Dynamic Analysis of Aircraft Landing Impact Using Landing-Region-Based Model

Abstract

Nomenclature Aa = pneumatic area Ah = hydraulic area Ao = area of opening in orifice plate Ap = cross-sectional area of metering pin or rod in plane of orifice A0 = net orifice area Cd = orifice discharge coefficient d = damping coefficient of supporting damper Fa = pneumatic force in shock strut FC = damping force applied on the floating mass Fh = hydraulic force in shock strut FK = spring force applied on the floating mass FS = total axial shock-strut force FVa = vertical force, applied at axle FVg = vertical force, applied to tire at ground g = gravitational constant h = bulge height (height of upper surface of floating mass over runway) KL = lift factor, L/w k = stiffness of supporting spring L = lift force m, r = constants corresponding to the various regimes of the tire-deflection process n = polytropic exponent for air-compression process in shock strut pa0 = air pressure in upper chamber of shock strut at zero stroke ph = hydraulic pressure in lower chamber of shock strut rd = radius of deflected tire s = shock-strut axial stroke v0 = air volume of shock strut at zero stroke w = total dropping weight w1 = weight of upper mass above strut w2 = weight of lower mass below strut w3 = weight of floating mass z1 = vertical displacement of upper mass from position at initial contact