Author(s)

G. Gatta, F. Romano & M. Pecora

Abstract

The aim of this work is to illustrate the features of an in-house developed piece of software (AEDC) to perform the aeroelastic analyses concerning the different steps of a high aspect ratio wing design. The wing is wholly made of composite material: a common high-strength graphite/epoxy is used for the spars and the facings of the skin panels in a honeycomb core sandwich. The code, written in Fortran language, is constituted of several modules: two modelling modules for the complete aeroelastic model definition and three analysis modules for divergence, flutter and gust analysis according to JAR 25 airworthiness design requirements. By means of a random gust analysis, AEDC determines/updates the external load characteristics (shear, bending and torque moment) acting on the wing and evaluates the equivalent static forces for the finite element model using a matched gust manoeuvre. Once the aerodynamic model of the wing and tail plane is constructed, a first load evaluation is obtained under the hypothesis of trimmed rigid aircraft, according to the Houbolt criteria. Using the results of preliminary wing sizing performed in a multi-level integrated procedure (MLISS), the elasticity of the structure is introduced in the aircraft trimming equations in order to update the previous loads. But if the loads change a new sizing is requested and so on. These iterations between external load updating and structural sizing run until the convergence is reached; the final structure has the minimum weight for the fixed load condition and doesn’t exhibit aeroelastic instabilities. Keywords: aspect ratio, composite honeycomb, trimming equations, flutter analysis, aeroelastic instability, random gust analysis, load characteristic, equivalent static force.

Keywords

aspect ratio, composite honeycomb, trimming equations, flutter analysis, aeroelastic instability, random gust analysis, load characteristic, equivalent static force.