Fuel sloshing effect on dynamic loads

The aim of this paper is to study how the effect of fuel sloshing can help to reduce the dynamic loads on the wing. The aircraft chosen for the study is the Airbus A400M military transport aircraft (Figure 1.1). Moreover, since the purpose is to understand in a better way the behavior of the aircraft, this paper could make the actual model (which is very precise) to be even more accurate in conditions with significant fuel movement compared with the real behavior. Chapter 1 will demonstrate that the critical case for sizing of the wing is an intermediate fuel contents configuration and will prove that a higher damping helps to reduce dynamic loads. An estimation of the dynamic loads reduction is presented for the A400M case. This chapter also comments different ways to model the sloshing produced by liquids and how it has been treated in certain fields of industry. In Chapter 2, a simplified model in NASTRAN is created to reproduce in a simpler way the behaviour of the wing. The main dynamic parameters of the wing (modal frequencies and modal shapes) have been used to create this model. Different variations and models are used in order to study the effect of fuel in dynamic loads. Chapter 3 presents a virtual test and describes the model used in Pam-Crash, the SPH (Smoothed Particle Hydrodynamics) technique and how to apply it. SPH technique is an advanced tool for representing liquid behaviour and by which more accurate results could be obtained. Chapter 4 covers the result of the virtual test applied to the Pam-Crash model. It includes the evolution of main parameters with the variation of fuel and ribs configurations. Chapter 5 proposes how to relate Pam-Crash data with NASTRAN data through two ways. It also contains the expected benefits that this test could bring to the industry. Chapter 6 proposes future work (improvements for the virtual test and a real physical test with its budget) and summarizes the steps followed.Ingeniería Aeroespacia