Abstract
The main objective of this paper is to investigate the buckling behavior of symmetric and non-symmetric carbon nanotube-reinforced composite (CNTRC) nanobeams with nonlocal strain gradient effects. For this purpose, a novel trigonometric shear deformation beam theory is employed, and the Galerkin method is used for analysis. The carbon nanotube-reinforced composite beam consists of a polymeric matrix reinforced with aligned and distributed single-walled carbon nanotubes (SWCNTs) having various reinforcement patterns. The material properties of the carbon nanotube-reinforced composite beams are estimated using the rule of mixture. The governing equations of the problem are derived based on the principle of total potential energy. The proposed theory accurately represents the parabolic distribution of transverse shear stress across the beam thickness and satisfies the zero traction boundary
conditions on the top and bottom surfaces without requiring shear correction factors. The mathematical models presented in this work are validated numerically by comparing them with existing literature to assess their accuracy and reliability. The buckling analyses of the carbon nanotube-reinforced composite nanobeams are conducted, considering various factors such as beam types, nonlocal length-scale parameter, strain gradient microstructure-scale parameter, geometry, carbon nanotube volume fraction, and boundary conditions. Additionally, new results are reported in this study, which can serve as a benchmark for future research.
Key Words
CNTRC beams; elastic buckling; Galerkin method; higher order nonlocal strain gradient theory; shear deformation beam theory
Address
Djillali Mokhefi, Aicha Bessaim, Mohammed Sid Ahmed Houari: 1Laboratoire d'Etude des Structures et de Mécanique des Matériaux, Département de Génie Civil, Faculté des Sciences et de la Technologie, Université Mustapha Stambouli, B.P. 305, R.P., Mascara 29000, Algeria
Zakaria Deffane: Aerospace Engineering Division, Universitat Politécnica de Catalunya, 08034, Barcelona, Spain
Hakima Houari-Belkadi: Dental Technology and Biomaterials Research Laboratory, Department of Dentistry-Oran's, Faculty of Medicine, University of Oran, 31000, Algeria
Belhocine Ali: Laboratoire d'Etude des Structures et de Mécanique des Matériaux, Département de Génie Civil, Faculté des Sciences et de la Technologie, Université Mustapha Stambouli, B.P. 305, R.P., Mascara 29000, Algeria
Ahmed Amine Daikh: Laboratoire d'Etude des Structures et de Mécanique des Matériaux, Département de Génie Civil, Faculté des Sciences et de la Technologie, Université Mustapha Stambouli, B.P. 305, R.P., Mascara 29000, Algeria; Artificial Intelligence Laboratory for Mechanical and Civil Structures, and Soil, University Centre of Naama, P.O. Box 66, Naama 45000, Algeria
Habib Hebali, Hadj Youzera: Laboratoire d'Etude des Structures et de Mécanique des Matériaux, Département de Génie Civil, Faculté des Sciences et de la Technologie, Université Mustapha Stambouli, B.P. 305, R.P., Mascara 29000, Algeria
Tarek Merzouki: LISV, University of Versailles Saint-Quentin, 10-12 avenue de l'Europe, 78140 Vélizy, France
Abstract
This paper is concerned with the study of propagation of Stoneley waves at the interface of two dissimilar transversely isotropic thermoelastic solids using new modified couple stress theory without energy dissipation and with two temperatures. The secular equation of Stoneley waves is derived in the form of the determinant by using appropriate boundary conditions i.e., the stress components, the displacement components, and temperature at the boundary surface between the two media are considered to be continuous at all times and positions. The dispersion curves giving the Stoneley wave velocity and attenuation coefficients with wave number are computed numerically. Numerical simulated results are depicted graphically to show the effect of two temperature on resulting quantities. Copper material has been chosen for the medium M_1 and magnesium for the medium M_2. Some special cases are also deduced from the present investigation.
Key Words
attenuation coefficient; new modified couple stress theory; secular equation; Stoneley wave velocity; Stoneley wave; transversely isotropic; two-temperatures
Address
Parveen Lata and Harpreet Kaur: Department of Mathematics, Punjabi University, Patiala, Punjab, India
Abstract
The GM(1,1) gray forecasting model is a type of short-term forecasting technique that has been successfully applied to management and engineering problems with only four dates. However, when a new system is built, the system is uncertain and variable, so the data collected is usually not clear, which cannot be used to predict the GM(1,1) gray model. To solve this problem, the fuzzy system derived from the collected fuzzy gray control parameter data is considered as derivation of GM(1,1) fuzzy gray model to obtain the projection values under the fuzzy system to be predicted. The method isn't restricted to either the TS fuzzy or Mamdani type. The proposed solution based on stability guarantee is a local one. Finally, an example will be described for clarification. A single controller can compensate for the effects of noise and harmonic noise at many performance points. And the dynamic performance of a single controller is satisfactory during the transient. for fairness Numerical and computer experiments are described in the perfection of the methods we offer in research.
Address
C.C. Hung: Faculty of National Hsin Hua Senior High School, Tainan, Taiwan
T. Nguyễn: Ha Tinh University, Dai Nai Ward, Ha Tinh City, Vietnam
C.Y. Hsieh: National Pingtung University Education School,
No.4-18, Minsheng Rd., Pingtung City, Pingtung County 900391, Taiwan
Abstract
Energy piles are green foundations that utilize the ground as a heat source or reservoir to provide renewable energy for buildings. However, the thermal cycles induced by energy piles may affect their structural behavior and interaction with the soil under seismic loading. This paper presents the first comprehensive study of the seismic performance of a high-rise building (HRB) on energy piled raft foundation using numerical modeling and simulation. A three-dimensional finite element model of a 15-story building with energy piles is developed and subjected to four different earthquake scenarios. The results show that the energy piles can reduce the seismic demand of the building in the cooling cycle, but they also increase the soil-structure interaction and pile-soil-pile interaction effects in the heating cycle. This paper also provides some insights for improving the seismic performance of high-rise buildings (HRBs) on energy piled raft foundations by using tuned mass dampers (TMDs) which can contribute to reducing the seismic response of the HRB when the soil is heated in the exchange of heat between the piles and the soil in the hot season.
Key Words
energy piles; high-rise building (HRB); numerical modeling; raft foundation; reinforced concrete (RC); seismic mitigation; seismic response; soil-pile-structure interaction; tuned mass damper (TMD)
Address
Denise-Penelope N. Kontoni: Department of Civil Engineering, School of Engineering, University of the Peloponnese, GR-26334 Patras, Greece; School of Science and Technology, Hellenic Open University, GR-26335 Patras, Greece
Ahmed Abdelraheem Farghaly: Department of Civil and Architectural Constructions, Faculty of Technology and Education, Sohag University, Sohag, 82524, Egypt
Abstract
The paper deals with a dynamic engineering problem in which a mass attached to a pendulum slides along a cable. In this problem, the pendulum mass and the cable are coupled in a model described by a system of algebraic differential equations (DAE). In this paper, the formulation of the system of differential equations modelling the problem is presented together with the determination of the initial conditions. The developed model is general in the sense of a free choice of support location, elastic rope properties, pendulum length and the inclusion of braking forces. This model can be used in the design of real rope structures such as zip lines. Many calculated values that can be measured on a real structure can be exported from the model and used for parameter calibration. In one example, the model is related to a real rope structure to illustrate and validate the model. The most important aspect of the model is its ability to estimate the safety of a ropeway quickly and easily.
Key Words
differential algebraic equations; elastic 3D rope/cable; sliding 3D pendulum; sliding mass
