Influence of Aircraft Lateral Deviation on Aircraft–Runway Random Vibration: A Probabilistic Perspective

Mainstream airport runway roughness indices and aircraft–runway coupled vibration studies are constructed under the implicit centreline taxi assumption, leaving the random lateral deviation of the actual aircraft trajectory outside the coupled vibration framework. Existing studies have revealed the importance of lateral deviation from the perspectives of wheel track distribution and cumulative damage; however, these approaches mainly treat lateral deviation as an exogenous statistical input for damage evaluation without embedding it into the aircraft–runway coupled vibration equations to resolve the joint probability evolution of the aircraft, wheel load and pavement responses. Unlike existing centreline- or fixed-wheel-path aircraft–runway coupled vibration models, this study embeds aircraft lateral deviation as a random variable into the wheel–pavement contact coordinates and the displacement–compatibility relation so that the three-dimensional runway roughness input varies randomly with the actual wheel path and further solves the probability distributions of the aircraft-side and pavement-side responses through PDEM. The IPDEM solution was cross-validated against 10,000 Monte Carlo simulations, with PDF shape deviations within 5% and mean/standard deviation within 3%. Results show that the centre-of-gravity acceleration reaches a coefficient of variation (COV) of 47.99% (about 3.7 times the 12.98% induced by aircraft weight randomness alone), and the main-landing-gear dynamic load coefficient COV reaches 1.84% (again, 2.9 times the 0.63% for weight randomness); the pavement bottom strain and vertical displacement attain COVs of 1.50% and 2.03%, respectively. Within the cases and comparison scope of this study, lateral deviation randomness is an important source of dispersion in the aircraft-side responses, and the CGA and DLC variability this induces is higher than that under aircraft weight randomness alone, providing a probabilistic baseline for reliability-based runway design and full-cross-section roughness evaluation.