Three-Dimensional High Fidelity Progressive Failure Damage Modeling of NCF Composites (original) (raw)
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50th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference, 2009
Initial development of a multiscale progressive damage and failure analysis tool for laminated composite structures is presented. The method models microdamage at the lamina level with the thermodynamically based Schapery Theory. Transverse cracking and ber breakage, considered failure mechanisms in this work, are modeled with failure criteria evaluate at the micro-constituent level using the Generalized Method of Cells.
Durability prediction of structural composites through a continuum damage mechanics approach
2010
The main objective of this research is to develop and implement a new analytical model that relies on a continuum-damage-mechanics approach to predict the evolution of plastic strain and mechanical damage until failure in a unidirectional fiber reinforced composite. The term "damage" is used only in the context of failure mechanisms associated with fracture, which are commonly associated with degradation in stiffness. Plastic and damage evolution are related to typical failure mechanisms in composite materials such as fiber, inter-fiber, and intra-fiber fracture. The plastic strain surface is defined based on the Tsai-Wu failure criterion, while the stiffness degradation damage surface is defined based on the energy-release crack growth. The coefficients that characterize the damage and the plastic surfaces are obtained from known material properties. Data obtained from inter-fiber shear load/unload experimental results are used to define the plastic and damage anisotropic associative evolution. The plastic and damage thresholds are obtained by using nonlinear extrapolation. The mathematical equations and physical principles underlying this model are formulated in the tensorial three-dimensional space and tailored to the primary objective of modeling damage evolution. This model is implemented as a new, user defined material in the commercial finite element analysis software ANSYS. The finite element results are validated by comparisons with published experimental data from shear load/unload in-plane tests, as well as with published experimental data from load/unload tension tests of a [±45°] 2S composite laminate. The comparison shows a good correlation between the model predictions and the experimental data. Finally, the new material model is implemented in ANSYS to predict the durability of a composite beam subjected to four-point bending, where the evolution of fiber, inter-laminar, and intra-laminar types of damage is quantified.
Mechanics of Materials, 2007
A continuum damage model for the prediction of the onset and evolution of intralaminar failure mechanisms and the collapse of structures manufactured in fiber-reinforced plastic laminates is proposed. The failure mechanisms occurring in the longitudinal and transverse directions of a ply are represented by a set of scalar damage variables. Crack closure effects under load reversal are taken into account by using damage variables that are established as a function of the sign of the components of the stress tensor. Damage activation functions based on the LaRC04 failure criteria are used to predict the different failure mechanisms occurring at the ply level.
A novel two-scale progressive failure analysis method for laminated fiber-reinforced composites
56th AIAA/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference, 2015
A novel, two-scale computational model has been developed to predict the progressive damage and failure responses of fiber-reinforced composite laminates using the material properties at the constituent (fiber and matrix) level. These properties were measured from coupon level tests on a unidirectional lamina of the same material system. In the proposed computational scheme, the macroscale finite element analysis (FEA) was carried out at the lamina level of a 3D laminate model, while micromechanical analysis was implemented concurrently at the subscale to compute the local fields at the fiber and matrix scale. Thus, the influence of matrix microdamage at the microscale manifests as the progressive degradation of the lamina stiffness, resulting in the nonlinear evolution of the stress versus strain response, while the lamina stiffness matrix remains positive-definite. The lamina post-peak strain softening response resulting from catastrophic failure modes including fiber tensile breakage, fiber kinking and matrix cracking, were modeled using the smeared crack approach (SCA). The interlaminar failure due to delamination was accounted for through cohesive elements inserted in-between the layers. The predictive capability of the proposed method is illustrated by comparing the computational results with experiment for three different lay-ups of IM-7/977-3 carbon fiber composite laminates subjected to various loading conditions, including both un-notched and open-hole specimens subjected to remote tensile and compressive loading, respectively.
A continuum damage model for composite laminates: Part I – Constitutive model
Mechanics of Materials, 2007
A continuum damage model for the prediction of the onset and evolution of intralaminar failure mechanisms and the collapse of structures manufactured in fiber-reinforced plastic laminates is proposed. The failure mechanisms occurring in the longitudinal and transverse directions of a ply are represented by a set of scalar damage variables. Crack closure effects under load reversal are taken into account by using damage variables that are established as a function of the sign of the components of the stress tensor. Damage activation functions based on the LaRC04 failure criteria are used to predict the different failure mechanisms occurring at the ply level.
Modeling the Progressive Failure of Laminated Composites with Continuum Damage Mechanics
Fracture Mechanics: Twenty-Third Symposium
An approach to the modeling of progressive failure that shows adequate results and can be used in practice to validate the strength of a composite structure is presented. The approach is based on the idea of instantaneous local failure in a layer in accordance with a failure criterion and further degradation of material stiffnesses. Calculation results for the progressive failure of a cross-ply specimen with a stress concentrator in the form of a circular hole are given. The pattern of layerwise failure growth is presented and compared with typical points of the stress-strain diagram. The efficiency of different failure criteria is studied for a composite specimen with known experimental data. The results of numerical simulation are compared with X-ray patterns of the specimen at different values of applied load. It is concluded that the method based on the 3D Hashin failure criterion gives the best qualitative and quantitative agreement with the experiment.
A physically based continuum damage mechanics model for thin laminated composite structures
The present work focuses on the development, implementation, and verification of a plane-stress continuum damage mechanics (CDM) based model for composite materials. A physical treatment of damage growth based on the extensive body of experimental literature on the subject is combined with the mathematical rigour of a CDM description to form the foundation of the model. The model has been implemented in the commercial finite element code, LS-DYNA and the results of the application of the model to the prediction of impact damage growth and its effects on the impact force histories in carbon fibre reinforced plastic laminates are shown to be physically meaningful and accurate. Furthermore, it is demonstrated that the material characterization parameters can be extracted from the results of standard test methodologies for which a large body of published data already exists for many composite materials. commonly used strain equivalence approach, a material containing damage, subjected to a strain, e, and under a state of stress, r, can be represented as an equivalent undamaged material subject to the same strain, e, but under an effective stress state,r r. This can be expressed mathematically by the relation:
Mesoscale modelling of tensile response and damage evolution in natural fibre reinforced laminates
Composites Part B: Engineering, 2017
is an open access repository that collects the work of Arts et Métiers ParisTech researchers and makes it freely available over the web where possible. This is an author-deposited version published in: https://sam.ensam.eu Handle ID: .http://hdl.handle.net/10985/17636 To cite this version : Zia MAHBOOB, Yves CHEMISKY, Fodil MERAGHNI, Habiba BOUGHERARA -Mesoscale modelling of tensile response and damage evolution in natural fibre reinforced laminates -a b s t r a c t A continuum damage mechanics based mesoscale model is developed within a thermodynamics framework to describe the in-plane tensile response in natural fibre composites. The standard Mesoscale Damage Theory (MDT) is modified to incorporate damage and inelasticity evolution in the fibredirection, thereby capturing the unique nonlinear fibre-direction response evidenced in natural fibre composites (NFC). The multi-ply damage model is validated using tests on Flax/epoxy laminates and available data on Carbon/epoxy laminates. Model parameters are identified for Flax/epoxy by applying an optimisation algorithm that compares numerical predictions with experimental data. Predictions of mechanical response, stiffness degradation, and inelasticity correlate very well with experimental observations of Flax-laminates. This modified-MDT model offers a predictive, robust tool to aid the development of NFC engineering structures.
Interlaminar damage model for polymer matrix composites
Journal of composite …, 2003
A constitutive model for fiber reinforced composite materials with damage and unrecoverable deformation, which for the first time accounts for interlaminar damage, is presented. The formulation is based on Continuous Damage Mechanics coupled with Classical Plasticity Theory in a consistent thermodynamic framework using internal state variables. In-plane damage and novel formulation of interlaminar damage are included in order to describe the main failure modes of laminates structures. A novel implementation of the constitutive model into a finite element formulation incorporating geometric nonlinearity is presented. The model uses a small number of adjustable parameters, which are identified from available experimental data. Comparisons with experimental data for composite laminates under torsion loading are shown to validate the model for interlaminar damage. Coupled material and geometrical non-linear analysis with simultaneous in-plane and interlaminar damage is demonstrated. The effect of warping on interlaminar damage is shown to be significant.
Non-linear mechanical damage modelling for long fibre-reinforced laminates
2006
A computational methodology is presented for modelling the material non-linear mechanical behaviour of composite structures made of FRP (Fibre-Reinforced Plastic) laminates. The model is based on the appropriate combination of the constitutive models of component materials, considered to behave as isolated continua, together with additional ‘closure equations’ that characterize the micromechanics of the composite from a morphological point of view. To this end, any appropriate constitutive model may be selected for each phase. Each component is modelled separately and the global response is obtained by assembling all contributions taking into account the interactions between components in a general phenomenological way. To model the behaviour of a single unidirectional (UD) composite lamina, a Serial-Parallel continuum approach has been developed assuming that components behave as parallel materials in the fibres alignment direction and as serial materials in orthogonal directions. ...