Compact device is used to determine impact sensitivity of material in static, high pressure, gaseous environment. It can also be instrumented to monitor and record pressure, temperature, and striker impact force. Device is used in conjunction with commercially available liquid oxygen impact tester which provides impact energy

Davis, L.

Pippen, D.

Stradling, J.

Whitaker, D.

English

NASA Technical Reports Server

NASA TECH BRIEF 
Manned Spacecraft Center S
Striker Pin 
Extension
Load Cell 
December 1972	 B72-102l6 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage 
commercial application. Tech Briefs are available on a subscription basis from the National Technical Information 
Service, Springfield, Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may 
be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546. 
Determination of Impact Sensitivity of Materials

at High Pressures 
.
The problem: 
The major systems that are currently being used to 
perform mechanical impact testing have a number of 
disadvantages including the following: 
1. The large volume of liquid oxygen required in the 
operation of these systems makes them a potential 
source of dangerous explosions. 
2. Tests are difficult to duplicate. 
3. They are slow and limited to a few tests per day. 
4. Because of the weight of the system, a hoist is re-
quired to lower and raise the test sample. 
Systems designed to overcome these difficulties are 
limited to a 1.04 x 10 7
 N/rn2
 (1500 psia) pressure and 
cannot measure the force imparted to the test sample. 
The solution: 
A new, compact device can determine the impact 
sensitivity of a material in a static, high-pressure, gaseous 
environment [up to 6.9 x 10 N/rn2
 (10 psia)]. It over-
comes the disadvantages of the prior devices, and can be 
instrumented to monitor and record pressure, temper-
ature, and the striker impact force. 
How it's done: 
This device (see figure) is used in conjunction with a 
commercially available liquid-oxygen (LOX) impact 
tester which provides the impact energy. The plummet 
of the LOX tester (not shown) is raised to the desired 
height and held there by an electro-magnet assembly. 
The test sample is placed in the sample holder shown in 
the figure, and the test chamber is pressurized to the 
required test pressure. Next, the striker-pin force is 
neutralized by pressurized nitrogen fed into the pneu-
matic amplifier chamber. 
When all the pressures are adjusted, the electromagnet 
releases the plummet which strikes the load cell and the 
striker pin, driving the pin against the sample. Record-
ings are made of the pressure, temperature, impact
force, and the plummet drop time. An oscilloscope 
attached to the load cell displays the force per unit 
time (energy) imparted to the striker pin. 
An interesting feature of this system is the pneumatic 
amplifier which increases the striker driving force to 
compensate for the retarding effect of the difference 
in pressure between the test chamber and the atmo-
sphere. 
A second prototype uses a load cell under the sample 
cup to measure both the static force prior to impact 
and the impact force. 
Sample	 Test 
Cup	 Chamber 
Impact Sensitivity Tester	 Base 
(continued overleaf) 
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.
https://ntrs.nasa.gov/search.jsp?R=19720000216 2020-03-17T03:33:29+00:00Z
Note: 
Requests for further information may be directed to 
Technology Utilization Officer 
Manned Spacecraft Center 
Code JM7 
Houston, Texas 77058 
Reference:. B72-10216
Patent status: 
NASA has decided not to apply for a patent. 
Source: L. Davis, D. Pippen,

and J. Stradling
Manned Spacecraft Center and

D. Whitaker of

Service Technology Corp.

under contract to
Manned Spacecraft Center 
(MSC-13700)
. 
. 
B72-10216
	 Category 07


Determination of impact sensitivity of materials at high pressures

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