MIL-DTL-11891G(AT)
3.3.4.5 Thermogravimetric analysis. This test will be performed in accordance with
ASTM E1131 during qualification to establish requirements for future reference during
production. Results of the TGA will be provided to the Government. The ranges for TGA are as
follows (see 4.7.2.8):
Plasticizer + Residue...............................+3%
Polymer...................................................+5%
Filler........................................................+5%
3.3.4.6 Test measurements with oscillating disk cure meter. A curing characteristics
curve (trace) shall be obtained as outlined in ASTM D2084 on the compounds used in the pad
(integral and/or replaceable) and roadwheel path of the track being submitted for qualification.
The traces will be provided to the Government. The following tolerances will be used in
production when compared to the charts representing traces of compounds used for fabrication of
components for qualification. Parameter definitions shall be according to ASTM D2084.
Alternative test methods and parameters may be used but must be identified in the control plan
and approved by the Preparing Activity (see 4.7.2.9).
Minimum torque (M): +2 lb-in (0.23 N-m)
Maximum torque (M): +4 lb-in (0.45 N-m)
Time to 60 percent of M: T(60) + 0.4 minutes
Time to reach 5 lb-in (0.57 N-m) above minimum torque: +0.4 minutes
3.3.4.7 Track pad and roadwheel path adhesion test. Adhesion tests will be conducted on
the finished products of the track systems being submitted for qualification. As a minimum, two
representative samples of the ground pad (replaceable and/or integral) and two representative
samples of the roadwheel path elastomer are required for the adhesion tests. One test specimen
from each component shall be prepared for test in accordance with 3.3.4.7.1 using the test
apparatus of ASTM D429, method B (see 4.7.2.10).
3.3.4.7.1 Sample preparation. The samples shall be prepared in the location as shown in
figures 1, 2, 3 and 4. The elastomer shall be cut down to the base metal along two (2) parallel
lines, leaving an elastomer strip 1 + 1/16 inch in width, 1/2 to 1 inch in thickness, with length
extending in the direction of maximum adhesive area. The elastomeric thickness shall be as
uniform as practical of the thickness shown in the respective figures for the component under test.
When necessary, the portion of the elastomer remaining outside of the 1-inch wide section of the
cut strip shall be removed from the metal base to avoid any edge constraint during the test. The
elastomer shall be stripped from the metal using a sharp knife for a sufficient distance to permit
firm gripping of the tab in the grip of the test machine head.
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