Automatic rifle was modified for remote, single-shot use. To simulate statistically--determined fragment size from rocket-motor casing blunt-nosed bullet was made of same alloy. Cartridge was loaded with enough powder to make bullet reach target at same estimated velocity as shrapnel from rocket casing

Smith, T. H., III

Snoke, B. A.

English

NASA Technical Reports Server

May 1974	 1	 B74-10052 
NASA TECH BRIEF 
Ames Research Center	 - A £ 
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. 
Economical Technique for Fragmentation Testing 
S
It is important to know the extent fragments can 
penetrate into critical subsystems should there be an 
explosion of primary systems such as steam boilers, 
storage tanks, rockets, etc. Ordinarily, a shrapnel or 
fragmentation penetration test is conducted with a 
form of high-velocity sled that drives a typical frag-
ment into the subsystem. However, this technique is 
very costly, and so it is expedient to determine whether 
another type of test can be substituted; thus, during 
investigation of fragment penetration effects on a 
spacecraft radioisotope heater in the event the launch 
vehicle exploded within 1 to 30 seconds after ignition, 
it was found that a test could be performed accurately 
and at greatly reduced cost by using a rifle to project 
a specially-formed bullet. The main concern was 
whether an encapsulated radioisotope heater unit 
could withstand a shrapnel barrage of high velocity 
fragments resulting from the explosion of a rocket-
motor casing. 
A 50-caliber automatic rifle was modified for 
remote, single-shot use. To simulate a statistically-
determined fragment size from the rocket-motor 
casing (1.3-mm thick, 5.33-cm square) a blunt-nosed 
bullet was made of the same alloy (Ti-6A1-4V) with 
dimensions of 12.85-mm diameter by 30.99-mm 
length and a weight of 17.69 grams. The cartridge 
was loaded with enough powder to make the bullet
reach the target at the same estimated velocity (562 
m/sec) as shrapnel from the rocket casing. 
The rifle was situated about 4.5 m from the target, 
which was suspended by nylon monofflament to 
minimize restraining forces; two grids placed in the 
intermediate region were connected to an electrical 
chronograph. The chronograph was started as the 
bullet pierced the first grid, and stopped when it 
passed through the second; bullet velocity was cal-
culated from the time of flight. 
Note: 
No additional documentation is available. Specific 
question, however, may be directed to: 
Technology Utilization Officer 
Ames Research Center 
Moffett Field, California 94035 
Reference: B74-10052 
Patent status: 
NASA has decided not to apply for a patent. 
Source: Thomas H. Smith III and Betty A. Snoke of

TRW, Inc. Systems Group 
under contract to

Ames Research Center

(ARC-10792) 
Category 04 
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.
io
https://ntrs.nasa.gov/search.jsp?R=19740000052 2020-03-17T14:00:09+00:00Z


Economical technique for fragmentation testing

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server