A Mathematical Model for Dynamic Vibration Analysis of a Landing Aircraft

PurposeVibration impact plays a key role in the process of aircraft damage and runway pavement deterioration.ProcedureAmong the objectives of obtaining the variation trend of landing vibration along runway, a simplified aircraft response model (ARM) was established by considering the wing up-lift effect. Then, a third-aircraft vibration equation based on the classical D'Alembert principle was proposed and solved with the help of Duhamel integral.ResultsTherefore, the dynamic characteristics of aircraft in different landing periods (touch-down period, deceleration period and taxiing period) were investigated both in time and frequency domains. The outcomes of theoretical analysis were validated by measuring the actual acceleration response of B737-800 aircrafts landing on both rigid and flexible runways. Furthermore, sensitivity analysis was conducted to investigated the influences of several key parameters on aircraft dynamic behavior, namely, the damping coefficient (c) and stiffness coefficient (k) of the main landing gear, effective mass (m), vertical velocity (vv) and acceleration (av) of the aircraft prior to touch-down.ConclusionsThe results show that, the proposed ARM is an effective tool in assessing dynamic vibration characteristics of the landing aircraft. Especially during the touch-down period, the calculated variation curve of acceleration is well-matched with the actual measured aircraft vibration data. The vibration impact of an aircraft on runway landing zone is proved to be severer than the other areas, which is agreed with the actual distributions of pavement deteriorations observed in runway management practice. Besides, both c and k are proved to be two key factors affecting aircraft vibration. In addition, ARM is proved to be an effective method for optimizing the landing gear design and a helpful tool for runway management agency to understand the mechanism of runway pavement deterioration.