Effect of the number of ribs on the aircraft wing gross weight

Marczi, Tomas (2002) Effect of the number of ribs on the aircraft wing gross weight. MSc(R) thesis, University of Glasgow.

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Abstract

The aim of the project is to develop a calculation process for the influence of the number of uniformly distributed ribs along the span of a two spar wing on the wing gross weight. The project is mainly concerned with the preliminary design of an Ultra Light Aircraft (ULA) or Very Light Aircraft (VLA) wing structure, when the structures engineers have no clear conception of the dimensions and detailed layout of the wing's internal structure. The developed calculation process is presented on one simple wing model. The estimation of the influence of the number of uniformly distributed ribs on the wing gross weight is based on the calculation of the minimum dimensions of the wing's internal structure components. The solution process is then adapted to in the structure calculation for three different spar load ratios and three different spar boom shapes. The project will be presented in four main parts: (i) Description of Model Used (Idealization), (ii) Aerodynamic Load Calculation, (ill) Minimal Structure Dimensions Calculation and (iv) Results Analysis. The first part of the project addresses the complicated calculation of the minimum dimensions of the wing structure. The analysis of the dependences between the internal wing structure dimensions and the appropriate simplifications used in the minimum dimensions calculation procedure are explained. The second part of the paper is concerned with the aerodynamic loading of the wing. Here the aerodynamic conditions are defined, from which the aerodynamic load distribution along the wing span is calculated. Also the analysis and extension of the German BVF method (chapter 9.1) for the chordwise pressure distributions is described. Using the comparison of wings according to their weight, the third part of the project calculates the minimum dimensions of the wing structure components. For these calculations, the equations of stress/strength equilibrium and geometric characteristics were combined to give the minimum dimensions. During the investigation of spar and boom geometry, an extension of the Gerard Method (E.F. Bruhn, 1973) (used for crippling stress calculations) was developed with the results are presented in the Appendix. The results of the investigation of the influence of the number of ribs uniformly distributed along the wing span are analysed and presented in the last part of the paper. An assessment is also made of the influence of aircraft weight on the calculation process and the resulting minimum dimensions. In addition, CFD and FEM calculations of one of the wing model layouts was performed for comparison purposes.

Item Type: Thesis (MSc(R))
Qualification Level: Masters
Keywords: Aerospace engineering, Mechanical engineering
Date of Award: 2002
Depositing User: Enlighten Team
Unique ID: glathesis:2002-71918
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 17 May 2019 09:31
Last Modified: 17 May 2019 09:31
URI: http://theses.gla.ac.uk/id/eprint/71918

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