Reza Attarnejad

Bio: Reza Attarnejad is an academic researcher from University of Tehran. The author has contributed to research in topic(s): Finite element method & Beam (structure). The author has an hindex of 17, co-authored 67 publication(s) receiving 1040 citation(s). Previous affiliations of Reza Attarnejad include University College of Engineering & University of Kashan.

Free vibration and stability analysis of axially functionally graded tapered Timoshenko beams with classical and non-classical boundary conditions

Abstract: Free vibration and stability analysis of axially functionally graded tapered Timoshenko beams are studied through a finite element approach. The exact shape functions for uniform homogeneous Timoshenko beam elements are used to formulate the proposed element. The accuracy of the present element is considerably improved by considering the exact variations of cross-sectional profile and mechanical properties in the evaluation of the structural matrices. Carrying out several numerical examples, the convergence of the method is verified and the effects of taper ratio, elastic constraint, attached mass and the material non-homogeneity on the natural frequencies and critical buckling load are investigated.

Free Vibration and Stability of Axially Functionally Graded Tapered Euler-Bernoulli Beams

Abstract: Structural analysis of axially functionally graded tapered Euler-Bernoulli beams is studied using finiteelement method. A beam element is proposed which takes advantage of the shape functions of homogeneous uniform beam elements. The effects of varying cross-sectional dimensions and mechanical properties of the functionally graded material are included in the evaluation of structural matrices. This method could be used for beam elements with any distributions of mass density and modulus of elasticity with arbitrarily varying cross-sectional area. Assuming polynomial distributions of modulus of elasticity and mass density, the competency of the element is examined in stability analysis, free longitudinal vibration and free transverse vibration of double tapered beams with different boundary conditions and the convergence rate of the element is then investigated.

Assessment of load carrying capacity of castellated steel beams by neural networks

Abstract: In this paper, load carrying capacity of simply supported castellated steel beams, susceptible to web-post buckling, is studied. The accuracy of the nonlinear finite element (FE) method to evaluate the load carrying capacity and failure mode of the beams is discussed. In view of the high computational burden of the nonlinear finite element analysis, a parametric study is achieved based on FE and an empirical equation is proposed to estimate the web-posts’ buckling critical load of the castellated steel beams. Also as other alternatives to achieve this task, the traditional back-propagation (BP) neural network and adaptive neuro-fuzzy inference system (ANFIS) are employed. In this case, the accuracy of the proposed empirical equation, BP network and ANFIS are examined by comparing their provided results with those of conventional FE analysis. The numerical results indicate that the best accuracy associates with the ANFIS and the neural network models provide better accuracy than the proposed equations.

Basic displacement functions for free vibration analysis of non-prismatic Timoshenko beams

Abstract: Presenting new functions, basic displacement functions (BDFs), a novel method based on mechanical/structural principles is introduced for free vibration analysis of arbitrarily tapered Timoshenko beams in preference to primarily mathematically based methodologies. BDFs are obtained through solving the governing equations of transverse motion of Timoshenko beams by means of power series method. It is shown that exact shape functions and consequently structural matrices could be derived in terms of BDFs through a purely mechanical approach. It is also demonstrated that the new shape functions depend on the geometrical and mechanical properties of the beam element and moreover, contrary to usual shape functions used in FE methods, are susceptible to the circular frequency. In order to verify the competency of the proposed method, several numerical examples for classical as well as non-classical boundary conditions are carried out and the results are compared with those in the literature.

A Mechanical-Based Solution for Axially Functionally Graded Tapered Euler-Bernoulli Beams

Abstract: In this article, structural analysis of axially functionally graded tapered beams is studied from a mechanical point of view using a finite element method. Introducing the concept of basic displacement functions (BDFs), it is shown that exact shape functions could be explicitly obtained in terms of BDFs via application of basic principles of structural mechanics. BDFs are obtained using the unit-dummy-load method. Carrying out static analysis, it is verified that exact results are provided by applying one or a few elements. The competency of the present element in stability and free vibration analyses is verified through several numerical examples.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

Introduction to the Finite Element Method

Abstract: This chapter introduces the finite element method (FEM) as a tool for solution of classical electromagnetic problems. Although we discuss the main points in the application of the finite element method to electromagnetic design, including formulation and implementation, those who seek deeper understanding of the finite element method should consult some of the works listed in the bibliography section.

Seismic Design Of Reinforced Concrete And Masonry Buildings

Abstract: Thank you very much for downloading seismic design of reinforced concrete and masonry buildings. As you may know, people have look hundreds times for their chosen novels like this seismic design of reinforced concrete and masonry buildings, but end up in harmful downloads. Rather than reading a good book with a cup of coffee in the afternoon, instead they cope with some infectious virus inside their laptop.

Free vibration analysis of axially functionally graded tapered Bernoulli–Euler microbeams based on the modified couple stress theory

Abstract: In the present study, vibration response of non-homogenous and non-uniform microbeams is investigated in conjunction with Bernoulli–Euler beam and modified couple stress theory. The boundary conditions of the microbeam are considered as fixed at one end and free at the other end. It is taken into consideration that material properties and cross section of the microbeam vary continuously along the longitudinal direction. Rayleigh–Ritz solution method is utilized to obtain an approximate solution to the free transverse vibration problem. A detailed study is carried out to show the effects of material properties and taper ratios on natural frequencies of axially functionally graded tapered microbeams. In order to demonstrate the validity and accuracy of the current analysis, some of present results are compared with previous results in the literature and an excellent agreement is observed between them.