Chemical Shrinkage and Residual Stresses in Laminated Composites during Cure

2005 ◽  
Vol 297-300 ◽  
pp. 2870-2875
Author(s):  
Soo Yong Lee ◽  
Jung Sun Park
Keyword(s):  
Finite Element ◽  
Residual Stresses ◽  
Composite Structures ◽  
Laminated Composites ◽  
Shear Deformation Theory ◽  
Chemical Shrinkage ◽  
Element Analysis ◽  
Finite Element Program ◽  
Residual Strains ◽  
Degenerated Shell Element

The residual stress that occurs in fiber-reinforced thermosetting composite materials during cure is one of the severe factors that can deteriorate the performance of composite structures. To investigate residual stresses occurring in laminated composites during cure, an incremental viscoelastic constitutive equation is derived as a function of temperature, degree of cure and chemical shrinkage. A finite element program is developed on the basis of a 3-D degenerated shell element and the first order shear deformation theory. Experiments were performed to measure the coefficients of chemical shrinkage of the Hercules AS4/3501-6 composite during cure. Residual strains were measured using strain gages during cure and compared with the results of finite element analysis. Good agreement is found between numerical and experimental results. It is found that the chemical shrinkage seriously affects the residual strains of the composite during cure.

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.

An Analysis of the Effects of Burnishing in Internal Broaching

2000 ◽  
Vol 28 (2) ◽  
pp. 163-173 ◽  
Author(s):  
V. Sajeev ◽  
L. Vijayaraghavan ◽  
U. R. K. Rao
Keyword(s):  
Finite Element ◽  
Residual Stresses ◽  
Material Behaviour ◽  
Element Analysis ◽  
Finite Element Program ◽  
Left Behind ◽  
The Finite Element Analysis ◽  
Non Linear ◽  
Element Program ◽  
Linear Material

The finite element analysis gives the stresses and deflections of the broach and workpiece while cutting and burnishing. This has been achieved by developing a suitable finite element program for solving linear and non-linear material behaviour problems. The broach has been considered to behave elastically. In case of burnishing, the stresses on the workpiece result in yielding, and hence, non-linear material behaviour is considered for the workpiece. The program has been further modified to compute residual stresses on the broached component. The movement of a single burnishing tooth through the workpiece is simulated in a step-by-step manner, leading to residual stresses on the broached surface. The burnishing tooth and corresponding portion of the workpiece are modelled using FEM. The effect of tool-work interference and the ratio of radial to axial force on the stresses and deflections while burnishing have been studied. The residual stresses left behind on the broached component have been analytically evaluated.

Three-dimensional finite element analysis for temperature filed of composite materials during the cure

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Zhangxin Guo ◽  
Zhiqiang Yu ◽  
Shiyi Wei ◽  
Guoliang Qi ◽  
Yongcun Li ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Composite Structures ◽  
Three Dimensional ◽  
Arbitrary Geometry ◽  
Element Analysis ◽  
Finite Element Program ◽  
Content Type ◽  
Dimensional Finite Element ◽  
Element Program

PurposeThe cure simulation of composite structures with arbitrary geometry can be investigated by the finite element program.Design/methodology/approachFinite element method is employed in this work.FindingsThe simulated results match the experimental results well, which demonstrates the finite element analysis models are reliable. Compared with the one- and two-dimensional finite element analysis, temperature and degree of cure can be calculated at any point within composite structures in the present simulation analysis. The cure simulation of composite structures with arbitrary geometry can be investigated by the finite element program.Originality/valueA coupled thermokinetic simulation of the liquid composite molding process based on a three-dimensional finite element method is presented. The cure simulation of composite structures with arbitrary geometry can be investigated by the finite element program.

scholarly journals PROCESS MODELING OF CARBON-EPOXY COMPOSITES: RESIDUAL STRESS DEVELOPMENT DURING CURE AND ANALYSIS OF FREE EDGE EFFECTS

Aviation ◽  
2019 ◽  
Vol 23 (1) ◽  
pp. 15-22 ◽  
Author(s):  
Darya Bondarchuk ◽  
Boris Fedulov
Keyword(s):  
Finite Element ◽  
Residual Stresses ◽  
Deep Understanding ◽  
Free Edge ◽  
Material Behavior ◽  
Shape Distortion ◽  
Element Analysis ◽  
Multilayered Composites ◽  
Numerical Grid ◽  
Residual Strains

Last decades, increased attention is paid to the deep understanding of the process induced residual stresses (locked-in) and their effect on shape distortion and fracture. Residual stresses evaluation is particularly important in multilayered composites with anisotropic thermo-mechanical properties, where the ply orientations and stacking sequences highly influence the appearing of manufacturing stresses. In the present study, the effect of free edge on residual stresses inherited during manufacturing of thermoset multilayered composites was investigated. In order to understand the stress-strain state in samples after free edge cut a simplified 2D plane strain finite element analysis was performed. Many phenomena, such as sensitivity of the results to the size of the numerical grid, stress redistribution and size of the area affected by free edge was analyzed. In the current research, the behavior of AS4/8552-1 carbon-epoxy composite during manufacturing cycle was studied by means of finite element modeling in ABAQUS. To describe the behavior of the composite material during the manufacturing process − including processes of formation, polymerization, development of residual strains and stresses was done by developed user subroutine-UMAT, describing the visco-elastic material behavior of the material. The program was implemented in ABAQUS and validated on the basis of literature data. The results of the study can be applied for prediction of residual stresses in composite structure by means of virtual simulation and further understanding the nature of fracture of composites.

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.

Torsional Analysis of a Steel Cord-Rubber Tire Belt Structure

1996 ◽  
Vol 24 (4) ◽  
pp. 339-348 ◽  
Author(s):  
R. M. V. Pidaparti
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Composite Structures ◽  
Three Dimensional ◽  
Element Model ◽  
Torsional Stiffness ◽  
Element Analysis ◽  
Rubber Belt ◽  
Steel Cord ◽  
Torsional Analysis

Abstract A three-dimensional (3D) beam finite element model was developed to investigate the torsional stiffness of a twisted steel-reinforced cord-rubber belt structure. The present 3D beam element takes into account the coupled extension, bending, and twisting deformations characteristic of the complex behavior of cord-rubber composite structures. The extension-twisting coupling due to the twisted nature of the cords was also considered in the finite element model. The results of torsional stiffness obtained from the finite element analysis for twisted cords and the two-ply steel cord-rubber belt structure are compared to the experimental data and other alternate solutions available in the literature. The effects of cord orientation, anisotropy, and rubber core surrounding the twisted cords on the torsional stiffness properties are presented and discussed.

Behaviour of Axially Loaded Composite Wall Panel by Using Finite Element Analysis

2015 ◽  
Vol 815 ◽  
pp. 49-53
Author(s):  
Nur Fitriah Isa ◽  
Mohd Zulham Affandi Mohd Zahid ◽  
Liyana Ahmad Sofri ◽  
Norrazman Zaiha Zainol ◽  
Muhammad Azizi Azizan ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Composite Structures ◽  
Element Analysis ◽  
Steel Sheets ◽  
Linear Behavior ◽  
Non Linear ◽  
Composite Wall ◽  
Experimental Values ◽  
Civil Engineering Infrastructure

In order to promote the efficient use of composite materials in civil engineering infrastructure, effort is being directed at the development of design criteria for composite structures. Insofar as design with regard to behavior is concerned, it is well known that a key step is to investigate the influence of geometric differences on the non-linear behavior of the panels. One possible approach is to use the validated numerical model based on the non-linear finite element analysis (FEA). The validation of the composite panel’s element using Trim-deck and Span-deck steel sheets under axial load shows that the present results have very good agreement with experimental references. The developed finite element (FE) models are found to reasonably simulate load-displacement response, stress condition, giving percentage of differences below than 15% compared to the experimental values. Trim-deck design provides better axial resistance than Span-deck. More concrete in between due to larger area of contact is the factor that contributes to its resistance.

Finite Element Analysis on the Deformation of Energy-Saving Wire-Mesh Frame Wallboard

2014 ◽  
Vol 501-504 ◽  
pp. 731-735
Author(s):  
Li Zhang ◽  
Kang Li
Keyword(s):  
Finite Element ◽  
Energy Saving ◽  
Theoretical Basis ◽  
Steel Wire ◽  
Wire Mesh ◽  
Design Parameters ◽  
Element Analysis ◽  
Finite Element Program ◽  
Element Program ◽  
Influence Degree

This paper analyzes the influence degree of related design parameters of wire-mesh frame wallboard on deformation through finite element program, providing theoretical basis for the design and test of steel wire rack energy-saving wallboard.

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