Abstract: On the assumption that the unevenness of runway profiles along the direction of taxi- ing is a stationary random function,techniques of piecewise constant-speed taxiing runs and piecewise linear representation of dynamic properties of airplane landing gears are adopted in this paper to approximately simplify the actual nonlinear and nonstationary random vibration prob-lems to the piecewise linear and stationary ones.By use of the frequency response functions to describe the dynamic characteristics of the airplane in the frequency domain,which include verti- cal translation and pitching modes of rigid body and the first n flexible modes of the airframe,a method of identifying the autospectral density functions of gear loads at the contact points with the runway from measured acceleration data at the centre of gravity of the airplane has been de- veloped in this work.The equivalent linear parameters of gear′s dynamic properties are obtained by iterative solution. Numerical results indicate that both the method and the program developed are feasible,which would be quite helpful to the design engineer particularly in evaluating fatigue damage of the structural system.

Key words: Random loads landing loads, taxiing, linearization