Helicopter Main Rotor Blade Root End under High Velocity Bird Impact

Abstract

A numerical simulation methodology has been successfully developed to model the bird strike on the innovative helicopter main rotor blade root end under high velocity bird impact. This paper demonstrates the state-of-the-art composite modelling methodology of main rotor blade and numerical bird models through experimental tests and simulation tools. The present work is based on the application of non-linear explicit finite element analysis to simulate the response of main rotor blade root end. The damage behavior under soft body impact depends upon bird size, blade size, blade span wise location of impact and bird orientation with respect to hitting location, blade rotational speed and rotorcraft cruise speed. Bird model is considered as hydrodynamic with length to diameter ratio of 2. A bird strike event is characterized by loads of high intensity and short duration. A transient explicit non-linear finite element based impact analysis using Autodyn has been carried out to predict bird strike resistance to withstand 1.0 kg bird at critical flight condition. The numerical simulation results are compared to experimental bird strike test data, leading to conclusions about the success of both the design concept and the simulation methodology. The comparison shows a very good agreement between experimental and simulated damage evolution during impact.