Characterization of real and substitute birds through experimental and numerical analysis of momentum, average impact force and residual energy in bird strike on three rigid targets: A flat plate, a wedge and a splitter

Abstract

To validate the increasingly used numerical models for optimization and verification of the designs subjected to bird strike, initial (calibration) tests are a necessity prior to full scale testing. Bird strike calibration tests on rigid targets specifically, give a valuable insight in the complex behaviour of a bird. This paper presents the results of a series of bird strike tests and simulations on three rigid targets (a plate, a wedge and a splitter) to quantify the forces originating from the change of momentum and splitting of the bird. In this study, momentum transfer is the key parameter to compare birds with different masses, materials, speeds, etc., as proposed in the reference works from the 20th century. The main purpose of this paper is fourfold: (i) to introduce another way to measure momentum transfer on these kinds of structures and therefore get more consistent results, (ii) to show that gelatine generates similar impact forces as real birds, (iii) to point out that apart from the change of direction of the momentum, the deviatoric and/or dissipating constitutive behaviour of the bird also plays an important role and (iv) to show that a simple plate structure can be used to measure the residual energy of the bird remainders after an impact event. In a series of numerical simulations, the performance of a SPH bird with an EOS material model is used to validate the analytical models.