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AERO3460/9460 Aerospace Design 1
● Aircraft component design● Certification Rules and Regulations● Flight Environment and Performance
constraints● Aircraft structures and material. Component
Failure modes ● Typical Industry processes.
AERO3460 Aerospace Design 1Frameworks and simple fittings
MECH2400 Mech Design(CAD Drawing, Design Methodology)
ENGG1802 MechanicsForce and Moment Equlibrium
AMME2301 Mech of Solids 12D and 3D structural analysis of beamsTension,Compression,Bending and Torsion
AERO3465 Aerospace Design 22D and 3D Monocoque Structures.Box beams, shear flow, stress distribution through attachments
AERO4460 Aerospace Design 3Full Configuration Design The BIG PICTURE
1. The Physical Environment● Atmosphere● Materials – Aluminium, Steel, Magnesium, Titanium● Alternate Composite materials● Frameworks -- Stresses and Strains● Joining methods● Failure Modes ● Safety Factors and Margins of Safety
2. The Legislative Enviroment● Categories of Aircraft – Fixed wing, Rotorcraft● Normal, Utility, Aerobatic, Transport.● Performance requirements● Weight and speed limits● Design Limits● Proof of Compliance (FARs)
The Atmosphere.
http://www.aerodynamics4students.com/properties-of-the-atmosphere/
Sections :
International Standard Atmosphere (ISA) Sea Level Conditions
ISA Variation with Altitude Variation due to Local Ground Conditions
Variation of Density due to Humidity Variation of Density with Extremely High Altitude
What are the Design Loads?
Aircraft Design Category
FAR 23 – Normal, Utility, Aerobatic Light AircraftFAR 25 – Transport AircraftFAR 27 – Normal, Utility, Aerobatic RotorcraftFAR 29 – Transport Rotorcraft
Primary parameters
*Aircraft Weight *Airspeeds
Types or Loads * Direct Loads. Forces applied to structure by external Mechanisms eg. Engine thrust, wing pressure loads
* Inertial Loads. Loads applied to structure due to acceleration of Masses. eg. Self Weight, Vertical loads due to manoeuvers
* Ground Handling and Miscellaneous Loads.
Analysis of simple Frameworks
Force equilibrium --- Free Body Diagram
Analyse Internal Forces
Types of Failure :
Tension Failure --- Yield Failure --- Ultimate Failure
Compression Failure --- Material Yield --- Column Failure --- Buckling Failure
Shear Failure --- exceeding max shear stress
Bending Failure --- Tension Component --- Compression Component --- Geometric Failure
Temperature weakening of material
Failure due to repetitive Loading (Fatigue)
Calculate Material stresses
Compare to allowables for the material.
MIL-HDBK-5H
1998
Freely available on Design Unit web site.
Current Industry Standard MMPDS https://www.mmpds.org/
Commercial product $$$ contains some newer alloys.
Factor of Safety
Limit (Yield) = 1.0 !!!no margin for error!!!Ultimate = 1.5Fittings = 1.1 → 1.15
Is it safe? Design Margin of Safety
0 – perfect
0 → 1 OK not too heavy
>> 1 Over designed Try again
Negative – no good, broken Try again
Factor of Safety=Failure LoadDesign Load
Margin of Safety=Failure LoadDesign Load
−1
Done
Design is an
Iterative Process
Some words of warning:
Aerospace contractors in Australia in many cases must work With US. FAA design rules and methods.
This means all work must be done in the IMPERIAL systemof units NOT SI. slug, lb, ft, in, psi, ksi, etc...
Must pass quiz component to pass this unit. Otherwise maximum mark is 45
All students should work in a harcopy logbook in the design classes. Not an IPAD or electronic notebook.