00199 - Aeronautical Structures

Learning outcomes

The course aims at providing students with:

• a general overview of different aircraft architectures and aeronautical structures
• an overview of airframe loads, design requirements and aeronautical regulations
• simplified methods for evaluating stresses in aircraft structures
• basic know-how about typical aircraft structures problems, like instability of thin panels and stringers

Course contents

Part I   

Introduction.
Aircraft architecture. Wing geometry. Aircraft structures classification.

Stresses evaluation in thin-walled structures.
Beam sections geometric characteristics evaluation (centre of gravity, inertia moments, etc.).
Normal and shear stresses evaluation in thin-walled beams. Shear centre.

Airframe loads.
Load factor determination. Symmetrical manoeuvres loads. Flight envelope.
Gust analysis and gust envelope.
Horizontal tail static and dynamic balancing loads.
Unsymmetrical loads due to a roll manoeuvre.
Landing loads: 1 and 2 degrees of freedom dynamic models; landing loads evaluation depending on aircraft attitude.


Part II

Aircraft structures.
Truss structures; beams.
General overview of different types of fuselages, engine mounts, cantilever and strut-braced wings, single and multiple spar wing structures.

Semimonocoque structures.
Description and definition.
Loads evaluation for a thin panel with a constant shear flow.
Evaluation of stringers normal stresses and panels shear stresses in a semimonocoque structure. Shear centre.
Multicell beam sections.
Ribs and frames analysis.
Tapered structures.
Cut-outs effects.

Joints and fittings.
Bolted and riveted joints. Loads evaluation. Joints and fittings safety margins evaluation.

Structures instability.
Introduction.
Long and short columns instability: Euler equation and Johnson relations.
Buckling of flat sheet in compression and bending.
Buckling of stiffened sheet in compression: effective sheet width.
Pure tension field beams.
Curved sheet in compression.

Readings/Bibliography

The following texts are recommended for further investigations:

• T.H.G. Megson, "Aircraft Structures for engineering students", Arnold (London) 1999
• E.F. Bruhn, "Analysis and design of flight vehicle structures", Jacobs Publishing inc. 1973
• M.C.Y. Niu, "Airframe structural design. Practical design information and data on aircraft structures", Conmilit Press Ltd. 1988
• M.C.Y. Niu, "Airframe stress analysis and sizing", Conmilit Press Ltd. 1988
• M.C.Y. Niu, "Composite airframe structures", Conmilit Press Ltd. 1988
• D.J.Peery, J.J. Azar, "Aircraft Structures", McGraw-Hill 1982
• V. Giavotto, "Strutture aeronautiche", edizioni CLUP Milano 1976
• D.P. Raymer, "Aircraft design: a conceptual approach", AIAA Education series, NewYork (NY) 1999
• A. Lausetti, "L'aeroplano progetto-strutture-installazioni", Levrotto& Bella
• G. Gabrielli, "Lezioni sulla scienza del progetto degli aeromobili", vol. II, Levrotto & Bella

Teaching methods

Lessons and practical applications.

Assessment methods

Written and oral examination: oral examination is subject to the written test approval.

During the written test it is forbidden to refer to any book, note or solved exercise.

Teaching tools

Slideshows (PPT and/or PDF formats)
Lesson Notes
Examples and solved exercises

Since January 2009 lessons notes and written tests (both in italian language) are available at AMS campus.

This material is partially available at the following web page:

http://www.ingfo.unibo.it/servizi/Programmi/2007-2008/costr_aer/costruzioni_aeronautiche.html

 

Office hours

See the website of Enrico Troiani

See the website of Franco Persiani