Missile nose fairings immersed in colloidal suspension prepared with various specific gravities simulate pressure profiles very similar to those encountered during reentry. Stress and deflection conditions similar to those expected during atmospheric reentry are thus attained in the laboratory

Mc Cann, R. J.

English

NASA Technical Reports Server

June 1966	 Brief 66-10214 
NASA TECH BRIEF 
NASA Tech Briefs are issued to summarize specific innovations derived from the U. S. space 
program and to encourage their commercial application. Copies are available to the public from 
the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia 22151. 
Colloidal Suspension Simulates Linear Dynamic Pressure Profile 
8.0 
7.0	 A 
6.0 
5.0 
4.0 
3.0 
2.0 
1.0
NORMAL PRESSURE PROFILE
ON NOSE CONE

DURING REENTRY 
B 
0 
1.0
PRESSURE PROFILE OF 
COLLOIDAL SUSPENSION 
2.0 
U) 3.0 
D 
U, 4.0 
cc 
a.
5.0 
6.0 
7.0 
O
	
a.  
40	 80	 120	 160	 200	 240
	
0 20 40 60 80 100 120 140 160 180 200 
VEHICLE STATION (IN.)	 DEPTH OF FLUID (IN.) 
The problem: 
To apply an experimental test load to a structure 
simulating the pressure profile present in actual use. 
Laboratory measurements of stresses on a missile 
nose fairing required an artificial load to simulate 
normal dynamic air pressure encountered during 
reentry. 
The solution: 
A colloidal suspension that may be prepared with 
various specific gravities to simulate many linear
pressure profiles. Missile nose fairings immersed in 
the suspension are subjected to stress patterns very 
similar to those encountered during reentry. 
How it's done: 
Dynamic air pressures present on a missile nose 
fairing during reentry are recorded by flight test 
monitoring. A plot of theoretical pressures normal 
to the fairing surface at various stations along the 
length of the surface is shown in the left figure. 
Between stations A and B, the pressure varied linearly 
with respect to axial vehicle station.
(continued overleaf) lak	
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To simulate this linear pressure profile for labora-
tory stress measurements, a colloidal suspension (so!) 
of 16 parts water, 100 parts iron pyrite, and 4 parts 
clay is prepared. A nose fairing with strain gauges 
and deflectometers mounted at selected axial stations 
is immersed in the suspension, and fluid pressure of 
the sol is indicated at depths corresponding to the 
structural stations. The pressure/depth line derived 
from this test is shown in the right figure to closely 
approximate the pressure profile shown in the left 
figure. Stress and deflection conditions very similar 
to those expected during atmospheric reentry are 
thus attained in the laboratory. 
Notes: 
1. This technique could be useful in underwater 
research.
2. The formulation of the sol can be varied to 
simulate a wide range of pressure profiles. 
3. Inquiries concerning this innovation may be di-
rected to: 
Technology Utilization Officer 
Western Operations Office 
150 Pico Boulevard 
Santa Monica, California, 90406 
Reference: B66-10214 
Patent status: 
No patent action is contemplated by NASA. 
Source: R. J. McCann
of Lockheed/Sunnyvale
under contract to

Western Operations Office 
(WOO-266) 
Brief 66-10214	 Category 05


Colloidal suspension simulates linear dynamic pressure profile

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