Improving the accuracy of the behaviour simulation of the material of the turbojet aircraft engine fan rotor blades in the event of a bird strike by using adapted finite element computational models

Abstract

One of the most topical issues in aircraft building is checking the engines for bird strike resistance, i.e. their airworthiness following an in-flight bird strike. The most critical aircraft units are the turbojet engines. In this case, the turbofan blading is affected the first thing. Its deformation or failure can result in the failure of the entire engine. Numerical simulation of the process allows for a qualitative and quantitative assessment of the consequences of a bird strike on the blades. This enables to avoid full-scale experiments and design properly the units affected by such action. The paper deals with improving the accuracy of simulation modelling of the behaviour of the material of the fan rotor blades of a turbojet aircraft engine in the event of bird strike by using adapted finite-element computational models. Bird action is argumentatively replaced with a system of equivalent quasistatic loads. The most critical events of blade impact with medium and big-size birds were selected by analysing experimental data. The force impulses were compared to determine the strike locations and the sizes and masses of birds that are most dangerous from the viewpoint of disturbance of strength properties. Variant computational analyses deal with studying construction behaviour under static action of the joint load by centrifugal forces and loads that simulate bird action on the fan blading. The stress–strain state characteristics are used to assess the behaviour of the material and its strength properties. Simulation accuracy is confirmed by comparison with the results of bench tests.