We recently conducted research on sticktion. The test involves the use of a hydraulic actuated drag sled which actuated within 16ms. (The fastest actuating drag sled ever constructed). The device was used to test the sticktion forces by lifting the test foot vertically and measuring the sticktion component. This device was mounted horizontally and the test foot was pulled horizontally to determine the slip-resistance. The residence time is determined automatically with electronic timers. The result of this study was to determine if a correlation exists between residence time and sticktion. Secondly, the test was to determine if a drag-sled sticktion can be corrected by subtracting the vertical sticktion measurements.

Summary of the Findings

Sticktion was not avoided with a 16ms residence time.

Sticktion was observed in wet testing

Sticktion was not a function of residence time and the vertical force components of sticktion were too small to measure with the test apparatus as constructed.

Future Interests:

• Determining if the delta between slip-index (Wet) and coefficient of friction (dry) is related to hazard. It might be expected that large deltas in these measurements might indicate a greater hazard potential as much as the COF or slip-index reading alone.
• Determining the impact of using the English XL on ramps.