University of Tehran
Journal of Computational Applied Mechanics
2423-6713
2423-6705
52
4
2021
12
01
Contact mechanics of human knee joint: Analytical approach
553
569
EN
SACHIN
KHOT
0000-0002-7883-7674
School of Mechanical Engineering KLE Technological University
BVB Campus, Vidyanagar Hubballi
sachin.khot@kletech.ac.in
Ravi
Guttal
0000-0002-4373-8852
KLE technological university Hubballi
Vidyanagar Hubballi
ravi_g@kletech.ac.in
10.22059/jcamech.2021.326466.633
A new methodology for modeling tibio-femoral articular contact of a knee joint based on contact models of the classical contact mechanics is established. The given analytical models of articular contact are extended to the case of contact between low strain arbitrary linear elastic tissues, i.e., cartilages and meniscus. The approach uses the geometries of contact surfaces and the generalization of the Hertzian contact theory of non-conforming bodies with frictionless contact interaction between elastic articular tissues. The normal and tangential contact displacements are determined analytically based on the exact solutions for the spherical contact between the articular tissues of the knee. The non-linear stiffness (secant and tangential stiffness) of the knee joint’s elastic half-space is derived using the analytical relationships. The method is demonstrated by exploring a case study, and the results are compared with the current literature to verify the fidelity of the proposed analytical approach. The analytical models facilitate accurate contact mechanics of the knee joint. Researchers may now use these analytical models to develop knee surrogate models in multibody dynamics.
Knee joint slip,knee joint displacement,stick-slip zones,non-linear stiffness,geometric nonlinearities
https://jcamech.ut.ac.ir/article_85248.html
https://jcamech.ut.ac.ir/article_85248_300d74809cccad78fe735477204b2017.pdf
University of Tehran
Journal of Computational Applied Mechanics
2423-6713
2423-6705
52
4
2021
12
01
Analytical solution of pulsating flow and forced convection heat transfer in a pipe filled with porous medium
570
587
EN
Fatemeh
Sobhnamayan
Department of Mechanical Engineering, University of Sistan and Baluchestan, Zahedan, Iran
fsobhenamayan@yahoo.com
Faramarz
Sarhaddi
Department of Mechanical Engineering, University of Sistan and Baluchestan, Zahedan, Iran
fsarhaddi@eng.usb.ac.ir
Amin
Behzadmehr
Department of Mechanical Engineering, University of Sistan and Baluchestan, Zahedan, Iran
abehzadmehr@eng.usb.ac.ir
10.22059/jcamech.2021.327163.638
In this paper, the pulsating flow and forced convection heat transfer in a pipe filled with porous medium is investigated. The pipe is under a constant heat flux. The governing equations of the problem includes continuity, Brinkman momentum equation and energy equation. Using complex analysis technique, an analytical solution for velocity profile and temperature distribution are obtained. Also, the effect of various design parameters on velocity profile and temperature distribution is studied. Results show that the pulsating effect on velocity and temperature profile increases with the increase of Darcy number and dimensionless amplitude of pressure gradient but decreases with the increase of viscosity ratio parameter, Prandtl number and dimensionless frequency. For high dimensionless frequency (Ω>30), the maximum velocity and temperature tend to be constant due to the decrease in wave amplitude.
Pulsating flow,Circular pipe,Porous medium,Forced convection
https://jcamech.ut.ac.ir/article_85249.html
https://jcamech.ut.ac.ir/article_85249_293c5dbecbedf3f302cc22c88433633b.pdf
University of Tehran
Journal of Computational Applied Mechanics
2423-6713
2423-6705
52
4
2021
12
01
CLOSED FORM SOLUTIONS OF THE NAVIER'S EQUATIONS FOR AXISYMMETRIC ELASTICITY PROBLEMS OF THE ELASTIC HALF-SPACE
588
618
EN
Charles
Chinwuba
Ike
0000-0001-6952-0993
Dept of Civil Engineering, Enugu State University of Science and Technology,
Enugu State, Nigeria
ikecc2007@yahoo.com
10.22059/jcamech.2021.329433.646
Closed form solutions are derived in this paper for Navier’s equations for axisymmetric elastic half-space problems. They are solved assuming body forces are disregarded. The Boussinesq problem is considered. The displacements are used to obtain the stress fields. The shear stress-free boundary conditions on the boundary plane and the equilibrium of vertical stress and applied load are used to completely determine displacements and stresses. Other axisymmetric load problems considered are: (i) uniform (ii) conical (iii) inverted conical distributions. In each case, the Boussinesq solution is used as a Green function, yielding the vertical stress field as double integration problem. The vertical stress field for uniform load is obtained in terms of complete elliptic integrals of the second and third kinds. The vertical stress distribution under the center of a circular foundation under uniform load is obtained as a particularization of the solution for vertical stress at any point in the elastic half-space. The same result is derived by using the point load solution as an integral Kernel function. For conical distribution of load, the point load solution is used as a Green function, reducing the problem to double integration. The closed form expressions obtained for the vertical stress distributions under the center of the circular foundation for all the axisymmetrical load distributions considered are radially symmetrical functions; which agree with the symmetrical nature of the problem. The results obtained for all the load types considered are identical with previous results found in the literature.
Navier's differential equations of equilibrium,Axisymmetric elasticity problem,Classical Boussinesq problem,Elastic Half-Space
https://jcamech.ut.ac.ir/article_85250.html
https://jcamech.ut.ac.ir/article_85250_7320520f89583cb5673ca780305f4c59.pdf
University of Tehran
Journal of Computational Applied Mechanics
2423-6713
2423-6705
52
4
2021
12
01
Implementation of Behavior-Based Navigation Algorithm on Four-Wheel Steering Mobile Robot
619
641
EN
Behzad
Saeedi
0000-0002-3244-1121
Mechatronics Laboratory, Department of Mechanical Engineering, Tarbiat Modares University, Tehran, Iran
behzadsaeedi@modares.ac.ir
Majid
Sadedel
0000-0002-0285-8460
Assistant Professor, Department of Mechanical Engineering, Tarbiat Modares University, Tehran, Iran.
majid.sadedel@modares.ac.ir
10.22059/jcamech.2021.330072.648
In recent years, wheeled autonomous mobile robots have become widely used in a number of industrial applications. Therefore, accurate and efficient controllers are required in order to assure safe and accurate navigation of these vehicles. In this study, an effective behavior-based navigation algorithm (BBNA) is applied to control the trajectory of the four-wheel steering (FWS) mobile robot. The BBNA combines the ‘Goal-to-Goal’ and ‘Obstacle Avoidance’ behaviors into one comprehensive navigation strategy. With this algorithm, many switching between modes occurs over a short amount of time, which increases the risk of creating the chattering phenomenon. Due to overcoming this phenomenon, an additional mode is considered between the ‘Go-to-Goal’ and ‘Obstacle Avoidance’ modes that is called ‘Follow-Wall’ behavior. At first, the BBNA was designed to control the navigation of a point mass robot. One of the significant characteristics of BBNA is that its control commands can be used to calculate the linear and angular velocity of a unicycle mobile robot. Thus, the BBNA can navigate the unicycle mobile robot successfully to the goal position. In order to apply the BBNA to an FWS mobile robot, its dynamic equations must be converted to those of a unicycle mobile robot. The present study determines the dynamic equations of the FWS mobile robot by using the Ackermann- Jeantnat model of steering. Since these equations are the same as those for the unicycle mobile robot, the FWS mobile robot can be controlled by the BBNA. Finally, the implementation of the BBNA for the FWS mobile robot is simulated using MATLAB software. Simulated results indicate that BBNA generates an optimal path by perfectly switching between ‘Go to Goal’, ‘Obstacle Avoidance’, and ‘Follow Wall’ modes, which keeps the FWS mobile robot arriving at the goal position.
Four-Wheel Steering Mobile Robot,Navigation Algorithm,Unicycle Mobile Robot,Behavior-Based Control
https://jcamech.ut.ac.ir/article_85251.html
https://jcamech.ut.ac.ir/article_85251_b63c1592eb4e9437e8e64e7a8e327f9d.pdf
University of Tehran
Journal of Computational Applied Mechanics
2423-6713
2423-6705
52
4
2021
12
01
Nonlinear coupled torsional-radial vibration of single-walled carbon nanotubes using numerical methods
642
663
EN
Mohammad Reza
Ebrahimian
Faculty of Mechanical Engineering, Kar Higher Education Institute, Qazvin, Iran
ebrahimian.reza@gmail.com
zahra
azimzadeh
Department of Mathematics, Yadegar-e-Imam Khomeini (RAH) Shahre Rey Branch, Islamic Azad University, Tehran, Iran
z.azimzadeh@yahoo.com
Alireza
Fatahi-Vajari
Department of Mechanical Engineering, Shahryar Branch, Islamic Azad University, Shahryar, Iran
afatahiva@yahoo.com
Mojtaba
Shariati
Department of Mechanical Engoneering, Shahid Chamran University of Ahwaz, Ahwaz, Iran
mojtaba.shariati456@gmail.com
10.22059/jcamech.2021.333435.661
This paper analyzes the nonlinear coupled torsional-radial vibration of single-walled carbon nanotubes (SWCNTs) based on numerical methods. Two partial differential equations that govern the nonlinear coupled torsional-radial vibration for such nanotube are derived using doublet mechanics (DM) principles. First, these equations are reduced to ordinary differential equations using Galerkin method and then solved using homotopy perturbation method (HPM) to obtain the nonlinear natural frequencies in coupled torsional-radial vibration mode. It is found that the obtained frequencies are complicated due to coupling between two vibration modes. The dependence of boundary conditions, vibration modes and nanotubes geometry on the nonlinear coupled torsional-radial vibration characteristics of SWCNTs are studied in details. It was shown that boundary conditions and maximum vibration velocity have significant effects on the nonlinear coupled torsional-radial vibration response of SWCNTs. It was also seen that unlike the linear model, as the maximum vibration velocity increases, the natural frequencies of vibration increase too. To show the effectiveness and ability of this method, the results obtained with the present method are compared with the fourth order Runge-Kuta numerical results and good agreement is observed. To the knowledge of authors, the results given herein are new and can be used as a basic work for future papers.
Homotopy Perturbation Method,nonlinear coupled torsional-radial vibration,single-walled carbon nano-tubes,natural frequency
https://jcamech.ut.ac.ir/article_85253.html
https://jcamech.ut.ac.ir/article_85253_3a30a1a2a792dc0d97d4614d996ea3d7.pdf
University of Tehran
Journal of Computational Applied Mechanics
2423-6713
2423-6705
52
4
2021
12
01
Analyses of entropy generation for a solar minichannel flat plate collector system using different types of nanofluids
664
681
EN
Lakhdar
Bouragbi
Mechanical Laboratory of Materials and Industrial Maintenance (LR3MI), Badji Mokhtar University, Annaba, Algeria
bouragbilakhdar@gmail.com
AZZOUZ
SALAHEDDINE
Mechanical Laboratory of Materials and Industrial Maintenance (LR3MI), Badji Mokhtar University, Annaba, Algeria
azzouzsalah@yahoo.fr
BRAHIM
MAHFOUD
0000-0002-0709-8958
Departement of mechanical, University of BOUIRA, Algeria
mahfoud.mah@gmail.com
10.22059/jcamech.2021.333705.662
The working fluid plays a major role in improving the efficiency of the energy system, so the method and criteria of choice are extremely important. Nevertheless, these methods are usually based on the First Law of Thermodynamics (FLT), while the concepts of entropy and irreversibility on which the Second Law of Thermodynamics (SLT) is based are often ignored in the choice of the fluid. In this paper, a new approach is proposed to select a fluid among a group of fluids in order to use it as a working fluid in a Minichannel Flat Plate Solar Collector (MFPSC). For this, a numerical simulation was performed on a fluid in laminar flow in a small rectangular channel subjected to a uniform heat flux of (1000 W/m2). The use of Computational Fluid Dynamics (CFD) based on the finite volume method was implemented to solve the governing equations. The essential parameters on which the selection is based are the entropy generation (Sgen), the irreversibility of entropy generation number (Ns), the Bejan number (Be), and the Energy Performance Criterion (EPC). The analyses were performed on a group of five fluids two conventional (water and methanol), the rest are nanofluids (Al2O3-H2O, CuO-H2O, and Fe3O4 -H2O). Multiple parallel-computation phases are defined by user-defined functions (UDFs) for all fluids. It is found that nanofluids offer higher heat transfer ability than conventional fluids, and the behavior of the nanofluid (CuO-H2O) shows on average a minimum total entropy generation (minimum irreversibility) compared to other fluids (conventional and nanofluids), which reduces the energy degradation and improves the heat transfer. Therefore, it is chosen as the working fluid for the MFPSC.
Collector, entropy generation,Irreversibility,minichannel, nanofluid
https://jcamech.ut.ac.ir/article_85254.html
https://jcamech.ut.ac.ir/article_85254_ba6abec79e6e85c66d2fc4dacd4226df.pdf
University of Tehran
Journal of Computational Applied Mechanics
2423-6713
2423-6705
52
4
2021
12
01
THE RADIAL POINT INTERPOLATION METHOD IN THE BENDING ANALYSIS OF SYMMETRIC LAMINATES USING HSDTS
682
716
EN
Daniel
Rodrigues
0000-0003-1101-9391
INEGI – Institute of Science and Innovation in Mechanical and Industrial Engineering
drodrigues@inegi.up.pt
Jorge
Belinha
0000-0002-0539-7057
School of Engineering, Polytechnic of Porto (ISEP)
job@isep.ipp.pt
Renato
Natal Jorge
0000-0002-7281-579X
Faculty of Engineering, University of Porto (FEUP), Department of Mechanical Engineering
rnatal@fe.up.pt
10.22059/jcamech.2021.323598.616
The bending analysis of composite structures is usually performed using the Finite Element Method (FEM), which is also used in many fields of engineering. However, other efficient, accurate, and robust numerical methods can be alternatives to FEM’s widespread use. This work focus on a meshless discretization technique - the Radial Point Interpolation Method (RPIM) – which only requires an unstructured nodal distribution to discretize the problem domain. The numerical integration of the Galerkin weak form governing the plate’s bending problem is performed using a background integration mesh. The nodal connectivity is enforced using the ‘influence-domain’ concept which is based on a radial search of nodes closer to an integration point. Thus, in this work, the RPIM is used to analyse the bending behaviour of symmetric cross-ply composite laminated plates using equivalent single layer (ESL) formulations, following different transverse high-order shear deformation theories (HSDTs). Varying the plate’s geometry and stacking sequences, the applied loads, or the plate model, several composite laminated plates are analysed. In the end, the meshless solutions are compared with analytical solutions available in the literature. The accuracy of the meshless approach is proved and several new numerical solutions for the bending of symmetric laminates are proposed.
Symmetric Laminated Plates,High-Order Shear Deformation Theories,Meshless method,Radial Point Interpolation Method (RPIM)
https://jcamech.ut.ac.ir/article_85268.html
https://jcamech.ut.ac.ir/article_85268_50ec865acfe40703b8375c63d5fa8a86.pdf
University of Tehran
Journal of Computational Applied Mechanics
2423-6713
2423-6705
52
4
2021
12
01
Modeling and Optimizing Creep behavior of A356 Al Alloy in Presence of Nickel Using Response Surface Method
717
730
EN
shahrouz
yousefzadeh
Department of Mechanical Engineering, Aligudarz branch,
Islamic Azad University, Aligudarz , Iran
shahrouzyousefzadeh@gmail.com
Mohammad
Varmazyar
Department of Mechanical Engineering, Aligudarz branch,
Islamic Azad University, Aligudarz , Iran
varmazyar.mohammad@yahoo.com
Mohammad
Morad
Sheikhi
Faculty of Mechanical Engineering, Shahid Rajaee Teacher
Training University, Tehran , Iran
m.sheikhi@srttu.edu
10.22059/jcamech.2021.332426.656
The present paper aims to model the creep behavior of A356 Al alloy in the presence of different amounts of nickel and evaluate the microstructure of the alloys using optical microscope and scanning electron microscope (SEM). Creep properties of the alloys were obtained using the impression creep method by a cylindrical indenter within the stress range of 0.027<σ/G<0.030 at 473-513K. As indicated by the results, adding nickel to A356 alloy would result in eliminating the harmful phases of iron, modifying the morphology of α-Al dendrites, and creating new nickel-rich phases, besides improving the creep strength of the alloy. This is due to the formation of nickel-rich intermetallic compounds and prevention from the formation of iron-rich phases. By calculating the creep activation energy and stress power, it was found that the climb controlled dislocation creep in the dominant mechanism network in the creep deformation of A356 alloy was in the cast state and under the studied conditions. Also, nickel had no effect on the creep mechanism. Besides, the equation of the creep deformation of the alloys (the relationship between temperature, stress, and stable-state creep strain rate) was obtained. This equation can be used to predict the stable-state creep strain rate at certain temperature and stress for A356 alloy and nickel-containing alloys under climb controlled dislocation creep conditions.
Optimization,A356 alloy,nickel,Microstructure,Impression creep,Creep mechanism,Response surface
https://jcamech.ut.ac.ir/article_85269.html
https://jcamech.ut.ac.ir/article_85269_43b01ead99e754f7aebb0aa6a83f492f.pdf
University of Tehran
Journal of Computational Applied Mechanics
2423-6713
2423-6705
52
4
2021
12
01
A review on functionally graded porous structures reinforced by graphene platelets
731
750
EN
faraz
kiarasi
Lecturer, Faculty of Mechanical Engineering, University of Eyvanekey
faraz_kia@ymail.com
masoud
babaei
Lecturer, Faculty of Mechanical Engineering, University of Eyvanekey
masoudbabaei@eyc.ac.ir
Pouya
Sarvi
University of Eyvanekey
pouyasarvii64@yahoo.com
kamran
asemi
0000-0002-7182-634X
Mechanical Engineering Department, Islamic Azad University- Tehran North Branch
k.asemi@iau-tnb.ac.ir
mohammad
hosseini
0000-0001-8880-5695
Department of Mechanical Engineering, University of Hormozgan, Bandar Abbas, Iran
mohammad.hosseini@hormozgan.ac.ir
Mostafa
Omidi Bidgoli
Department of Mechanical Engineering, Islamic Azad University, Badroud branch, Badroud, Iran.
mostafaomidibidgoli@gmail.com
10.22059/jcamech.2021.335739.675
Nowadays, there is a high demand for great structural implementation and multifunctionality with excellent mechanical properties. The porous structures reinforced by graphene platelet (GPLs) having valuable properties, such as heat resistance, lightweight, and excellent energy absorption, have been considerably used in different engineering implementations. However, stiffness of porous structures reduces significantly, due to the internal cavities, by adding GPLs into porous medium, effective mechanical properties of porous structure considerably enhances. To boost the efficiency and capability of structures, functionally graded (FG) porous structures reinforced by GPLs have been suggested in the literature. Therefore, some researchers tried to figure out the fantastic characteristics of these structures and research activities in this emerging area have been rapidly increasing. The present paper (a) briefly reviews the mechanical properties of functionally graded porous composites reinforced by GPLs and discusses the existing micromechanics model for the prediction of effective mechanical properties; (b) presents a comprehensive review on the mechanical analyses of these structures; (c) discuses the challenges and possible future works.
Functionally Graded Materials,Graphene platelets,Composite structures,Mechanical analyses,Porous
https://jcamech.ut.ac.ir/article_85255.html
https://jcamech.ut.ac.ir/article_85255_6e0596c195d9a08da80b4bbe6ffade00.pdf
University of Tehran
Journal of Computational Applied Mechanics
2423-6713
2423-6705
52
4
2021
12
01
Physical and chemical properties of nano-liposome, application in nano medicine
751
767
EN
Vahid
Eskandari
Nanoscience and Nanotechnology Research Center, University of Kashan, Kashan, Iran
vahid.22345@gmail.com
Mohammadreza
Sadeghi
Institute of technology, University of Linköping, Linköping, Sweden
mohammadreza6546d89@gmail.com
Amin
Hadi
Cellular and Molecular Research Center, Yasuj University of Medical Sciences, Yasuj, Iran
amin.hadi@ut.ac.ir
10.22059/jcamech.2021.336004.677
The liposome is derived from two Greek roots: 'Lipo' meaning fat and 'Some' meaning structure. Liposomes can be made from natural phospholipids and cholesterol and, if necessary, other additives. Liposomes were first discovered by Bangham in 1961 due to their simple, self-fulfilling structure and low cost. Liposomes are spherical vesicles with a membrane composed of bilayer phospholipids that are used to release drugs or genetic material into the cell. Current research is focused on liposome technology based on the preparation and development of long-circulating liposomes, lipid components' changing, and vesicles' charge amount. Liposomes, in addition to pharmaceutical carriers, are used in cutaneous, respiratory, food industries, injectable, and in genetic engineering and diagnostic applications. This paper reviews the physical and chemical characteristics, structure, construction methods, and applications of nanoliposomes in various uses as drug carriers, including the treatment of specific diseases.
Nanoliposomes,Nanoliposomes fabrication methods,Nanoliposomes applications,Characteristics of nanoliposomes
https://jcamech.ut.ac.ir/article_85261.html
https://jcamech.ut.ac.ir/article_85261_63627ff69935dbf2b7f0b2bd1c266e4f.pdf