AIRCRAFT STRUCTURES [AE _]

Course objectives:
To provide students a sound knowledge of Civil Aircraft structure design criteria and in-depth knowledge on design process.

1. Introduction to Aircraft Structural Design (6 hours)
1. Structural layout of the Airplane and components,
2. Structural design V-n diagram
3. loads acting on major components such as
1. Wing
2. Fuselage
3. Tails
4. Landing gear etc.
4. Concept of allowable stress and margin of safety.
2. Unsymmetrical Bending (6 hours)
1. Bending stresses in beams of unsymmetrical sections
2. Bending of symmetric sections with skew loads
3. Shear Flow in Open Sections (6 hours)
1. Thin walled beams,
2. Concept of shear flow,
3. Shear center, Elastic axis.
1. With one axis of symmetry,
2. With wall effective and ineffective in bending,
3. Unsymmetrical beam sections.
4. Shear Flow in Closed Sections (10 hours)
1. Bredt–Batho formula,
2. Single and multi – cell structures
1. Approximate methods
2. Shear flow in single & multi-cell structures under torsion.
3. Shear flow in single and multi-cell under bending with walls effective and ineffective.
5. Buckling of Plates (6 hours)
1. Rectangular sheets under compression
2. Local buckling stress of thin walled sections
3. Crippling stresses by Needham’s and Gerard’s methods
4. Thin walled column strength
5. Sheet – stiffener panels
6. Effective width, inter-rivet and sheet wrinkling failures
6. Joints and Fittings And Introduction to Post Buckling (6 hours)
1. General theory for the design of fittings,
2. Estimation of fitting design loads,
3. Design of riveted, bolted and weldingjoints,
4. Post buckling of structures,
5. Concept of effective width.
7. Stress Analysis in Wing and Fuselage (10 hours)
1. Procedure –
   1. Shear and bending moment distribution for semi cantilever and other types of wings and fuselage,
   2. Thin webbed beam.
   3. With parallel and non-parallel flanges,
   4. Shear resistant web beams,
   5. Tension field Web beams (Wagner’s).
8. Design of Aircraft Structure (9 hours)
1. Design criteria
1. Safety Factor
2. Design life criteria
2. Analysis method
   1. Life Assessment procedures
3. Design Principle
1. Future Air worthiness Requirements
2. Two bay crack criteria
3. Widespread Fatigue damage

Practical:

1. Wind / Fuselage / Empennage Design project for UAVs and use various criteria to determine safety.
2. Experimental validation of stiffened plate deformation.