AERO 214. Introduction to Aerospace Mechanics of Materials. Lecture 1

Transcription

1 AERO 214 Introduction to Aerospace Mechanics of Materials Lecture 1

2 Ancient Structures Parthenon in Athens, Greece (c. 440 BC) Persepolis in Shiraz, Iran (c. 500 BC) The Coliseum in Rome, Italy (c AD) Notre Dame in Paris, France (c AD)

3 Traditional Structures Brooklyn Bridge NY, NY ( ) Eiffel Tower in Paris, France (c ) Modern Crane and Skyscrapers

4 What Changed? From: Introduction to Aerospace Structural Analysis by Allen, D.H. and Haisler, W.; John Wiley & Sons, Inc. 1985

5 Structures and Aerospace

6 The Four Branches of Aerospace Structures and Materials The physical vehicle Aerodynamics How the atmosphere makes the physical vehicle fly Propulsion How to move the physical vehicle and make the atmosphere sufficiently cooperate Dynamics and Control How we describe the motion of the physical vehicle and move the physical vehicle from place to place as desired

7 The Four Questions for a Structural Analyst What is the load path? How does the load changes as the environment, working conditions change? How do the structural members carry the load? Tension, compression, bending, shear torsion How do the load bearing structures fail? The failure modes: Corrosion, fatigue, ductile/brittle fracture, high temperature, creep How does the analyst calculates the load to failure for those structures

8 Aircraft from a Purely Structural Point of View From Justin Wilkerson REU Presentation

9 The Wing Spar as a Primary Structural Element

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17 The Four Branches of Aerospace and Mechanics Structures and Materials Solid Mechanics: the study of the response of solid materials to applied loads Materials: the study of why one solid responds differently in response to loads than another one does Aerodynamics and Propulsion Fluid Mechanics: the study of the response of fluid materials to applied loads (has a materials component in terms of differences in fluid behaviors) Emphasizes fluid mechanics, thermodynamics, and chemistry, but is also influenced by solid mechanics Dynamics and Control AERO 201, 214, 304 (beam and torsion), 306 (FEA), 413 (materials engineering), 420 (aeroelasticity), 489 (fracture), 405,

18 Cost of this Lecture The real cost of your education is $500 per credit hour This 3 hour course costs $1,500 each This is $100/week each There are two meetings per week, thus $50 per meeting There are 45 students, thus each meeting costs $2,250 A 90 minute lecture costs $25/minute

19 Cost of an Airplane Car: $21,000/$3,000lb = $7/lb Orthopedic Implant =$900/1Oz = $15,000/lb Commercial airliner: Boeing 787 Dreamliner: $175M/225,000lb = $750/lb Boeing LR: $296.0M / 342,900 = $850/lb Combat aircraft: F35 JSF: $120M/30,000lb = $4,000/lb F22 Raptor: $300M/43,000lb = $7,000/lb Dassault Rafale $120M/20,000lb= $6,000/lb Al: $3/lb Ti: $20/lb Composite: $50/lb Most of the aircraft cost is labor This is good for materials engineers This is bad for U.S. engineers competing in a global labor market Cost to launch a satellite: $15,000/lb - $30,000/lb

20 Importance of Materials: Shape Factor and Material Properties At the most fundamental level, the properties of any physical thing depend on what materials it is made of and how these materials are spatially arranged This is true of molecular structures, transportation structures (airplanes), civil engineering structures, and everything physical

21 Importance of Materials: Shape Factor and Material Properties A simple example of isomerism is given by propanol: it has the formula C3H8O (or C3H7OH) and occurs as two isomers: propan-1-ol (n-propyl alcohol; I) and propan-2-ol (isopropyl alcohol; II) Note that the position of the oxygen atom differs between the two: it is attached to an end carbon in the first isomer, and to the center carbon in the second. There is, however, another isomer of C3H8O which has significantly different properties: methoxyethane (methyl-ethyl-ether; III). Unlike the isomers of propanol, methoxyethane has an oxygen connected to two carbons rather than to one carbon and one hydrogen. This makes it an ether, not an alcohol, as it lacks a hydroxyl group, and has chemical properties more similar to other ethers than to either of the above alcohol isomers.

22 Importance of Materials: The Structure of Physical Science Nine physical principles: Balance of Linear Momentum Balance of Angular Momentum Conservation of Mass Conservation of Energy Second Law of Thermodynamics Gauss Law Ampere s Law Faraday s Law Gauss-Faraday Law Kinematics: the study of particle motion Material Properties

23 Materials for Aerospace Structures Aluminum Titanium Composites: Ceramic Fiber-Reinforced Polymer Matrix Composites High Temperature Materials: Superalloys and Ceramics Wood is fascinating and historically important, but we will not have time to study it

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26 Composition of Modern Aircraft: Percent of Structural Weight McDonnell Douglas F/A-18 Hornet F/A 18C/D F/A 18 E/F Aluminum Steel Titanium Carbon Epoxy Other 13 15

27 Composition of Modern Aircraft: Percent of Structural Weight Boeing 777 Dreamliner Boeing 787 Aluminum Steel 10 Titanium 15 Carbon Epoxy Other 5