scholarly journals An Experimental Investigation of Combined Symmetric-Asymmetric Composite Laminates

2019 ◽  
Vol 3 (3) ◽  
pp. 71
Author(s):  
Guy Kemmann ◽  
Oliver Myers
Keyword(s):  
Boundary Condition ◽  
Experimental Investigation ◽  
Finite Element ◽  
Equilibrium State ◽  
Composite Laminates ◽  
Composite Laminate ◽  
Substantial Loss ◽  
Equilibrium Shapes ◽  
Rectangular Laminate ◽  
Clamped Edge

It has been found that certain asymmetric composite laminates exhibit bistability, where the composite laminate exhibits multiple stable static equilibrium states. If the bistable composite is actuated, it will snap to its secondary equilibrium state and then remain there without further actuation. This study investigates how the amount of symmetry in a combined symmetric asymmetric rectangular laminate under an imposed clamped edge boundary condition affects the bistability and the curvature of the laminate. Laminates with varying amounts of asymmetry were fabricated and then measured using a profilometer to capture the curvatures of the equilibrium shapes. The results showed that up to 20% symmetry can be introduced in the laminate without a substantial loss in snap through curvature, and that up to 83% symmetry can be introduced in the laminate before bistability is lost. Finite element simulations were conducted in Abaqus and showed good correlation with the experimental results.

Study on Bearing Behaviors of Bolted Joints in Composite Laminates

2013 ◽  
Vol 652-654 ◽  
pp. 1509-1513
Author(s):  
Tao Huang ◽  
Zhe Su
Keyword(s):  
Experimental Investigation ◽  
Finite Element ◽  
Finite Element Model ◽  
Composite Laminates ◽  
Element Model ◽  
Bolted Joints ◽  
Stress And Strain ◽  
Bolted Joint ◽  
Bearing Stress ◽  
The Relationship

An experimental investigation was conducted to determine the bearing stress of single-lap double bolted composite joints. The bearing stress of a group of specimen was presented and the relationship between the stress and strain was obtained. The experimental results show that the damage of the bolted joints was a progressive process; and the ultimate bearing stress depends not only on the laminates’ strength but also on the bolt strength. A finite element model was created based on the bolted joint specimen to simulate the loading – displacement response. The numerical results verified the experiment results qualitatively.

Analysis of reinforced concrete beams strengthened in flexure with composite laminates

1999 ◽  
Vol 26 (5) ◽  
pp. 646-654 ◽  
Author(s):  
C Nitereka ◽  
K W Neale
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Composite Laminates ◽  
Composite Structures ◽  
Composite Laminate ◽  
Concrete Beams ◽  
Steel Reinforcement ◽  
Nonlinear Finite Element ◽  
Reinforced Concrete Beams ◽  
Reinforced Composite

The structural behaviour of reinforced concrete beams strengthened in flexure by means of externally bonded fibre reinforced composite laminates is simulated numerically using a nonlinear finite element layered model. The full-bond assumption between the composite laminate, steel reinforcement, and the concrete is assumed, and shear deformations are neglected. Interlayer compatibility is achieved by imposing the same displacements at the interfaces of adjacent layers. The concrete is assumed to be nonlinear in compression and to exhibit a post-cracking tension-stiffening behaviour in tension. The behaviour of the steel reinforcement is modelled as elastic-plastic, while that for the composite laminate is linear elastic using an equivalent elastic modulus obtained from the so-called "classical lamination theory" of composite structures. An incremental, iterative displacement-control numerical analysis is developed. The finite element code is validated using published test results for conventional reinforced concrete beams, as well as for beams strengthened with composite laminates. A comparison of the numerical and experimental curves shows very good agreement. The effects of various parameters on the behaviour of composite-strengthened concrete beams are examined.Key words: reinforced concrete beams, fibre reinforced composite strengthening, nonlinear finite element analysis.

Critical buckling load of composite laminates containing delamination using differential quadrature method and ABAQUS finite element

2021 ◽  
pp. 030932472199657
Author(s):  
Hamed Edalati ◽  
Vahid Daghigh ◽  
Kamran Nikbin
Keyword(s):  
Finite Element ◽  
Composite Laminates ◽  
Composite Laminate ◽  
Differential Quadrature Method ◽  
Compressive Load ◽  
Differential Quadrature ◽  
Buckling Load ◽  
Quadrature Method ◽  
Critical Buckling Load ◽  
Finite Element Package

Differential quadrature method (DQM) was used to compute the critical buckling load (CBL) of composite laminates containing complex delamination shapes. The composite laminate was initially flat; however, it buckled under a compressive load due to weak adhesive between the outer ply and the whole composite laminate. Previous data obtained for composite laminates containing circular or elliptical delaminations by finite element and the Rayleigh-Ritz methods as well as DQM available in the literature were used to validate the accuracy of the approach. A good agreement between the results was observed. To show the ability of this approach for calculating the CBL of a composite laminate containing complex delamination shape, a crescent-shaped delamination was considered. The CBLs for various stacking sequences of such a composite laminate were then calculated and discussed. The commercial finite element package, ABAQUS was used to validate the DQM results for crescent delamination.

scholarly journals Effect of repair methods on mechanical behaviors of repair area in composite laminate fuselage skin with different damage size

2018 ◽  
Vol 2 (3) ◽  
Author(s):  
Liping Liu 1 ◽  
Yucan Wang 1 ◽  
Jing Tian 1 ◽  
Ruifeng Wang 1 ◽  
Jianxin Xu 1
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Composite Laminates ◽  
Composite Laminate ◽  
Simulation Models ◽  
Mechanical Behaviors ◽  
Adhesive Film ◽  
Element Simulation ◽  
Hybrid Repair ◽  
Fuselage Skin

Composite laminates are widely used in the large civil aircrafts because of their excellent mechanical properties. The maintenance and repair of composite laminates become essential. In this paper, a new adhesive-rivet hybrid repair of composite laminate fuselage skin is presented. For the circular hole damage with the diameter of 90mm and 50mm, the finite element simulation models of adhesive repair and adhesive-rivet hybrid repair were built respectively. Uniform pressure load was applied on these finite element models. The mechanical properties of laminate motherboard, patch and adhesive film for these four models were analyzed. The effects of adhesive repair, adhesive-rivet hybrid repair on mechanical behaviors of repair areas of composite laminate fuselage skins with different damage size were studied. By analyzing the mechanical behaviors of these two repair methods, a suitable repair method can be obtained.

R-Curve Modelling of Mode I Delamination in Multidirectional Carbon/Epoxy Composite Laminates

2014 ◽  
Vol 606 ◽  
pp. 159-163 ◽  
Author(s):  
K.J. Wong ◽  
Xiao Jing Gong ◽  
Shahram Aivazzadeh ◽  
Mohd Nasir Tamin
Keyword(s):  
Fracture Toughness ◽  
Finite Element ◽  
Composite Laminates ◽  
Composite Laminate ◽  
Epoxy Composite ◽  
Mode I ◽  
Fibre Bridging ◽  
Element Simulation ◽  
Force Displacement ◽  
Mode I Delamination

In the present work, the mode I delamination behaviour of a quasi-isotropic quasi-homogeneous carbon/epoxy composite laminate with adjacent plies of 0o//45o is studied numerically. To describe the R-curve behaviour observed during crack propagation, a linear-exponential traction-separation law is proposed, where the fracture toughness and the increment in the fracture energy could be considered separately in the model. This model is then implemented in the finite element simulation of the delamination process in the composite laminate. Numerical results indicate that with the incorporation of the fibre bridging effect leads to a well-predicted force-displacement response of the composite laminates.

Modelling Orthotropic Viscoelastic Behaviour of Composite Laminates Using a Coincident Element Method

2003 ◽  
Vol 11 (8) ◽  
pp. 669-677 ◽  
Author(s):  
L. Nallainathan ◽  
X.L. Liu ◽  
W.K. Chiu ◽  
R. Jones
Keyword(s):  
Finite Element ◽  
Composite Laminates ◽  
Composite Laminate ◽  
Viscoelastic Behaviour ◽  
Elastic Behaviour ◽  
Shell Elements ◽  
Numerical Examples ◽  
Orthotropic Composites ◽  
Finite Element Package ◽  
Finite Element Procedure

In this paper a finite element procedure for modelling the viscoelastic behaviour of orthotropic composites is presented. The procedure uses the commercially available finite element package ABAQUS and requires no code development. The procedure utilises two coincident shell elements to model the orthotropic viscoelastic behaviour of a composite laminate. The first element exhibits isotropic and viscoelastic behaviour, while the second element exhibits orthotropic and elastic behaviour. The elements are superimposed in such a way that they are coincident. That is, the two shell elements share the same nodes and hence deform together. Consequently, it is expected that this combined hybrid model will exhibit combined orthotropic and viscoelastic behaviour. Numerical examples are presented to illustrate the capability and accuracy of the new procedure.

A Framework for Experimental-Numerical Analysis of Woven Laminates Failure

2014 ◽  
Vol 680 ◽  
pp. 245-248
Author(s):  
Mohd Zailani Mohd Zairil Hafizi ◽  
Mohd Din Muhamad Irwan ◽  
Mohd Adnan Zurri Adam ◽  
Jamaluddin Mahmud
Keyword(s):  
Finite Element ◽  
Composite Laminates ◽  
Composite Laminate ◽  
Deformation Behaviour ◽  
Unidirectional Composite ◽  
Design Parameters ◽  
Woven Composite ◽  
Work Related ◽  
Finite Element Package ◽  
Set Up

Woven composite laminates have been widely used in various application and rapidly replacing unidirectional composite laminates. Thus, it is vital to understand clearly their material parameters and characteristic. Apparently, it is very difficult to analyse the design parameters of a unidirectional composite laminate, and thus due to its weaving structure, analysing numerically the parameters of a woven composite laminate is even more difficult. Therefore, this paper aims to review the work related to woven laminates with respect to its testing and simulations. During the initial stage, a tensile test is conducted according to ASTM D3039 on the 2×2 twill weave carbon fibre woven prepeg where the material constants (E1, E2, G12 and ν12) and the deformation behaviour will be obtained. The later stage will involve the development of a finite element modelling and simulation by means of commercial finite element package ANSYS 14.0 to replicate the experimental set-up. Ultimately, the outcomes and findings between the experimental and numerical approaches will be compared and reported.

A Hybrid Finite Element Approach to Composite Laminate Elasticity Problems With Singularities

1983 ◽  
Vol 50 (4a) ◽  
pp. 835-844 ◽  
Author(s):  
S. S. Wang ◽  
F. G. Yuan
Keyword(s):  
Finite Element ◽  
Composite Laminates ◽  
Composite Laminate ◽  
Stress Singularity ◽  
Free Edge ◽  
Anisotropic Elasticity ◽  
Hybrid Finite Element Method ◽  
Hybrid Finite Element ◽  
Elasticity Problems ◽  
Basic Equations

A hybrid finite element method is presented for studying composite laminate elasticity problems with singularities. The basic equations of laminate anisotropic elasticity and stress singularities in composite laminates are discussed briefly. Formulation of a singular, hybrid composite-wedge element for this class of problems is given in detail. Two numerical examples are shown to illustrate the accuracy and efficiency of the present method of approach. The first example is the well-known laminate free-edge problem, which has a rather weak stress singularity; the second one is the important composite problem, which is shown to have a strong stress singularity. Results are compared with existing analytical elasticity solutions for these problems. Excellent solution accuracy, convergence, and computational efficiency are demonstrated.

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