scholarly journals Finite Element Analysis of Nonlinear Bioheat Model in Skin Tissue Due to External Thermal Sources

Mathematics ◽  
2021 ◽  
Vol 9 (13) ◽  
pp. 1459
Author(s):  
Marin Marin ◽  
Aatef Hobiny ◽  
Ibrahim Abbas
Keyword(s):  
Finite Element ◽  
Thermal Power ◽  
Bioheat Transfer ◽  
Transfer Model ◽  
Bioheat Equation ◽  
Element Analysis ◽  
Various Boundary Conditions ◽  
Heating Source ◽  
Design Variables ◽  
Thermal Sources

In this work, numerical estimations of a nonlinear hyperbolic bioheat equation under various boundary conditions for medicinal treatments of tumor cells are constructed. The heating source components in a nonlinear hyperbolic bioheat transfer model, such as the rate of blood perfusions and the metabolic heating generations, are considered experimentally temperature-dependent functions. Due to the nonlinearity of the governing relations, the finite element method is adopted to solve such a problem. The results for temperature are presented graphically. Parametric analysis is then performed to identify an appropriate procedure to select significant design variables in order to yield further accuracy to achieve efficient thermal power in hyperthermia treatments.

Finite Element Modeling for Steel Cord Analysis in Radial Tires

2013 ◽  
Vol 41 (1) ◽  
pp. 60-79 ◽  
Author(s):  
Wei Yintao ◽  
Luo Yiwen ◽  
Miao Yiming ◽  
Chai Delong ◽  
Feng Xijin
Keyword(s):  
Finite Element ◽  
High Efficiency ◽  
Force Measurement ◽  
Three Dimensional ◽  
Local Stress ◽  
Tension Force ◽  
Center Line ◽  
Element Analysis ◽  
Design Variables ◽  
Steel Cord

ABSTRACT: This article focuses on steel cord deformation and force investigation within heavy-duty radial tires. Typical bending deformation and tension force distributions of steel reinforcement within a truck bus radial (TBR) tire have been obtained, and they provide useful input for the local scale modeling of the steel cord. The three-dimensional carpet plots of the cord force distribution within a TBR tire are presented. The carcass-bending curvature is derived from the deformation of the carcass center line. A high-efficiency modeling approach for layered multistrand cord structures has been developed that uses cord design variables such as lay angle, lay length, and radius of the strand center line as input. Several types of steel cord have been modeled using the developed method as an example. The pure tension for two cords and the combined tension bending under various loading conditions relevant to tire deformation have been simulated by a finite element analysis (FEA). Good agreement has been found between experimental and FEA-determined tension force-displacement curves, and the characteristic structural and plastic deformation phases have been revealed by the FE simulation. Furthermore, some interesting local stress and deformation patterns under combined tension and bending are found that have not been previously reported. In addition, an experimental cord force measurement approach is included in this article.

Probabilistic finite element analysis in heat transfer to a nuclear fuel rod bumper support

2004 ◽  
Vol 218 (12) ◽  
pp. 1499-1505
Author(s):  
Rama Subba Reddy Gorla
Keyword(s):  
Heat Transfer ◽  
Finite Element ◽  
Nuclear Fuel ◽  
Cost Effective ◽  
Distribution Functions ◽  
Cumulative Distribution ◽  
Element Analysis ◽  
Transfer Rates ◽  
Fuel Rod ◽  
Design Variables

Heat transfer from a nuclear fuel rod bumper support was computationally simulated by a finite element method and probabilistically evaluated in view of the several uncertainties in the performance parameters. Cumulative distribution functions and sensitivity factors were computed for overall heat transfer rates due to the thermodynamic random variables. These results can be used to identify quickly the most critical design variables in order to optimize the design and to make it cost effective. The analysis leads to the selection of the appropriate measurements to be used in heat transfer and to the identification of both the most critical measurements and the parameters.

Enhanced Vibration Control of Ultrasonic Tooling Using Finite Element Analysis

1991 ◽  
Author(s):  
Kevin O’Shea
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Cross Sections ◽  
High Frequency ◽  
Excellent Correlation ◽  
Accurate Identification ◽  
Element Analysis ◽  
Optimum Configuration ◽  
Slot Length ◽  
Design Variables

Abstract The use of finite element analysis (FEA) in high frequency (20–40 kHz), high power ultrasonics to date has been limited. Of paramount importance to the performance of ultrasonic tooling (horns) is the accurate identification of pertinent modeshapes and frequencies. Ideally, the ultrasonic horn will vibrate in a purely axial mode with a uniform amplitude of vibration. However, spurious resonances can couple with this fundamental resonance and alter the axial vibration. This effect becomes more pronounced for ultrasonic tools with larger cross-sections. The current study examines a 4.5″ × 6″ cross-section titanium horn which is designed to resonate axially at 20 kHz. Modeshapes and frequencies from 17–23 kHz are examined experimentally and using finite element analysis. The effect of design variables — slot length, slot width, and number of slots — on modeshapes and frequency spacing is shown. An optimum configuration based on the finite element results is prescribed. The computed results are compared with actual prototype data. Excellent correlation between analytical and experimental data is found.

Evaluation and Repair of Cracks on Statically Loaded Beams Using Piezoelectric Actuation

2021 ◽  
Vol 11 (1) ◽  
pp. 34-49
Author(s):  
Goutam Roy ◽  
Brajesh Kumar Panigrahi ◽  
Goutam Pohit
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Ritz Method ◽  
Actuation Voltage ◽  
Piezoelectric Actuation ◽  
Cracked Beam ◽  
Element Analysis ◽  
Various Boundary Conditions ◽  
Piezoelectric Patch ◽  
Loading Patterns

In the present work, damage produced by a crack in a statically loaded beam is first evaluated. Subsequently, an attempt is made to repair the effect of the crack by attaching a piezoelectric patch to the beam as an actuator. Static analysis of PZT patched cracked beam along with rotational spring is performed using Ritz method. Subsequently, a finite element analysis is performed by using ABAQUS 6.12 to collate the analytical results. It is shown in the study that when PZT patch is subjected to external electric field, it yields a local reactive moment, which counters the crack effects. An equation is procured in order to compute the required actuation voltage for repairing of cracks. A parametric study is performed for various boundary conditions and loading patterns. It is distinctly noticed that the technique nullifies the discontinuity in slope curve which develops due to a crack.

Development and Analysis for a New Compliant XY Micropositioning Stage Applied for Nanoindentation Tester System

2019 ◽  
Vol 894 ◽  
pp. 60-71
Author(s):  
Minh Phung Dang ◽  
Thanh Phong Dao ◽  
Hieu Giang Le ◽  
Ngoc Thoai Tran
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Taguchi Method ◽  
Optimization Problems ◽  
High Reliability ◽  
Hybrid Approach ◽  
Element Analysis ◽  
Amplification Ratio ◽  
Design Variables ◽  
The Finite Element Analysis

A Compliant XY micropositioning stage is purported for situating a material sample in nanoindentation tester process. This paper aims to develop, analyze and optimize a XY compliant micropositioning stage. The working stroke of proposed XY stage is amplified by combining the four-lever and a bridge amplification mechanism. To enhance the performances of the stage, the main geometric parameters are optimized by an integration method of Taguchi method, response surface method (RSM) and genetic algorithm (GA). Firstly, static analysis and dynamic analysis are conducted by the finite element analysis in order to predict initial performances of the XY stage. Secondly, the number of experiments and the data are retrieved by combination of the finite element analysis-integrated Taguchi method. Thirdly, the effects of main design variables on the output response sensitivity are considered. Later on, mathematical model for the amplification ratio was established by the RSM. Finally, based on the mathematical equation, the GA is adopted to define the optimal design variables. The results of numerical validations are in a good agreement with the predicted results. The results depicted that the proposed hybrid approach ensures a high reliability for engineering optimization problems.

The Main Effect of Design Variables for a Safety Valve on a Fracture Pressure

2007 ◽  
Vol 345-346 ◽  
pp. 1581-1584
Author(s):  
Sang Woo Lee ◽  
Dae Young Shin ◽  
Kyoung Jin Chun
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Thin Plate ◽  
Safety Valve ◽  
Analysis Method ◽  
Element Analysis ◽  
Finite Element Analysis Method ◽  
Fracture Pressure ◽  
Design Variables ◽  
Circular Thin Plate

The safety valve has been designed to protect high pressure vessels. A fracture plate made of a circular thin plate is located within the safety valve. The circular thin plate has an outlet for fluid release and to help decrease the pressure. As such, fracture of the circular thin plate can occur at the appointed pressure. In this study, design variables of the safety valve were used to control fracture pressure so that it was easy to apply in the development of a new model of a safety valve. Design variables were fluid diameter of the safety valve, thickness of the fracture plate, filet radius of the clamping bolt, fracture pressure, and clamped torque of the clamping bolt. Design variables were selected, since the fracture experiment indicated that these variables might play a critical role in the fracture of the circular thin plate. Fracture pressure was calculated by the finite element analysis method and analyzed to affect the design variables on the fracture pressure. Using regression analysis, main design variables such as the fluid diameter, the thickness and the fillet were selected and the relationships of the variables were expressed by a regression equation. Furthermore, finite element analysis method and the regression equation were verified comparing with the experiment result.

Design of composite helicopter rotor blades to meet given cross-sectional properties

2005 ◽  
Vol 109 (1100) ◽  
pp. 471-475 ◽  
Author(s):  
S. L. Lemanski ◽  
P. M. Weaver ◽  
G. F. J. Hill
Keyword(s):  
Finite Element ◽  
Objective Function ◽  
Helicopter Rotor ◽  
Design Parameters ◽  
Stochastic Methods ◽  
Element Analysis ◽  
Cross Sectional ◽  
Design Variables ◽  
Non Linear ◽  
Optimisation Methods

Abstract This paper examines the design of a composite helicopter rotor blade to meet given cross-sectional properties. As with many real-world problems, the choice of objective and design variables can lead to a problem with a non-linear and/or non-convex objective function, which would require the use of stochastic optimisation methods to find an optimum. Since the objective function is evaluated from the results of a finite element analysis of the cross section, the computational expense of using stochastic methods would be prohibitive. It is shown that by choosing appropriate simplified design variables, the problem becomes convex with respect to those design variables. This allows deterministic optimisation methods to be used, which is considerably more computationally efficient than stochastic methods. It is also shown that the design variables can be chosen such that the response of each individual cross-sectional property can be closely modelled by a linear approximation, even though the response of a single objective function to many design parameters is non-linear. The design problem may therefore be reformulated into a number of simultaneous linear equations that are easily solved by matrix methods, thus allowing an optimum to be located with the minimum number of computationally expensive finite element analyses.

scholarly journals A Comprehensive Thermal and Structural Transient Analysis of a Boiler’s Steam Outlet Header by Means of a Dedicated Algorithm and FEM Simulation

Energies ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 111 ◽  
Author(s):  
Marcin Pilarczyk ◽  
Bohdan Węglowski ◽  
Lars O. Nord
Keyword(s):  
Finite Element ◽  
Power Unit ◽  
Thermal Power ◽  
High Capacity ◽  
Fem Simulation ◽  
Temperature Fields ◽  
Transient Temperature ◽  
Element Analysis ◽  
Start Up

Increasing the share of renewables in energy markets influences the daily operation of thermal power units. High capacity power units are more frequently operated to balance power grids and, thus, steam boilers are exposed to unfavorable transient states. The aim of this work was to perform thermal and structural analyses of a boiler’s outlet steam header, with a capacity of 650∙103 kg/h (180 kg/s) of live steam. Based on the measured steam pressure and temperatures on the outer surface of the component, transient temperature fields were determined by means of an algorithm that allows determination of transient stress distributions on the internal and external surfaces, as well as at stress concentration regions. In parallel, a finite element method simulation was performed. A comparison of the obtained results to a finite element analysis showed satisfactory agreement. The analyses showed that the start-up time could be reduced because the total stress did not exceed the allowed values during the regular start-up of the analyzed power unit. The algorithm was efficient and easy to implement in the real control systems of the power units. The numerical approach employed in the presented algorithm also allowed for determination of the time- and place-dependent heating rate value, which can be used as input data for the control system of the power unit.

Effect of Cenosphere Addition on Mechanical Properties of Bamboo and E-Glass Fiber Reinforced Epoxy Hybrid Composites

2020 ◽  
Vol 12 (4) ◽  
Author(s):  
B.K. Venkatesh ◽  
R. Saravanan
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Glass Fiber ◽  
Hybrid Composite ◽  
Power Plants ◽  
Hybrid Composites ◽  
Thermal Power ◽  
Element Analysis ◽  
Weight Percentage ◽  
Experimental Values

Cenosphere is a ceramic-rich industrial waste produced during burning of coal in the thermal power plants. This study deals with the effect of cenosphere as particulate filler on mechanical behaviour of woven bamboo-glass hybrid composites. The hybrid composite consists of bamboo and E-glass fiber as reinforcement and epoxy as matrix. Cenosphere of different weight percentage (0.5, 1, 1.5 and 2 %) was added to the hybrid composite. The samples were tested as per ASTM standards for their mechanical properties to establish the effect of filler content. It is found that the mechanical properties are significantly influenced by addition of waste ceramic filler cenosphere up to 2 wt.% and increases the tensile, flexural and inter-laminar shear strength in comparison to unfilled composite. Finite element analysis is also done using Midas NFX and the simulation results are compared with experimental results. From the results, it has been found that the experimental values obtained from tensile testing and flexure testing nearly matches with finite element values.

Stochastic Modeling and Analysis of a Heavy Duty Radiator

2020 ◽  
Vol 12 (3) ◽  
Author(s):  
V. Hariram ◽  
P. Robin Roy
Keyword(s):  
Finite Element ◽  
Stochastic Simulation ◽  
Stress Responses ◽  
Normal Distribution Function ◽  
Element Analysis ◽  
Joint Stress ◽  
Limit Values ◽  
Random Design ◽  
Monte Carlo Simulation Technique ◽  
Design Variables

Governmental agencies across the globe are constantly evolving with stringent emission laws to tackle the problem of CO2 and NOx/SOx emissions. New emission standards force the Truck OEM’s to redesign the engine. The paper is aimed to measure the header tube joint stress of the radiator subjected to random variations in geometry, shape and material properties. Linear analysis will not consider the uncertainty and randomness due to tolerance, process changes, part-part variation etc. Stochastic finite element analysis (FEA) is carried out to account the uncertainty in the system. The finite element model of radiator system is built and baseline linear simulation is performed to obtain the baseline deformation and baseline stress responses. Then the uncertainty and random variation due to the geometry, material and shape variable is defined by a normal distribution function. Random designs are generated by defining the upper and lower bound limit values for the input design variable. Random designs are populated using Monte-Carlo simulation technique. 250 random design points are created for each design variables. Then stochastic simulation is performed to evaluate the responses at random design points. Statistical and probabilistic tools are used to post process the simulation results. The paper showcases application of stochastic simulation method which aids in indentifying the robust design with minimum variations. This also enables engineers and designers to understand the relationship and significance between different design variables in designing energy efficient systems.

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