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Volume 49, Number 3, November 10 2023

In this study, the feasibility and applicability of a friction damper with a vertical installation scheme are investigated. This device is composed of a steel section and two friction hinges at both ends which dissipate seismic energy. Due to its small width and vertical installation scheme, the proposed damper can minimize the interference with architectural functions. To evaluate the performance of the proposed damper, its mechanical behavior is theoretically evaluated and the required formulas for the yield strength and elastic stiffness are derived. The theoretical formulas are verified by establishing the analytical model of the damper in the SAP2000 software and comparing their results. To further investigate the performance of the developed damper, the provided analytical model is applied to a 4-story reinforced concrete (RC) structure and its performance is evaluated before and after retrofit under the Maximum Considered Earthquake (MCE) hazard level. The seismic performance is thoroughly evaluated in terms of maximum interstory drift ratio, displacement time history, residual displacement, and energy dissipation. The results show that the proposed damper can be efficiently used to protect the structure against seismic loads.

Key Words
friction damper; nonlinear time history analysis; seismic dampers; seismic performance; seismic retrofit

Mohammad Mahdi Javidan and Jinkoo Kim:Department of Global Smart City, Sungkyunkwan University, Suwon, Republic of Korea

Asad Naeem:Department of Civil and Architectural Engineering, Balochistan University of Information Technology, Quetta, Pakistan

In this study, the three-dimensional finite element method is used to analyze the behavior of corner cracks in finitethickness plates repaired with a composite patch. The normalized stress intensity factor at the crack front is used as fracture criterion. Comparison of stress intensity factor values at the internal and external positions of repaired quarter-elliptical corner crack was done, for three repair techniques. The influence of mechanical and geometrical properties of the adhesive layer and the composite patch on the variation of the stress intensity factor (SIF) at the crack-front was highlighted. The obtained results show that the application of double patch leads to a remarkable reduction of SIF at the crack front, compared to facial and lateral repairs.

Key Words
adhesive; bonded composite repair; corner crack; finite element method; stress intensity factor

Abdelkader Boulenouar, Mohammed A. Bouchelarm:Laboratoire de Materiaux et Systemes Reactifs - LMSR. Djillali Liabes University of Sidi Bel Abbes. 22000 Sidi Bel Abbes, Algeria

Noureddine Benseddiq:2Unite de Mecanique de Lille, EA 7512 UML, University of Lille, 59000 Lille, France

Due to the fact that the nonlinear low-velocity impact response of graphene platelets reinforced metal foams (GPLRMF) doubly curved shells have not been investigated in the existing works, this paper aims to solve this issue. Using Reddy's high-order shear deformation theory (HSDT), the nonlinear governing equations of GPLRMF doubly curved shells are obtained by Euler-Lagrange method, discretized by Galerkin principle, and solved by the fourth-order Runge-Kutta method to obtain the impact force and central deflection. The nonlinear Hertz contact law is applied to determine the contact force. Finally, the impacts of graphene platelets (GPLs) distribution pattern, porosity distribution form, porosity coefficient, damping coefficient, impact parameters (radius and initial velocity), GPLs weight fraction, pre-stressing force and different shell types on the low-velocity impact curves are analyzed. It can be found that, among the four shell structures, the impact resistance of spherical shell is the best, while that of cylindrical shell is the worst.

Key Words
doubly curved shells; graphene platelets; low-velocity impact; metal foam; nonlinear

Hao-Xuan Ding, Yi-Wen Zhang, Yin-Ping Li and Gui-Lin She:College of Mechanical and Vehicle Engineering, Chongqing University, Chongqing 400044, China

This article focuses on the study of the buckling behavior of two-dimensional functionally graded (2D-FG) nanosize tubes, including porosity, based on the first shear deformation and higher-order theory of the tube. The nano-scale tube is simulated using the nonlocal gradient strain theory, and the general equations and boundary conditions are derived using Hamilton's principle for the Zhang-Fu's tube model (as a higher-order theory) and Timoshenko beam theory. Finally, the derived equations are solved using a numerical method for both simply-supported and clamped boundary conditions. A parametric study is performed to investigate the effects of different parameters, such as axial and radial FG power indices, porosity parameter, and nonlocal gradient strain parameters, on the buckling behavior of the bi-dimensional functionally graded porous tube. Keywords: Nonlocal strain gradient theory; buckling; Zhang-Fu's tube model; Timoshenko theory; Two-dimensional functionally graded materials; Nanotubes; Higher-order theory.

Key Words
buckling; higher-order theory; nanotubes; nonlocal strain gradient theory; Timoshenko theory; twodimensional functionally graded materials; Zhang-Fu's tube model

Xiaozhong Zhang:Department of International Applied Technology, Yibin University, Yibin 644000, Sichuan, China

Jianfeng Li:1)Faculty of Engineering, China University of Geosciences (Wuhan), Wuhan 430000, Hubei, China
2)Zhongjiao Yuanzhou Transportation Technology Group Co., Ltd. Fujian Branch, Fuzhou 350109, Fujian, China
3)Hainan Cloud Spacetime Information Technology Co., Ltd, Danzhou 571700, Hainan, China
4)XING YUN CHEN (Hongkong) Technology Co., Ltd, Hongkong 999077, China

Yan Cui:School of Civil Engineering, Hebei Polytechnic Institute, Shijiazhuang 050091, Hebei, China

Mostafa Habibi:1)Faculty of Architecture and Urbanism, UTE University, Calle Rumipamba S/N and Bourgeois, Quito, Ecuador
2)Department of Biomaterials, Saveetha Dental College and Hospital, Saveetha Institute of Medical and Technical Sciences,
Chennai 600 077, India
3)Institute of Research and Development, Duy Tan University, Da Nang 550000, Vietnam
4)Center of Excellence in Design, Robotics, and Automation, Department of Mechanical Engineering, India

H. Elhosiny Ali:Department of Physics, Faculty of Science, King Khalid University, P.O. Box 9004, Abha 61413, Saudi Arabia

Ibrahim Albaijan:Mechanical Engineering Department, College of Engineering at Al Kharj, Prince Sattam Bin Abdulaziz University, Al Kharj 11942, Saudi Arabia

Tayebeh Mahmoudi:Hoonam Sanat Farnak Engineering and Technology Company, Postal code: 6931876647, Ilam, Iran

In this research, the study of the thermoelastic flexural analysis of silicon carbide/Aluminum graded (FG) sandwich 2D uniform structure (plate) under harmonic sinusoidal temperature load over time is presented. The plate is modeled using a simple two dimensional integral shear deformation plate theory. The current formulation contains an integral terms whose aim is to reduce a number of variables compared to others similar solutions and therefore minimize the computation time. The transverse shear stresses vary according to parabolic distribution and vanish at the free surfaces of the structure without any use of correction factors. The external load is applied on the upper face and varying in the thickness of the plates. The structure is supposed to be composed of "three layers" and resting on nonlinear visco-Pasternak's-foundations. The governing equations of the system are deduced and solved via Hamilton's principle and general solution. The computed results are compared with those existing in the literature to validate the current formulation. The impacts of the parameters (material index, temperature exponent, geometry ratio, time, top/bottom temperature ratio, elastic foundation type, and damping coefficient) on the dynamic flexural response are studied.

Key Words
thermoelastic flexural response; FG sandwich plates; 2D integral theory; visco-Pasternak's foundation

Abdeldjebbar Tounsi:Industrial Engineering and Sustainable Development Laboratory, University of Relizane, Faculty of Science & Technology, Mechanical
Engineering Department, Algeria

Adda Hadj Mostefa and Abdelmoumen Anis Bousahla:ndustrial Engineering and Sustainable Development Laboratory, Department of Civil Engineering, University of Relizane,
Faculty of Science & Technology, Algeria

Abdelouahed Tounsi:1)YFL (Yonsei Frontier Lab), Yonsei University, Seoul, Korea
2)Department of Civil and Environmental Engineering, King Fahd University of Petroleum & Minerals,
31261 Dhahran, Eastern Province, Saudi Arabia
3)Department of Civil and Environmental Engineering, Lebanese American University, 309 Bassil Building, Byblos, Lebanon

Mofareh Hassan Ghazwani:Mechanical Engineering Department, Faculty of Engineering, Jazan University P. O. Box 45142, Jazan, Kingdom of Saudi

Fouad Bourada:Material and Hydrology Laboratory, University of Sidi Bel Abbes, Faculty of Technology, Civil Engineering Department, Algeria

Abdelhakim Bouhadra:1)Material and Hydrology Laboratory, University of Sidi Bel Abbes, Faculty of Technology, Civil Engineering Department, Algeria
2)Department of Civil Engineering, Faculty of Science and Technology, Abbes Laghrour University of Khenchela, Algeria

The missile is affected by both spinning and axial motion during its movement, which will have a very adverse impact on the stability and reliability of the missile. This paper regards missiles as cylindrical shell structures with spinning and axial motion. In this article, the forced vibration of carbon nanotube-reinforced composites (CNTRCs) cylindrical shells with spinning motion and axial motion is investigated, in which the clamped-clamped and simply-simply supported boundary conditions are considered. The displacement field is described by the first-order shear theory, and the vibration equation is deduced by using the Euler-Lagrange equation, after dimensionless processing, the dimensionless equation of motion is obtained. The correctness of this paper is verified by comparing with the results of the existing literature, in which the simplysimply supported ends are taken into account. In the end, the effects of different parameters such as spinning velocity, axial velocity, carbon nanotube volume fraction, length thickness ratio and load position on the resonance behavior of cylindrical shells are given. It can be found that these parameters can significantly change the resonance of axially moving and rotating moving CNTRCs cylindrical shells.

Key Words
axial motion; carbon nanotubes; cylindrical shell; forced vibration; spinning motion

Jia-Qin Xu and Gui-Lin She:College of Mechanical and Vehicle Engineering, Chongqing University, Chongqing 400044, China

Successive wetting and drying cycles of concrete due to weather changes can endanger the safety of engineering structures over time. Considering wetting and drying cycles in concrete tests can lead to a more correct and reliable design of engineering structures. This study aims to provide a model that can be used to estimate the resistance properties of concrete under different wetting and drying cycles. Complex sample preparation methods, the necessity for highly accurate and sensitive instruments, early sample failure, and brittle samples all contribute to the difficulty of measuring the strength of concrete in the laboratory. To address these problems, in this study, the potential ability of six machine learning techniques, including ANN, SVM, RF, KNN, XGBoost, and NB, to predict the concrete's tensile strength was investigated by applying 240 datasets obtained using the Brazilian test (80% for training and 20% for test). In conducting the test, the effect of additives such as glass and polypropylene, as well as the effect of wetting and drying cycles on the tensile strength of concrete, was investigated. Finally, the statistical analysis results revealed that the XGBoost model was the most robust one with R2 = 0.9155, mean absolute error (MAE) = 0.1080 Mpa, and variance accounted for (VAF) = 91.54% to predict the concrete tensile strength. This work's significance is that it allows civil engineers to accurately estimate the tensile strength of different types of concrete. In this way, the high time and cost required for the laboratory tests can be eliminated.

Key Words
machine learning, reinforced concrete, steel-concrete composite, tensile strength, wetting‒drying cycles

Ibrahim Albaijan:Mechanical Engineering Department, College of Engineering at Al-Kharj, Prince Sattam Bin Abdulaziz University, Al Kharj 16273, Saudi Arabia

Danial Fakhri:Department of Applied Sciences, Universite du Quebec a Chicoutimi, Chicoutimi, QC, G7H 2B1, Canada

Adil Hussein Mohammed:Department of Communication and Computer Engineering, Faculty of Engineering, Cihan University-Erbil, Kurdistan Region, Iraq

Arsalan Mahmoodzadeh:IRO, Civil Engineering Department, University of Halabja, Halabja, 46018, Iraq

Hawkar Hashim Ibrahim:Department of Civil Engineering, College of Engineering, Salahaddin University-Erbil, 44002 Erbil, Kurdistan Region, Iraq

Khaled Mohamed Elhadi:Civil Engineering Department, College of Engineering, King Khalid University, Saudi Arabia

Shima Rashidi:Department of Computer Science, College of Science and Technology, University of Human Development,
Sulaymaniyah, Kurdistan Region, Iraq

Dynamic response and economic of a laminated porous concrete beam reinforced by nanoparticles subjected to harmonic transverse dynamic load is investigated considering structural damping. The effective nanocomposite properties are evaluated on the basis of Mori-Tanaka model. The concrete beam is modeled by the sinusoidal shear deformation theory (SSDT). Utilizing nonlinear strains-deflection, energy relations and Hamilton's principal, the governing final equations of the concrete laminated beam are calculated. Utilizing differential quadrature method (DQM) as well as Newmark method, the dynamic displacement of the concrete laminated beam is discussed. The influences of porosity parameter, nanoparticles volume percent, agglomeration of nanoparticles, boundary condition, geometrical parameters of the concrete beam and harmonic transverse dynamic load are studied on the dynamic displacement of the laminated structure. Results indicated that enhancing the nanoparticles volume percent leads to decrease in the dynamic displacement about 63%. In addition, with considering porosity of the concrete, the dynamic displacement enhances about 2.8 time.

Key Words
DQM; dynamic response; laminated concrete porous beam; nanoparticles; newmark method

Guixiao Xu:School of Digital Economy and information management, Chongqing College of Mobile Communication, Hechuan 401520, Chongqing, China

F. Ming:Department of Mechanical Engineering, University of Hong Kong, Hong Kong

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