Effect of Pick Spacing and Warp and Weft Volume Fraction on Intrinsic Residual Stresses in 3D Woven Composites

2019 ◽  
Author(s):  
TODD GROSS ◽  
HILARY BUNTROCK ◽  
KOSTIANTYN VASYLEVSKYI ◽  
IGOR TSUKROV ◽  
BORYS DRACH
Keyword(s):  
Residual Stresses ◽  
Volume Fraction ◽  
Woven Composites ◽  
3D Woven Composites

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.

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.

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.

scholarly journals Effect of Microcracks on the Tensile Properties of 3D Woven Composites

Coatings ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 794
Author(s):  
Jian Huang ◽  
Qian Zhao ◽  
Yubo Feng ◽  
Haili Zhou ◽  
Fangfang Sun ◽  
...  
Keyword(s):  
Tensile Properties ◽  
Residual Strength ◽  
Volume Fraction ◽  
Tensile Load ◽  
Image Correlation ◽  
Woven Composites ◽  
Stress Strain ◽  
Correlation Relationship ◽  
Residual Properties ◽  
3D Woven Composites

This study provides an experimental investigation on the effect of microcracks on the tensile properties of 3D woven composites. A four-step experimental procedure using the combination of micro-XCT, acoustic emission (AE) and digital image correlation (DIC) is here proposed. Typical tensile damage behaviors were characterized by the stress–strain curves, AE signal analysis and DIC full field strain measurement. Due to a typical four stages stress–strain behavior, phenomena of stiffness degradation and stiffness hardening were successively found during the tensile process. Samples with various damage levels were produced by the in situ AE monitoring. Their 3D microcrack morphologies show the crack initiation, propagation process and the damage modes. Detectable damages initiated during the stress range from 65.98% to 72.93% σs. The cracks volume fraction (CVF) shows a positive correlation relationship with the corresponding tensile load. Moreover, the CVF was used to characterize the degree of damage. The samples with various phased damages were tested again in the fourth step to obtain their residual modulus and residual strength. Detected microcracks have little influence on the residual strength, while the residual modulus witnesses a regular decrease along with the damage increase. The effect of microcracks on the tensile properties is characterized by the relationships between the gradually increased damages and the corresponding residual properties which provide a foundation for damage evaluation of 3D woven structures in service.

Tensile properties of defect-prefabricated 3D woven composites: Experiments and simulations

2021 ◽  
pp. 152808372110395
Author(s):  
Liming Xu ◽  
Deng’an Cai ◽  
Chao Li ◽  
Xingyu Jin ◽  
Guangming Zhou
Keyword(s):  
Mechanical Properties ◽  
Volume Fraction ◽  
Research Work ◽  
Three Dimensional ◽  
Woven Composites ◽  
Structural Components ◽  
Damage Models ◽  
3D Woven Composites ◽  
Near Net Shape ◽  
Von Mises

Three-dimensional (3D) woven composites have been widely used in structural components due to their excellent mechanical and near-net-shape properties. However, for some special applications, it is expected that 3D woven composites can be damaged at designated locations under a specific load. In this research work, a new kind of defect-prefabricated 3D woven composites (DP3DWCs) are designed, where defects are prefabricated by cutting weft or warp yarns in defect-free 3D woven composites (DF3DWCs). The tensile mechanical properties of the DF3DWCs and the DP3DWCs are investigated experimentally and numerically. The mesoscopic geometry models of the DF3DWCs and the DP3DWCs were established by multi-objective searching algorithm. The progressive damage models were established using the 3D Hashin criteria and the von Mises failure criterion. Numerical results agree well with the experimental data. The influence of the number of defect layers on the mechanical properties was also discussed. The obtained results indicate that the defects have little effect on the elastic modulus, while tensile strengths decrease linearly with the increase of the number of defect layers. Failure mechanisms of yarns and matrix in the non-defective and defective materials were studied, and the volume fraction of elements of each failure mode was computed and analysed.

scholarly journals Open hole quasi-static and fatigue characterisation of 3D woven composites

2015 ◽  
Vol 131 ◽  
pp. 765-774 ◽  
Author(s):  
S. Dai ◽  
P.R. Cunningham ◽  
S. Marshall ◽  
C. Silva
Keyword(s):  
Woven Composites ◽  
Open Hole ◽  
3D Woven Composites
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