Figure 4-10. Schematic of a nonlinear damage band growing from a
stress concentrator in a textile composite . . . . . . . . . . . . . . . . . . . . . 4-18
Figure 4-11. A kink band formed in fatigue in a misaligned segment
of a stuffer in an AS4/1895 layer-to-layer interlock weave . . . . . . . 4-20
Figure 5-1. Translationally invariant 2D laminate . . . . . . . . . . . . . . . . . . . . . . . . 5-2
Figure 5-2. Comparison of the elastic constants predicted for
tows in an AS4/1895 composite using various
models from the literature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3
Figure 5-3. Alternative unit cells (short and long dash lines
at upper left) in a plane woven laminate. The
smaller, solid-lined rectangle (lower right) shows
a reduced cell that takes advantage of reflection
symmetry about a vertical plane . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-7
Figure 5-4. Nonperiodic strains in a periodic structure under
nonuniform external loads. Schematic of two unit
cells in a larger array . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-8
Figure 5-5. Schematic of a 3D interlock weave. The numbers at the right
show the sequence of occurrence of warp weaver tows
encountered on progressing into the plane of the figure . . . . . . . . . . 5-9
Figure 5-6. Coefficient of variation of Young's modulus measurements
as a function of the size of the gauge used relative to the
unit cell dimension in that direction. Gauge sizes shown
in inches in inset; 1 in. ≈ 25.4 mm. . . . . . . . . . . . . . . . . . . . . . . . . . . 5-10
Figure 5-7. Coordinates for transformation of tow properties . . . . . . . . . . . . . . . 5-15
Figure 5-8. Three orthogonal symmetry planes (two marked by dashed
lines and the third being the plane of the figure) in a stack of
woven plies, implying orthotropy over gauge lengths that
are larger than the ply thickness and the period of the weave . . . . . . 5-16
Figure 5-9. A simple paradigm for estimating the contributions of
shear and bending to the deflection of a tow . . . . . . . . . . . . . . . . . 5-17
Figure 5-10. Schematics of buckling of an aligned tow under compression.
(a) When relatively soft through-thickness reinforcement
acts as a soft elastic foundation, allowing deflections over
relatively long wavelengths. (b) When stiff through-
thickness reinforcement restricts lateral deflections to the
intervals between successive through-thickness tows . . . . . . . . . . . 5-19
Figure 5-11. Choices of unit cell in quasi-laminar textile composites.
(a) Two approaches to modeling laminate properties.
(b) Variant of whole thickness cell in (a) for
analyzing stacking effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-22
