Abstract
The application of short, fiber-reinforced polymer composite pipes has been increasing rapidly. A comprehensive
review of the prior research reveals that the majority of the previously-reported studies have been conducted on the filamentwound composite pipes, and fewer studies have been reported on the mechanical behavior of short, randomly-oriented fiber
composite pipes. On this basis, the main objective of this research endeavor is to investigate the mechanical behavior and failure
modes of short, randomly-oriented glass-fiber composite pipes under three-point bending tests. To this end, an experimental
study is performed in order to explore the load-bearing capacity, failure mechanism, and deformation performance of such pipes.
Fourteen properly-instrumented composite pipe specimens with different diameters, thicknesses, lengths, and nominal pressures
have been tested and also simulated using the finite element approach for verification purposes. This study demonstrates the
effectiveness of the diameter-to-thickness ratio, length-to-diameter ratio, and nominal pressure on the mechanical behavior and
deformation performance of short, randomly-oriented glass-fiber composite pipes.
Key Words
composite pipe; experimental investigation; finite element simulation; randomly-oriented glass fiber; threepoint bending test
Address
Salar Rasti, Hossein Showkati, Borhan Madroumi Aghbashi and Soheil Nejati Ozani:Department of Civil Engineering, Urmia University, Urmia, Iran
Tadeh Zirakian:Department of Civil Engineering and Construction Management, California State University, Northridge, CA, USA
Abstract
This article investigates the static thermo-mechanical response of anisotropic thick laminated composite plates on
Visco-¬Pasternak foundations under various thermal load conditions (linear, non-linear, and uniform) along the transverse
direction (thickness) of the plate, while keeping the mechanical load constant. The governing equations, which represent the
thermo-mechanical behavior of the composite plate, are derived from the principle of virtual displacements. Using Navier's type
solution, these equations are solved for the composite plate with simply supported condition. The Visco-¬Pasternak foundation
type is included by considering the impact of the damping on the classical foundation model, which is modeled by Winkler's
linear modulus and Pasternak's shear modulus. The excellent accuracy of the present solution is confirmed by comparing the
results with those available in the literature. The study investigates the impact of geometric ratios, thermal expansion coefficient
ratio, damping coefficient and foundation parameters on the thermo-mechanical flexural response of the composite plate.
Overall, this article provides insights into the behavior of composite plates on visco-Pasternak foundations and may be useful for
designing and analyzing composite structures in practical applications.
Key Words
composite laminates; thermo-mechanical load; visco-Pasternak foundations
Address
Fatima Bounouara: 1)Departement de Genie Civil, Faculte d'Architecture et de Genie Civil, Universite des Sciences et de la Technologie d'Oran, BP 1505 El M'naouer, USTO, Oran, Algeria 2)Material and Hydrology Laboratory, University of Sidi Bel Abbes, Faculty of Technology, Civil Engineering Department, Algeria
Mohamed Sadoun: Laboratoire d'Etude des Structures et de Mecanique des Materiaux, Departement de Genie Civil, Faculte des Sciences et de la Technologie,
Universite Mustapha Stambouli B.P. 305, R.P. 29000 Mascara, Algerie
Mahmoud Mohamed Selim Saleh: Department of Mathematics, Al-Aflaj College of Science and Humanities, Prince Sattam Bin Abdulaziz University, Al-Aflaj, Al-Kharj 710- 11912, Saudi Arabia
Abdelbaki Chikh: 1) Material and Hydrology Laboratory, University of Sidi Bel Abbes, Faculty of Technology, Civil Engineering Department, Algeria 2) Universite Ibn Khaldoun, BP 78 Zaaroura, 14000 Tiaret, Algerie
Abdelmoumen Anis Bousahla: 6Laboratoire de Modelisation et Simulation Multi-echelle, Universite de Sidi Bel Abbes, Algeria
Abdelhakim Kaci: 1) Material and Hydrology Laboratory, University of Sidi Bel Abbes, Faculty of Technology, Civil Engineering Department, Algeria 2) Universite Dr. Tahar Moulay, Faculte de Technologie, Departement de Genie Civil et Hydraulique, BP 138 Cite En-Nasr 20000 Saida, Algerie
Fouad Bourada:1) Material and Hydrology Laboratory, University of Sidi Bel Abbes, Faculty of Technology, Civil Engineering Department, Algeria 2) Science and Technology Department, Faculty of Science and Technology, Tissemsilt University, Algeria
Abdeldjebbar Tounsi: Industrial Engineering and Sustainable Development Laboratory, University of Relizane, Faculty of Science & Technology, Mechanical Engineering Department, Algeria
Abdelouahed Tounsi:1) Material and Hydrology Laboratory, University of Sidi Bel Abbes, Faculty of Technology, Civil Engineering Department, Algeria 2)YFL (Yonsei Frontier Lab), Yonsei University, Seoul, Korea 3)Department of Civil and Environmental Engineering, King Fahd University of Petroleum & Minerals, 31261 Dhahran, Eastern Province, Saudi Arabia
Abstract
Experimental and analytical studies were conducted to clarify the influencing mechanisms of the longitudinal
reinforcement on performance of axially loaded Reinforced Concrete-Filled Steel Tube (R-CFST) short columns. The
longitudinal reinforcement ratio was set as parameter, and 10 R-CFST specimens with five different ratios and three ConcreteFilled Steel Tube (CFST) specimens for comparison were prepared and tested. Based on the test results, the failure modes, load
transfer responses, peak load, stiffness, yield to strength ratio, ductility, fracture toughness, composite efficiency and stress state
of steel tube were theoretically analyzed. To further examine, analytical investigations were then performed, material model for
concrete core was proposed and verified against the test, and thereafter 36 model specimens with four different wall-thickness of
steel tube, coupling with nine reinforcement ratios, were simulated. Finally, considering the experimental and analytical results,
the prediction equations for ultimate load bearing capacity of R-CFSTs were modified from the equations of CFSTs given in
codes, and a new equation which embeds the effect of reinforcement was proposed, and equations were validated against
experimental data. The results indicate that longitudinal reinforcement significantly impacts the behavior of R-CFST as steel
tube does; the proposed analytical model is effective and reasonable; proper ratios of longitudinal reinforcement enable the RCFSTs obtain better balance between the performance and the construction cost, and the range for the proper ratios is
recommended between 1.0% and 3.0%, regardless of wall-thick
Key Words
analytical study; experimental study; load bearing capacity; longitudinal reinforcement; R-CFST;
reinforcement ratio
Address
Alifujiang Xiamuxi:1)College of Architecture and Civil Engineering, Xinjiang University, Urumqi 830017, China
2(Key Laboratory of Building Structure and Earthquake Engineering, Urumqi 830017, China
Caijian Liu and Alipujiang Jierula:College of Architecture and Civil Engineering, Xinjiang University, Urumqi 830017, China
Abstract
As the most popular shear connection in composite structures, mature concrete has been widely investigated by
considering mechanical properties of stud connectors (SCs) embedded. To further enhance the fabrication efficiency of
composite structures and solve the contradiction between construction progress and structural performance, it is required to
analyze the shear performance of stud connections of composite structures with different concrete ages. 18 typical vertical pushout tests were carried out on stud shear connectors at concrete ages of 7 days, 14 days, and 28 days. Also, the effects of concrete
age, stud spacing and stud diameter on the shear capacity, connection stiffness and failure mode of the connectors were studied.
A new relationship expression of load-slip for SCs with various concrete ages was proposed. The existing design code for the
SCs shear strength was evaluated according to the experimental data, and a more practical prediction equation for the shear
capacity of SCs with different concrete ages was established. A great agreement was observed between the experimental and
theoretical results, which can provide a reference for engineering practices.
Abstract
In this paper, the dynamic response of a simply-supported composite sandwich plate with a viscoelastic core based
on the Golla-Hughes-McTavish (GHM) viscoelastic model is investigated analytically. The formulation is developed using the
three-layered sandwich panel theory. Hamilton's principle has been employed to derive the equations of motion. Since classical
models, like kelvin-voigt and Maxwell models, cannot express a comprehensive description of the dynamic behavior of
viscoelastic material, the GHM method is used to model the viscoelastic core of the plate in this research. The main advantage of
the GHM model in comparison with classical models is the consideration of the frequency-dependent characteristic of
viscoelastic material. Identification of the material parameters of GHM mini-oscillator terms is an essential procedure in
applying the GHM model. In this study, the focus of viscoelastic modeling is on the development of GHM parameters
identification. For this purpose, a new method is proposed to find these constants which express frequency-dependent behavior
characterization of viscoelastic material. Natural frequencies and loss factors of the sandwich panel based on ESL and threelayered theories in different geometrics are described at 30°C and 90°C; also, the comparisons show that obtained natural
frequencies are grossly overestimated by ESL theory. The argumentations of differences in natural frequencies are also
illustrated in detail. The obtained results show that the GHM model presents a more accurate description of the plate's dynamic
response by considering the frequency dependency behavior of the viscoelastic core.
Abstract
The paper proposes two hybrid metaheuristic optimization and artificial neural network (ANN) methods for the
close prediction of the ultimate axial compressive capacity of concentrically loaded concrete filled double skin steel tube
(CFDST) columns. Two metaheuristic optimization, namely genetic algorithm (GA) and particle swarm optimization (PSO),
approaches enable the dynamic training architecture underlying an ANN model by optimizing the number and sizes of hidden
layers as well as the weights and biases of the neurons, simultaneously. The former is termed as GA-ANN, and the latter as
PSO-ANN. These techniques utilize the gradient-based optimization with Bayesian regularization that enhances the optimization
process. The proposed GA-ANN and PSO-ANN methods construct the predictive ANNs from 125 available experimental
datasets and present the superior performance over standard ANNs. Both the hybrid GA-ANN and PSO-ANN methods are
encoded within a user-friendly graphical interface that can reliably map out the accurate ultimate axial compressive capacity of
CFDST columns with various geometry and material parameters.
Address
Quang-Viet Vu:1)Laboratory for Computational Civil Engineering, Institute for Computational Science and Artificial Intelligence,
Van Lang University, Ho Chi Minh City, Vietnam
2)Faculty of Civil Engineering, School of Technology, Van Lang University, Ho Chi Minh City, Vietnam
3)Center of Excellence in Applied Mechanics and Structures, Department of Civil Engineering,
Chulalongkorn University, Bangkok 10330, Thailand
Sawekchai Tangaramvong and Thu Huynh Van: Center of Excellence in Applied Mechanics and Structures, Department of Civil Engineering,
Chulalongkorn University, Bangkok 10330, Thailand
George Papazafeiropoulos:Department of Structural Engineering, National Technical University of Athens, Zografou, Athens 15780, Greece
Abstract
In order to directly apply seawater and sea sand in construction without desalination, a type of square concrete-filled
steel tube (CFST) encased with prefabricated seawater sea-sand concrete filled Polyvinyl Chloride (PVC)/Glass Fiber
Reinforced Polymer (GFRP) tube column was proposed. Twenty short columns were tested under uniaxial loads, and the test
parameters included inner tube types, seawater sea-sand concrete replacement ratios, concrete strength, the wrapping area of
Carbon Fiber Reinforced Polymer (CFRP) strips and the thickness of GFRP tube. The effects of the parameters on failure
modes, loading capacity, ductility and strain responses were discussed. All the tested specimens failed with serious buckling of
the steel tubes and fracture of the inner tubes. The specimens had good residual bearing capacity corresponding to 64% to 88.9%
of the peak capacity. The inner GFRP tubes and PVC tubes wrapped by CFRP strips provided stronger confinement to the core
concrete, and were good choices for the proposed columns. Moreover, an analytical model for the composite column with
different inner tube types was proposed.
Address
Rong Su and Xian Li:1)Jiangsu Key Laboratory of Environmental Impact and Structural Safety in Civil Engineering,
China University of Mining and Technology, Xuzhou 221116, Jiangsu, China
2)State Key Laboratory for Geomechanics & Deep Underground Engineering,
China University of Mining and Technology, Xuzhou 221116, Jiangsu, China
Ziwei Li:Jiangsu Key Laboratory of Environmental Impact and Structural Safety in Civil Engineering,
China University of Mining and Technology, Xuzhou 221116, Jiangsu, China
Abstract
When studying the resonance problem of nanoplates, the existing papers do not consider the influences of geometric
nonlinearity and initial geometric imperfection, so this paper is to fill this gap. In this paper, based on the nonlocal strain gradient
theory (NSGT), the nonlinear resonances of functionally graded (FG) nanoplates with initial geometric imperfection under
different boundary conditions are established. In order to consider the small size effect of plates, nonlocal parameters and strain
gradient parameters are introduced to expand the assumptions of the first-order shear deformation theory. Subsequently, the
equations of motion are derived using the Euler-Lagrange principle and solved with the help of perturbation method. In addition,
the effects of initial geometrical imperfection, functionally graded index, strain gradient parameter, nonlocal parameter and
porosity on the nonlinear forced vibration behavior of nanoplates under different boundary conditions are discussed.
Key Words
forced vibration; functionally graded material; initial geometric imperfection; nanoplates; nonlocal strain
gradient theory
Address
Jia-Qin Xu, Gui-Lin She, Yin-Ping Li and Lei-Lei Gan:College of Mechanical and Vehicle Engineering, Chongqing University, Chongqing 400044, China
