Lecture 12- Structures 2

# Lecture 12- Structures 2 - AOE 2104-Aerospace and Ocean...

This preview shows pages 1–8. Sign up to view the full content.

AOE 2104--Aerospace and Ocean Engineering Fall 2010 Virginia Tech October 19, 2010 Aircraft Structures 2 Click to edit Master subtitle style AOE 2104 Introduction to Aerospace Engineering Aircraft Structures 2

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
AOE 2104--Aerospace and Ocean Engineering Fall 2010 Virginia Tech October 19, 2010 Aircraft Structures 2 Had an overview of the history of aircraft structures Named major structural components of the fuselage and wing Any questions? Last time…
AOE 2104--Aerospace and Ocean Engineering Fall 2010 Virginia Tech October 19, 2010 Aircraft Structures 2 To answer this, we need to understand a little about solid mechanics Stress – what is it? A measure of intensity of forces over a particular surface in a body Stress is 3-Dimensional and has 9 components in it’s matrix! Essentially it is how hard the atoms at a point in a material are being pulled apart or pushed together. For now, we will consider 1-D only What happens when an external force is applied to a material? Solid tends to deform Material attempts to resist change by an internal force The force per unit area is called stress! (1-D) How does the structure cope with ground and in flight loads? A F area force = = σ

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
AOE 2104--Aerospace and Ocean Engineering Fall 2010 Virginia Tech October 19, 2010 Aircraft Structures 2 Compressive – acts perpendicular to cross-sectional area (pushing) Tensile – acts perpendicular to cross-sectional area (pulling) Shear – acts tangentially to cross-sectional area A look at the three forms of stress A F area force = = τ F F F F F F
AOE 2104--Aerospace and Ocean Engineering Fall 2010 Virginia Tech October 19, 2010 Aircraft Structures 2 When stress acts on a material it tends to change shape and size For the rods, the length looks like it should change, right? Say the original length is L then we can write Stress and strain can be related! How? Hooke’s Law E is the modulus of elasticity or Young’s modulus What are the units of E? A look at the strain L L length originial length in change = = ε ε σ E =

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
AOE 2104--Aerospace and Ocean Engineering Fall 2010 Virginia Tech October 19, 2010 Aircraft Structures 2 Shear strain is just a little different Here the material is undergoing what looks like an angular deformation of θ . Can we use E here? No! G is the modulus of rigidity or shear modulus Materials tend to be about half as strong in shear as compared to tensile forcing A look at the strain θ τ G = τ
AOE 2104--Aerospace and Ocean Engineering Fall 2010 Virginia Tech October 19, 2010 Aircraft Structures 2 Consider an aircraft wing experiencing a lift force Think again about the same wing and lift force generating an aerodynamic moment – causes tangential shear stress What about temperature? Will this have an effect?

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### What students are saying

• As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

Kiran Temple University Fox School of Business ‘17, Course Hero Intern

• I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

Dana University of Pennsylvania ‘17, Course Hero Intern

• The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

Jill Tulane University ‘16, Course Hero Intern