Calibration and Qualification of the
Dr.
Abstract: A set of fixtures consisting of a carriage,
cradle, simulated plenum, and simulated deck have been designed for the WOX
(White Oak Experimental)-7B shock test machine to enable shock qualification of
missiles and canisters for use in the MK 41 VLS (Vertical Launching System).
A set of requirements for simulating shipboard shock with a machine was
provided by NSSC code O5P3.
The testing was performed using a “generic” encanistered
missile in a VLS MK 14 Canister. The generic missile is an I-beam with a
number of round supports of the same diameter as a Tomahawk missile. The
supports center the beam in the canister and provide contact with the lateral
shock pads and base plate of the canister. The base plate is attached to the
canister through liquid spring shock isolators. The loaded weight of the
canister and simulated missile is the same as a tactical “all up round.” The
missile interaction with the canister is approximately the same with the
canister during the shock motion as it would be with a real missile. The I-beam
and canister are Tomahawk program assets that have been used for many other
shock tests.
With the WOX-MSTM equipment, the missile is loaded into a “cradle” fixture that
has a simulated ship deck on one end and a simulated MK41 plenum on the other end.
The cradle is installed on a “carriage” that has wheels that run on tracks
leading back to the WOX. The WOX is a heavy weight shock test machine
that employs an 11,000 lb. hammer to impact a set of transfer beams that apply
the force of impact to the carriage. The cradle and carriage are
adjustable so that the shock motion is oblique to the canister axis. The
canister can be rotated about its own axis in the cradle.
A series of eleven tests was conducted in the presence of NSSC representatives
that showed the how the input could be proportioned along the test item
axes. The final tests were at angles of obliquity and rotation that
produced the correct proportionality, and at a drop height that produced the
correct velocity along the canister axes. The so-called “average
acceleration” for each channel of canister input motion data was also
computed. The average accelerations also met the requirements of NSSC
O5P3. The velocity spectrums were computed using the shock spectrum method
and Fourier analysis. These also met the requirements, completing
qualification of the machine for shock testing encanistered
missiles on cruisers and destroyers.
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