2283. Wing Primary Structure Weight Estimation of Transport Aircrafts in the Pre-Development Phase

Paper

Abstract

Accurate weight prognosis without powerful software tools is becoming an almost hopeless task. In the pre-development phase of modern transport aircraft the geometry is not fixed and many parameter studies have to be performed. The wing of the plane has to be optimized to minimize the operating costs. The wing weight is directly influenced by geometrical changes and the materials used. A precise and reliable wing weight prognosis method is the basis for the assessment of the viability of a plane. This paper details the process of the wing weight estimation method used in the weights prognosis department at Daimler-Benz Aerospace Airbus. The software tool FAME-W (Fast and Advanced Mass Estimation of Wings) is described with emphasis on the multidisciplinary character of the computer approach. In the pre-development phase of an aircraft only limited knowledge of the design is available. For a qualified wing weight estimation the dimensioning loadcases, the structural layout, and other essential information must be quantified. In order to establish a precise loads calculation the mass and stiffness distribution of the wing is necessary. The most promising way for a time and cost effective solution of this iterative problem is an integration of all relevant technical disciplines in one software-tool requiring only minimum data for input. During its mission a plane is exposed to changing flight conditions. For example, due to fuel consumption the weight of the plane is not constant, in the climb, cruise, and the descent phase of one flight different gust loads must be considered at each altitude. To consider the resulting large number of independent load cases in an acceptable time an analytical/numerical algorithm based on the the classical theory of multicellular shells, beam and structural instability theory extended by the calculation of special effects like differential bending was chosen. The aerodynamics are taken into account by an integrated software module. A module for the calculation of the structural deformation allows the dimensioning of the elastic structure including the re-calculation of the aerodynamic loads. This paper describes the method and process for wing primary structure weight estimation of transport aircraft in the pre-development phase.