Molded composites made from type-2 Morganite and/or boron are suitable for structural skins. Layered-in-depth omniweave construction yields higher in-plane strength characteristics than fiber-pitch angle construction, and strength and moduli data vary with fiber orientation

Belman, R.

Edighoffer, H.

Fenton, R.

Lowe, D.

Wexler, M.

English

NASA Technical Reports Server

July 1971
	 Brief 71-10245 
NASA TECH BRIEF 
Marshall Space Flight Center 
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Evaluation of Omniweave Reinforcement for Composite Fabrication 
Experimentation and structural analyses indicate 
that molded composites incorporating omniweave 
fabrics, made from type-11 Morganite and/or boron, 
are suitable for structural -
 skins. Compared with 
conventional high-strength, lightweight skins, the 
omniweave skins save from 30% (pressurized ap-
plications) to 60% (unpressurized applications) in 
weight. 
Twenty-two omniweave fabrics made from S-glass 
(20-filament end roving), type-11 Morganite (10,000-
filament end roving), Thornel-50S (two-ply yarn), 
boron (tungsten-cored, 0.32 cm wide filament tape), 
and mixtures of these materials, all of which were 
preimpregnated with epoxy resins, were woven and 
tested. Four different omniweave geometries were 
employed. Difficulties were experienced in weaving 
wide specimens with Thornel and boron, but all 
materials can be woven. The weaving was done 
primarily to test the manufacturing feasibility of the 
omniweave method. 
In the composites molded from all of these multi-
directional fabrics, the level of porosity was generally 
lower than 5%. .Selected composites were evaluated 
for flexural, tensile, compression, interlaminar, and 
shear properties, and the effects of weave geometry 
and type of fiber on mechanical properties were 
noted. The OMNI computer code was used for 
analytically estimating the composites' properties. 
Composites made from boron preimpregnated with 
l-1T424 epoxy-phenolic resin showed tensile properties 
comparable to those of a unidirectional composite 
having a similar volume fraction of fiber. The fact 
that composites of S-glass and Morganite showed 
slightly poorer mechanical properties than those pre-
dicted by structural analysis indicates that process-
ing techniques could be improved. 
Data trends indicate that the layered-in-depth 
omniweave construction yields higher in-plane strength 
characteristics than the fiber-pitch-angle construction, 
and that strength and moduli data varied with fiber 
orientation, as had been predicted. The transverse-
compression properties of several S-glass and Mor-
ganite composites were significantly higher than ex-
pected. Values for interlaminar shear failure could 
not be obtained by the short-beam-shear approach, 
and the primary mode of failure was predominantly 
flexural stress. 
Mechanical-property prediction curves for S-glass, 
Màrganite, Thornel, and boron composites were 
generated by the OMNI computer program as func-
tions of omniweave geometry and fiber-volume frac-
tion. In general, the test data closely followed 
these predicted curves. Off-axis tensile tests were 
performed on a unidirectional composite of S-glass 
and epoxy to furnish realistic inputs for the OMNI 
computer code. 
Note: 
The following documentation may be obtained 
from:
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Springfield, Virginia 22151 
Single document price $3.00 
(or microfiche $0.95) 
Reference: 
NASA-CR-102916 (N71-11441), Evaluation 
of Omniweave (GE) Method of Composite 
Fabrication - Graphite Filament
LI)IIIIIILICJ II erie_li) 
This document was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States 
Government nor any person acting on behalf of the United States
Government assumes any liability resulting from the use of the 
information contained in this document, or warrants that such use 
will be free from privately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19710000244 2020-03-17T02:20:03+00:00Z
Patent status: 
Inquiries about obtaining rights for the commercial 
use of this invention may be made to: 
Patent Counsel 
Mail Code A&TS-PAT 
George C. Marshall Space Flight Center 
Marshall Space Flight Center, Alabama 35812 
Source: M. Wexler, R. Fenton, D. Lowe,
H. Edighoffer, and R. Belman of

General Electric Co.

under contract to

Marshall Space Flight Center

(MFS-20946) 
Brief 71-10245
	 Category 04,08


Evaluation of omniweave reinforcement for composite fabrication

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