Cohesive Finite Element Based Modeling of Damage in Composite Materials

2002 ◽  
Author(s):  
Rajesh S. Kumar ◽  
Ramesh Talreja
Keyword(s):  
Finite Element ◽  
Composite Materials ◽  
Composite Laminates ◽  
Damage Evolution ◽  
Crack Density ◽  
Cohesive Zone Modeling ◽  
Cohesive Law ◽  
Transverse Cracks ◽  
Damage State ◽  
Viscoelastic Composite

Damage in composite laminates affects its overall viscoelastic response. Constitutive equations have been developed for composite laminates considering a fixed damage state. A complete description, however, requires suitable damage evolution laws. This paper is focused on studying damage evolution in viscoelastic laminates using a cohesive finite element approach. A two dimensional, four nodded finite element is developed incorporating a rate-independent traction-displacement cohesive law. This element is used in conjunction with plane strain bulk elements behaving in a linear viscoelastic manner to simulate crack evolution between two existing transverse cracks in symmetric cross-ply laminates. The effects of loading strain-rate, ply constraint and initial crack density are studied. This study shows expected trends in the behavior and indicates the suitability of cohesive zone modeling to study damage evolution in viscoelastic composite materials.

MICROMECHANICAL FINITE ELEMENT PREDICTION OF INTERLAMINAR TRACTION-SEPARATION LAWS USING J-INTEGRAL APPROACH

2021 ◽  
Author(s):  
CHRISTOPHER S. MEYER ◽  
BAZLE Z. HAQUE ◽  
DANIEL J. O’BRIEN ◽  
OHN W. GILLESPIE, JR.
Keyword(s):  
Finite Element ◽  
Composite Laminates ◽  
Element Model ◽  
Unidirectional Composite ◽  
Woven Composites ◽  
Cohesive Zone Modeling ◽  
Integral Approach ◽  
J Integral ◽  
Dynamic Impact ◽  
Transverse Cracks

Dynamic impact loading of woven composites leads to mesoscale damage such as interlaminar transverse cracks and intralaminar tow-tow delamination cracks. At the microscale, this damage may be modeled as fracture between [90/90] and [0/90] unidirectional composite laminates. Microscale finite element model (FEM) resolution of dynamic impact at structural length scale is intractable, but mesoscale FEM resolution is possible with current computational resources. However, mesoscale cohesive zone modeling of this damage requires appropriate tractionseparation laws. These laws are predicted in this work with fiber length-scaleresolved FEMs, which include residual stress, experimentally measured, ratedependent, nonlinear matrix behavior, and experimentally measured, computationally validated, rate-dependent fiber-matrix interface properties. The J-integral from elastoplastic fracture mechanics is computed under mode I and mode II loading and differentiated to determine the traction-separation laws.

Evolution of Crack Density in Cross-Ply Laminates - Application of a Coupled Stress and Energy Criterion

2016 ◽  
Vol 713 ◽  
pp. 262-265
Author(s):  
Maria Kashtalyan ◽  
I.G. García ◽  
Vladislav Mantič
Keyword(s):  
Composite Laminates ◽  
Crack Density ◽  
Great Influence ◽  
Energy Criterion ◽  
Matrix Cracking ◽  
Transverse Cracks ◽  
Transverse Cracking ◽  
Finite Fracture Mechanics ◽  
Equivalent Constraint Model ◽  
Constraint Model

The first damage mode to appear in continuous fibre-reinforced composite laminates subjected to in-plane loading is usually transverse cracking, i.e. matrix cracking in the off-axis plies of the laminate. Since the density of transverse cracks has a great influence on the subsequent failure steps like delaminations, it is important to be able to predict it accurately. In this paper, the evolution of crack density with increasing external load is predicted using a combination of the Coupled Criterion of Finite Fracture Mechanics and the Equivalent Constraint Model.

A Damage Evolution Model for Viscoelastic Composite Laminates

2001 ◽  
Vol 23 (1) ◽  
pp. 3 ◽  
Author(s):  
EA Armanios ◽  
RB Bucinell ◽  
DW Wilson ◽  
NV Akshantala ◽  
LC Brinson
Keyword(s):  
Composite Laminates ◽  
Damage Evolution ◽  
Evolution Model ◽  
Viscoelastic Composite

scholarly journals Continuum damage mechanics modeling of composite laminates including transverse cracks

2017 ◽  
Vol 27 (6) ◽  
pp. 877-895 ◽  
Author(s):  
Tomonaga Okabe ◽  
Sota Onodera ◽  
Yuta Kumagai ◽  
Yoshiko Nagumo
Keyword(s):  
Composite Laminates ◽  
Damage Mechanics ◽  
Elastic Moduli ◽  
Crack Density ◽  
Continuum Damage Mechanics ◽  
Damage Variable ◽  
Continuum Damage ◽  
Transverse Cracks ◽  
Element Analysis ◽  
The Finite Element Analysis

In this study, the continuum damage mechanics model for predicting the stiffness reduction of composite laminates including transverse cracks is formulated as a function of crack density. To formulate the model, first the damage variable in the direction normal to the fiber of a ply including transverse cracks is derived. The damage variable is derived by the model assuming a plane strain field in the isotropic plane and using the Gudmundson–Zang model for comparison. The effective compliance based on the strain equivalent principle proposed by Murakami et al. and classical laminate theory are then used to formulate the elastic moduli of laminates of arbitrary lay-up configurations as a function of the damage variable. Finally, the results obtained from this model are compared to the finite-element analysis reported in previous studies. The model proposed in this paper can predict the stiffness of laminates containing damage due to transverse cracks (or surface crack) from just the mechanical properties of a ply and the lay-up configurations. Furthermore, this model can precisely predict the finite-element analysis results and experiment results for the elastic moduli of the laminate of arbitrary lay-up configuration, such as cross-ply, angle ply, and quasi-isotropic, including transverse cracks. This model only considers the damage of the transverse crack; it does not consider damage such as delamination. However, this model seems to be effective in the early stage of damage formation when transverse cracking mainly occurs. The model assuming plane strain field in the isotropic plane which is proposed in this paper can calculate the local stress distribution in a ply including transverse cracks as a function of crack density. The damage evolution of transverse cracks can thus be simulated by determining the fracture criterion.

Hygrothermal Effect on Stiffness Reduction Modeling Damage Evolution in Cross-Ply Composite Laminates

2012 ◽  
Vol 629 ◽  
pp. 79-84
Author(s):  
M. Sahnoun ◽  
D. Ouinas ◽  
N. Benderdouche ◽  
M. Bouazza ◽  
J. Viña
Keyword(s):  
Mechanical Properties ◽  
Composite Material ◽  
Composite Materials ◽  
Composite Laminates ◽  
Crack Density ◽  
Micromechanical Model ◽  
Displacement Function ◽  
Internal Layers ◽  
Stiffness Reduction ◽  
Hygrothermal Effect

An analytical model based on the displacement function of the opening of crack applied by Lundmark and Varna [26] in the internal layers to study the evolution of the decrease of stiffness in a laminate is investigated. The results of axial rigidity versus the crack density are presented for three composite materials. The influences of the temperature and moisture on the mechanical properties of composite material are highlighted. The micromechanical model of the laminates used in present study describes the degradation of the mechanical properties of composite material by the variation in the temperature and moisture. The hygrothermal effect is observed to be harmful for composite materials.

scholarly journals Hierarchical Composites with Electrophoretically Deposited Carbon Nanotubes for In Situ Sensing of Deformation and Damage

Nanomaterials ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1262
Author(s):  
Colleen M. Murray ◽  
Sagar M. Doshi ◽  
Dae Han Sung ◽  
Erik T. Thostenson
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Response ◽  
Crack Density ◽  
Aqueous Dispersion ◽  
Transverse Cracks ◽  
Damage State ◽  
Transverse Cracking ◽  
Hierarchical Composites ◽  
Acoustic Emission Sensors ◽  
In Situ Sensing

As composites are used increasingly in structural components, novel techniques for detecting micro-scale damage are required. Their nanoscale size and high aspect ratio allow carbon nanotubes to create electrically conductive pathways that enable sensing. In this work, carbon nanotubes are deposited onto glass fabric using electrophoretic deposition to create hierarchical composites. Polyethylenimine functionalized carbon nanotubes are deposited from an aqueous dispersion using an electric field. Symmetric cross-ply composites are investigated as a model system to demonstrate the ability to detect incipient damage and transverse microcracks. The specimens are subjected to tensile loading, and a resistance increase is observed because of two key mechanisms—A reversible change in nanotube-nanotube tunneling gaps due to elastic straining of the network and a permanent severing of paths in the conducting network due to formation of transverse cracks in the 90° plies. By analyzing the electrical response, the damage state can be identified. Acoustic emission sensors are used to validate the results. The strength and Young’s modulus of the composites with integrated carbon nanotubes are similar to the control specimens. Crack density measurements using edge replication reveal that transverse cracking can be suppressed, demonstrating multi-functionality with improved damage tolerance and integrated sensing.

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