Matrix Cracking-Induced Delamination Propagation in Graphite/Epoxy Laminated Composites Due to a Transverse Concentrated Load

2009 ◽  
pp. 86-86-16 ◽  
Author(s):  
S Liu ◽  
Z Kutlu ◽  
F-K Chang
Keyword(s):  
Laminated Composites ◽  
Matrix Cracking ◽  
Concentrated Load ◽  
Delamination Propagation

Static strength prediction in laminated composites by using discrete damage modeling

2016 ◽  
Vol 51 (10) ◽  
pp. 1473-1492 ◽  
Author(s):  
Kevin Hoos ◽  
Endel V Iarve ◽  
Michael Braginsky ◽  
Eric Zhou ◽  
David H Mollenhauer
Keyword(s):  
Compressive Strength ◽  
Input Data ◽  
Damage Mechanics ◽  
Laminated Composites ◽  
Matrix Cracking ◽  
Damage Modeling ◽  
Fiber Failure ◽  
Failure Patterns ◽  
Open Hole ◽  
Discrete Damage Modeling

Discrete Damage Modeling of complex local failure patterns in laminated composites including matrix cracking, delamination, and fiber failure was performed. Discrete Damage Modeling uses the Regularized eXtended Finite Element Method for the simulation of matrix cracking at initially unknown locations and directions independent of the mesh orientation. Cohesive interface model is used both for Mesh Independent Cracking as well as delamination propagation. The fiber failure mode is modeled by two different methods in tension and compression. Tensile failure is predicted by Critical Failure Volume criterion, which takes into account volumetric scaling of tensile strength. Compression fiber failure is simulated with a single parameter continuum damage mechanics model with non-compressibility condition in the failed region. Ply level characterization input data were used for prediction of notched and unnotched laminate strength. All input data required for model application is directly measured by ASTM tests except tensile fiber scaling parameter and compression fiber failure fracture toughness, which were taken from literature sources. The model contains no internal calibration parameters. Tensile and compressive strength of unnotched and open hole composite laminates IM7/977-3 has been predicted and compared with experimental data. Three different layups, [0/45/90/−45]2S, [30/60/90/−60/−30]2S, and the [60/0/−60]3S, were modeled and tested and showed good agreement with experiment in the case of tensile loading, whereas the compressive strength was generally under predicted for unnotched laminates and overpredicted for open hole laminates.

Simulated Lamb wave propagation method for nondestructive monitoring of matrix cracking in laminated composites

2021 ◽  
pp. 147592172110086
Author(s):  
A Mardanshahi ◽  
MM Shokrieh ◽  
S Kazemirad
Keyword(s):  
Wave Propagation ◽  
Lamb Wave ◽  
Model Updating ◽  
Laminated Composites ◽  
Matrix Cracking ◽  
Damping Coefficient ◽  
Nondestructive Monitoring ◽  
Wave Propagation Method ◽  
Updating Procedure ◽  
Lamb Wave Propagation

The estimation of the damping coefficient may help to improve the damage detection in composite materials. The purpose of this study was to develop the simulated Lamb wave propagation method for nondestructive monitoring of matrix cracking in laminated composites via the accurate estimation of their damping coefficient. Cross-ply composite specimens with different crack densities were fabricated and tested by the Lamb wave propagation technique. The phase velocity of the Lamb wave and the damping coefficient of the specimens were measured. The finite element models were developed at micro-scale (representative volume elements) and macro-scale (laminated specimens) levels to simulate the Lamb wave propagation in composite specimens. An optimization process was performed through the model updating procedure to achieve finite element models that were in good agreement with experiments. The phase velocity and damping coefficient, obtained from the updated FE models for two crack densities other than those used in the model updating procedure, were successfully examined by experimental results. It was also revealed that the damping coefficient and the rate of increase in the damping coefficient in terms of the crack density were higher for the composite laminates with a higher number of 90° layers. The damping of the fiber–matrix interphase and crack regions were considered in the model and shown as a significant contribution to the overall damping of the composite specimens. The proposed simulated Lamb wave propagation method can be used as a virtual lab for in-situ monitoring of laminated composites with different material properties, stacking sequences, and crack densities.

Mesh-independent matrix cracking and delamination modeling in laminated composites

2011 ◽  
Vol 88 (8) ◽  
pp. 749-773 ◽  
Author(s):  
Endel V. Iarve ◽  
Mark R. Gurvich ◽  
David H. Mollenhauer ◽  
Cheryl A. Rose ◽  
Carlos G. Dávila
Keyword(s):  
Laminated Composites ◽  
Matrix Cracking
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