Stability analysis of shimmy under the consideration of tire pavement contact mechanics behavior

Abstract

The analysis and research on shimmy stability are generally based on established tire parameters and flat and rigid pavement models. Modern aircraft taxiing requires verification and comprehensive evaluation in combination with landing gear shimmy physical tests and special scenario flight tests. The size of tire imprints affects the dynamic characteristics of tires, and empirical formulas do not take into account the contour shape and contact surface state of tires. At the same time, the study and analysis of shimmy often overlook the influence of pavement curvature. Based on this, in order to study the mutual influence of tire contact deformation and pavement curvature on shimmy stability, this paper takes the landing gear system as the research object, combines shimmy analysis methods, line contact models, and point contact models, and establishes a shimmy analysis model that considers the elastic-plastic deformation of tire pavement contact. The accuracy of the theoretical model is verified through imprint tests, and deviation coefficients are introduced to analyze the differences in shimmy response results between traditional models and contact models. The results show that the new tire deformation theory can better fit the test data and consider the effects of tire configuration, grooves, and contact surface curvature; The tire imprints obtained by different algorithms have certain differences, and tire imprints have a significant impact on the stability of shimmy; The critical damping deviation required for anti shimmy of the landing gear system decreases with the increase of the ratio of flywheel to tire radius, and can reach a deviation of over 20% for both point contact and line contact models; Ensuring that the tire has the same imprint length and the same compression amount will result in deviations in the evaluation of the stability analysis of the shimmy, and the results of the shimmy test bench need to be corrected.