Abstract
The three-phase-lag model, thermoelasticity without energy dissipation (G-N II) theory and thermoelasticity with energy dissipation (G-N III) theory are applied to study the effect of rotation on a fiber-reinforced thermoelastic medium. The exact expressions for the physical quantities were obtained by using the normal mode analysis. The numerical results for the field quantities are given in the physical domain and illustrated graphically in the absence and presence of rotation, Coriolis acceleration as well as reinforcement parameters.
Key Words
fiber-reinforced; coriolis acceleration; Green-Naghdi theory; thermoelasticity; multi-phase-lag
Address
Amnah M. Alharbi: Department of Mathematics, College of Science, Taif University, P.O. Box 11099, Taif, 21944, Saudi Arabia
Samia M. Said and Mohamed I.A. Othman: Department of Mathematics, Faculty of Science, Zagazig University, P.O. Box 44519, Zagazig, Egypt
Abstract
Hollow structural section (HSS) columns have been increasingly popular due to their structural and architectural merits. However, practical difficulty lies in developing proper connections. The through-diaphragm connections are considered as suitable connection type that is widely adopted in Asian countries. However, the stress concentration occurs at the location connecting through-diaphragm and steel beam. Furthermore, the actual load path from the beam flange is not uniformly transferred to the HSS column as conventionally assumed. In this paper, tensile tests were further conducted on three additional specimens with beam flange plate to evaluate the load versus displacement response. The load-displacement curves, yield and ultimate capacity, ductility ratio were obtained. Furthermore, the strain development at different loading levels was discussed comprehensively. It is shown that the studied connection configuration significantly reduces the stress concentration. Meanwhile, simplified trilinear load-displacement analytical model for specimen under tensile load was presented. Good agreement was found between the theoretical and experimental results.
Key Words
structural behavior; HSS column; connection; tensile loading; analytical model
Address
Ying Qin: Key Laboratory of Concrete and Prestressed Concrete Structures of Ministry of Education, School of Civil Engineering, Southeast University, Nanjing, China;
State Key Laboratory of Green Building in Western China, Xi'an University of Architecture & Technology, Xi'an, China
Jingchen Zhang, Peng Shi, Yifu Chen, Yaohan Xu and Zuozheng Shi: Key Laboratory of Concrete and Prestressed Concrete Structures of Ministry of Education, School of Civil Engineering, Southeast University, Nanjing, China
Abstract
In this research paper, the free vibrational response of laminated composite plates is investigated using a non-polynomial refined shear deformation theory (NP-RSDT). The most interesting feature of this theory is the parabolic distribution of transverse shear deformations while ensuring the conditions of nullity of shear stresses at the free surfaces of the plate without requiring the Shear correction factor "Ks". A fourth-nodded isoparametric element with four degrees of freedom per node is employed for laminated composite plates. The numerical analysis of simply supported square anti-symmetric cross-ply and angle-ply laminated plate is carried out using a special discretization based on four-node finite element method which four degrees of freedom per node. Several numerical results are presented to show the effect of the coupling parameters of the plate such as the modulus ratios, the thickness ratio and the plate layers number on adimensional eigen frequencies. All numerical results presented using the current finite element method (FEM) is presented in 3D curve form.
Key Words
laminated composite plates; free vibration; refined plate theory; finite element method, eigen frequencies
Address
Mohammed Sehoul: Laboratory of Materials and Reactive Systems, Department of mechanical Engineering, University of Sidi Bel Abbes,
Faculty of Technology, Algeria;
Département de Technologie, Centre Universitaire Nour Bachir. EL Bayadh, BP 900 El Bayadh 32000 Algeria
Soumia Benguediab: Material and Hydrology Laboratory, University of Sidi Bel Abbes, Faculty of Technology, Civil Engineering Department, Algeria;
Université Dr Tahar Moulay, Faculté de Technologie, Département de Génie Civil et Hydraulique,
BP 138 Cité En-Nasr 20000 Saida, Algérie
Mohamed Benguediab: Laboratory of Materials and Reactive Systems, Department of mechanical Engineering, University of Sidi Bel Abbes,
Faculty of Technology, Algeria
Mahmoud M. Selim: Department of Mathematics, Al-Aflaj College of Science and Humanities, Prince Sattam bin Abdulaziz University, Al-Aflaj 710-11912 Saudi Arabia
Fouad Bourada: Material and Hydrology Laboratory, University of Sidi Bel Abbes, Faculty of Technology, Civil Engineering Department, Algeria;
Département des Sciences et de la Technologie, université de Tissemsilt, BP 38004 Ben Hamouda, Algeria
Abdelouahed Tounsi: Material and Hydrology Laboratory, University of Sidi Bel Abbes, Faculty of Technology, Civil Engineering Department, Algeria;
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
Muzamal Hussain: Department of Mathematics, Govt. College University Faisalabad, 38000, Faisalabad, Pakistan
Abstract
Concrete filled steel tubes (CFSTs) are extensively used in a variety of structures due to their structural and economic advantages over other types of structures. Considerable research has been conducted with regards to their short-term behaviour, and very limited studies have focused on their long-term behaviour. In this study, a series of tests were carried out on high strength squat (short) CFSTs and concrete cylinders under controlled conditions of temperature and humidity to better understand their time dependent behaviour. A number of parameters were investigated including the influence of steel and concrete bond, confinement, level of sustained load and sizes of specimens. The results revealed that creep strains increased by more than 40% if there was no bonding between steel tube and concrete core. As expected, creep and shrinkage of concrete inside a steel tube were significantly less than those developed in exposed concrete. At the end of a creep period of six months, all the specimens were tested to failure to observe the influence of sustained loads on the ultimate strength. It was found that creep does not have a major effect on the strength of short CFSTs in the specific experimental study conducted here, which was less than 2.5%.
Key Words
concrete-filled steel tubes; composite; creep; high strength; shrinkage
Address
Saad Younas and Ehab Hamed: School of Civil and Environmental Engineering, The University of New South Wales, Sydney, Australia
Dongxu Li and Brian Uy: School of Civil Engineering, The University of Sydney, NSW 2006, Australia
Abstract
Plastic deformation of link beams in eccentrically braced frames is the primary dissipating source of seismic energy. Despite the excellent compatibility with the architectural designs, previous researches indicate the deficiency of flexural yielding links compared to the shear yielding ones because of their localized plastic deformation. Previous investigations have shown that implementing web openings in beams could be an efficient method to improve the seismic performance of moment-resisting connections. Accordingly, this research investigates the use of flexural links with stiffened and un-stiffened web openings to eliminate localized plasticity at the ends of the link. For this purpose, the numerical models are generated in finite element software "Abaqus" and verified against experimental data gathered from other studies. Models are subjected to cyclic displacement history to evaluate their behavior. Failure of the numerical models under cyclic loading is simulated using a micromechanical based damage model known as Cyclic Void Growth Model (CVGM). The elastic stiffness and the strength-based and CVGM-based inelastic rotation capacity of the links are compared to evaluate the studied models' seismic response. The results of this investigation indicate that some of the flexural links with edge stiffened web openings show increased inelastic rotation capacity compared to an un-perforated link.
Key Words
Eccentrically Braced Frames (EBF); Reduced web section (RWS); finite element modeling (FEM); cyclic loading
Address
S. Erfani and A. Vakili: Department of Civil and Environmental Engineering, Amirkabir University of Technology, Tehran, Iran
V. Akrami: Faculty of Engineering, University of Mohaghegh Ardabili, Ardabil, Iran
Abstract
The compressive strength of circular concrete filled steel tubular (C-CFST) stubs strengthened with carbon fiber reinforced polymer (CFRP) is studied theoretically. According to previous experimental results, the failure process and mechanism of circular CFRP-concrete filled steel tubular (C-CFRP-CFST) stubs is analyzed, and the loading process is divided into 3 stages, i.e., elastic stage, elasto-plastic stage and failure stage. Based on continuum mechanics, the theoretical model of C-CFRP-CFST stubs under axial compression is established based on the assumptions that steel tube and concrete are both in three-dimensional stress state and CFRP is in uniaxial tensile stress state. Equations for calculating the yield strength and the ultimate strength of C-CFRP-CFST stubs are deduced. Theoretical predictions from the presented equations are compared with existing experimental results. There are a total of 49 tested specimens, including 15 ones for comparison of yield strength and 44 ones for comparison of ultimate strength. It is found that the predicted results of most specimens are within an error limit of 10%. Finally, simplified equations for calculating both yield strength and ultimate strength of C-CFRP-CFST stubs are proposed.
Abstract
Currently, there is a lack of research in the design approach to avoid column wall failure in the concrete filled double skin steel tubular (CFDST) column-beam connections. In this paper, a finite element model has been developed and verified by available experimental data to analyze the failure mechanism of CFDST column-beam connections. Various finite element models with different column hollow ratios () were established. The simulation result revealed that with increasing the failure mode gradually changed from yielding of end plate, to local failure of the column wall. Detailed parametric analyses were performed to study the failure mechanism of column wall for the CFDST column-beam connection, in which the strength of sandwiched concrete and steel tube and thickness of steel tube were incorporated. An analytical model was proposed to predict the moment resistance of the assembled connection considering the failure of column wall. The simulation results indicate that the proposed analytical model can provided a conservative prediction of the moment resistance. Finally, an upper bound value of was recommend to avoid column wall failure for CFDST column-beam connections.
Key Words
concrete filled double skin steel tubular; column wall failure; finite element model; assembled beam to column connection
Address
Lei Guo and Wanqian Wang: School of Civil Engineering, Hefei University of Technology, Tunxi Road 193, Anhui Province, 230009, China
Jingfeng Wang and Binggen Zhan: School of Civil Engineering, Hefei University of Technology, Tunxi Road 193, Anhui Province, 230009, China;
Anhui Civil Engineering Structures and Materials Laboratory, Tunxi Road 193, Anhui Province, 230009, China
T.Y. Yang: Department of Civil Engineering, University of British Columbia, Vancouver, BC, Canada
Abstract
This paper investigates the effect of micromechanical models on the bending behavior of bidirectional functionally graded (BDFG) beams subjected to different mechanical loading. The material properties of the beam are considered to be graded in both axial and thickness directions according to a power law. The beam's behavior is modeled by the mean of quasi 3D displacement field that contain undetermined integral terms and involves a reduced unknown functions. Navier's method is employed to determine and compute the displacements and stress for a simply supported beam. Different homogenization schemes such as Voigt, Reus, and Mori-Tanaka are employed to analyze the response of the BDFG beam subjected to linear, uniform, exponential and sinusoidal distributed loading. The results obtained by the present method are compared with available results in the literature and a good agreement was found. Several numerical results are presented in tabular form and in figures to examine the effects of the material gradation, micromechanical models and types of loading on the bending response of BDFG beams. It can be concluded that the present theory is not only accurate but also simple in predicting the bending response of BDFG beam subjected to different static loads.
Key Words
BDFG beams; quasi-3D model; bending; micromechanical models; different loading; displacements; stress
Address
Abdeljalil Meksi: Departement of Civil engineering, Faculty of architecture and civil engineering,
University of sciences and technology Mohamed Boudiaf, Oran, Algeria
Samir Benyoucef and Mohamed Sekkal: Material and Hydrology Laboratory, University of SidiBel Abbes, Faculty of Technology, Algeria
Rabbab Bachir Bouiadjra: Material and Hydrology Laboratory, University of SidiBel Abbes, Faculty of Technology, Algeria;
Departement of Civil Engineering, University Mustapha Stambouli of Mascara, Algeria
Mahmoud M. Selim: 4Department of Mathematics, Al-Aflaj College of Science and Humanities,
Prince Sattam bin Abdulaziz University, Al-Aflaj 710-11912, Saudi Arabia
Abdelouahed Tounsi: Material and Hydrology Laboratory, University of SidiBel Abbes, Faculty of Technology, Algeria;
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;
Muzamal Hussain: Department of Mathematics, Govt. College University Faisalabad, 38000, Faisalabad, Pakistan
