Struktursensitivität von Höhenleitwerksstrukturen mit kammerloser hybrider Laminarerhaltung auf Vogelschlag (Bachelorarbeit)

Abstract

Hybrid laminar flow control (HLFC) is studied since the 1930s. However, the technology is only applied at a low level in civil aviation. While the research on laminar flow control concerns the drag reduction by shape and air friction on air foils, the HLFC employs suction systems on the aerodynamic surface. The design of an HLFC system applied on a horizontal tail plane (HTP)/ stabiliser needs to consider the airworthiness requirements. In this way, a critical flight condition shall not happen by bird strike. Typically, stabilisers leading edges (LE) are tested under bird strike upon application on passenger aircrafts. In the given work, five different preliminary HLFC designs of an HPT-LE are analysed by the explicit finite element method (FEM) under typical impact conditions. The conditions are varied in terms of impact orientation and velocity plus the ply angle in the composite inner skin laminate. This variation was conducted by coupling the FEM with a stochastic processor. In a global approximation by multi-dimensional design spaces, the relationship between variables and system response can be used to study the structural sensitivity of the models. The present work compares the preliminary designs and identifies a high sensitivity of the impact velocity and the angle of attack. The sweep angle in contrast, has less influence and no specific maximum or minimum. By variation of the ply angle in the laminate, the sensitivity of the composite on impact can be reduced. The work analyses the arguments for evaluation and optimisation of the preliminary designs. The method of global approximation was examined with respect to predictability.