scholarly journals A continuum damage description for a discrete crack modeling approach for delamination migration in composite laminates

2018 ◽  
Author(s):  
D.C. Pham ◽  
Jim Lua ◽  
Dianyun Zhang
Keyword(s):  
Composite Laminates ◽  
Continuum Damage ◽  
Modeling Approach ◽  
Discrete Crack

scholarly journals A continuum damage description for a discrete crack modeling approach for delamination migration in composite laminates

2018 ◽  
Author(s):  
DC Pham
Keyword(s):  
Principal Stress ◽  
Composite Laminates ◽  
Damage Mechanics ◽  
Matrix Crack ◽  
Matrix Cracking ◽  
Displacement Curve ◽  
Continuum Damage ◽  
State Matrix ◽  
Damage Initiation ◽  
Discrete Crack

A three-dimensional discrete crack embedded within a continuum damage mechanics (CDM) model is developed for an effective characterization of delamination migration in composite laminates subjected to static loading. 3D Hashin failure criterion is implemented for damage initiation prediction under a 3D stress state. Matrix crack initiation criteria coupled with a maximum principal stress direction are employed to determine the location and orientation of a discrete matrix crack within an element. Given the orientation of the initiated matrix crack, the resulting stiffness degradation is characterized in the local principal stress coordinate system and an energy driven failure mechanism is included to capture the crack growth. By coupling the cohesive model for delamination and the discrete damage embedded CDM for matrix cracking, their synergistic interaction can be captured during the simulation of the delamination migration. The predictive capability of the enhanced modeling strategy is examined through simulation of a delamination migration in a cross-ply tap laminate. The predicted results are compared with the experimental data published by NASA and good agreements are achieved in terms of load displacement curve and the location of crack branching.

Development of continuum damage in the creep rupture of notched bars

1984 ◽  
Vol 311 (1516) ◽  
pp. 103-129 ◽  
Keyword(s):  
New York ◽  
Damage Mechanics ◽  
Axial Stress ◽  
Numerical Procedure ◽  
Creep Damage ◽  
Continuum Damage Mechanics ◽  
Constant Load ◽  
Creep Rupture ◽  
Continuum Damage ◽  
Discrete Crack

The creep rupture of circumferentially notched, circular tension bars which are subjected to constant load for long periods at constant temperature is studied both experimentally and by using a time-iterative numerical procedure which describes the formation and growth of creep damage as a field quantity. The procedure models the development of failed or cracked regions of material due to the growth and linkage of grain boundary defects. Close agreement is shown between experimental and theoretical values of the representative rupture stress, of the zones of creep damage and of the development of cracks for circular (Bridgman, Studies in large plastic flow and fracture , New York: McGraw-Hill (1952)) and British Standard notched specimens (B.S. no. 3500 (1969)). The minimum section of the circular notch is shown to be subjected to relatively uniform states of multi-axial stress and damage while the B.S. notch is shown to be subjected to non-uniform stress and damage fields in which single cracks grow through relatively undamaged material. The latter situation is shown to be analogous to the growth of a discrete crack in a lightly damaged continuum. The continuum damage mechanics theory presented here is shown to be capable of accurately predicting these extreme types of behaviour.

Coupling of Continuum Damage Mechanics with De-Cohesive Element for Delamination Analysis in Laminated Composites

2010 ◽  
Vol 123-125 ◽  
pp. 527-530
Author(s):  
Hossein Hosseini-Toudeshky ◽  
Bijan Mohammadi
Keyword(s):  
Mesh Generation ◽  
Composite Laminates ◽  
Damage Mechanics ◽  
Plate Theory ◽  
Continuum Damage Mechanics ◽  
Constitutive Law ◽  
Interface Element ◽  
Continuum Damage ◽  
Interface Modeling ◽  
Edge Delamination

To predict the progressive damages including the large delamination growth in composite laminates, a new interface de-cohesive constitutive law is developed which is compatible with 3D continuum damage mechanics (CDM). To avoid the difficulties of 3D mesh generation and 3D interface modeling between the layers, the interface element is implemented in the Reddy’s full layer-wise plate theory. An angle-ply laminate is analyzed to evaluate the developed CDM+Interface procedure in edge delamination initiation and evolution at final stage of CDM damage progress.

Prediction of Inelastic Behavior of Composite Laminates Using Multi-Surface Continuum Damage-Plasticity

2008 ◽  
Vol 47-50 ◽  
pp. 773-776 ◽  
Author(s):  
Bijan Mohammadi ◽  
Hossein Hosseini-Toudeshky ◽  
Mohammad Homayoun Sadr-Lahidjani ◽  
Shahram Aivazzadeh
Keyword(s):  
Composite Laminates ◽  
Damage Mechanics ◽  
Failure Load ◽  
Internal Variable ◽  
Damage Analysis ◽  
Continuum Damage ◽  
Inelastic Behavior ◽  
Surface Plasticity ◽  
Plastic Damage ◽  
Failure Loads

The recently performed investigations in continuum plastic-damage analysis of composite laminates by the authors showed that using a single hardening internal variable for damage and plasticity surfaces may prone to significant errors in response and failure load for some lay-ups. In this paper, the new technique of coupled continuum plastic-damage mechanics including multisurface dissipation potentials are employed to improve the results. The response and failure loads of the laminated composites with different lay-ups are predicted using elastic, damage, and damageplasticity conditions with single and multi surface plasticity and compared with the available experimental results.

A continuum damage and discrete crack-based approach for fatigue response and residual strength prediction of notched laminated composites

2017 ◽  
Vol 51 (15) ◽  
pp. 2203-2225 ◽  
Author(s):  
Eugene Fang ◽  
Xiaodong Cui ◽  
Jim Lua
Keyword(s):  
Fatigue Damage ◽  
Air Force ◽  
Residual Strength ◽  
Damage Mechanics ◽  
Finite Thickness ◽  
Strength Prediction ◽  
Continuum Damage ◽  
Failure Initiation ◽  
Damage Characterization ◽  
Discrete Crack

This paper presents a combined continuum damage and discrete crack (CDDC) modelling approach for fatigue damage characterization and post-fatigue residual strength prediction of laminated composite components with a hole. In order to capture both the fatigue cycle-driven material degradation and discrete damage-induced stress concentration and redistribution, an overlapped element approach is developed based on a combined user-defined material (UMAT) and user-defined element (UEL). An Abaqus element coupled with UMAT for fatigue damage characterization is used to detect the location of failure initiation, while the discrete crack network-based (DCN) UEL is applied to insert a crack without remeshing. The intensified stress field induced by the newly inserted matrix crack is used for the evaluation of failure initiation and stiffness degradation. The UMAT for the fatigue analysis has incorporated the stress-cycle ( S-N) curves for the damage evolution characterization associated with matrix and fiber based on the tested S-N curves for plies at their different orientations. A continuum damage mechanics (CDM) approach is used for the fatigue-driven delamination initiation and propagation by insertion of a finite thickness interface layer at each ply interface. Both the blind and recalibrated predictions are performed for specimens of three different layups under the Air Force Tech Scout 1 program. The predicted fatigue failure progression and the stiffness against cycle curves are compared with the test data provided by the Air Force Research Lab (AFRL). In addition, post-fatigue residual strength predictions are performed for these notched specimens under tension and compression.

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