Airframe Structural Design, Basic
TeachersHIRAMOTO, Takashi
Grade, SemesterYear 3 2nd semest [Department of Aerospace Engineering, Faculty of Science and Engineering]
CategoryBasic Major Subjects
Elective, CreditsElective Requisites 2credit
 Syllabus Number2B304

Course Description

For aircraft structures, weight reduction is a major goal. In order to achieve its purpose, there are structural methods and design methods suitable for parts and members. The purpose of the lecture is to understand the analysis method of aircraft structural design. In the lecture, we will learn the design method for various structures while paying attention to the load flow and transfer that the aircraft structure designer would think.
In this lecture, students will acquire knowledge and techniques on DP1.

Course Objectives

In this course, we will focus on items that are particularly necessary for the structural design of aircraft and the aim is to acquire the basic idea of aircraft structural design.
(1) Section properties of asymmetric cross section can be calculated and internal load can be obtained
(2) Bending and torsion analysis of thin plate structure can be done
(3) It is possible to express internal load distribution by expressing load transfer between members using free body diagram
(4) Understand the calculation method for the compression member (ex. effective width of the reinforcing plate)
(5) Calculate the tension field to evaluate the strength after shear buckling
(6) Understand the idea of fatigue design and damage-tolerance design against repeated load and calculate fatigue strength

Grading Policy

It is evaluated according to the task (30%) to be carried out as appropriate and the examination (70%) to be conducted at the end of the term.
The answers and explanations given in the lecture will be shown.

Textbook and Reference

KindTitleAuthorPublisher
TextbookText to be used in the lecture will be presented at the LMS.
ReferencesStructural Mechanics of Aircraft,
ISBN 978-4782840740
J. Niisawa et al.Industrial Book
ReferencesAircraft structural mechanics (revised new edition),
ISBN 978-4903814674
S. KobayashiPleiades publication

Requirements(Assignments)

This lecture is on the extension of lecture contents of "Introduction to aeronautical engineering", "Solid Mechanics 1 & 2", and "Fundamental Design Technology of an Airplane". Therefore, although it is not mandatory, it is desirable that you take them.
In addition, it is vital that design calculation is actually done by yourself. You cannot understand by reading answers alone. So please try to solve the examples and the tasks by yourself first.

Note

Schedule

1Aircraft structures and basics of structural design: Understand the characteristics of aircraft structure, basic role of structural members
2Load acting on aircraft: Learn the loads imposed during operation of the aircraft
3Section properties: Learn about the cross-sectional characteristics of the basic members in considering structural design. Also, consider the stress (bending stress) generated by bending
4Torsion: Consider the twist of the round bar, the thin plate, the closed cross section, and the multi cell structure
5Shear stress due to bending: Learn how to calculate shear stress due to bending of a structure subjected to shear load from a basic biaxial symmetric cross section beam to an airfoil cross section
6Asymmetric Beams: Learn about loading on asymmetric beams that are common in real structures
7Free Body Diagram and Shear Field: Learn about the shear flow of the thin plate and the load distribution of the axial member based on the idea of free body diagram for the typical aircraft structure composed of flange and web
8Curved surface shear field: Solve curved web structure according to shear field theory. Also understand the semi-monocoque structure and box beam analysis method which is a typical aircraft structural style
9Static strength and Bending fracture strength: Learn about concept of static strength in structural design and concept of strength after plasticity of members subject to bending
10Buckling of the compression member (1): Learn buckling calculation used in aircraft design such as practical formula considering plastic buckling and buckling when subjected to lateral load
11Buckling of compression member (2): Learn the buckling phenomenon and its strength evaluation that occur when compressive load is applied to a column, flat plate, curved plate
12Tension field: Learn the calculation method of the structural style that shares the shear load with thin plates frequently used for aircraft construction
13Laminate theory of composite materials: Learn the basics of laminate theory used for stress and strain analysis of composite structure
14Fatigue strength of aircraft structure: Learn the fatigue life calculation method which is the basis of safety life design, and the foundation of fracture mechanics which is the basis of damage tolerance design
15Sandwich structure: Learn the concept of sandwich panel design, which is characterized by its light weight and high rigidity, which is often used in aircraft structures.