A frangible metal tube has the capability to dissipate the energy generated when a vehicle lands with excessive velocity. The tube is so placed that, at impact, it is forced against a die and, as it fragments, energy is absorbed

Hathaway, M.

Mc Gehee, J. R.

Zavada, E.

English

NASA Technical Reports Server

February 1964 1964
NASA TECH BRIEF
Brief 63-10304 
This NASA Tech Brief is issued by the Technology Utilization Division to acquaint industry 
with the technical content of an innovation derived from the NASA space program. 
Break-up of Metal Tube Makes One-Time Shock Absorber, Bars Rebound 
Downward Force 
Landing Skid 
The problem: Design a lightweight shock ab-
sorber, or energy-absorbing system, which will safely 
dissipate the large amount of energy generated if a 
spacecraft lands with excess velocity on the Earth, the 
Moon, or another planet. Low rebound following 
shock absorption is highly desirable. 
The solution: Place a metal tube—in this case a 
hard aluminum alloy—so that the downward motion 
of the spacecraft forces the tube against a suitably 
shaped die, such as a torus. As the tube presses 
against the die, it shatters by successive fragmentation. 
How it's done: Energy absorption results when a 
force is required to fragment the tube through a large 
portion of its length. The energy absorption capability 
of frangible metal tubing, such as 2024-T3 aluminum 
alloy, has been shown by NASA investigations to be
Pieces break off as 
energy is absorbed 
as high as 31,000 foot-pounds of energy per pound of 
tubing. Any number of frangible tube and die combi-
nations could be used in a spacecraft landing system, 
depending upon design requirements. Length and 
diameter of the tubes could be varied, within limits, 
to suit the application. 
The tube must be oriented so that the force is 
applied along the tube's longitudinal axis and not 
tangentially. Some mechanism, such as a linkage, 
could be used to ensure axial loading of the tubes. 
Energy-absorption capability of this device is much 
greater than most existing energy absorption processes. 
Another valuable characteristic is the almost total lack 
of rebound. Putting a taper on the end of the tube 
contacting the die enables the designer to avoid the 
high initial forces otherwise required to start the frag-
(continued ovetleat) 
This document was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States Gosern-
ment, nor NASA, nor any person acting on behalf of NASA; A. Makes 
any warranty or representation, express or implied, with respect to the 
accuracy, completeness, or usefulness of the information contained in
this document, or that the use of any information, apparatus, method, 
or process disclosed in this document may not infringe privately-owned 
rights; or B. Assumes any liabilities with respect to the use of, or for 
damages resulting from the use of, any information, apparatus, method, 
or process disclosed in this document.
https://ntrs.nasa.gov/search.jsp?R=19630000048 2020-03-11T16:45:42+00:00Z
menting process and also permits some control of the 
rate of force application. 
Notes: 
1. Other applications of this one-time shock absorber 
might include elevator decelerators, instrument 
mountings, mountings for passenger seats and 
impact testing. Other potential industrial uses are 
in automobile and aircraft seat belts, guard rails on 
highways, and shock protection equipment for the 
transportation of high-cost or delicate machinery. 
2. NASA TN D-1477 entitled "A Preliminary Experi-
mental Investigation of an Energy-Absorption 
Process Employing Frangible Metal Tubing," by
John R. McGehee, October 1962, provides infor-
mation on this innovation. 
Patent status: NASA encourages the immediate 
commercial use of this invention. It is owned by 
NASA and a patent application has been filed. When 
patented, royalty-free, nonexclusive licenses for its 
commercial use will be available. Inquiries concern-
ing license rights should be made to NASA Head-
quarters, Washington, D.C., 20546. 
Source: John R. McGehee, Melvin Hathaway,

and Edmond Zavada
Langley Research Center (Langley 1-A) 
Brief 63-10304


Break-up of metal tube makes one-time shock absorber, bars rebound

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