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    Three-dimensional interlaminar stress analysis at free edges of general cross-ply composite laminates

    , Article Materials and Design ; Volume 24, Issue 2 , 2003 , Pages 121-130 ; 02641275 (ISSN) Tahani, M ; Nosier, A ; Sharif University of Technology
    2003
    Abstract
    A layerwise theory is used to investigate analytically the interlaminar stresses near the free edges of general cross-ply composite laminates under uniform axial extension. Laminates with finite dimensions are considered and full three-dimensional stresses in the interior and the boundary-layer regions are calculated. The results obtained from this theory are compared with those available in the literature. It is found that the edge-effect problem of general cross-ply laminates is actually a quasi three-dimensional problem and its stress analysis can be restricted to a generic two-dimensional cross-section of the laminates. © 2003 Elsevier Science Ltd. All rights reserved  

    Edge effects of uniformly loaded cross-ply composite laminates

    , Article Materials and Design ; Volume 24, Issue 8 , 2003 , Pages 647-658 ; 02641275 (ISSN) Tahani, M ; Nosier, A ; Sharif University of Technology
    Elsevier Ltd  2003
    Abstract
    Interlaminar stresses resulting from bending of rectangular cross-ply composite laminates are determined using a layer wise laminate theory. Two types of laminates are considered. First a fully simply supported laminate subjected to bi-directional bending is analyzed. The results obtained from this theory are compared with those of the published three-dimensional elasticity solutions to verify the validity and accuracy of the present theory. Then laminates with two edges simply supported and the other two edges free are examined. The results indicate the presence of significant interlaminar stresses near the free edges. © 2003 Elsevier Ltd. All rights reserved  

    Free edge stress analysis of general cross-ply composite laminates under extension and thermal loading

    , Article Composite Structures ; Volume 60, Issue 1 , 2003 , Pages 91-103 ; 02638223 (ISSN) Tahani, M ; Nosier, A ; Sharif University of Technology
    2003
    Abstract
    An elasticity formulation for finite general cross-ply (symmetric and unsymmetric) laminates subjected to extension and/or a layerwise temperature distribution is developed. It is shown that the edge-effect problem of such laminates is actually a quasi-threedimensional problem and its stress analysis can be restricted to a generic two-dimensional cross-section of the laminates. A layerwise theory is used to investigate analytically the interlaminar stresses near the free edges of general cross-ply composite laminates. The results obtained from this theory are compared with those available in the literature. It is found that the theory can predict very accurately the stresses in the interior... 

    A finite element model for tapered laminated beams incorporated with magnetorheological fluid using a layerwise model under random excitations

    , Article Mechanics of Advanced Materials and Structures ; Apr , 2018 , Pages 1-8 ; 15376494 (ISSN) Momeni, S ; Zabihollah, A ; Behzad, M ; Sharif University of Technology
    Taylor and Francis Inc  2018
    Abstract
    Laminated composite beams with variable thickness are being widely used in many engineering applications. To enhance the dynamic behavior of structures subject to random loading, tapered laminated beams incorporated with magnetorheological (MR) fluids (MR-tapered beam) are proposed. A finite element model has been developed for random vibration analysis of MR-tapered beam based on layerwise displacement theory. The effects of thickness ratios of tapered beam, magnetic fields, statistical properties, correlation and autocorrelation on dynamic behaviors of structures have been investigated. The proposed structural element significantly enhances the dynamic response of MR-tapered beam under... 

    A finite element model for tapered laminated beams incorporated with magnetorheological fluid using a layerwise model under random excitations

    , Article Mechanics of Advanced Materials and Structures ; Volume 27, Issue 1 , 2020 , Pages 12-19 Momeni, S ; Zabihollah, A ; Behzad, M ; Sharif University of Technology
    Taylor and Francis Inc  2020
    Abstract
    Laminated composite beams with variable thickness are being widely used in many engineering applications. To enhance the dynamic behavior of structures subject to random loading, tapered laminated beams incorporated with magnetorheological (MR) fluids (MR-tapered beam) are proposed. A finite element model has been developed for random vibration analysis of MR-tapered beam based on layerwise displacement theory. The effects of thickness ratios of tapered beam, magnetic fields, statistical properties, correlation and autocorrelation on dynamic behaviors of structures have been investigated. The proposed structural element significantly enhances the dynamic response of MR-tapered beam under... 

    Stress analysis in symmetric composite laminates subjected to shearing loads

    , Article International Journal of Mechanical Sciences ; Volume 75 , 2013 , Pages 16-25 ; 00207403 (ISSN) Mousanezhad viyand, D ; Yazdani Sarvestani, H ; Nosier, A ; Sharif University of Technology
    2013
    Abstract
    In the present study, an analytical solution is proposed to determine the interlaminar stresses in long symmetric laminated composite plates subjected to shearing loads. An improved first-order shear deformation theory (IFSDT) and a simplified IFSDT (SIFSDT) are utilized to calculate the unknown constants appearing in the reduced elasticity displacement field which actually demonstrate the global deformations of the plate. Then the numerical values of the interlaminar normal and shear stresses are established through the laminates by using Reddy's layerwise theory. Finally, several numerical examples are presented to study the interlaminar stresses in the interfaces of the layers and through... 

    Development of an accurate finite element model for N-layer MR-laminated beams using a layerwise theory

    , Article Mechanics of Advanced Materials and Structures ; Volume 25, Issue 13 , 2018 , Pages 1148-1155 ; 15376494 (ISSN) Momeni, S ; Zabihollah, A ; Behzad, M ; Sharif University of Technology
    Abstract
    Laminated composite beams incorporated with magneto-rheological fluid are being used in variety of critical applications. An N-layer magneto-rheological-laminated beam based on layerwise theory has been developed to study the dynamic characteristics. For simulation purpose, an MR-laminated beam with five layers is considered in which two layers filled with magneto-rheological and three layers are made of composite materials. The results of simulations are compared with existing layerwise, first-order shear-deformation theory and experimental tests where it shows the accuracy and functionality of the present model. The complex shear modulus of magneto-rheological fluid has been determined... 

    Interlaminar hygrothermal stresses in laminated plates

    , Article International Journal of Solids and Structures ; Volume 44, Issue 25-26 , 2007 , Pages 8119-8142 ; 00207683 (ISSN) Bahrami, A ; Nosier, A ; Sharif University of Technology
    2007
    Abstract
    Within the elasticity formulation the most general displacement field for hygrothermal problems of long laminated composite plates is presented. The equivalent single-layer theories are then employed to determine the global deformation parameters appearing in the displacement fields of general cross-ply, symmetric, and antisymmetric angle-ply laminates under thermal and hygroscopic loadings. Reddy's layerwise theory is subsequently used to determine the local deformation parameters of various displacement fields. An elasticity solution is also developed in order to validate the efficiency and accuracy of the layerwise theory in predicting the interlaminar normal and shear stress... 

    Vibration behavior of laminated composite beams integrated with magnetorheological fluid layer

    , Article Journal of Mechanics ; Volume 33, Issue 4 , 2017 , Pages 417-425 ; 17277191 (ISSN) Naji, J ; Zabihollah, A ; Behzad, M ; Sharif University of Technology
    Cambridge University Press  2017
    Abstract
    Vibration behavior of adaptive laminated composite beams integrated with magnetorheological (MR) fluid layer has been investigated using layerwise displacement theory. In most of the existing studies on the adaptive laminated beams with MR fluids, shear strain across the thickness of magnetorheological (MR) layer has been assumed a constant value, resulting in a constant shear stress in MR layer. However, due to the high shear deformation pattern inside MR layer, this assumption is not adequate to accurately describe the shear strain and stress in MR fluid layer. In this work a modified layerwise theory is employed to develop a Finite Element Model (FEM) formulation to simulate the laminated... 

    Free vibration analysis of rotating laminated cylindrical shells under different boundary conditions using a combination of the layerwise theory and wave propagation approach

    , Article Scientia Iranica ; Volume 16, Issue 2 B , 2009 , Pages 168-176 ; 10263098 (ISSN) Ramezani, S ; Ahmadian, M. T ; Sharif University of Technology
    2009
    Abstract
    In this paper, vibration analysis of rotating laminated composite cylindrical shells using a combination of the layerwise theory and wave propagation approach is investigated. This combination enables us to study all the conventional boundary conditions in our analysis. Results obtained have been compared with those available in the literature and a good agreement has been observed. In contrast to the Equivalent Single Layer theories (ESL), the layerwise theory is constructed on the basis ofC°- continuity through the laminate thickness. For the surface of the shell, a displacement field based on the wave propagation approach is proposed. The effect of Coriolis and centrifugal accelerations... 

    Stress Analysis in Symmetric Composite Laminates Subjected to Shearing Load

    , M.Sc. Thesis Sharif University of Technology Mousanezhad Viyand, Davood (Author) ; Nosier, Asghar (Supervisor)
    Abstract
    In the present study, an analytical solution is developed to calculate the interlaminar stresses in long symmetric laminated composite plates subjected to shearing load. At first, upon the successive integrations of the strain-displacement relations and using the existing patterns in deformation of a long symmetric laminate, the general displacement field is extracted and simplified to the final form. Presented solution is based on a combined method containing the equivalent single-layer (ESL) theories beside the Reddy’s layerwise theory. In this method, the equivalent single-layer theories are utilized because of their simplicity and low computational efforts rather than the layerwise... 

    Inter-Laminar Stress Analysis in Boundary Layer Region of Symmetrically Laminated Plates Under Torsion

    , M.Sc. Thesis Sharif University of Technology Jamalimehr, Amin (Author) ; Nosier, Asghar (Supervisor)
    Abstract
    In the present research an analytical solution is studied for interlaminar stresses in boundary layer region of symmetric composite laminates under torsion. Based on geometrical and physical grounds the existing displacement field in literature is simplified in order to accommodate to torsion of symmetric laminates. Displacement field is divided to global and local parts. The solution procedure consists of combined equivalent single layer theories and layerwise theory of Reddy. ESL theories are more computationally economic while LWTs are considerably accurate in determining local behavior of plate. Further, based on second order shaer deformation theory and Ritz approximate variational... 

    Vibration Based Health Monitoring for Damage Detection of Composite Laminates

    , M.Sc. Thesis Sharif University of Technology Ghaffari, Hamid Reza (Author) ; Zabihollah, Abolghasem (Supervisor)
    Abstract
    Development of composite materials is one of the boldest technological advances of the last half of the twentieth century. This is due to their specific characteristics mostly considerably high strength-to-weight ratio, compared to metals and their highly customizing properties for different applications which make them a suitable material to be used in variety of domain from aerospace and automobiles to medical and sport equipments. Multi-stable asymmetrical laminates and non-uniform thickness laminated composite beams are being used as structural elements in a wide range of advanced engineering applications. Multi-stable asymmetrical laminates can be snapped between two or more geometries... 

    Layerwise theory in modeling of magnetorheological laminated beams and identification of magnetorheological fluid

    , Article Mechanics Research Communications ; Volume 77 , 2016 , Pages 50-59 ; 00936413 (ISSN) Naji, J ; Zabihollah, A ; Behzad, M ; Sharif University of Technology
    Elsevier Ltd 
    Abstract
    In recent years, structures integrated with magnetorheological (MR) fluid have been considered for their tunable dynamic characteristics. Shear modulus of MR layer in composite structure is dramatically lower than the elastic layers, leading to high shear deformation inside the MR layer, thus classical theories are not accurate enough to predict the dynamic behavior of such structures. In present study a layerwise displacement theory has been utilized to predict a more accurate deformation for MR-composite beam and equation of motions derived using finite element model (FEM). ASTM E756-98 was employed to evaluate the complex shear modulus of MR fluid. By experimental test a practical... 

    Development of an accurate finite element model for N-layer MR-laminated beams using a layerwise theory

    , Article Mechanics of Advanced Materials and Structures ; 2017 , Pages 1-8 ; 15376494 (ISSN) Momeni, S ; Zabihollah, A ; Behzad, M ; Sharif University of Technology
    Taylor and Francis Inc  2017
    Abstract
    Laminated composite beams incorporated with magneto-rheological fluid are being used in variety of critical applications. An N-layer magneto-rheological-laminated beam based on layerwise theory has been developed to study the dynamic characteristics. For simulation purpose, an MR-laminated beam with five layers is considered in which two layers filled with magneto-rheological and three layers are made of composite materials. The results of simulations are compared with existing layerwise, first-order shear-deformation theory and experimental tests where it shows the accuracy and functionality of the present model. The complex shear modulus of magneto-rheological fluid has been determined... 

    Vibration characteristics of laminated composite beams with magnetorheological layer using layerwise theory

    , Article Mechanics of Advanced Materials and Structures ; Volume 25, Issue 3 , 2018 , Pages 202-211 ; 15376494 (ISSN) Naji, J ; Zabihollah, A ; Behzad, M ; Sharif University of Technology
    Taylor and Francis Inc  2018
    Abstract
    Vibration characteristics of laminated composite beams with magnetorheological (MR) layer are investigated using layerwise theory. In most studies, shear strain across the thickness of MR layer has been considered as a constant value, which does not precisely describe the shear strain. In this study, layerwise theory is employed to develop a finite element formulation to investigate MR-laminated beams. Experimental tests under different magnetic fields are carried out to verify the numerical results. Layerwise numerical results are compared with the experimental results and other theories. An empirical expression for complex shear modulus is presented. The effects of MR layer thickness on... 

    Free-edge stresses in general composite laminates

    , Article International Journal of Mechanical Sciences ; Volume 50, Issue 10-11 , 2008 , Pages 1435-1447 ; 00207403 (ISSN) Nosier, A ; Maleki, M ; Sharif University of Technology
    2008
    Abstract
    In the present study, by starting from the reduced form of elasticity displacement field for a long flat laminate, an analytical method is developed in order to accurately calculate the interlaminar stresses near the free edges of generally laminated composite plates under extension. The constant parameter appearing in the reduced displacement field, which describes the global rotational deformation of a laminate, is appropriately obtained by employing an improved first-order shear deformation theory. The accuracy and effectiveness of the proposed first-order theory are verified by means of comparison with the results of Reddy's layerwise theory as a three-dimensional benchmark. Reddy's... 

    Interlaminar stresses in antisymmetric angle-ply laminates

    , Article Composite Structures ; Volume 78, Issue 1 , 2007 , Pages 18-33 ; 02638223 (ISSN) Nosier, A ; Bahrami, A ; Sharif University of Technology
    2007
    Abstract
    Based on elasticity theory the reduced form of displacement field is developed for long antisymmertic angle-ply composite laminates subjected to extensional and/or torsional loads. Analytical solutions to the edge-effect problem of such laminates under a uniform axial strain are developed using the first-order shear deformation theory of plates and Reddy's layerwise theory. For a special set of boundary conditions an elasticity solution is presented to verify the validity and accuracy of the layerwise theory. Various numerical results are then developed within the layerwise theory for the interlaminar stresses through the thickness and across the interfaces of antisymmetric angle-ply... 

    Free-edge stresses in antisymmetric angle-ply laminates in extension and torsion

    , Article International Journal of Solids and Structures ; Volume 43, Issue 22-23 , 2006 , Pages 6800-6816 ; 00207683 (ISSN) Nosier, A ; Bahrami, A ; Sharif University of Technology
    2006
    Abstract
    The first-order shear deformation theory and the layerwise theory of laminated plates are employed to analyze the edge-effect problem of an antisymmetric angle-ply laminate subjected to arbitrary combinations of extensional and torsional loads. The first-order theory is used for predicting the unknown constant parameters appearing in the reduced displacement field of elasticity which, on the other hand, signify the global behavior of the laminate. A layerwise theory is then utilized to determine the local interlaminar stresses within the boundary-layer regions of laminates. In order to closely examine the behavioral characteristics of interlaminar stresses, various numerical examples are... 

    Stress Analysis of in Cross-ply Laminates in Bending

    , M.Sc. Thesis Sharif University of Technology Yazdani Sarvestani, Hamid Reza (Author) ; Nosier, Asghar (Supervisor)
    Abstract
    In the present study, an analytical solution is developed to calculate the interlaminar stresses in long generally cross-ply laminated composite plates subjected to bending. At first, upon the integration of the strain-displacement relations and using the existing patterns in deformation of the long laminate, the general displacement field is extracted and simplified to the final form. Presented solution is based on a combined method containing the equivalent single-layer (ESL) theories beside the Reddy’s layerwise theory. In this method, the equivalent single-layer theories are utilized because of their simplicity and low computational efforts rather than the layerwise theory in evaluation...