Safe runway operations are an important consideration and challenge for airport authorities. Investigations have shown that runway friction is greatly reduced during wet weather operations. Any traction failure during high-speed landing and take off of an aircraft could lead to accidents and loss of human life. In practice, runway friction is estimated with a ground vehicle, such as continuous friction measuring equipment equipped with a Pavement International Association of Road Congress (PIARC) tire. Recommendations for safe runway friction are based on statistical correlations between such devices and aircraft tires. However, such correlations do not incorporate the variability of the field conditions to the test condition. This paper presents an approach that uses a three-dimensional finite element (FE) model capable of simulating a rolling aircraft tire at any given operating conditions. The highlight of the approach is the consideration of FE meshes of asphalt surfaces rather than artificial surfaces. The model was used to determine the effect of aircraft tire operating conditions on runway friction. The trends of results predicted by the model agree with the previous experimental studies on aircraft tires. It was also found that the computed wet friction of a PIARC tire and an aircraft tire are different, particularly for the extreme operating conditions of tire inflation pressure and water depth. This result indicates that an intrinsic variability exists between the friction coefficients of an aircraft tire and a PIARC tire.

Hydroplaning is a major safety concern in wet-weather driving. Grooved tires have been commonly used to improve skid resistance and increase the hydroplaning speed. Tire grooves help in the expulsion of water from the tire pavement contact region by providing escape channels. Past researchers have shown that tire groove spacing, groove width and groove depth affect skid resistance. However, analytical tools are unavailable for highway engineers to evaluate hydroplaning speed taking into consideration basic geometric parameters such as tire groove width, groove depth and spacing etc. The present paper describes a numerical analytical tool to study the effect of tire groove spacing, groove width and groove depth on hydroplaning speed by means of earlier verified analytical hydroplaning modeling for tire having transverse groove pattern, longitudinal groove pattern and combined transverse and longitudinal groove pattern on plane pavement surface are analyzed in this paper.

Grooving of tire tread is necessary to provide sufficient skid resistance for wet-weather driving and to reduce the risk of hydroplaning. Many different groove patterns of tire tread are found in the market. However, their relative effectiveness in reducing hydroplaning risk is generally not known to motorists and highway engineers. The effects of changes in the groove depth of a tire tread's groove pattern also deserve further investigation. This paper presents an analytical study that aims to characterize quantitatively the influence of different tire-tread patterns and groove depths on the hydroplaning behavior of passenger cars. The analysis is performed by means of a computer simulation model with a three-dimensional finite element approach. The following six forms of tire-tread groove patterns are considered: (a) longitudinal groove pattern, (b) transverse groove pattern, (c) V-groove pattern with 20° V-cut, (d) V-groove pattern with 40° V-cut, (e) combined groove pattern consisting of longitudinal grooves and edge horizontal grooves, and (f) combined groove pattern consisting of longitudinal grooves and 20° V-cut grooves. The analysis shows that a parameter computed as the groove volume per tread area of the tire is a useful performance indicator to assess the effectiveness of various tire-tread groove patterns in reducing vehicle hydroplaning risk. The significance of V-shape grooves is discussed. For vehicular operations involving both forward and lateral movements, the analysis indicates that a combined pattern would provide a good compromise in lowering hydroplaning risk sufficiently in different modes of vehicle movements.