The resultant of the rocking angles, ( /g84y&/g84z), gives a total rocking angle of 1.77 degrees. Due to the  arrangement of the shear ties, rotation about the shear tie centerline, ( /g84x) to the extent shown above is  not possible. Actual /g84x rotations are small in comparison to /g84y&/g84z. Based on this data, 1, 2, and 3-sigma loads, displacements, and cycles were defined for the wear test.  These test requirements are shown in Table 3.  Table 3. Wear Test Moments and Rocking Angles  Case Overturning Moment  N-m (in-lb) Rocking Angle  degCycles Frequency [Hz]   3 /g86 855 (7565) 1.77 3 1.5  2 /g86 570 (5043) 1.18 32 5  1 /g86 285 (2522) 0.59 145 5 Test Description  In order to correctly envelope the flight wear environment, the following criteria were met in the design of  the wear test:  1. Requirement: Shear tie wear testing shall employ the same wear mode as the flight application  Compliance: The test simulates the dominant wear mode, which is rocking about the instant-center of the spherical wear surface.  2. Requirement: Shear tie wear testing shall occur under the same contact stress level, and with the  same normal load distribution around the contact line. Compliance: Shear Tie Testing was performed using a flight-like LLA assembly, which was  preloaded to the flight preload using the flight preloading procedure.  3. Requirement: The test specimens must have the same contact geometry as the flight design  Compliance: Shear tie test articles were built to flight drawings & standards.  4. Although the frequency that wear cycles occur is considered to be less important than other  parameters, it is good to get as close as possible to the flight wear cycle frequency. The flight wear mode occurs at a low frequency (~20 Hz). Testing was performed at a low frequency, and was limited by the capability of the Instron machine to main control at high displacements. (Failure to maintain position control would result in damage to the test article). A cycling  frequency of 5 Hz was achieved for 1 /g86 & 2/g86 tests, and 3 /g86 tests were limited to 1.5 Hz due to the  larger stroke.  Test Conservatism The level of test conservatism applied during a wear test should be carefully considered. In the case of  shear ties, there is often a higher level of uncertainty associated with wear predictions than a typical wear prediction. In addition, solid lubricant coatings are prone to lot-to-lot variations, which demand either a larger sample size, or a higher level of conservatism. In the case of this test, there was a high level of confidence that the shear ties would survive the test, so a high level of conservatism was used.  Conservatism was maintained by several factors. First, design load factors were used to define the wear  environment. These design loads were, on average, about 100% higher than coupled-loads analysis  predictions. In addition, friction was ignored in determining the shear tie rocking angles. Finally, the number of 1-sigma cycles was doubled to account for any wear that could occur during acoustic ground  tests, which resulted in the 145 cycles shown in Table 3.  Pass-Fail Criteria The following pass/fail criteria were used for the test:  1. Successful deployment/separation of the shear tie interface after being subjected to all three load  cycling cases, while utilizing only the “static” kickoff force provided by the LLA assembly (slow release of preload).  162