Academic literature on the topic 'Runway friction testing'

Airport runway friction coefficient test vehicle is the key equipment to test the runway friction coefficient, it's test precision directly affects the safety of aircraft. The international civil aviation organization prescribed slip ratio is 12%.How to maintain this value is a key part. This thesis aims to do research for this slip ratio control system. High speed on-off valve is its core part. The traditional friction coefficient testing vehicle adopt servo valve. But servo valve is high demanding on its operating environment and its expensive. Using high speed on-off valve is good to avoid these disadvantages. The simulation results show that the method is reliable and effective.

ABSTRACT For modeling an aircraft tire using the brush model method, the friction coefficient μ between rubber and asphalt should not only be described in terms of the applied pressure and sliding velocity/slip ratio, but also by local temperature inside the contact area. Its influence cannot be neglected, since it leads to significant material property changes. Therefore, investigations on different test rigs are analyzed using thermal recordings of an infrared camera. First measurements are done on a high speed linear tester (HiLiTe), a test rig at the Institute of Dynamics and Vibration Research (IDS) at Leibniz University Hanover, Germany. It allows testing single tread block samples with a constant slip ratio of 100%, that is, pure sliding, on a variety of surfaces such as dry and wet asphalt or concrete, as well as on snow and ice. Results in this paper show that the convection has a smaller impact on tread block cooling than the actual contact between runway surface and sample. Since colder surface temperatures lead to higher friction, this effect antagonizes the excitation frequency, which heats up the rubber sample at high velocities. On long-lasting test sequences a quasi–steady-state friction coefficient might be achieved once these effects start to converge. Still, owing to permanent slip, the abrasion leads to cooling as the hot top layer of the rubber is removed occasionally. In addition to these quasi–steady-state measurements on HiLiTe, the thermal behavior of an aircraft tire is investigated with an autonomously running test rig. It allows realistic testing on an airfield runway by altering load, speed, and slip angle of the tire within and beyond the regions of a passenger aircraft. During the measurements, new and partially unknown effects could be observed. The temperature is mostly influenced by the slip angle followed by speed and load. Furthermore, the contact between tire and runway leads to cooling of the tread but does not affect the temperature inside the grooves. They heat up separately and tend to transfer heat to the tread if the cooling by the runway becomes too low.

Sustainability at airports has received attention recently as owners have worked to incorporate sustainable practices into projects and daily operations. Several guides have been published by airport agencies to document sustainable practices. One potential practice involves alternative paving materials for airfield pavements. Specifically, fiber-reinforced asphalt concrete has shown promising results and has recently been used to resurface Runway 1–19 at the Jackson Hole Airport in Jackson, Wyoming. This paper explores the feasibility of using fiber-reinforced asphalt concrete as a sustainable paving strategy for airfields. The study includes an extensive literature review, performance testing of an asphalt mixture, cost analysis, a sustainable credit summary, and a carbon dioxide emission comparison. Laboratory testing showed that the Jackson Hole Airport mixture performed better than a control mixture produced in the laboratory with similar materials. Further analysis concluded that a fiber-reinforced, porous asphalt friction course could qualify for several sustainable site credits. In addition, the minimal upfront cost of fibers makes this product attractive because the cost can be recouped by an approximate 1-year extension in service life. Pavement design simulations indicated a reduction in equivalent carbon dioxide emissions through the extension of service life. Recommendations for the use of fiber-reinforced asphalt concrete on airfields are provided based on the findings of this study and future research is identified.

A number of serious rail runaway accidents have occurred in recent years on long and high grade downhill tracks in mountain terrains in Canada, causing fatal injuries and huge property loss. They were caused by brake failure, misunderstanding of brake features, maintenance deficiency and/or improper brake application on the trains. Train dynamics simulation, brake ratio testing, and dynamometer testing on friction heat fade helped disclose the causes and contributing factors in the cases presented in this paper. Guidelines were revised for safer train operation, equipment requirements and maintenance practice in the mountain terrain conditions.