Analysis of Bird Strike under Blunt and Splitting Impact

Abstract

The forward faced components of passenger aircraft and large helicopters need to be certified for their performance under bird-strike loading. In bird-strike conditions the load is transferred via a perpendicular or oblique (blunt impact), a nose (splitting) or a rotating blade (slicing) surface, dependent on the position on and orientation of the aircraft. Under the impact structures may fail or resist sometimes without deformation. When it comes to bird-strike certification of structures real birds are needed. However, it is known that real bird testing lacks of repeatability [Wilbeck]. To overcome these negative effects substitute birds have been developed since the beginning of systematic impact testing. The ornithological basis for current substitute bird approaches have been summarised by Budgey. The idea is to replicate the tissue of birds shaped reminiscent of prepared real birds. So far, substitute birds have not been acceptable in aircraft certification due to non-reproducible effects, too. Furthermore, one single substitute bird design has never been scrutinized under different loading modes and various structural components before. A basic evaluation of soft bodies like real or substitute birds often comprises a blunt or perpendicular impact on a load measurement device. These tests are done on rather rigid test devices. The approach of fundamental studies shall be extended to substitute birds under splitting impact. The evaluations of test and simulation results to quantify a validation are presented. One objective is to show repeatability of one method (test, e.g.), the other to quantify the extent of correspondence of two methods.