Evaluation of fiber glass reinforced plastic materials concludes that fiber glass construction is lighter than aluminum alloy construction. Low thermal conductivity and strength makes the fiber glass material useful in cryogenic tank supports

Bartlett, D. H.

English

NASA Technical Reports Server

September 1968
	 Brief 68-10360 
NASA TECH BRIEF 
NASA Tech Briefs are issued to summarize specific innovations derived from the U . S. space program, 
to encourage their commercial application. Copies are available to the public at 15 cents each 
from the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia 22151. 
Fiberglass- Reinforced Structural Materials for Aerospace Application 
.
An extensive investigation has been conducted to 
evaluate fiberglass-reinforced plastic materials for 
application in aerospace structures. These materials 
are of particular interest for such applications because 
of their low density, unidirectional strength, low 
thermal conductivity, and fabricability. Possibly the 
greatest potential of the materials is in their proposed 
use as tension supports for cryogenic tanks. 
The investigation was carried out along four lines: 
These were: (I) a literature survey; (2) conceptual 
design, detail design, and analysis; (3) development of 
a manufacturing plan, identification of process con-
trols, and fabrication of parts; and (4) preparation 
of a test plan, testing, and analysis of results. 
The literature review resulted in the selection of 
composite materials and adhesives that could be 
expected to have the best characteristics at ambient 
and cry.ogenic temperatures. Epoxy resins and fiber-
glass reinforcements were the materials chosen for 
experimental evaluation. The specific structural ele-
ments investigated were tension rods, tubular struts, 
and I beams. Comparisons were made with their 
metallic counterparts to determine the thermal and 
weight advantages of using fiberglass-reinforced 
plastic structures. The tension rods and tubular struts 
were considered for cryogenic tank supports, and were 
compared with similar members made from low-ther-
mal conductivity alloys. The beams were conceived
as payload support members where light weight, 
rather than low thermal conductivity was of primary 
concern. 
It is concluded from the investigation that fiberglass 
construction offers some weight saving when com-
pared with aluminum alloy construction in the case of 
beams and struts. A greater potential of the fiberglass 
material is realized in cryogenic tank supports, as the 
result of its low thermal conductivity and strength. 
Deflections are greater and stiffness is less than for 
comparable metallic parts. Therefore in cases where 
stiffness design criteria prevail and thermal conduc-
tivity is not a factor, advanced composites employing 
filamentary materials of boron or carbon are believed 
to be more competitive with metallic materials. 
Note: 
Complete details may be obtained from: 
Technology Utilization Office 
Marshall Space Flight Center 
Huntsville, Alabama 35812 
Reference: B68-10360 
Patent status: 
No patent action is contemplated by NASA. 
Source: D. H. Bartlett 
of The Boeing Company 
under contract to 
Marshall Space Flight Center 
(M FS- 14806) 
Category 03 
This document was prepared under the sponsorship of the National 	 Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States 	 information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United States
	 will be free from privately owned rights.
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Fiber glass reinforced structural materials for aerospace application

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