Abstract
The objective of this work is to study the effects of the modification of material properties on the vibration of the FGM beam using an integral shear strain model. In the present theory, the rotational displacement is replaced by an integral term in the displacement fields. The use of a shear correction factor is not necessary because our model gives a parabolic description of shear stress through the thickness while satisfying the conditions of zero shear stresses on the bottom and top surfaces of the beam. The FGM beam is assumed that the beam is a mixture of metal and ceramic, and that its properties change depending on the power functions of the thickness of the beam such as: linear, quadratic, cubic and inverse quadratic. By applying Hamilton's principle, general formulas were obtained
to obtain the frequencies of the FGM beam. The effects of changing compositional characteristics of materials
presented by volume fraction of FGM beams with simply supported edges on free vibration and some mode shapes
are investigated.
Key Words
effects of changing materials properties; FGM beam; integral shear deformation model; vibration
Address
Mokhtar Ellali: Smart Structures Laboratory, University of Ain Témouchent-Belhadj Bouchaib,46000, Algeria
Mashhour A. Alazwari: Mechanical Engineering Department, Faculty of Engineering, King Abdulaziz University, Jeddah, Saudi Arabia
Mokhtar Bouazza: Department of Civil Engineering, University Tahri Mohammed of Bechar, Bechar 08000, Algeria; Laboratory of Materials and Hydrology (LMH), University of Sidi Bel Abbes, Sidi Bel Abbes 2200, Algeria
Mohamed A. Eltaher: Mechanical Design and Production Department, Faculty of Engineering, Zagazig University,
P.O. Box 44519, Zagazig, Egypt; Mechanical Engineering Department, Faculty of Engineering, King Abdulaziz University, P.O. Box 80204, Jeddah, Saudi Arabia
Noureddine Benseddiq: Mechanics Laboratory of Lille, CNRS UMR 8107, University of Lille 1, 59655 Villeneuve d
Abstract
This paper investigates the dynamic response of structures during earthquakes and provides a clear understanding of soil-structure interaction phenomena. It analyses various parameters, comprising ground shear wave velocity and structure properties. The effect of soil impedance function form on the structural response of the system through the use of springs and dashpots with two frequency cases: independent and dependent frequencies. The superstructure and the ground were modeled linearly. Using the substructure method, two different approaches are used in this study. The first is an analytical formulation based on the dynamic equilibrium of the soil-structure system modeled by an analog model with three degrees of freedom. The second is a numerical analysis generated with 2D finite element modeling using ABAQUS software. The superstructure is represented as a SDOF system in all the SSI models assessed. This analysis establishes the key parameters affecting the soil-structure interaction and their effects. The different results obtained from the analysis are compared for each studied case (frequency-independent and frequency-dependent impedance functions). The achieved results confirm the sensitivity of buildings to soil-structure interaction and highlight the various factors and effects, such as soil and structure properties, specifically the shear wave velocity, the height and mass of the structure. Excitation frequency, and the foundation anchoring height, also has a significant impact on the fundamental parameters and the response of the coupled system at the same time. On the other hand, it have been demonstrated that the impedance function forms play a critical role in the accurate evaluation of structural behavior during seismic excitation. As a result, the evaluation of SSI effects on structural response must take into account the dynamic properties of the structure and soil accordingly.
Key Words
impedance function; seismic response; soil-structure interaction (SSI); viscoelastic model
Abstract
This work aims to show a model to estimate the minimum cost (Thickness and area of steel in X and Y directions) for design a circular isolated footing with eccentric column that considers that the surface in contact with the ground works partially under compression. The formulation is shown by integration to find the moments, the bending shears and the punching shear using the pressure volume under the footing. Some researchers show the minimum cost design for circular isolated footings for an eccentric column assuming that the contact area works completely in compression, others consider the contact surface with the ground working partially in compression for a column in the center of the base. Three numerical examples are developed to obtain the complete design, which are: Example 1 for a column in the center of the base, Example 2 for a column at a distance of 1.50 m from the center of the base in the X direction, Example 3 for a column at a distance of 1.50 m from the center of the base in both directions. Also, a comparison of the new model against the model proposed by other authors is presented. The comparison shows that the new model generates a great saving of up to 43.74% for minimum area and 48.44% for minimum cost design in a column located in the center of the base, and when the column is located at a distance of radius/2 starting from the center of the base in the X direction generates great savings of up to 45.24% for minimum area and 31.80% for minimum cost design. Therefore, it is advisable to use the model presented in this study.
Key Words
bending shears; circular isolated footings; minimum cost design; moments; punching shear; surface in contact with the ground works partially under compression
Address
Inocencio Luévanos-Soto: Facultad de Ingeniería, Ciencias y Arquitectura, Universidad Juárez del Estado de Durango,
Av. Universidad S/N, Fracc. Filadelfia, CP 35010, Gómez Palacio, Durango, México
Arnulfo Luévanos-Rojas, Victor Manuel Moreno-Landeros: Instituto de Investigaciones Multidisciplinaria, Universidad Autónoma de Coahuila, Blvd. Revolución No, 151 Ote, CP 27000, Torreón, Coahuila, México
Griselda Santiago-Hurtado: Facultad de Ingeniería Civil, Universidad Autónoma de Coahuila, CP 27276, Torreón, Coahuila, México
Abstract
This paper studies, the analysis of nonlinear thermal vibration of fluid-infiltrated FG nanobeam with voids. The effect of nonlinear thermal in a FG ceramic-metal nanobeam is determined using Murnaghan's model. Here the influence of fluids in the pores is investigated using the Skempton coefficient. Hamilton's principle is used to find the equation of motion of functionally graded nanobeam with the effect of refined higher-order state space strain gradient theory (SSSGT). Numerical solutions of the FG nanobeam are employed using Navier's solution. These solutions are validated against the impact of various parameters, including imperfection ratio, fluid viscosity, fluid velocity, amplitude, and piezoelectric strain, on the behavior of the fluid-infiltrated porous FG nanobeam.
Key Words
FG porous piezoelectric beam; fluid infiltrated nanobeam; nonlinear thermal; Refined higher order SSSGT; variable nonlocal
Address
L. Rubine, R. Selvamani: Department of Mathematics, Karunya Institute of Technology and Sciences, Coimbatore-641114, Tamilnadu, India
F. Ebrahimi: Department of Mechanical Engineering, Imam Khomieni International University, Qazvin, Iran
Abstract
The present study aims to investigate the free vibration of bi-directional functionally graded (BDFG) beams using a refined shear deformation (RSD) theory. Power law variation of material composition was considered along thickness and longitudinal directions. The beams are considered simply supported. The methodology adopted is the Hamilton principle and the governing equation was solved using Navier's method for simply supported boundary conditions. A metal-ceramic combination of materials was used to provide gradation as per power law variation. The equivalent elasticity modulus and density of BDFG were computed using the rule of mixture. The results of the study were related to published works and found to be a good match. The effect of grading parameters
in the thickness and longitudinal direction was studied to investigate its impact on the natural frequency.
Key Words
BDFG beams; free vibration; Hamilton principle; refined shear deformation theory
Address
Nafissa Zouatnia: Department of Civil Engineering, University of Tiaret, BP 78 Zaaroura, Tiaret, 14000, Algeria
Lazreg Hadji: Department of Civil Engineering, University of Tiaret, BP 78 Zaaroura, Tiaret, 14000, Algeria; Laboratory of Geomatics and Sustainable Development, University of Tiaret, Algeria
Hassen Ait Atmane: Laboratory of Structures Geotechnics and Risks, Department of Civil Engineering, Hassiba Benbouali University of Chlef, Algeria
Mokhtar Nebab: Laboratory of Structures Geotechnics and Risks, Department of Civil Engineering, Hassiba Benbouali University of Chlef, Algeria; Department of Civil Engineering, Faculty of Technology, University of M'Hamed BOUGARA Boumerdes, Algeria
Royal Madan: Department of Mechanical Engineering, Graphic Era (Deemed to be University), Dehradun 248002, Uttarakhand, India
Riadh Bennai: Laboratory of Structures Geotechnics and Risks, Department of Civil Engineering, Hassiba Benbouali University of Chlef, Algeria
Mouloud Dahmane: Ecole National Superieur D'hydraulique, Blida, 09000, Blida, Algeria
