Plasticity Analysis of Laminated Composite Plates

1982 ◽  
Vol 49 (4) ◽  
pp. 740-746 ◽  
Author(s):  
Y. A. Bahei-El-Din ◽  
G. J. Dvorak
Keyword(s):  
Composite Laminates ◽  
Laminated Composite ◽  
Composite Plates ◽  
Laminated Plates ◽  
Plastic Behavior ◽  
Elastic Plastic ◽  
Local Stresses ◽  
The Individual ◽  
Hardening Rules ◽  
Yield Conditions

Elastic-plastic behavior of symmetric metal-matrix composite laminates is analyzed for the case of in-plane mechanical loading. The overall response of the laminate at each instant is derived from the elastic-plastic deformation of the individual fibrous layers, and from their mutual constraints. Constitutive equations of the laminated plates are presented in terms of initial yield conditions, hardening rules, and instantaneous compliances. Local stresses, hardening parameters, and strains are found in each lamina and in the fiber and matrix phases within each lamina. Specific results are obtained with the continuum model of elastic-plastic fibrous composites [1] which has been recently developed by the authors. Comparisons of analytical results with experimental measurements are made for certain laminated plates.

Buckling of the Composite Laminates under Mechanical Loads with Different Layups using Different Plate Theories

2015 ◽  
Vol 24 (1) ◽  
pp. 096369351502400 ◽  
Author(s):  
Mohammad Amin Torabizadeh
Keyword(s):  
Composite Laminates ◽  
Laminated Composite ◽  
Composite Plates ◽  
Laminated Plates ◽  
Laminated Composite Plates ◽  
Modulus Ratio ◽  
Type Method ◽  
Verification Method ◽  
Plate Aspect Ratio ◽  
Good Agreement

An analytical and numerical solution for general laminated composite plates under mechanical loading is presented based on different lamination plate theories (CLPT and FSDT). General lamination was evaluated by assumption of cross-ply and angle-ply laminated plates. In order to this, Navier-type method and simply supported boundary conditions for rectangular laminates are applied. As a verification method, a finite element code using ANS YS is also developed. Effects of lamination scheme, axial load direction, modulus ratio, plate aspect ratio and lamination angle on critical buckling loads of laminated composite are also investigated and good agreement is found between evaluated results and those available in open literature.

Physical Ultrasonics of Composites

2011 ◽  
Author(s):  
Dale Chimenti ◽  
Stanislav Rokhlin ◽  
Peter Nagy
Keyword(s):  
Composite Laminates ◽  
Stiffness Matrix ◽  
Composite Plates ◽  
Anisotropic Media ◽  
Anisotropic Materials ◽  
Ultrasonic Waves ◽  
Laminated Plates ◽  
Structure Characteristic ◽  
Major Advance

Physical Ultrasonics of Composites is a rigorous introduction to the characterization of composite materials by means of ultrasonic waves. Composites are treated here not simply as uniform media, but as inhomogeneous layered anisotropic media with internal structure characteristic of composite laminates. The objective here is to concentrate on exposing the singular behavior of ultrasonic waves as they interact with layered, anisotropic materials, materials which incorporate those structural elements typical of composite laminates. This book provides a synergistic description of both modeling and experimental methods in addressing wave propagation phenomena and composite property measurements. After a brief review of basic composite mechanics, a thorough treatment of ultrasonics in anisotropic media is presented, along with composite characterization methods. The interaction of ultrasonic waves at interfaces of anisotropic materials is discussed, as are guided waves in composite plates and rods. Waves in layered media are developed from the standpoint of the "Stiffness Matrix", a major advance over the conventional, potentially unstable Transfer Matrix approach. Laminated plates are treated both with the stiffness matrix and using Floquet analysis. The important influence on the received electronic signals in ultrasonic materials characterization from transducer geometry and placement are carefully exposed in a dedicated chapter. Ultrasonic wave interactions are especially susceptible to such influences because ultrasonic transducers are seldom more than a dozen or so wavelengths in diameter. The book ends with a chapter devoted to the emerging field of air-coupled ultrasonics. This new technology has come of age with the development of purpose-built transducers and electronics and is finding ever wider applications, particularly in the characterization of composite laminates.

Determination of Vibration Source Locations in Laminated Composite Plates Using Lamb Wave Analysis

2010 ◽  
Vol 123-125 ◽  
pp. 899-902
Author(s):  
Chao Du ◽  
Qing Qing Ni ◽  
Toshiaki Natsuki
Keyword(s):  
Lamb Wave ◽  
Guided Waves ◽  
Lamb Waves ◽  
Laminated Composite ◽  
Composite Plates ◽  
Wave Dispersion ◽  
Laminated Plates ◽  
Vibration Source ◽  
Arrival Times ◽  
Wave Velocities

Signals propagate on plate-like structures as ultrasonic guided waves, and analysis of Lamb waves has been widely used for on-line monitoring. In this study, the wave velocities of symmetric and anti-symmetric modes in various directions of propagation were investigated. Since the wave velocities of these two modes are different, it is possible to compute the difference in their arrival times when these waves propagated the distance from the vibration source to sensor. This paper presents an evaluation formulation of wave velocity and describes a generalized algorithm for locating a vibration source on a thin, laminated plate. With the different velocities of two modes based on Lamb wave dispersion, the method uses two sensors to locate the source on a semi-infinite interval of a plate. The experimental procedure supporting this method employs pencil lead breaks to simulate vibration sources on quasi-isotropic and unidirectional laminated plates. The transient signals generated in this way are transformed using a wavelet transform. The vibration source locations are then detected by utilizing the distinct wave velocities and arrival times of the symmetric and anti-symmetric wave modes. The method is an effective technique for identifying impact locations on plate-like structures.

A cell-based smoothed finite element formulation for viscoelastic laminated composite plates considering hygrothermal effects

2020 ◽  
pp. 002199832098005
Author(s):  
Sy-Ngoc Nguyen ◽  
Tam T Truong ◽  
Maenghyo Cho ◽  
Nguyen-Thoi Trung
Keyword(s):  
Finite Element ◽  
Shear Deformation Theory ◽  
Laminated Composite ◽  
Composite Plates ◽  
Integral Form ◽  
Complex Stress ◽  
Laminated Plates ◽  
Element Formulation ◽  
Composite Laminated Plates ◽  
Smoothed Finite Element Method

In the present study, the viscoelastic analysis is investigated for composite laminated plates using a smoothed finite element method called cell/element based smoothed discrete shear gap method. Moreover, the hygrothermal effects is considered on the viscoelastic responses of composite laminated plates. The first-order shear deformation theory is employed due to its simplicity and accuracy. With the help of the convolution theorem in Laplace transformation, the complex stress-strain relationship in integral form is simplified to linear in transformed domain. Therefore, all computing procedures are performed in the transformed domain and then, using inverse techniques (Fast Fourier Transform) to converted back to the real-time domain. The study provides an effective computational tool to analyze the viscoelastic response of laminated composite taking into account the influence of the time and hygrothermal effects.

Analytical Solutions of Refined Plate Theories of Cross-Ply Composite Laminates

1991 ◽  
Vol 113 (4) ◽  
pp. 570-578 ◽  
Author(s):  
A. A. Khdeir ◽  
J. N. Reddy
Keyword(s):  
Boundary Conditions ◽  
Exact Solutions ◽  
Composite Laminates ◽  
Laminated Composite ◽  
Composite Plates ◽  
Third Order ◽  
State Space Approach ◽  
Various Boundary Conditions ◽  
Shear Deformation Theories ◽  
Space Approach

Exact solutions of rectangular laminated composite plates with different boundary conditions are studied. The Le´vy-type solutions of the classical, first-order and third-order shear deformation theories are developed using the state-space approach. The finite-element solutions for the three theories are also computed and compared with the exact solutions for various boundary conditions.

scholarly journals Analysis of cross-ply laminated plates using isogeometric analysis and unified formulation

2014 ◽  
Vol 1 (1) ◽  
Author(s):  
S. Natarajan ◽  
A.J.M. Ferreira ◽  
Hung Nguyen-Xuan
Keyword(s):  
Free Vibration ◽  
Isogeometric Analysis ◽  
Laminated Composite ◽  
Composite Plates ◽  
Laminated Plates ◽  
Smooth Functions ◽  
B Splines ◽  
Modification Factor ◽  
Carrera Unified Formulation ◽  
Plate Kinematics

AbstractIn this paper, we study the static bending and free vibration of cross-ply laminated composite plates using sinusoidal deformation theory. The plate kinematics is based on the recently proposed Carrera Unified Formulation (CUF), and the field variables are discretized with the non-uniform rational B-splines within the framework of isogeometric analysis (IGA). The proposed approach allows the construction of higher-order smooth functions with less computational effort.Moreover, within the framework of IGA, the geometry is represented exactly by the Non-Uniform Rational B-Splines (NURBS) and the isoparametric concept is used to define the field variables. On the other hand, the CUF allows for a systematic study of two dimensional plate formulations. The combination of the IGA with the CUF allows for a very accurate prediction of the field variables. The static bending and free vibration of thin and moderately thick laminated plates are studied. The present approach also suffers fromshear locking when lower order functions are employed and shear locking is suppressed by introducing a modification factor. The effectiveness of the formulation is demonstrated through numerical examples.

Investigation on Interlaminar Shear Stresses in Laminated Composite Plates under Thermal and Mechanical Loading

2014 ◽  
Vol 592-594 ◽  
pp. 451-455
Author(s):  
Nagaraj Murugesan ◽  
Vasudevan Rajamohan
Keyword(s):  
Finite Element ◽  
Thermal Environment ◽  
Laminated Composite ◽  
Composite Plates ◽  
Laminated Plates ◽  
Shear Stresses ◽  
Laminated Composite Plates ◽  
Interlaminar Stresses ◽  
Composite Laminated Plates ◽  
Interlaminar Shear

In this study the combined effect of thermal environment and mechanical loadings on the interlaminar shear stresses of both moderately thin and thick composite laminated plates are numerically analyzed. The finite element modeling of laminated composite plates and analysis of interlaminar stresses are performed using the commercially available software package MSC NASTRAN/PATRAN. The validity of the present finite element analysis is demonstrated by comparing the interlaminar stresses developed due to mechanical loadings derived using the present FEM with those of available literature. Various parametric studies are also performed to investigate the effect of thermal environment on interlaminar stresses generated in asymmetric cross-ply composite laminated plates of different length to thickness ratios (L/H) and boundary conditions with identical mechanical loadings. It is observed that the elevated thermal environment under identical mechanical loading lead to higher interlaminar shear stresses varying with length to depth ratio and boundary conditions in asymmetric cross-ply laminated composite plates.

A Novel Finite-Element– Numerical-Integration Model for Composite Laminates Supported on Opposite Edges

2007 ◽  
Vol 74 (6) ◽  
pp. 1114-1124 ◽  
Author(s):  
Tarun Kant ◽  
Sandeep S. Pendhari ◽  
Yogesh M. Desai
Keyword(s):  
Finite Element ◽  
Differential Equations ◽  
Composite Laminates ◽  
Three Dimensional ◽  
Laminated Composite ◽  
Composite Plates ◽  
Coupled System ◽  
Integration Model ◽  
Numerical Integrators ◽  
Support Conditions

An attempt is made here to devise a new methodology for an integrated stress analysis of laminated composite plates wherein both in-plane and transverse stresses are evaluated simultaneously. The method is based on the governing three-dimensional (3D) partial differential equations (PDEs) of elasticity. A systematic procedure is developed for a case when one of the two in-plane dimensions of the laminate is considered infinitely long (y direction) with no changes in loading and boundary conditions in that direction. The laminate could then be considered in a two-dimensional (2D) state of plane strain in x-z plane. It is here that the governing 2D PDEs are transformed into a coupled system of first-order ordinary differential equations (ODEs) in transverse z direction by introducing partial discretization in the finite inplane direction x. The mathematical model thus reduces to solution of a boundary value problem (BVP) in the transverse z direction in ODEs. This BVP is then transformed into a set of initial value problems (IVPs) so as to use the available efficient and effective numerical integrators for them. Through thickness displacement and stress fields at the finite element discrete nodes are observed to be in excellent agreement with the elasticity solution. A few new results for cross-ply laminates under clamped support conditions are also presented for future reference and also to show the generality of the formulation.

scholarly journals Nonlinear Free Vibration for Viscoelastic Moderately Thick Laminated Composite Plates with Damage Evolution

2010 ◽  
Vol 2010 ◽  
pp. 1-15 ◽  
Author(s):  
Y. F. Zheng ◽  
L. Q. Deng
Keyword(s):  
Free Vibration ◽  
Transverse Shear ◽  
Superposition Principle ◽  
Laminated Composite ◽  
Composite Plates ◽  
Laminated Plates ◽  
Damage Effect ◽  
Laminated Composite Plates ◽  
Nonlinear Free Vibration ◽  
The Galerkin Method

The nonlinear free vibration for viscoelastic cross-ply moderately thick laminated composite plates under considering transverse shear deformation and damage effect is investigated. Based on the Timoshenko-Mindlin theory, strain-equivalence hypothesis, and Boltzmann superposition principle, the nonlinear free vibration governing equations for viscoelastic moderately thick laminated plates with damage are established and solved by the Galerkin method, Simpson integration, Newton-Cotes, Newmark, and iterative methods. In the numerical results, the effects of transverse shear, material viscoelasticity, span-thickness ratio, aspect ratio, and damage effect on the nonlinear free vibrating frequency of the viscoelastic cross-ply moderately thick laminated plates are discussed.

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