Implementation of Numerical Models to Evaluate Intrinsic Residual Stresses in 3D Woven Composites by Blind Hole Drilling Tests

2020 ◽  
Author(s):  
KOSTIANTYN VASYLEVSKYI ◽  
IGOR TSUKROV ◽  
HILARY BUNTROCK ◽  
TODD GROSS ◽  
BORYS DRACH
Keyword(s):  
Residual Stresses ◽  
Numerical Models ◽  
Woven Composites ◽  
Hole Drilling ◽  
Blind Hole ◽  
3D Woven Composites

EXPERIMENTALLY VALIDATED SIMULATIONS OF BLIND HOLE DRILLING IN 3D WOVEN CARBON/EPOXY COMPOSITE WITH PROCESSING-INDUCED RESIDUAL STRESSES

2021 ◽  
Author(s):  
ARTURO LEOS ◽  
KOSTIANTYN VASYLEVSKYI ◽  
IGOR TSUKROV ◽  
TODD GROSS ◽  
BORYS DRACH
Keyword(s):  
Residual Stresses ◽  
Epoxy Matrix ◽  
Mechanical Performance ◽  
Matrix Cracking ◽  
Woven Composites ◽  
Hole Drilling ◽  
Blind Hole ◽  
Matrix Cracks ◽  
Numerical Predictions ◽  
3D Woven Composites

Manufacturing-induced residual stresses in carbon/epoxy 3D woven composites arise during cooling after curing due to a large difference in the coefficients of thermal expansion between the carbon fibers and the epoxy matrix. The magnitudes of these stresses appear to be higher in composites with high throughthickness reinforcement and in some cases are sufficient to lead to matrix cracking. This paper presents a numerical approach to simulation of development of manufacturing-induced residual stresses in an orthogonal 3D woven composite unit cell using finite element analysis. The proposed mesoscale modeling combines viscoelastic stress relaxation of the epoxy matrix and realistic reinforcement geometry (based on microtomography and fabric mechanics simulations) and includes imaginginformed interfacial (tow/matrix) cracks. Sensitivity of the numerical predictions to reinforcement geometry and presence of defects is discussed. To validate the predictions, blind hole drilling is simulated, and the predicted resulting surface displacements are compared to the experimentally measured values. The validated model provides an insight into the volumetric distribution of residual stresses in 3D woven composites. The presented approach can be used for studies of residual stress effects on mechanical performance of composites and strategies directed at their mitigation.

Comparison of Two Approaches to Model Cure-Induced Microcracking in Three-Dimensional Woven Composites

2012 ◽  
Author(s):  
Igor Tsukrov ◽  
Michael Giovinazzo ◽  
Kateryna Vyshenska ◽  
Harun Bayraktar ◽  
Jon Goering ◽  
...  
Keyword(s):  
Finite Element ◽  
Residual Stresses ◽  
Volume Fraction ◽  
Three Dimensional ◽  
Woven Composites ◽  
Finite Element Models ◽  
The Matrix ◽  
3D Woven Composites ◽  
The Difference ◽  
Resin Curing

Finite element models of 3D woven composites are developed to predict possible microcracking of the matrix during curing. A specific ply-to-ply weave architecture for carbon fiber reinforced epoxy is chosen as a benchmark case. Two approaches to defining the geometry of reinforcement are considered. One is based on the nominal description of composite, and the second involves fabric mechanics simulations. Finite element models utilizing these approaches are used to calculate the overall elastic properties of the composite, and predict residual stresses due to resin curing. It is shown that for the same volume fraction of reinforcement, the difference in the predicted overall in-plane stiffness is on the order of 10%. Numerical model utilizing the fabric mechanics simulations predicts lower level of residual stresses due to curing, as compared to nominal geometry models.

Modeling of Cure-Induced Residual Stresses in 3D Woven Composites of Different Reinforcement Architectures

2013 ◽  
Vol 577-578 ◽  
pp. 253-256 ◽  
Author(s):  
Igor Tsukrov ◽  
Borys Drach ◽  
Harun Bayraktar ◽  
Jon Goering
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
Finite Element Modeling ◽  
Room Temperature ◽  
Woven Composites ◽  
Element Modeling ◽  
The Matrix ◽  
3D Woven Composites ◽  
Resin Curing

This paper presents finite element modeling effort to predict possible microcracking of the matrix in 3D woven composites during curing. Three different reinforcement architectures are considered: a ply-to-ply weave, a one-by-one and a two-by-two orthogonal through-thickness reinforcement. To realistically reproduce the as-woven geometry of the fabric, the data from the Digital Fabric Mechanics Analyzer software is used as input for finite element modeling. The curing processed is modeled in a simplified way as a uniform drop in temperature from the resin curing to room temperature. The simulations show that the amount of residual stress is strongly influenced by the presence of through-thickness reinforcement.

Micromechanical Modeling for the Evaluation of Elastic Moduli of Woven Composites

2012 ◽  
Vol 525-526 ◽  
pp. 73-76 ◽  
Author(s):  
Daisei Abe ◽  
Omar Bacarreza ◽  
M.H. Aliabadi
Keyword(s):  
Mechanical Properties ◽  
Numerical Models ◽  
Impact Resistance ◽  
Textile Composites ◽  
Woven Composites ◽  
Micromechanical Modeling ◽  
Unit Cells ◽  
3D Woven Composites ◽  
Predicted Values ◽  
Complex Architecture

Textile composites have increasingly been used as a structural material because of their balanced properties, higher impact resistance, and easier handling and fabrication compared with unidirectional composites. However, the complex architecture of textile composites leads to difficulties in predicting the response in spite of the fact that there is the need to determine mechanical properties in product design. Micromechanical analysis, using the Finite Element Method, was conducted in order to evaluate the effective mechanical properties of plain woven and 3D woven composites. In this study, numerical models of unit cells were used and it is shown that the predicted values of homogenized mechanical properties using the developed procedure were in good agreement with experimental results.

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