International Journal of Mechanics

ISSN: 1998-4448
Volume 14, 2020

Notice: As of 2014 and for the forthcoming years, the publication frequency/periodicity of NAUN Journals is adapted to the 'continuously updated' model. What this means is that instead of being separated into issues, new papers will be added on a continuous basis, allowing a more regular flow and shorter publication times. The papers will appear in reverse order, therefore the most recent one will be on top.

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Volume 14, 2020

Title of the Paper: Droplet Formation of an Anisotropic Liquid


Authors: A. Pezzutti, G. Araujo

Pages: 100-106


Abstract: The process of formation of new morphologies by confinement in nano-droplets, created from a dewetting process, was simulated. The obtained structures showed a great similarity with the experimental results present in the literature. The developed model captures the fundamental interactions that determine the dynamics of the phase separation process of a copolymer system confined between a rigid substrate and a free surface. Furthermore, its numerical resolution is highly efficient as a result of the implementation of Eyre algorithm.

Title of the Paper: Dynamic Time Analysis of Glass Fiber Reinforced Polymer – Numerical Simulation and Experiment


Authors: Zuzana MurĨinková

Pages: 94-99


Abstract: Composites are known for their significant damping, however, both reinforcement type or layered arrangement influence the response of material: mechanical, thermal, electrical etc. The paper provides the dynamic time analysis of glass fiber reinforced polymer samples of various layups. The mechanical response to dynamic excitation was tested by numerical simulation and experiment. The excitation function was the unit impulse force generating free damped vibrations. Experimental results were evaluated in time domain to obtain damping parameters. For numerical simulation, the commercial software was used to visualize deformed model in individual damping phases, Mises stress distribution in individual laminate layers, and comparison of that for different layups.

Title of the Paper: CAE Modeling Rubber-metal Body Mounting of the Body-on-frame Car in Crash Simulations


Authors: V.A. Tsittser, S.V. Alekseev, A.V. Tarasov, A.I. Borovkov

Pages: 88-93


Abstract: The aim of the study was to research the behavior of the rubber-metal body mounting under various modeling options and to select the optimal, from the point of view of ensuring the accuracy of the results in the crash tests simulations. Body supports provide a link between the body and the car frame, and this has a critical effect on the impact test results of the car. The article discusses various options for modeling the body mounting by the degree of simplification from the simplest model with a rigid connection between the body and the frame to the model that takes into account the non-linearity of the stiffness characteristics of the supports, contact interaction between parts of the mounting and its surrounding parts, tension of the supports and failure. The results of virtual tests of a car with various options for modeling mountings were compared with the results of real tests. As a result of the study, a methodology for modeling the body supports was developed, which allows providing the necessary measurement error in virtual crash test modeling.

Title of the Paper: Design of Estimator for Computing Yaw and Pitch for a Twin Rotor MIMO system


Authors: Santhosh K. V., Preeti Mohanty

Pages: 79-86


Abstract: Performance of any system is identified through the observation of significant system parameters. Required parameters have to be measured using suitable sensors. But in some scenarios, it is difficult to measure some of the parameters due to issues in the placement of sensors. In such cases, estimators are developed to measure the parameters indirectly. In this paper, an attempt is made to develop an estimator to monitor the value of pitch and yaw of a twin-rotor multi input multi output system. The observer is developed using two methods one using Luenberger’s equations and the other using an Artificial Neural Network (ANN). For training the neural network model, the backpropagation algorithm is used. Tests have been conducted to analyze and compare the behavior of both observers. From the results, it is evident that a Luenberger observer performs better when sufficient system information is available and ANN observer performs better when inadequate system information is available.

Title of the Paper: Analysis of the Spatial Behaviour of Masonry Bridges Via Hierarchical FEM Modelling: the Devil’s Bridge


Authors: I. Corbi, O. Corbi, F. Tropeano

Pages: 72-78

Abstract: The contribution of the fill to the global behavior of masonry vaulted bridges may be primarily significant. Nevertheless, ordinary analyses conducted on masonry bridges usually consider only the main structural vaulted elements. The paper reports some results obtained through a numerical simulation developed on a FEM model of an ancient bridge, the Devil’s bridge on Sele river at Barrizzo, in the Campania region. The study is aimed at showing how the fill may be contributing with a significant static action , changing the real carrying capacity of the bridge as regards applied loads. The study allows to highlight the spatial behavior of the single components and of the overall structure as well, in terms of stresses and deformed configurations under the self- weight and the accidental loads.

Title of the Paper: Approximations of the Sixth Order with the Polynomial and Non-polynomial Splines and Variational-difference Method


Authors: I. G. Burova

Pages: 62-71

Abstract: This paper discusses the approximations with the local basis of the second level and the sixth order. We call it the approximation of the second level because in addition to the function values in the grid nodes it uses the values of the function, and the first and the second derivatives of the function. Here the polynomial approximations and the non-polynomial approximations of a special form are discussed. The non-polynomial approximation has the properties of polynomial and trigonometric functions. The approximations are twice continuously differentiable. Approximation theorems are given. These approximations use the values of the function at the nodes, the values of the first and the second derivatives of the function at the nodes, and the local basis splines. These basis splines are used for constructing variational-difference schemes for solving boundary value problems for differential equations. Numerical examples are given

Title of the Paper: Compressive Strength of Interlocking Concrete Pavement Block influenced by Admixtures


Authors: Parinita Baruah, Sudip Basack, Ghritartha Goswami

Pages: 58-61

Abstract: The interlocking concrete pavement blocks are quite commonly used to construct the pedestrian walkways and parking lots of transport infrastructure. Such blocks need adequate compressive strength to withstand the design live loads. In this paper, the influence of admixtures on the compressive strength of the blocks are studied through a series of laboratory investigations. The M35 grade of concrete conforming to the Indian Standard code of practice has been used with a standard superplasticizer as admixtures added at specified weights. The study implied that the use of admixtures alters the compressive strength of concrete blocks significantly.

Title of the Paper: CFD Study for the Flow Behaviour of Nanofluid Flow over Flat Plate


Authors: M. M. Klazly, G. Bognár

Pages: 49-57

Abstract: Computation fluid dynamics (CFD) modelling of laminar heat transfer behaviour of three types of nanofluids over flat plate are studied. In the modelling the two dimensional under laminar model is used. The base fluid is pure water and the volume fraction of nanoparticles in the base fluid is 0, 1, 2, 3, and 4%. The applied Reynolds number range considered is 997.1 ≤ Re ≤ 9971. For modelling of the physical properties of the nanofluid, single phase approach is used. The effect of the volume fraction and the type of nanoparticles on the physical properties has been evaluated and presented. Then, the analysis the flow behaviour of these three nanofluids is conducted by presenting the effect of increasing the nanoparticles concentration on the velocity profile, wall shear stress, skin friction coefficient, and average heat transfer coefficient. The results show that the type of nanoparticles is an important parameter for the heat transfer enhancement as each type has shown dissimilar behaviour in this study. Moreover, a polynomial correlation has been obtained to present the relation of the wall shear stress, skin friction coefficient and average heat transfer coefficient as a function of the volume fraction for the three nanofluids.

Title of the Paper: Coastal Ground Water Flow and Management: A State-of-the-Art Review


Authors: Ghritartha Goswami, Sudip Basack, Nikos Mastorakis, Abhishek Saikia, Baby Nilo, Nasir Ahmed

Pages: 37-48

Abstract: Seawater intrusion has led to salinization of fresh groundwater reserves in coastal areas worldwide and has forced the closure of water supply wells. There is a paucity of well-documented studies that report on the reversal of SWI after the closure of a well field. Saline water from a storm surge can flow down storm-damaged submerged water supply wells and contaminate boreholes and surrounding aquifers. Water is an invaluable commodity in nature and can be a limiting resource to man and other living beings. Water quality is influenced by both natural and anthropogenic intervention where the former includes local climate, geology etc., and the latter covers the construction of dams and embankments, irrigation practices, indiscriminate disposal of industrial effluents etc. Therefore, it is highly desirable to properly manage groundwater resources for drinking-water supply by controlling saltwater intrusion. A cost effective method Abstraction, Desalinization and Recharge was found to be efficient.

Title of the Paper: Entropy Generation of MHD Poiseuille Flow with Hall and Joule Heating Effects


Authors: A. A. Opanuga, O. O. Agboola, H. I. Okagbue, A. M. Olanrewaju

Pages: 28-36

Abstract: In this article investigation has been conducted on the effects of Hall parameter, rotation parameter and Joule heating on the entropy generation of fully developed electrically conducting Poiseuille flow. The coupled system of ordinary differential equations for the flow are obtained, non-dimensionalised and solutions are constructed by Adomian decomposition technique. The effects of Hall current, Ion-slip, Joule heating and magnetic parameters on the velocity, temperature, entropy generation and Bejan number are explained and shown graphically. The results indicate that fluid entropy generation is induced by increase in Hall current, rotation and Joule heating parameters. Furthermore Bejan number is accelerated by Hall current, rotation, Magnetic and Joule heating parameters which signifies that heat transfer irreversibility dominates entropy generation.

Title of the Paper: Analysis and Control of Flow Parameters through Sluice Gate in Dam


Authors: Sudip Basack, Ghritartha Goswami, Prandeep Deka, Partha Pratim Borah, Nikos Mastorakis

Pages: 22-27

Abstract: Controlling the discharge through a gravity dam by means of sluice gate is quite common technique. Although extensive theoretical and experimental studies on discharge parameters are available, most of these studies reported sedimentation and river-bed conditions resulting in reduced discharge through a dam, although limited research has focused on controlling and adjusting the discharge considering practical scenario. This paper presents a simplified analytical model applied to a typical case study on a typical dam in western India which was used the lift irrigation technique for improving the discharge. The approach focuses on the parametric studies for predicting the variations in discharge ratio employing a range of geometrical parameters such as area and aspect ratio of the individual sluice gates and their total number. It was found that the discharge is largely affected by minor alteration in these parameters. A set of important conclusions was drawn from the entire study.

Title of the Paper: Solving the Problem of Constraints Due to Dirichlet Boundary Conditions in the Context of the Mini Element Method


Authors: Ouadie Koubaiti, Ahmed Elkhalfi, Jaouad El-Mekkaoui, Nikos Mastorakis

Pages: 12-21

Abstract: In this work, we propose a new boundary condition called CA;B to remedy the problems of constraints due to the Dirichlet boundary conditions. We consider the 2D-linear elasticity equation of Navier-Lam´e with the condition CA;B. The latter allows to have a total insertion of the essential boundary condition in the linear system obtained without going through a numerical method like the lagrange multiplier method, this resulted in a non-extended linear system easy to reverse. We have developed the mixed finite element method using the mini element space (P1 + bubble, P1). Finally we have shown the efficiency and the feasibility of the limited condition CA;B.

Title of the Paper: Slurry Pipeline for Fluid Transients in Pressurized Conduits


Authors: Tarik Chakkour, Fayssal Benkhaldoun

Pages: 1-11

Abstract: Morocco is known by the pipeline from Khouribga to Jorf Lasfar that is considered as one of the most world’s largest for the slurry transportation. This phosphate slurry undergoes different manufacturing process. During this process, the rheological properties of the slurry have been taken into account, and next adapted for our study. There are numerous approaches in the literature which investigate different Eulerian-Lagrangian, Eulerian-Eulerian and Stochastic models to simulte the slurry flow [1], [2]-[3]. Actually, it is very difficult to consider all variables for establishing a general model, we build an Eulerian and a homogeneous one in easier framework. Among these variables, there is the stress tensor which is involved in the model. Since it is considered null, then the non-Newtonian fluid is approched by multiple friction factors. In the present work, a onedimensional three-fluid model is developed in Python. The physical model features a mass and momentum balance for each fluid. It allows to predict the pressure drop and flow patterns. The hydraulic transport of slurry system in horizontal tubes has been investigated. To simulate it dynamically, continuity and momentum equations used in applied engineering problem, are solved together. These equations are conveniently solved using the method of characteristics (MOC). The reason for utilizing this method is the robustness and efficiency compared to the finite volume method (FVM). The originality for this work takes into account the physical discontinuity at interface separating slurry and water which mix with each other. The numerical results from the numerical code model head and pressure losses. We test numerically the fitting of the model with the real physical problem. Then the model is used on simplified examples in order to show its capability to be used to predict the flow behaviour in different regimes, showing consequently its consistency.