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CONTENTS
Volume 5, Number 4, October 2020
 

Abstract
Dynamic characteristics of a scale-dependent porous metal foam cylindrical shell under a traveling load have been explored within this article based on a numerical approach. Within the material texture of the metal foams, uniform and non-uniform porosities may be dispersed. Based upon differential quadrature method (DQM) and Laplace transforms, the equations of motion for a shear deformable scale-dependent shell may be solved numerically. Scale-dependent shell modeling has been provided based upon strain gradient elasticity. Solving the equations will give the shell deflection as a function of load speed. Also, it is reported that shell deflection relies on the porosity dispersion and strain gradient influences.

Key Words
Dynamic characteristics of a scale-dependent porous metal foam cylindrical shell under a traveling load have been explored within this article based on a numerical approach. Within the material texture of the metal foams, uniform and non-uniform porosities may be dispersed. Based upon differential quadrature method (DQM) and Laplace transforms, the equations of motion for a shear deformable scale-dependent shell may be solved numerically. Scale-dependent shell modeling has been provided based upon strain gradient elasticity. Solving the equations will give the shell deflection as a function of load speed. Also, it is reported that shell deflection relies on the porosity dispersion and strain gradient influences.

Address
Raad M. Fenjan, Ridha A. Ahmed, Luay Badr Hamad and Nadhim M. Faleh:Al-Mustansiriah University, Engineering Collage P.O. Box 46049, Bab-Muadum, Baghdad 10001, Iraq

Abstract
In this paper, a cylindrical shell is immersed in a non-viscous fluid using first order shell theory of Sander. These equations are partial differential equations which are solved by approximate technique. Robust and efficient techniques are favored to get precise results. Employment of the Rayleigh-Ritz procedure gives birth to the shell frequency equation. Use of acoustic wave equation is done to incorporate the sound pressure produced in a fluid. HankelHanke's functions of second kind designate the fluid influence. Mathematically the integral form of the Lagrange energy functional is converted into a set of three partial differential equations. Throughout the computation, simply supported edge condition is used. Expressions for modal displacement functions, the three unknown functions are supposed in such way that the axial, circumferential and time variables are separated by the product method. Comparison is made for empty and fluid-filled cylindrical shell with circumferential wave number, length- and height-radius ratios, it is found that the fluid-filled frequencies are lower than that of without fluid. To generate the fundamental natural frequencies and for better accuracy and effectiveness, the computer software MATLAB is used.

Key Words
Langrange functional; fluid-filled; MATLAB; Hankel

Address
Muzamal Hussain,Muhammad Nawaz Naeem:Department of Mathematics, Govt. College University Faisalabad, 38000, Faisalabad, Pakistan
Aamir Shahzad:Department of Physics, Govt. College University Faisalabad, Faisalabad 38040, Pakistan
Muhammad Taj:Department of Mathematics, University of Azad Jammu and Kashmir, Muzaffarabad, Azad Kashmir, Pakistan
Sehar Asghar:Department of Mathematics, Govt. College University Faisalabad, 38000, Faisalabad, Pakistan
Alireza Fatahi-Vajari:Department of Mechanical Engineering, Shahryar Branch, Islamic Azad University, Shahryar, Iran
Rahul Singh :University Department of Mechanical Engineering, Rajasthan Technical University, Kota 324010, India
Abdelouahed Tounsi:Materials and Hydrology Laboratory University of Sidi Bel Abbes, Algeria Faculty of Technology Civil Engineering Department
,Department of Civil and Environmental Engineering, King Fahd University of Petroleum & Minerals, 31261 Dhahran, Eastern Province, Saudi Arabia

Abstract
This study aimed to develop an optimal model of transportation for people with disabilities. To achieve this goal, powers of research and design should be involved, including CAD software. This paper investigates both: the concept of optimal model of transportation for people with disabilities (functional, ergonomic, constructive, technological and aesthetic solutions included); and its implementation as a fully-fledged 3D-model designed in SolidWorks environment. The optimal model of transportation is complex and consists of two objects. The first object is for indoors that is a wheelchair, the second one is for street driving that is an individual vehicle. The optimal model of transportation is universal and multifunctional, which have become possible with parametric feature-based approach utilized in SolidWorks.

Key Words
industrial design; SolidWorks CAD software; optimal model of transportation; people with disabilities; wheelchair; individual vehicle

Address
Nataliia Vergunova and Sergey Vergunov:Department of Design and Art, O.M. Beketov National University of Urban Economy in Kharkiv,17, Marshal Bazhanov Street, Kharkiv, 61002, Ukraine

Abstract
Functionally graded material (FGM) illustrates a novel class of composites that consists of a graded pattern of material composition. FGM is engineered to have a continuously varying spatial composition profile. Current work focused on buckling analysis of beam made of stepwise linear and quadratic graded material in axial direction subjected to axial span-load with piecewise function and rested on shear layer based on classical beam theory. The various boundary and natural conditions including simply supported (S-S), pinned – clamped (P-C), axial hinge – pinned (AH-P), axial hinge – clamped (AH-C), pinned – shear hinge (P-SHH), pinned – shear force released (P-SHR), axial hinge – shear force released (AH-SHR) and axial hinge – shear hinge (AH-SHH) are considered. To the best of the author's knowledge, buckling behavior of this kind of Euler-Bernoulli beams has not been studied yet. The equilibrium differential equation is derived by minimizing total potential energy via variational calculus and solved analytically. The boundary conditions, natural conditions and deformation continuity at concentrated load insertion point are expressed in matrix form and nontrivial solution is employed to calculate first buckling loads and corresponding mode shapes. By increasing truncation order, the relative error reduction and convergence of solution are observed. Fast convergence and good compatibility with various conditions are advantages of the proposed method. A MATLAB code is provided in appendix to employ the numerical procedure based on proposed method.

Key Words
buckling; stepwise axially graded beam; linear and quadratic material gradation; piecewise load function; shear layer

Address
Abbas Heydari:Department of civil engineering, Faculty of Razi, Ardabil branch,Technical and Vocational University (TVU), Ardabil, Iran

Abstract
Tunnels have been an integral part of human civilization. Due to complexity in its design and structure, the stability of underground structures under extreme loading conditions has utmost importance. Increased terrorism and geo-political conflicts have forced the engineers and researchers to study the response of underground structures, especially tunnels under blast loading. The present study has been carried out to seek the response of tunnel structures under blast load using the finite element technique. The tunnel has been considered in quartzite rock of northern India. The Mohr-Coulomb constitutive model has been adopted for the elastoplastic behaviour of rock. The rock model surrounding the tunnel has dimensions of 30 m x 30 m x 35 m. Both unlined and lined (concrete) tunnel has been studied. Concrete Damage Plasticity model has been considered for the concrete lining. Four different parameters (i.e., tunnel diameter, liners thickness, overburden depth and mass of explosive) have been varied to observe the behaviour under different condition. To carry out blast analysis, Coupled-Eulerian-Lagrangian (CEL) modelling has been adopted for modelling of TNT (Trinitrotoluene) and enclosed air. JWL (Jones-Wilkins-Lee) model has been considered for TNT explosive modelling. The paper concludes that deformations in lined tunnels follow a logarithmic pattern while in unlined tunnels an exponential pattern has been observed. The stability of the tunnel has increased with an increase in overburden depth in both lined and unlined tunnels. Furthermore, the tunnel lining thickness also has a significant effect on the stability of the tunnel, but in smaller diameter tunnel, the increase in tunnel lining thickness has not much significance. The deformations in the rock tunnel have been decreased with an increase in the diameter of the tunnel.

Key Words
blast load; Coupled-Eulerian-Lagrangian; rock tunnel; concrete liners; Jones-Wilkins-Lee

Address
Mohammad Zaida and Md. Rehan Sadique:Department of Civil Engineering, ZHCET, Aligarh Muslim University, Aligarh, U.P., India

Abstract
This paper presents a study conducted with the aim of developing a model of tendering based on a technique of artificial intelligence by managing and controlling the factors of success or failure of construction projects through the evaluation of the process of invitation to tender. Aiming to solve this problem, analysis of the current environment based on SWOT (Strengths, Weaknesses, Opportunities, and Threats) is first carried out. Analysis was evaluated through a case study of the construction projects in Algeria, to bring about the internal and external factors which affect the process of invitation to tender related to the construction projects. This paper aims to develop a mean to identify threats-opportunities and strength-weaknesses related to the environment of various national construction projects, leading to the decision on whether to continue the project or not. Following a SWOT analysis, novel artificial intelligence models in forecasting the project status are proposed. The basic principal consists in interconnecting the different factors to model this phenomenon. An artificial neural network model is first proposed, followed by a model based on fuzzy logic. A third model resulting from the combination of the two previous ones is developed as a hybrid model. A simulation study is carried out to assess performance of the three models showing that the hybrid model is better suited in forecasting the construction project status than RNN (recurrent neural network) and FL (fuzzy logic) models.

Key Words
risk management; construction projects; recurrent neural network; fuzzy logic; hybrid model

Address
Amina Boughaba and Mohamed Bouabaz: Department of Civil Engineering, University 20 Aout 1955, LMGHU Laboratory, BP.26, Skikda 21000, Algeria


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