Pricnciple of Modeling Textile Composite
Pricnciple of Modeling Textile Composite
Pricnciple of Modeling Textile Composite
Composites
Issues
Reliability
Material Characterization Unit Cell Modelling
Material Variations
Modelling Needs
Correct kinematics
Reasonable assumptions
Correct properties
Correlation between experiment and predictions
Kinematics
Homogeneous
Heterogeneous
Mosaic
Homogeneous
"Smearing Method"
Don't identify individual phases
Only concerned with point correlations of phases
Model typically insensitive to geometric parameters
Heterogeneous
Rules of mixtures
Modified Matrix Method (XYZ)
Stiffness Averaging (FGM)
Compliance Averaging
Property Blending
Homogeneous Philosophy
Fiber Properties Micromechanics Unidirectional
Matrix Properties Properties
Type II Type I
30 30
25 25
Exper 20
20
MM-1
15 MM-2 15
FGM 10
10
5 5
0 0
E11 E22 E33 E11 E22 E33
Variations on Homogeneity
3.8
FGM
3.6 Kregers
MMM
3.4
3.2
2.8
2.6 q
2.4
2.2
2
0 15 30 45
E11as a function of Weave Angle
Homogeneous Advantages
Y
1.2
Ex
Normalized Modulus
1.1
Ez
Gxy
1.0
Gyz
0.9
0.8
0.7
0.1 0.2 0.3 0.4 0.5
Waviness Ratio
X
Stick Example
Y
Matrix Member
Fiber Member
Z
Stick Comparison
100 80
75 60
Stress (ksi)
Stress (ksi)
50 40
25 20
0 0
0 0.25 0.5 0.75 1 0 0.5 1 1.5 2 2.5 3
Strain Strain
By
Sub-volume
"Sugar
Cube"
Mosaic Advantages
1.2
1.1
Normalized
Tensile 1
Modulus
0.9
0.8
0.7
0 2 4 6 8
Gage Area/ Unit Cell Area
Location of Test Cell
with Respect to Unit Cells in a Triaxial Braid
Predicted Tensile Moduli for 60° Triaxial Braid AS-4/
Epoxy Test Cell with y1 = b and x1 = 4.1a
Predicted and Experimental Tensile Modulus of a Triaxially Braided AS-4/
Epoxy Composite with 45° Braid Angle and 12% Longitudinal Yarns
Predicted and Experimental Tensile Modulus of a Triaxially Braided AS-
4/Epoxy Composite with 45° Braid Angle and 46% Longitudinal Yarns
Predicted and Experimental Tensile Modulus of a Triaxially Braided AS-4/
Epoxy Composite with 70° Braid Angle and 46% Longitudinal Yarns
Physical Limitations