Numerical and experimental modeling for bird and hail impacts on aircraft structure

Abstract

Aircraft bird-strike events are very common and dangerous. Hailstone impacts represent another threat for aircraft structures. As part of the certification process, an aircraft must demonstrate the ability to land safely after impact with a foreign object at normal flight operating speeds. Since experimental studies can be cost prohibitive, validated numerical impact simulation seems to be a viable alternative. Modelling of these soft body impacts still represents a challenge, involving modelling of both the target and the projectile. Here the smooth particle hydrodynamics method (SPH), which has been used successfully in ballistic applications involving bird strike scenarios, is extended to hail impact. The paper thus presents the meshless SPH numerical method as a novel modeling approach. The method is applied to model bird and hail impacts which are problems that traditional FEM based modeling methods typically struggle to solve because of involved mesh distortion problems. The numerical results are then evaluated by comparing with the data collected during recent experimental tests. The data acquisition methods are also described and evaluated for applications where the short duration of the impact presents a challenge. The accuracy of the numerical results allows us to conclude that the models developed can be used in the certification and/or design process of moving (aircraft) and stationary (wind turbines) composite structures subject to bird and hail impact. ©2010 Society for Experimental Mechanics Inc.