Development of Deceleration-Based Runway Friction Measurement Methods
ERDC Vicksburg United States
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Runway surface friction is a critical safety concern on all airfields however, current friction measurement equipment is expensive. Airfield managers have identified a need for contingency friction assessment tools that are cost-effective and commonly found. The current Air Force standard for pavement friction measurement is a high-speed continuous friction measuring equipment CFME device, the Findley Irvine GripTester. Operation of the GripTester is both labor-intensive and cost-prohibitive. This report details the development of an alternative, more economical measure of a surfaces frictional characteristics using accelerometers. Accelerometers were standard friction assessment tools in the late 20th century before CFMEs became standard practice. Accelerometer-based friction testers measure the peak deceleration of a vehicle during the braking motion. The vehicles deceleration is proportional to the surfaces friction coefficient. This report documents research conducted to evaluate the use of smartphone accelerometers and vehicle engine control units ECUs having sufficient accuracy and precision to function as deceleration-based friction assessment tools. Findings herein show that smartphone accelerometers, given sufficient experimental controls, can operate as deceleration-based friction assessment tools. This report also details unsuccessful attempts to extract usable deceleration data from vehicle ECUs and the potential future of such efforts. Regressions are presented that show correlation between smartphone deceleration measurements and high-speed GripTester measurements.
- Test Facilities, Equipment and Methods