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CONTENTS
Volume 52, Number 1, July 10 2024
 

Abstract
This paper introduces a system allows for seismic isolation of the pallet from the rack in the down-aisle direction, occupies minimal vertical space (5 cm) and ±7.5 cm of deformation range. A conceptual model of the isolation system is presented, leading to a constitutive equation governing its behavior. A first experimental campaign studying the response of the isolation system's components was conducted to calibrate the parameters of its constitutive equation. A second experimental campaign evaluated the response of the isolation system with mass placed on it, subjected to cyclic loading. The results of this second campaign were compared with the numerical predictions using the pre-calibrated constitutive equation, allowing a double-blind validation of the constitutive equation of the isolation system. Finally, a numerical evaluation of the isolation system subjected to a synthetic earthquake of one component. This evaluation allowed verifying attributes of the proposed isolation system, such as its self-centering capacity and its effectiveness in reducing the absolute acceleration of the isolated mass and the shear load transmitted to the supporting beams of the rack.

Key Words
constitutive numerical model; double-blind validation; down-aisle direction; experimental tests; pallet isolation

Address
Marcelo Sanhueza-Cartes:Facultad de Ingenieria, Universidad Catolica de la Santisima Concepcion, Concepcion, Chile

Nelson Maureira-Carsalade:Facultad de Ingenieria, Universidad Catolica de la Santisima Concepcion, Concepcion, Chile

Eduardo Nunez:Facultad de Ingenieria, Universidad Catolica de la Santisima Concepcion, Concepcion, Chile

Angel Roco-Videla:Universidad Arturo Prat, Iquique-Chile


Abstract
This research investigates the application of novel functionally graded small-scale materials (FGSMs) in sport and sports structures through an engineering design lens. Functionally graded materials (FGMs) offer tailored material properties, promising enhanced performance and durability. Utilizing an interdisciplinary approach, this study explores the integration of FGSMs in sports equipment and infrastructure. Design considerations specific to sports engineering are emphasized, including lightweight, high-strength materials capable of withstanding dynamic loads. Advanced manufacturing techniques, such as additive manufacturing and nanotechnology, enable precise control over material composition and microstructure. Computational modeling is employed to evaluate the mechanical behavior and performance characteristics of FGSM-based components. Through case studies and comparative analyses, the study showcases the potential of FGSMs to revolutionize sports equipment and structures, offering improved performance, safety, and sustainability. This research contributes to the advancement of sports engineering by exploring the design and application of FGSMs in sport and sports structures.

Key Words
functionally graded structures; light-weight structures; numerical analysis; sport; stability analysis

Address
Changyou Wang:Capital University of Economics and Business, Fengtai, 100070, Beijing, 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)Department of Mechanical Engineering, Faculty of Engineering, Haliç University, 34060, Istanbul, Turkey
4)Institute of Research and Development, Duy Tan University, Da Nang 550000, Viet Nam
5)Faculty of Electrical-Electronic Engineering, Duy Tan University, Da Nang 550000, Viet Nam

Tayebeh Mahmoudi:Hoonam Sanat Farnak, Engineering and Technology knowledge-based enterprise Company, Ilam, Iran

Abstract
A very widely used analytical method (mathematical model), mentioned in Eurocode 3, to examine the connections' bending behavior is the component-based method that has certain weak points shown in the plastic behavior part of the momentrotation curves. In the component method available in Eurocode 3, for simplicity, the effect of strain hardening is omitted, and the bending behavior of the connection is modeled with the help of a two-line diagram. To make the component method more efficient and reliable, this research proposed its advanced version, wherein the plastic part of the diagram was developed beyond the guidelines of the mentioned Regulation, implemented to connect the end plate, and verified with the moment-rotation curves found from the laboratory model and the finite element method in ABAQUS. The findings indicated that the advanced component method (the method developed in this research) could predict the plastic part of the moment-rotation curve as well as the conventional component-based method in Eurocode 3. The comparison between the laboratory model and the outputs of the conventional and advanced component methods, as well as the outputs of the finite elements approach using ABAQUS, revealed a different percentage in the ultimate moment for bolt-extended end-plate connections. Specifically, the difference percentages were -31.56%, 2.46%, and 9.84%, respectively. Another aim of this research was to determine the optimal dimensions of the end plate joint to reduce costs without letting the mechanical constraints related to the bending moment and the resulting initial stiffness, are not compromised as well as the safety and integrity of the connection. In this research, the thickness and dimensions of the end plate and the location and diameter of the bolts were the design variables, which were optimized using Particle Swarm Optimization (PSO), Snake Optimization (SO), and Teaching Learning-Based Optimization (TLBO) to minimization the connection cost of the end plate connection. According to the results, the TLBO method yielded better solutions than others, reducing the connection costs from 43.97 to 17.45€ (60.3%), which shows the method's proper efficiency.

Key Words
ABAQUS; advanced component-based method; FEM; moment-rotation curve; optimization algorithms

Address
Ali Sadeghi:Civil Engineering Department, University of Sistan and Baluchestan, Zahedan, Iran

Mohammad Reza Sohrabi:Civil Engineering Department, University of Sistan and Baluchestan, Zahedan, Iran

Seyed Morteza Kazemi:Department of Civil Engineering, Kashmar Branch, Islamic Azad University, Kashmar, Iran

Abstract
This paper proposes an analytical solution for the free vibration, bending and buckling a functionally graded (FG) beam resting on viscoelastic foundation. The materials characteristics of the FG beam are considered to be varying across the thickness according several power law functions. The governing equations are found analytically using a quasi-3D model that contains undetermined integral forms and involves few unknowns to derive. Navier's method for simply supported beam is employed to solve the problem. Numerical examples are presented and studied to demonstrate the accuracy and effectiveness of the proposed model. Then, a detailed parametric study is presented in the form of tables and graphs to study and analyze the effects of the different parameters on the response of FG beams with different material compositions resting on a viscoelastic foundation.

Key Words
bending; FG beam; material composition; vibration; buckling; viscoelastic foundation

Address
Brahim Laoud:Material and Hydrology Laboratory, Civil Engineering Department, Faculty of Technology, University of Sidi Bel Abbes, Algeria

Samir Benyoucef:Material and Hydrology Laboratory, Civil Engineering Department, Faculty of Technology, University of Sidi Bel Abbes, Algeria
Attia Bachiri:Departement genie civil, faculte de genie civil et d'architecture, Universite Ammar Telidji Laghouat, Algeria

Rabbab Bachir Bouiadjra:1)Material and Hydrology Laboratory, Civil Engineering Department, Faculty of Technology, University of Sidi Bel Abbes, Algeria
2)Departement of Civil Engineering, University Mustapha Stambouli of Mascara, Algeria

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

Mahmoud M Selim:Department of Mathematics, College of Science and Humanities, Prince Sattam bin Abdulaziz University, Al-Kharj 11942, Saudi Arabia

Hosam A. Saad:Department of Chemistry, College of Science, Taif University, P.O. Box 11099, Taif, 21944, Saudi Arabia

Abstract
The management of waste tire rubber has become a pressing environmental and health issue, requiring sustainable solutions to mitigate fire hazards and conserve natural resources. The performance of waste materials in structural components needs to be investigated to fabricate sustainable structures. This study aims to investigate the behavior of glass fiber reinforced polymer (GFRP) reinforced rubberized concrete (GRRC) compressive components under compressive loads. Nine GRRC circular compressive components, varying in longitudinal and transverse reinforcement ratios, were constructed. A 3D nonlinear finite element model (FEM) was proposed by means of the ABAQUS software to simulate the behavior of the GRRC compressive components. A comprehensive parametric analysis was conducted to assess the impact of different parameters on the performance of GRRC compressive components. The experimental findings demonstrated that reducing the spacing of GFRP stirrups enhanced the ductility of GRRC compressive components, while the addition of rubberized concrete further improved their ductility. Failure in GRRC compressive components occurred in a compressive columnar manner, characterized by vertical cracks and increased deformability. The finite element simulations closely matched the experimental results. The proposed empirical model, based on 600 test samples and considering the lateral confinement effect of FRP stirrups, demonstrated higher accuracy (R2=0.835, MSE = 171.296, MAE = 203.549, RMSE = 195.438) than previous models.

Key Words
axial strength; compressive components; Finite Element Model (FEM); GFRP bars; waste tire rubber aggregates

Address
Mohamed Hechmi El Ouni:1)Department of Civil Engineering, College of Engineering, King Khalid University, PO Box 394, Abha 61411 KSA.
2)Center for Engineering and Technology Innovations, King Khalid University, Abha 61421, Saudi Arabia

Ali Raza:Department of Civil Engineering, University of Engineering and Technology Taxila, 47050, Pakistan

Abstract
Analytical methods for assessment of the out-of-plane buckling of unbraced top chords of truss bridges may look obsolete while comparing them to finite element analysis. However they are, usually, superior when rapid assessment is necessary. Analytical methods consider the top chord as a bar on elastic supports provided by bracing (Holt, Timoshenko). Correct assessment of the support elasticity (stiffness) is crucial. In the case of truss bridge spans of traditional structural layout (cross-beams at the truss chord nodes only), the elasticity may be set based on the analysis of the, so called, U-frame stiffness. Here the analyses consider the U-frame itself (a pair of verticals and a cross-beam) or the U-frame with adjacent diagonals or the pair of diagonals (in the absence of verticals) and the members of the bottom chord in the adjacent panels. For all the cases, the stability analysis of the chord as a bar in compression is necessary. Unfortunately, the method cannot be applied to contemporary truss bridges without verticals, that usually have independent cross-beam decks (the cross-beams attached to truss chords at their nodes and between them). This is the motivation for the analysis resulting in the method of setting the stiffness of the equivalent U-frame for the aforementioned truss bridges. Truss girders of both, gussetless and gusseted, joints are taken into account.

Key Words
critical force; gussetless truss girder; half-through truss bridge; stability; unbraced chord

Address
Wojciech Siekierski :Poznan University of Technology, ul. Piotrowo 5, 61-138 Poznan, Poland

Abstract
This article focuses on the static and dynamic analysis and optimization of an anisogrid lattice plate subjected to axial compressive load with simply supported boundary conditions. The lattice plate includes diagonal and transverse ribs and is modeled as an orthotropic plate with effective stiffness properties. The study employs the first-order shear deformation theory and the Ritz method with a Legendre approximation function. In the realm of optimization, the Non-dominated Sorting Genetic Algorithm-II is utilized as an evolutionary multi-objective algorithm to optimize. The research findings are validated through finite element analysis. Notably, this study addresses the less-explored areas of optimizing the geometric parameters of the plate by maximizing the buckling load and natural frequency while minimizing mass. Furthermore, this study attempts to fill the gap related to the analysis of the post-buckling behavior of lattice plates, which has been conspicuously overlooked in previous research. This has been accomplished by conducting nonlinear analyses and scrutinizing post-buckling diagrams of this type of lattice structure. The efficacy of the continuous methods for analyzing the natural frequency, buckling, and post-buckling of these lattice plates demonstrates that while a degree of accuracy is compromised, it provides a significant amount of computational efficiency.

Key Words
anisogride; buckling; free vibration; lattice plate; multi-objective optimization; post-buckling; Ritz method

Address
F. Rashidia, A. Farrokhabadi and M. Karamooz Mahdiabadi:Department of Mechanical Engineering, Tarbiat Modares University, Tehran, Iran

Abstract
This study presents a replaceable reduced beam section (R-RBS) located at the column end in moment resisting frames (MRFs). An end of the R-RBS is connected to column by using end-plate moment connection and the other end of that is connected to main beam with beam splice connection. Therefore, the RBS that is expected to yield under an earthquake can be easily replaceable. Geometry of the RBS and the thickness of the beam splice connection are the prime variables of this study. A total of eight experimental test was carried out to examine the seismic performance of the proposed R-RBS with the connection details. The results obtained from experimental studies demonstrated that plate sizes of the beam splice connection significantly affect the seismic performance of RBSs used in MRFs.

Key Words
beam to column connections; moment resisting frame; reduced beam section; replaceable; splice

Address
Yasin Onuralp Ozkilic:1)Department of Civil Engineering, Faculty of Engineering, Necmettin Erbakan University, Konya 42000, Turkey
2)Department of Civil Engineering, Lebanese American University, Byblos, Lebanon
3)World-Class Research Center "Advanced Digital Technologies", State Marine Technical University,
Saint Petersburg, 190121, Russian Federation

Mehmet Bakir Bozkurt:Department of Civil Engineering, Manisa Celal Bayar University, Manisa, 45140, Turkey

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