A SERVICE OF

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THE CHOICE BETWEEN TEXTILES AND TAPE LAMINATES
3-11
0
200
400
600
800
Tension Strength (MPa)
Unnotched
Tension
Open Hole
Tension
dia. = 6.35 mm
Unstitched
Stitched 1600
den. Kevlar
Fig. 3-5. Tensile strengths of stitched and unstitched IM7/3501-6 laminates. Stitching
with 0.125 in. (3.1 mm) pitch (between penetrations within a row) and 0.20 in. (5.0 mm)
spacing between the stitching rows. (from [3.10])
Compression Strength (MPa)
IM7
AS4
IM7
IM7
AS4
IM7*
Unnotched
Compression
Open Hole
Compression
Dia. = 6.35 mm
Compression
After Impact
Unstitched
Stitched 1600 den. Kevlar
Stitched 1000 den. Kevlar
Stitched 1250 den S2 Glass
* IM7/8551-7 Prepreg
46 J
54 J
100
200
300
400
500
600
700
0
54 J
Fig. 3-6. Compression strengths and CAI data for stitched and unstitched laminates
(from [3.10]).
3.4.4 3D Interlock Weaves
Substantial data exist for the tensile and compressive strengths of 3D interlock
weaves when loads are aligned with either stuffers or fillers, although no data are available
for equivalent tape laminates. Using instead strength estimates based on the strengths of