amount of oxygen supply in the biological tissue loose homeostasis, thereby the concentration of O 2 and the liberation of CO 2 in the human body demands a special attention. The present study based on finite element method employed to the mass diffusion equation with suitable conditions has been established. The main objective of this work is to understand the behavior of O 2 through various compartments of the capillary bed. The concentration of O 2 at plasma and capillary layers has been estimated which in turn leads to understand the situation of oxygen transport during various situations.

A MATHEMATICAL MODEL FOR THE ESTIMATION OF THERMAL STRESS AND DEVELOPMENT OF COLD INJURIES ON THE EXPOSED ORGANS OF HUMAN BODY

2016 ◽  
Vol 16 (05) ◽  
pp. 1650062 ◽  
Author(s):  
M. A. KHANDAY ◽  
FIDA HUSSAIN ◽  
AIJAZ NAJAR ◽  
KHALID NAZIR
Keyword(s):  
Mathematical Model ◽  
Finite Element ◽  
Thermal Stress ◽  
Human Body ◽  
Thermal Damage ◽  
Cell Damage ◽  
Bioheat Equation ◽  
Peripheral Tissues ◽  
Thermoregulatory System ◽  
Extreme Cold

The severe ambient temperature always disrupts the normal thermoregulatory system of the human body. The decrease in core temperature leads to hypothermia and the development of cold injuries takes place at the exposed shells of the human body. The intensity of the cold exposure and its duration leads to various degrees of frostbites and resulting cell damage and fluid passage from the necrotic regions. In this paper, variational finite element has been employed to estimate the thermal damage due to severe cold conditions. The formulation of the model is based on Pennes’ bioheat equation and mass diffusion equation. Moreover, the fluid passage from the cold injuries at the peripheral tissues of the human body with respect to extreme cold conditions has been analyzed in relation with other parameters.

An Eight-Node Hexahedral Finite Element with Rotational DOFs for Elastoplastic Applications

2019 ◽  
Vol 11 (1) ◽  
pp. 54-66
Author(s):  
Ayoub Ayadi ◽  
Kamel Meftah ◽  
Lakhdar Sedira ◽  
Hossam Djahara
Keyword(s):  
Mathematical Model ◽  
Finite Element ◽  
Plastic Zone ◽  
Displacement Vector ◽  
Small Strain ◽  
Benchmark Problems ◽  
Plasticity Model ◽  
Vector Approximation ◽  
Calculation Code

Abstract In this paper, the earlier formulation of the eight-node hexahedral SFR8 element is extended in order to analyze material nonlinearities. This element stems from the so-called Space Fiber Rotation (SFR) concept which considers virtual rotations of a nodal fiber within the element that enhances the displacement vector approximation. The resulting mathematical model of the proposed SFR8 element and the classical associative plasticity model are implemented into a Fortran calculation code to account for small strain elastoplastic problems. The performance of this element is assessed by means of a set of nonlinear benchmark problems in which the development of the plastic zone has been investigated. The accuracy of the obtained results is principally evaluated with some reference solutions.

Modal Analysis of the Axial Compressor Blade: Advanced Time-Dependent Electronic Interferometry and Finite Element Method

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Mykhaylo Tkach ◽  
Serhii Morhun ◽  
Yuri Zolotoy ◽  
Irina Zhuk
Keyword(s):  
Experimental Data ◽  
Mathematical Model ◽  
Finite Element ◽  
High Reliability ◽  
Axial Compressor ◽  
Time Dependent ◽  
Experimental Setup ◽  
Vibration Modes ◽  
Compressor Blades ◽  
Isoparametric Finite Element

AbstractNatural frequencies and vibration modes of axial compressor blades are investigated. A refined mathematical model based on the usage of an eight-nodal curvilinear isoparametric finite element was applied. The verification of the model is carried out by finding the frequencies and vibration modes of a smooth cylindrical shell and comparing them with experimental data. A high-precision experimental setup based on an advanced method of time-dependent electronic interferometry was developed for this aim. Thus, the objective of the study is to verify the adequacy of the refined mathematical model by means of the advanced time-dependent electronic interferometry experimental method. The divergence of the results of frequency measurements between numerical calculations and experimental data does not exceed 5 % that indicates the adequacy and high reliability of the developed mathematical model. The developed mathematical model and experimental setup can be used later in the study of blades with more complex geometric and strength characteristics or in cases when the real boundary conditions or mechanical characteristics of material are uncertain.

2-D electromagnetic modeling by finite‐element method with a dipole source and topography

Geophysics ◽  
2000 ◽  
Vol 65 (2) ◽  
pp. 465-475 ◽  
Author(s):  
Yuji Mitsuhata
Keyword(s):  
Finite Element ◽  
Delta Function ◽  
Dipole Source ◽  
Electromagnetic Modeling ◽  
Secondary Field ◽  
Controlled Source ◽  
Transient Electromagnetic ◽  
Isoparametric Finite Element ◽  
Anomalous Bodies ◽  
Element Technique

I present a method for calculating frequency‐domain electromagnetic responses caused by a dipole source over a 2-D structure. In modeling controlled‐source electromagnetic data, it is usual to separate the electromagnetic field into a primary (background) and a secondary (scattered) field to avoid a source singularity, and only the secondary field caused by anomalous bodies is computed numerically. However, this conventional scheme is not effective for complex structures lacking a simple background structure. The present modeling method uses a pseudo‐delta function to distribute the dipole source current, and does not need the separation of the primary and the secondary field. In addition, the method employs an isoparametric finite‐element technique to represent realistic topography. Numerical experiments are used to validate the code. Finally, a simulation of a source overprint effect and the response of topography for the long‐offset transient electromagnetic and the controlled‐source magnetotelluric measurements is presented.

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