FACULTY

APPLIED TECHNOLOGIES

DEPARTMENT

AIRCRAFT TECHNOLOGY ENGINEERING

LEVEL OF STUDIES

UNDERGRADUATE

MODULE CODE

AE3140

SEMESTER OF STUDIES

^5th

COURSE TITLE

 AIRCRAFT STRUCTURE

INDEPENDENT TEACHING ACTIVITIES

TEACHING HOURS PER WEEK

CREDIT UNITS

Lectures  

2

4

Practice

1

0

                                                                                                  Laboratory

2

2

COURSE TYPE

Specialty course

PRE-REQUIRED COURSES:

TEACHING AND EXAMINATION LANGUAGE

GREEK

THE COURSE IS OFFERED TO ERASMUS STUDETNS 

COURSE WEBSITE (URL)

Learning Objectives

After successfully completing the course, students should be able to:

·                  Describe the constructions used for the aircraft structure (wing, fuselage, tailplane, etc.)

·                  Name the types of imposed loads and their function in the aircraft structural elements.

·                  Nate the types and characteristics of the materials used for each structural part of the aircraft.

·                  Calculate the thin walled cell like structres that are used for the consturction of the aircraft wings and fuselage.

·                  Calculate the boundary loads in order to ensure strucrural stability in the aircraft construction.

·                  Calculate the strength of basic elements made from composite materials.

·                  Calculate the working loads of the connectors used in aircraft constructions.

·                  Analyze and use mathematical formulas, read, describe and prepare drawings, simple designs and diagrams, apply their knowledge carefully using the manufacturer's instructions, interpret the results from different sources and measurments and do corrective actions whenever it is required.

General Skills

Search, analysis and combination of data and information with the use of the necessary technologies

Adjustment to new conditions 

Decision making

Development of free, creative, critical thinking

Working in an international environment 

Working in an interdisciplinary environment 

Production of new research ideas

Unit 1: Introduction
Basic distinction of the structures used for the airframe composition: wing, fuselage, empennage, vertical stabilizer, high lift devices, flight control devices, landing gear.   Materiasl used for the aircraft constuction.  Aluminum alloys, steels, titanium, composite materials.  Loads on the structural aircraft elements.  Flight loads due to accelerations, aerodynamic loads, various loads.  Basic analysis of the stractural element function.  Introductory concepts from the elasticity theory- material strength.  Stress, strain, principal stresses, stress transformations, stress-transformation relationships, Mohr cycle, transformation energy, failure criteria.  Statically deteriminate structures:  Unit strength concept in lattices, level lattices, space lattices. Statically indeterminate beams and lattices. Methods of calculating forces and displacements in hyperstatic beams and lattices. Calculation and dimensioning of lattices. Hiperstatic lattices in aircraft construction. 

Unit 2: Bending of thin walled beam with open and closed cross-section 
Application of the Unit strength principle, calculation of stresses and strains, shear of bending beam, shear center, shear flow. Shear of thin walled beam with open and closed cross-section: calculation of stresses and strains, shear center, shear flow, axial strain.  Shear of multi cell beam.

Unit 3: Torsion of thin walled beam with open and closed cross-section
Calculation methods of stresses and strains, steering angle, shear center, axial strain. Airframes.  Use of frames in the constuction of aircraft.  Calculation of airframes.  Cutting, normal, shear forces and moments on the frames. Symmetric and antisymmetric loading. Elastic center method.

Unit 4: Shells
Shell theory. Monocoque shell fuselage. Monocoque shell fuselage philosophy. Shell theory application.  Fuselage torsional strain. Distinction of support cases.  Shear flow in critical cross-sections.  Bending fuselage strain.  Calculation of normal and shear flow on a bending fuselage.  Fuselage bending and torsional strain. Calculation of multi-cell fuselages. Monocoque shell wing. Monocoque shell wing philosophy.  Wing torsional strain.  Distinction of support cases.  Shear flow in critical cross-sections.  Torque box wing construction.  Bending wing strain.  Distinction of support cases.  Calculation of normal and shear flow on a bending  wing.  Wing bending and torsional strain. Calculation of multi-cell wings.

Unit 5: Composite materials
Use of composite materials in aircraft constructions. Coating, structural parts.  Materials, consruction methods and types of composite materials used in aircraft structures. Anisotropy of composite materials.  Principal strains of composite material elements.  Calculation of stresses and deformations.  Bonding of structural elements made of composite materials.

Unit 6: Structure connectors
Riveting. Rivet categories. Types of riveting failure.  Strength of connections with riveting.   Bolts. Types  of bolts. Types of bolt failure. Strength of connections with bolts. Safety coefficients for the connector operation. Design of various connection types. 

Unit 7: Structural Stability 
Elastic and non elastic beam bending, thin plate bending, stiffened plate bending, shear panel stability. Air elasticity elements.  Structural oscillations. Dynamic air elasticity phenomena. 

Unit 8: Special issues about the design, certification and maintenance of aircraft stucture
Aircraft design philosophies:  Safe Life, Fail Safe. Airworthiness certification: safety factors, flight envelope, determination of loading coefficients. Aircraft structural integrity: structure design with damage tolerance, shear mechanics, structure fatigue, non destructive checks and inspections, aircraft structural integrity programs.

Unit 9: Aircraft structures-General concepts. Airworthines requirements for structural strength
Structure classification, primary, secondary, tertiary. Safetey after failure, safe life span, failure tolerance.  Zonal and station identification systems.  Stress, strain, bending, compression, shear, torsion, tension, arrow stress, fatigue. Water and air distribution. System installation supplies. Thunderbolt protection system.  Construction methods: fuselage surface under stress, shapers,  auxiliary beams,  longitudinal beams,  diaphragms, struts, horizontal beams, floor structures, reinforcements, coating methods and anticorrosion protection, wing, tail section and engine joints.  Structure assembly techniques: riveting, screwing, seaming.  Surface protection methods, such as chroming, anodizing, painting. Surface cleaning.  Aircraft symmetry:  allignment methods and symmetry control.  Board structure-Airplanes.  Fuselage (ΑΤΑ 52/53/56). Compression construction and sealling. Connectors on wing, stabilizers, pylons and landing gear. Seat installation and loading system. Doors: construction, mechanisms, operation and safety mechanisms.  Window and windscreen construction and mechanisms.

Unit 10: Wings (ΑΤΑ 57)
Construction. Fuel storage. Connectors for the landing gear system, pylons, control surfaces and high lift/drag systems. Stabilizers (ΑΤΑ 55). Construction. Control surface connection.Flight control surfaces. Construction and connection.  Mass balancing and aerodynamics. Aerodynamic cowlings/pylons  (ΑΤΑ 54). Construction. Fire protection diaphragms.  Engine bases. Cabin airconditioning and Copression (ΑΤΑ 21). Air supply. Air supply sources including engine expansion, APU and ground air supply.  Airconditioning.  Airconditioning systems.  Air and steam recycling machines.  Distribution systems. Flow system, temperature and humidity regulation system.  Compression.  Compression systems.  Control and indication including contol and safety valves.  Cabin pressure regulators.  Safety and warning mechanisms.  Protection and warning systems.  Instrumentation/Electronic systems.  Instrument systems  (ΑΤΑ 31).  Pitot static pressure tube : altitude, air speed indicator, vertical speed indicator. Gyroscopics: artificial horizon, attitude indicator,  direction indicator,  horizontal position indicator,  revolution and roll indicator,  revolution and slide indicator. Compasses: direct reading compass, distant reading compass. Angle of attack indicator,  Stall warning systems.  Other aircraft systems indicators.  Electronic systems.  Basic knowledge of operation and  system diagrams. Automated flight control system (ΑΤΑ 22). Communications  (ΑΤΑ 23). Navigation systems (ΑΤΑ 34). Electric power (ΑΤΑ 24). Installation and operation of collectors. Direct current generator. Alternating current generator. Emergency generator. Voltage regulation.  Power distribution. Converters, transformers, rectifiers. Circuit protection. External/ground power supply.

Unit 11: Equipment (ΑΤΑ 25).
Emergency equipment requirements. Seats, seat belts. Cabin layout . Equipment provision. Cabin equipment  installation. Cabin entertainment equipment.  Aircraft kitchen installation. Load handling and load restraint equipment.   Internal scale.  Fire protection  (ΑΤΑ 26). Fire detection systems, smoke detection and warning systems.   Fire extinguishing systems. System testing. Flight controls  (ΑΤΑ 27). Primary controls: aileron,  elevator, rudder, spoiler. Balance control.  Active load control.  High lift devices. Spoiler, airbrakes. System operation: manual, hydraulic, pressurized air, electrical, flight control with electronic means.  Artificial sense, yaw damper, rudder limiter. Balancing and regulation.  Stall protection system. Fuel systems  (ΑΤΑ 28). System layout. Fuel tanks. Supply systems.  Evacuation, ventilation and drainage. Cross feed and transfer. Indicators and warnings.  Supply and fuel pump removal. Longitudinal balance fuel system.  Hydraulic Power (ΑΤΑ 29). System layout. Hydraulic fluids.  Tanks and hydraulic fluids storage. Pressure generation:  electrical, mechanical, pressurized air. Emergency pressure generation. Pressure control.  Power distribution.  Indicators and warning systems. Interaction with other systems.  Protection from ice and rain  (ΑΤΑ 30). Ice formation, detection. Anti icing systems: electrical, hot air and chemical. Deicing systems : electrical, pressurized air  and chemical.  Rain repulsion systems.  Ηeat of fuel filler cap and fuel drain cap.  Landing gear system (ΑΤΑ 32). Construction, vibration damping. Extension and retraction systems: normal and emergency. Indicators and warning. Wheels, brakes, anti slide system and automatic pedal system. Tyres. Steering wheels. 

Unit 12: Lights (ΑΤΑ 33).
External: navigation, landing, taxiing, ice lights. Internal: cabin, cockpit, load lights. Emergency lights. Oxygen (ΑΤΑ 35). System layout : cockpit, cabin. Sources, storage, loading and distribution.  Supply regualtion. Indicators and warning systems.  Air/vacuum systems (ΑΤΑ 36). System layout. Sources: engine  ( ΑΡΙ), compressors. Tanks, ground supply. Pressure control.  Distribution.  Indicators and warning systems.  Interaction with other systems. Water/Sewage (ΑΤΑ 38). Water system layout, supply, distribution, service and drainage.  Lavatory system layout, toilet water and service.  Corrosion isssues. Aircraft maintenance systems  (ΑΤΑ 45). Central maintenance computers. Data loading systems.  Electronic library system.  Printing.  Damage point monitoring. Structure monitoring.

1^st Lab Activity
Calculation of aerodynamic loads acting on various types of airfoils according to NACA. Deterimination of aerodynamic forces and moments.  Comparison of theroretical against experimental results. This activity will take place in the subsonic wind tunnel of the Aerodynamics Laboratory.

2^nd Lab Activity
Calculation of stresses and displacements in hyperstatic level lattice. Comparison of experimental against theoretical values. Determination of safety coefficient. 

3^rd Lab Activity
Simple bending of cantilever ring beam. Simple torsion of cantilever ring beam.  Deterimination of stresses and strains.  Comparison of experimental measurements against theoretical values according to Material Strenght. 

5^th Lab Activity
Assymetrical bending (bending-torsional strain )of thin walled beam with C and Z cross-section. Calculation of stresses and strains.  Shear center. Steering angle.  Cross-section geometry effect (shape, hollow, compact).   Comparison of experimental against theoretical values. Comparison of results in association with Lab Activity 4.

6^th Lab Activity
Symmetric and assymentric  stress of simpe frames. Determination of cutting, normal, shear forces and displacements.  Comparison of experimental results against theoretical values according to the application of the elastic center solution method.

7^th Lab Activity
Strength of riveted joints in shear stress.  Strength of screwed joints in shear stress.Comparison of various types of metal connections. Comparison of experimental against theoretical values. 

8^th Lab Activity
Bending of carriers. Deterimination of critical bending load.  Comparision of measuremets against theoretical calculations deriving from the application of various methods. Effect of geometric characteristics of various carrier cross-sections.

9^th Lab Activity
Calculation of complex beam elasticity point.  Simple bending of beam made of multilayered material. Comparison of experimental against theoretical values.   Determination of beam safety coefficient. Comparison of weight-volume ratio for a metal beam and composite material beam. 

10^th Lab Activity
Bending-torsion stress on a simple monocoque shell wing. Displacement measurement on the wing tips and wing roots.  Stress analysis of  wing-fuselage attachment.  Comparison of experimental measurments  against theoretically calculated  values.

ΤEACHING METHOD

Face to face

USE OF INFORMATION AND COMMUNICATION TECHNOLOGIES

Potential use of asynchronous tele-education.

TEACHING ORGANIZATION

STUDENT EVALUATION

Problem solving,

Lab activities,

Written assignments

Α. Μπαλντούκας, Σημειώσεις και ασκήσεις στη Δομή Αεροσκαφών, Έκδοση 2015.

Κούλλιας και Γ. Καρακιόζογλου, Στοιχεία Υπολογισμού Κατασκευής και Συντήρησης Αεροσκαφών, Εκδόσεις Ζαμπάρα 2005, ISBN 960 – 88860 – 0 - 7

Γ. Καρακιόζογλου, Δομή Αεροσκαφών και Ελικοπτέρων, Έκδοση ΥΑΕ (Υπηρεσία Αεροπορικών Εκδόσεων της Πολεμικής Αεροπορίας)

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H. D. Curtis»Fundamentals of Aircraft Structural Analysis», McGraw-Hill, 1997.

J. Cutler «Understanding Aircraft Structures» 3rd Ed., Blackwell Science Ltd., 1999.

B. K. Donaldson «Analysis of Aircraft Structures», McGraw-Hill, 1993

D. J. Peery , J. J. Azar «Aircraft Structures», McGraw-Hill, New York, 1982.

R. M. Rivello «Theory and Analysis of Flight Structures», McGraw-Hill, 1970.

 J. M.Gere, S. P. Timoshenko «Mechanics of Materials», CBS Publishers, 1986.

F. K. Teichmann «Fundamentals of Aircraft Structural Analysis», Hayden Book Co., New York, 1968.

S. P. Timoshenko «Strength of Materials» Vols I - II, Princeton, D.Von Nostrand Co. 1988.

Ι. Γ. Κούλιας «Αεροναυπηγική» Τόμος Ι, ΥΑΕ, 1983.

E. F. Bruhn «Analysis and Design of Flight Vehicle Structures», Tri-State Offset Company, USA, 1977.

M. C. Y. Niu «Airframe Structural Design, Practical Design Information and Data on Aircraft Structures» Conmilit Press Ltd, Hong Kong, 1988.

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J. R. Vinson, R. L. Sierakowski «The Behavior of Structures Composed of Composite Materials» Martinus Nijhoff Publ., 1986.