Abstract

An infinitely long membrane tube under lateral compression between various rigid surfaces is used as a model to illustrate the load carrying mechanism in tires. The surfaces include parallel flat plates, indentors, and surfaces which are flat and parallel except for a semicircular hump. Such configurations are relevant to deflection of tires against flat ground, the plunger test of tire behavior, and tire enveloping properties.

In the flat plate case, compression rate appreciably affects both the force‐deflection relations and strength. But even at its weakest the structure bursts only at very high deflection. In the indentor case, burst cannot occur unless the initial pressure exceeds a value dependent on the indentor radius to which behavior is otherwise insensitive. Regarding envelopment, the magnitude of the disturbance due to the presence of a hump increases with decreasing tube inflation pressure.

Abstract

Knowledge of the tire sidewall deformation is necessary for accurate modeling of the response of a pneumatic tire to applied forces. An experimental method, the moire fringe technique, is described which permits the contouring of the tire surface under all normal operating conditions. Results are presented for a series of tests which were conducted to determine the tire sidewall deformation due to static loading, centrifugal force, combined vertical and centrifugal loading, and high speed operation (during which standing waves are present in the tire sidewall).

Abstract

Recent technological advances in ultrasonic flaw detecting apparatus (broad band characteristic) have shown that ultrasonic pulse‐echo inspection of aircraft tires is now possible. The acoustic properties of rubber and rubber composites have been studied so that optimum system requirements may be determined. A prototype inspection system has been constructed to demonstrate the ability of pulse‐echo ultrasonics to locate critical internal flaws and structural elements in tires. Electronic and mechanical refinements necessary to complete automated inspection systems are discussed and the importance of defect standards for aircraft tires considered.

Abstract

Tire wear data from two tread wear tests on different courses have been analyzed to determine how patterns of wear are affected by the course. The coefficient of variation (CV) was used as a measure of irregular wear. Tires which exhibited irregular wear (large CV) exhibited the same pattern of wear on both courses; that is, the location of the fastest wearing ribs was unchanged. Those that wore more evenly showed distinct differences in wear pattern on the two courses although all ribs wore at about the same rate. However, some of the changes observed for particular brands of tires may have been the result of tire design changes. Tread life was projected for tires based on the fastest disappearing groove and on the average of all groove depth readings. The rankings of the tires by both methods on the two courses were highly correlated; there does not appear to be any advantage to one method over the other for relative rating.

Abstract

The meaningfulness of multisectioned tire tests has been the subject of considerable controversy for many years. In this exposition analysis of the data from such tests is discussed from a statistician's point of view. The applicable statistical model for analyzing such data is discussed, as well as data transformation and estimation of tire‐compound interaction effects. It is concluded that, given the proper analysis, multisectioned tire tests are a valid means for comparing treadwear of several compounds.