Finite Element Modeling of Composites System in Aerospace Application

2012 ◽  
Vol 245 ◽  
pp. 316-322
Author(s):  
Ramadan A. Al-Madani ◽  
M. Jarnaz ◽  
K. Alkharmaji ◽  
M. Essuri
Keyword(s):  
Finite Element ◽  
Composite Structure ◽  
Composite Laminates ◽  
Composite Structures ◽  
Mechanical Response ◽  
Laminated Composite ◽  
Orthotropic Materials ◽  
Laminate Structure ◽  
Metallic Structures ◽  
Modeling And Analysis

The characteristics of composite materials are of high importance to engineering applications; therefore the increasing use as a substitute for conventional materials, especially in the field of aircraft and space industries. It is a known fact that researchers use finite element programs for the design and analysis of composite structures, use of symmetrical conditions especially in complicated structures, in the modeling and analysis phase of the design, to reduce processing time, memory size required, and simplifying complicated calculations, as well as considering the response of composite structures to different loading conditions to be identical to that of metallic structures. Finite element methods are a popular method used to analyze composite laminate structures. The design of laminated composite structures includes phases that do not exist in the design of traditional metallic structures, for instance, the choice of possible material combinations is huge and the mechanical properties of a composite structure, which are anisotropic by nature, are created in the design phase with the choice of the appropriate fiber orientations and stacking sequence. The use of finite element programs (conventional analysis usually applied in the case of orthotropic materials) to analysis composite structures especially those manufactured using angle ply laminate techniques or a combination of cross and angle ply techniques, as well considering the loading response of the composite structure to be identical to that of structures made of traditional materials, has made the use of, and the results obtained by using such analysis techniques and conditions questionable. Hence, the main objective of this paper is to highlight and present the results obtained when analyzing and modeling symmetrical conditions as applied to commercial materials and that applied to composite laminates. A comparison case study is carried out using cross-ply and angle-ply laminates which concluded that, if the composition of laminate structure is pure cross-ply, the FEA is well suited for predicting the mechanical response of composite structure using principle of symmetry condition. On the other hand that is not the case for angle-ply or mixed-ply laminate structure.

Design and Analysis of an Aircraft Composite Hinge Bracket Using Finite Element Approach

2014 ◽  
Vol 629 ◽  
pp. 158-163
Author(s):  
Wai Chee Mun ◽  
Ahmad Rivai ◽  
Omar Bapokutty
Keyword(s):  
Finite Element ◽  
Composite Structures ◽  
Laminated Composite ◽  
Composite Plates ◽  
Metallic Structures ◽  
Aircraft Structures ◽  
Finite Element Approach ◽  
Heterogeneous Nature ◽  
Element Approach ◽  
Margin Of Safety

The use of composite materials in aircraft structures have been increasing for the past decade. The anisotropic and heterogeneous nature of composites remains a major challenge to the design and analysis of composite aircraft structures. Composite structures require a different design approach compared to the design of metallic structures. This paper aims to provide a step by step definitive guide to design and analyze composite structures using finite element approach. A simplified design model for the composite structural design was used to analyze an aircraft composite hinge bracket. The composite hinge bracket which is made of IM7/8552 laminated composite plates was successfully designed with a margin of safety of 0.216 and a weight savings of 43.77 percent was estimated.

Effect of Ply Stacking Sequence on Structural Response of Symmetric Composite Laminates

2014 ◽  
Author(s):  
Mosfequr Rahman ◽  
Saheem Absar ◽  
F. N. U. Aktaruzzaman ◽  
Abdur Rahman ◽  
N. M. Awlad Hossain
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Analytical Model ◽  
Composite Laminates ◽  
Structural Response ◽  
Laminated Composite ◽  
Analytical Models ◽  
Orthotropic Materials ◽  
Stacking Sequence ◽  
Element Analysis

In this work, the effect of ply stacking sequence on the structural response of multi-ply unidirectional fiber-reinforced composite laminates was evaluated using finite element analysis. The objective of this study was to develop a computational model to analyze the stress response of individual plies in a composite laminate for a given stacking sequence. A laminated composite plate structure under tensile loading was modeled in ANSYS. Stress profiles of the individual plies were obtained for each lamina. An Epoxy matrix with both unidirectional Graphite and Kevlar fibers was considered for the model. Three dimensional sectioned shell elements (SHELL181) were used for meshing the model. Several sets of stacking sequences were implemented, symmetrical to the mid-plane of the laminate. Symmetric stacking configurations of 6 layers stacked in ply angles of [0/45/-45]s, [0/60/-60]s, [0/45/90]s, and an 8-layered arrangement of [0/45/60/90]s were modeled for the analysis. The layer thickness was maintained at 0.1 mm. The results were compared against an analytical model based on the generalized Hooke’s law for orthotropic materials and classical laminate theory. A numerical formulation of the analytical model was implemented in MATLAB to evaluate the constitutive equations for each lamina. The stress distributions obtained using finite element analysis have shown good agreement with the analytical models in some of the cases.

A Study of the Effect of Finite Element Meshing in the Modeling of Elastoplastic Degradation of Composite Laminates

2017 ◽  
Vol 14 (01) ◽  
pp. 1730001 ◽  
Author(s):  
S. Sadat ◽  
A. Mokaddem ◽  
B. Doumi ◽  
N. Benrekaa ◽  
A. Boutaous ◽  
...  
Keyword(s):  
Finite Element ◽  
Composite Laminates ◽  
Composite Structures ◽  
Laminated Composite ◽  
Mesh Size ◽  
Industrial Applications ◽  
Simulation And Optimization ◽  
Laminated Composite Structures ◽  
Finite Element Meshing ◽  
Good Agreement

Due to the increased use of composite materials in industrial applications, reliable and consistent finite element methods are required for the simulation and optimization of composite structures. In this paper, we presented the effect of finite element meshing in the modeling of degradation in composite structures under tensile stress; we have used an elastoplastic model to simulate the damage and plasticity behavior occurring in laminated composite structures carbon/epoxy: T300/914. This model works with different elements and the results obtained are not sensitive to mesh size. Thus, we have showed that two different meshes give the same results. Our findings are in good agreement compared to the experimental data.

Inelastic finite element analysis of fibre-reinforced composite laminates with damage

1998 ◽  
Vol 212 (8) ◽  
pp. 717-729
Author(s):  
C L Chow ◽  
F Yang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Composite Laminates ◽  
Composite Structures ◽  
Laminated Composite ◽  
Equilibrium Equations ◽  
Element Analysis ◽  
Finite Element Program ◽  
Reinforced Composite ◽  
Non Linear

In this study, a method of finite element analysis is presented to examine the three-dimensional inelastic behaviour of fibre-reinforced composite laminates with damage. The constitutive model for the characterization of mechanical responses of non-linear composite materials to damage that was proposed recently by the authors is employed. The formulation of the elastic damage stress-strain relationship in incremental form is first developed and then incorporated within the context of the displacement-based finite element procedure. Solution of the non-linear equilibrium equations is obtained with the modified Newton—Raphson iteration technique. Numerical implementation of the stress calculation is discussed in detail. Results predicted using the present finite element program for uniaxial off-axis tensile loading of unidirectional graphite/epoxy composite laminates show satisfactory agreement with those obtained from experiments. Other results describing the development of damage zones, the inelastic effect on stress distributions and material property variations due to damage in cross-ply laminated composite structures are also examined and discussed.

A Spectral Finite Element Model for Wave Propagation Analysis in Laminated Composite Plate

2006 ◽  
Vol 128 (4) ◽  
pp. 477-488 ◽  
Author(s):  
A. Chakraborty ◽  
S. Gopalakrishnan
Keyword(s):  
Finite Element ◽  
Wave Propagation ◽  
Shear Deformation ◽  
Mechanical Response ◽  
Laminated Composite ◽  
Wave Number ◽  
Single Element ◽  
Element Formulation ◽  
Frequency Wave ◽  
Spectral Finite Element

A new spectral plate element (SPE) is developed to analyze wave propagation in anisotropic laminated composite media. The element is based on the first-order laminated plate theory, which takes shear deformation into consideration. The element is formulated using the recently developed methodology of spectral finite element formulation based on the solution of a polynomial eigenvalue problem. By virtue of its frequency-wave number domain formulation, single element is sufficient to model large structures, where conventional finite element method will incur heavy cost of computation. The variation of the wave numbers with frequency is shown, which illustrates the inhomogeneous nature of the wave. The element is used to demonstrate the nature of the wave propagating in laminated composite due to mechanical impact and the effect of shear deformation on the mechanical response is demonstrated. The element is also upgraded to an active spectral plate clement for modeling open and closed loop vibration control of plate structures. Further, delamination is introduced in the SPE and scattered wave is captured for both broadband and modulated pulse loading.

scholarly journals An Improved Analytical Solution for Process-Induced Residual Stresses and Deformations in Flat Composite Laminates Considering Thermo-Viscoelastic Effects

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2506 ◽  
Author(s):  
Chao Liu ◽  
Yaoyao Shi
Keyword(s):  
Differential Equation ◽  
Finite Element ◽  
Analytical Solution ◽  
Residual Stresses ◽  
Composite Laminates ◽  
Composite Structures ◽  
Numerical Models ◽  
Element Analysis ◽  
Current Time ◽  
Viscoelastic Effects

Dimensional control can be a major concern in the processing of composite structures. Compared to numerical models based on finite element methods, the analytical method can provide a faster prediction of process-induced residual stresses and deformations with a certain level of accuracy. It can explain the underlying mechanisms. In this paper, an improved analytical solution is proposed to consider thermo-viscoelastic effects on residual stresses and deformations of flat composite laminates during curing. First, an incremental differential equation is derived to describe the viscoelastic behavior of composite materials during curing. Afterward, the analytical solution is developed to solve the differential equation by assuming the solution at the current time, which is a linear combination of the corresponding Laplace equation solutions of all time. Moreover, the analytical solution is extended to investigate cure behavior of multilayer composite laminates during manufacturing. Good agreement between the analytical solution results and the experimental and finite element analysis (FEA) results validates the accuracy and effectiveness of the proposed method. Furthermore, the mechanism generating residual stresses and deformations for unsymmetrical composite laminates is investigated based on the proposed analytical solution.

Analysis of Symmetric Angle-Ply Laminated Composite Skew Plates Using Hybrid Trefftz Finite Element

2019 ◽  
Author(s):  
Subhasankar Dwibedi
Keyword(s):  
Finite Element ◽  
Composite Structures ◽  
Plate Theory ◽  
Laminated Composite ◽  
Composite Plates ◽  
Point Load ◽  
Shear Stresses ◽  
Skew Angle ◽  
Distributed Load ◽  
Trefftz Finite Element

Abstract Analysis of symmetric angle-ply skew laminated composite plates has been presented in the study using a newly developed hybrid Trefftz finite element (hTFE). Mindlin’s plate theory has been used to develop the present hTFE. The forms of displacement are assumed such that governing partial differential equations are satisfied a priori inside the element domain. Particular solutions of the governing equations have been ignored and Trefftz functions are derived using the homogenous solutions only. Inter-element continuity has been established by employing another displacement field along the edges of the hTFEs. The transverse shear stresses have been ignored at the top and bottom surfaces of the laminate. The angle of inclination of the width of the plate with the y-axis has been taken as the skew angle and different forms of skew plates are obtained by varying the skew angle. Sinusoidally distributed load (SDL), uniformly distributed load (UDL), and point load (PL) have been subjected to the top surface of the laminate and the non-dimensionalized center point deflection have been evaluated to assess the performance of the present hTFE. The observation from the present study further reinforce the versatility of the hTFE method for analysis of composite structures with complex shapes or geometries.

scholarly journals Finite Element Modelling of Frequency-Dependent Dynamic Behaviour of Viscoelastic Composite Structures

2004 ◽  
Vol 13 (1) ◽  
pp. 096369350401300 ◽  
Author(s):  
Evgeny Barkanov ◽  
Andris Chate
Keyword(s):  
Finite Element ◽  
Composite Structures ◽  
Laminated Composite ◽  
Element Analysis ◽  
Viscoelastic Composite ◽  
Fitting Procedure ◽  
Damping Characteristics ◽  
Storage And Loss Moduli ◽  
Free Vibration Frequency ◽  
Viscoelastic Layers

Finite element analysis of sandwich and laminated composite structures with viscoelastic layers is performed. The present implementation gives the possibility to preserve the frequency dependence for the storage and loss moduli of viscoelastic materials exactly. Moreover, the storage and loss moduli in this case are defined directly in the frequency domain by an experimental technique for each material and can be used after curve fitting procedure in the numerical analysis. Damping characteristics of viscoelastic composite structures are evaluated by the energy method, the method of complex eigenvalues, from the resonant peaks of the frequency response function and using the steady state vibrations. Numerical examples are given to demonstrate the validity and application of the approaches developed for the free vibration, frequency and transient response analyses.

Mechanical Behavior of Laminated Composites with Circular Holes

2013 ◽  
Vol 550 ◽  
pp. 1-8 ◽  
Author(s):  
Habib Achache ◽  
Benali Boutabout ◽  
Djamel Ouinas
Keyword(s):  
Finite Element ◽  
Stress Concentration ◽  
Composite Structures ◽  
Laminated Composites ◽  
Three Dimensional ◽  
Laminated Composite ◽  
Element Formulation ◽  
Composites Materials ◽  
Circular Holes ◽  
Fibers Orientation

This paper presents a numerical method for the evaluation of the stress concentration factor (SCF) in three dimensional laminated composites under mechanical loads. The proposed method uses the finite element formulation. The composites materials based on the epoxy matrix and reinforcing fibers are extensively used in aircraft structures due to their high specific characteristics. However, the withstanding of composite structures can be significantly reduced by the addition of geometric singularities, such as perforations or notches. To Analyses the stress concentration around geometrical notches, several studies as analytical, numerical and experimental techniques are available. The stress distribution in a laminated composite plate with the presence of a circular hole was investigated using the finite element method. In order, the results obtained by this study are compared with those reported in literature. The aim of this analysis is to evaluate numerically the factor of stress concentration under the influence of several parameters such as fibers orientation, the mechanical characteristics of composites and the distance between notches of cross-laminated.

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