Bi-Normal Coordinates in Discrete Systems with Application to an Aircraft Shimmy Problem

摘要

The use of bi-normal coordinate theory in the analysis of practical discrete systems provides the substantial benefits of conceptual value/physical insight, computational utility, and enhanced redesign capability. These benefits are explained and demonstrated in the present effort with attention to practical considerations. Section 1 extends the theory and presents the new material together with some previously available results in a coordinated manner. In particular, the nature of response in a single homogenous phasor mode is described in detail. Also, an expression for the derivative of an eigenvalue is developed and explained. Section 2 reports the analysis of an aircraft nosegear shimmy problem using bi-normal coordinate methods. Stability boundaries, mode shapes, and sensitivities to parameter changes are presented. Derivatives of eigenvalues are used in Section 3 to illustrate automated minimum weight design for a shimmy-free nosegear. Recommendations for further research are made. (Author)