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CONTENTS
Volume 39, Number 6, June25 2021
 

Abstract
Observations on the crush responses and the energy absorption characteristics of single- and bi-layer deep-drawn cups subjected to experimental axial impact loading are presented in this manuscript. Bi-layer plates composed of aluminum and stainless steel alloys were fabricated by joining with adhesive and formed by a deep drawing process to produce the final cup shape. Impact testing was performed using a custom-built drop-tower system with a mass of 45.45 kg and impact velocities ranging from 2.8 m/s to 4.5 m/s. Various material and geometric parameters for the bi- and single-layer cups were considered in the study. Numerical simulations were conducted to investigate the deformation mechanisms and crushing behavior of the combined shells. Furthermore, based on the polynomial response surface method and using non-domain sorting genetic algorithm II, some multi-objective optimizations were performed on specific energy absorption, stroke efficiency, specific total efficiency, and initial peak load. Experimental and numerical results illustrated that the deformation of the bi-layer cups was different from the single-layer cups, especially in the head zone. Moreover, the specific total efficiency for specimens having a diameter of 55 mm and 65 mm were approximately 35% and 55% less than cups with a diameter of 45mm, respectively. It was found that the layer order of the bi-layer cup influences the energy absorption capacities of the specimen. Specifically, cups with steel as the outer layer experienced crush force efficiency and total efficiency of 6% and 5% higher than those with an aluminum outer layer, respectively.

Key Words
mechanical response; crashworthiness characteristics; bi- and single-layer cups; energy absorption; impact; combined shells

Address
M.A. Ghasemabadian: Department of Mechanical Engineering, Ferdowsi University of Mashhad, Mashhad, Iran;
University of Windsor, Department of Mechanical, Automotive and Materials Engineering,
401 Sunset Avenue, Windsor, Ontario N9B 3P4, Canada
M. Kadkhodayan: Department of Mechanical Engineering, Ferdowsi University of Mashhad, Mashhad, Iran
W. Altenhof and Y. Liu:University of Windsor, Department of Mechanical, Automotive and Materials Engineering,
401 Sunset Avenue, Windsor, Ontario N9B 3P4, Canada



Abstract
This paper is aimed to review the use of artificial intelligence (AI) algorithms in diverse civil engineering applications such as predicting and evaluating the different parameters of composite beams and shear connectors and determining the compressive strength of concrete. Also, the application of AI methods especially artificial neural network (ANN) in construction engineering and management including prediction and estimation, decision-making, classification or selection, optimization and risk analysis and safety has been thoroughly discussed. Furthermore, the integration of Artificial Neural network (ANN) with other soft computing methods, such as Backpropagation (BP), imperialist competitive algorithm (ICA), support vector regression (SVR), back-propagation neural network (BPNN), Genetic Algorithms (GA) and Multilayer feed forward (MLFF) has been reviewed. It has been reported that the combination of ANN with other intelligence algorithms leads to providing more accurate results. Moreover, the performance of ANN with other soft computing techniques, such as BP, BPNN, SVR, GA, ICA, and MLFF in various fields has been compared and ANN in many cases had superiority over other models.

Key Words
soft computing; artificial neural network; construction management; building materials; composite beams

Address
Yan Cao, Qiangfeng Wang, Xueming Qian and Leijie Fu: School of Mechatronic Engineering, Xi'an Technological University, Xi'an, 710021 China
Yousef Zandi: Department of Civil Engineering, Tabriz Branch, Islamic Azad University, Tabriz, Iran
Alireza Sadighi Agdas: Ghateh Gostar Novin Company, Tabriz, Iran
Karzan Wakil: Department of Computer, College of Science, University of Halabja, Halabja 46018, Kurdistan Region, Iraq;
Research Center, Sulaimani Polytechnic University, Sulaimani 46001, Kurdistan Region, Iraq
Abdellatif Selmi: Department of Civil Engineering, College of Engineering, Prince Sattam Bin Abdulaziz University, Al‑Kharj 11942, Saudi Arabia
Civil Engineering Laboratory, Ecole Nationale D'Ingénieurs deTunis (ENIT), B.P. 37, Lbelvédère1002, Tunis, Tunisia
Alibek Issakhov: Al-Farabi Kazakh National University, Almaty, Kazakhstan;
Kazakh-British Technical University, Almaty, Kazakhstan
Angel Roco-Videla: Programa Magister en ciencias químico-biológicas. Facultad de Ciencias de la Salud. Universidad Bernardo O'Higgins. Santiago-Chile;
Departamento de ingeniería Civil, Facultad de Ingeniería. Universidad Católica de la Santísima Concepción, Concepción-Chile


Abstract
A circular steel-yielding demountable shear connector is proposed. The connector consists of a short perforated circular hollow section (CHS) welded on a base plate which in turn is bolted on the top flange of a steel section. The connector provides longitudinal shear resistance in all directions through yielding of steel and is used in conjunction with precast hollow core slab units. The mechanical behaviour is first studied using a previously validated detailed finite element model simulating horizontal pushout tests, by conducting a series of parametric studies to identify all failure modes of the novel connector. Based on the results of the numerical pushout tests, design equations to predict the strength of the connector are proposed. A composite beam using hollow core slabs and various degrees of shear connection is then simulated to verify the applicability of the circular connector and the implications in the design of composite beams.

Key Words
composite beam; demountable shear connector; circular yielding pocket (CYP); precast hollow core slab; shear strength

Address
Jun He: School of Civil Engineering, Changsha University of Science and Technology, Hunan, China;
Institute for Infrastructure and Environment, Heriot-Watt University, Edinburgh, UK
George Vasdravellis: Institute for Infrastructure and Environment, Heriot-Watt University, Edinburgh, UK
Sihao Wang: Department of Bridge Engineering, Tongji University, Shanghai, China

Abstract
This paper proposed an innovative RC column with encased prefabricated high-strength concrete filled steel tube core, and four RC columns with encased prefabricated high-strength CFST core and a RC control-column were tested under lateral low cyclic loading. All specimens were evaluated by the cracks developments, failure patterns, hysteretic behavior, skeleton curves, strength and stiffness degradation, ductility and energy dissipation capacity. The effects of stirrup ratio and welding studs of prefabricated CFST core were investigated in details. The experiment results indicated that compared with the RC control-column, the performances of RC columns with encased prefabricated high-strength CFST core, including the hysteretic behavior, strength degradation, ductility and energy dissipation, were significantly improved. Higher stirrup ratio of the RC column with encased prefabricated high-strength CFST core leaded to higher ductility and more satisfactory energy dissipation capacity, stiffness degradation. Studs could effectively combine prefabricated high-strength CFST core and surrounding concrete, which significantly increase the integrity of RC column with encased prefabricated high-strength CFST core. Based on the test results, a numerical model was established to further analyze the cyclic behavior of the test specimens, and the numerical results agreed well with the test results, which showed the feasibility for the further parametric study. Finally, on the basis of the plastic stress theory, a calculation model for seismic bending moment capacity of RC column with encased prefabricated high-strength CFST core was established, and the results obtained form the formulas showed good agreement with the experiments.

Key Words
steel-concrete composite column; prefabricated high-strength CFST core; cyclic behavior; experimental study; bearing capacity

Address
Dongde Sun, Yong Yang, Yicong Xue, Kang An and Yang Chen: School of Civil Engineering, Xi'an University of Architecture & Technology, Xi'an, Shaanxi 710055, China
Yunlong Yu: School of Civil Engineering, Xi'an University of Architecture & Technology, Xi'an, Shaanxi 710055, China;
Key Lab of Structure and Earthquake Resistance, Xi'an, Shaanxi 710055, China

Abstract
Soil nailing is one of the most common and important techniques to exchange conventional retaining systems for deep excavation. This approach contains a significant saving in cost and time of construction compared to conventional retaining systems. In this paper, an attempt has been made to evaluate the dynamical response of a deep vertical excavation on ground of 8 m height using soil nail wall. It has been tried to investigate the effects of different modeling approaches on the dynamic response of soil-nailed walls by considering the three behavioral methods; Mohr Coulomb (MC), hardening soil (HS) and hardening soil model with Small-Strain stiffness ensued from small strains (HSS). Nonlinear time history analysis has been implemented to compare the displacements under the sinus excitation with 0.5, 1, and 1.5 Hz with PGA= 0.3 g. Different points along the height of the wall are selected and considered. At the last part of this paper, incremental dynamic analysis (IDA) was implemented to the soil nail wall to consider the effect of the different earthquake records on the response of the wall. The IDA curve is also presented for the considered soil nail wall.

Key Words
soil nail walls; MC model; HS model; HSS model; PLAXIS 2D; dynamic analysis; Incremental dynamic analysis (IDA)

Address
Mahdi Bayat and Amir Homayoon Kosarieh: Department of Civil Engineering, Roudehen Branch, Islamic Azad University, Roudehen, Iran
Mehran Javanmard: Department of Civil Engineering, Faculty of Engineering, University of Zanjan, Zanjan, Iran

Abstract
In this work, the hygrothermal effect on the behavior of hybrid laminated composite plate has been investigated using high-order shear deformation theory and finite element analysis. The equation of motion of the laminated plate is obtained using Hamilton's principle, and the mathematical expressions are obtained using Navier's solution for different boundary conditions. The engineering moduli for the different cases: non-hybrid composite and hybrid composite are calculated using the law of mixtures. The mechanical properties of hybrid composite plate are considered as temperature and humidity dependent. The results obtained with finite element analysis using Abaqus and analytical approach show a good agreement in predicting the fundamental frequencies of hybrid cross-ply laminated plates under hygrothermal loading.

Key Words
complex terrain; typhoon wind field; CFD simulation; surface roughness length; topography

Address
Mohamed A. Ben Henni: MATIM, Université de Reims Champagne-Ardenne - Campus du Moulin de la Housse BP 1039 - 51687 Reims cedex 2, France;
Laboratory of Geomatics and Sustainable Development, Ibn Khaldoun University of Tiaret, Algeria
Boussad Abbès and Fazilay Abbès: MATIM, Université de Reims Champagne-Ardenne - Campus du Moulin de la Housse BP 1039 - 51687 Reims cedex 2, France
T. Hassaine Daouadji: Department of Civil Engineering, Ibn Khaldoun University, BP 78 Zaaroura, 14000 Tiaret, Alegria;
Laboratory of Geomatics and Sustainable Development, Ibn Khaldoun University of Tiaret, Algeria
Belkacem Adim: Laboratory of Geomatics and Sustainable Development, Ibn Khaldoun University of Tiaret, Algeria



Abstract
In this paper, a fracture criterion for predicting the failure of the cracked composite specimens under mixed mode I/II loading is provided. Various tests performed on composite components reveal that cracks always grow along the fibers in the isotropic media. Using a new material model called reinforcement isotropic solid (RIS) concept, it is possible to extend the isotropic mixed mode fracture criteria into composite materials. In the proposed criterion, maximum shear stress (MSS) theory which is widely used for failure investigation of un-cracked isotropic materials will be extended to composite materials in combination with RIS concept. In the present study, cracks are oriented along the fibers in the isotropic material. It is assumed that at the onset of fracture, crack growth will be in a path where the shear stress has the highest value according to the MSS criterion. Investigating the results of this criterion and comparing with the available experimental data, it is shown that, both the crack propagation path and the moment of crack growth are well predicted. Available mixed mode I/II fracture data of various wood species are used to evaluate and verify the theoretical results.

Key Words
extended maximum shear stress path; fracture criterion; mixed mode I/II loading; composite materials; reinforcement isotropic solid model; RIS concept; crack growth

Address
Sadra Shahsavar and Mahdi Fakoor: Faculty of New Sciences and Technologies, University of Tehran, Tehran, Iran
Filippo Berto: Norwegian University of Science and Technology, Norway

Abstract
In this article, free vibration attributes of zigzag double-walled carbon nanotubes (CNTs) based on nonlocal elastic shell model have been investigated. The impact of small scale is being perceived by establishing Flügge shell model. The wave propagation is engaged to frame the ruling equations as eigen value system. The influence of nonlocal parameter subjected to different end supports has been overtly examined. A suitable choice of material properties and nonlocal parameter been focused to analyze the vibration characteristics. The new set of inner and outer tubes radii investigated in detail against aspect ratio and length. The dominance of boundary conditions via nonlocal parameter is shown graphically. The results generated furnish the evidence regarding applicability of nonlocal shell model and also verified by earlier published literature.

Key Words
free vibration; nonlocal material; double-walled CNTs; Flügge shell model; WPA

Address
Sehar Asghar, Muzamal Hussain, Muhammad N. Naeem and Zainab Ali: Department of Mathematics, Govt. College University Faisalabad, 38040, Faisalabad, Pakistan
Mohamed Amine Khadimallah: Prince Sattam Bin Abdulaziz University, College of Engineering, Civil Engineering Department, BP 655, Al-Kharj, 16273, Saudi Arabia;
Laboratory of Systems and Applied Mechanics, Polytechnic School of Tunisia, University of Carthage, Tunis, Tunisia
Khaled Mohamed Khedher: Department of Civil Engineering, College of Engineering, King Khalid University, Abha 61421, Saudi Arabia;
Department of Civil Engineering, High Institute of Technological Studies, Mrezgua University Campus, Nabeul 8000, Tunisia
Muhammad Taj: Department of Mathematics, University of Azad Jammu and Kashmir, Muzaffarabad, 1300, Azad Kashmir, Pakistan
Abdelouahed Tounsi: YFL (Yonsei Frontier Lab), Yonsei University, Seoul, Korea
Department of Civil and Environmental Engineering, King Fahd University of Petroleum & Minerals, 31261 Dhahran,
Eastern Province, Saudi Arabia




Abstract
In the current study, large deflection analysis of a functionally graded saturated porous (FGSP) rectangular plate subjected to transverse loading which is located on a nonlinear three-parameter elastic foundation is provided. The constitutive law for the porous materials is written based on Biot's model which considers the effect of fluids within the pores. The mechanical properties of the plate are changed through its thickness according to different functions which are called porosity distributions. The shear deformation effects are taken into account, accordingly, the first-order shear deformation theory (FSDT) is used to describe the displacement components of the plate. Employing the Minimum total potential energy principle and calculus of variation, the governing equations, and associated boundary conditions are extracted. A generalized differential quadrature method (GDQM) is used to solve them for various boundary conditions. The results for the simpler state are validated with the previously published works and then the effects of different parameters on the deflection of the plate are investigated. It is seen increasing the porosity and Skempton coefficient, enhances and reduces the deflection of the structure, respectively. The results of this study may help to design and manufacture more reliable engineering structures that are exposed to loads.

Key Words
porous materials; nonlinear bending analysis; nonlinear elastic foundation; FSDT; GDQM

Address
Khaled Alhaifi: Department of Automotive and Marine Engineering, College of Technological Studies-PAAET, El-Shuwaikh, Kuwait
Ehsan Arshid : Department of Mechanical Engineering, Qom Branch, Islamic Azad University, Qom, Iran;
Department of Solid Mechanics, Faculty of Mechanical Engineering, University of Kashan, Kashan, Iran
Ahmad Reza Khorshidvand: Department of Mechanical Engineering, South Tehran Branch, Islamic Azad University, Tehran, Iran


Abstract
In presented paper, moving load problem of functionally graded beams is investigated with porosity effects based on the first shear beam theory. The material properties of beam vary along the axial direction. The porosity is depicted by two different distributions along axial direction. The governing equations of problem are derived by using the Lagrange procedure. In the solution of the problem the Ritz method is used and algebraic polynomials are used with the trivial functions for the Ritz method. In the solution of the moving load problem, the Newmark average acceleration method is used in the time history. In the numerical examples, the effects of material graduation, porosity distribution, porosity coefficients and velocity of moving load on the dynamic responses of axially functionally graded beam are presented and discussed. The dynamic responses are obtained for different boundary conditions.

Key Words
functionally graded beams; moving load problems; porosity; Ritz method

Address
Ş.D. Akbaş: Department of Civil Engineering, Bursa Technical University, 16330, Bursa, Turkey

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