HigherEd 2.0

Introduction to bending. This is a good one! The discussion about the radius of curvature, the nature of the deformation, the neutral axis, and all the rest…there’s alot of good mechanics here. There is an important but slightly less energetic discussion of sign conventions. In any case, the mechanics here are […]

 

 Lecture 13: Bending basics: Play Now | Play in Popup | Download

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This is a mashup of strength of materials content and statics content. It’s really a bridge lecture from Chapter 5 to Chapter 6, and as such it contains some of each. Have a look at the stress concentration stuff (just like in Ch. 4), and then spend some time reflecting on the shear […]

 

 Lecture 12: Stress concentrations (torsion), V & M: Play Now | Play in Popup | Download

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I have gotten a bit behind on posting these, so here are the first two lectures on torsion. Module 10 focuses on the basic mechanics of torsion and a derivation of the torsion formula. Module 11 then shifts gears and discusses the angle of twist. All of this is good information and […]

 

 Lecture 10: Torsion basics: Play Now | Play in Popup | Download

 

 Lecture 11: Angle of twist: Play Now | Play in Popup | Download

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Just getting caught up here…this is the final lecture from Chapter 4 and it covers some issues in normal stress and stress concentrations. The key here is to look at the correct chart, and read that chart the correct way. Not too difficult, but it does require some practice. There are some […]

 

 Lecture 9: Stress concentrations (axial loading): Play Now | Play in Popup | Download

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This is a good one about static indeterminacy. For these kinds of problems, here is the general strategy:

draw FBD and write the equilibrium equations, and identify all the unknowns
compare the number of unknowns to the number of equilibrium equations
if you have more unknowns than equilibrium equations, you need more equations!
write […]

 

 Module 8: Static indeterminacy (axial loading): Play Now | Play in Popup | Download

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So here it is. Axial load (leading to strain and stress) in all its glory. I guess the key here is that the equation is really versatile, in the sense the we can use it alone, or in a summation, or in combination like what we saw in the problems from Wednesday […]

 

 Module 7: Axial Loading: Play Now | Play in Popup | Download

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This is the final bit of lecture about mechanical properties, and it focuses on Poisson’s ratio. This quantity was apparently first described by a French mathematician, and I’m sure this appears in Timoshenko’s History of the Strength of Materials. This lecture talks a bit about the typical values for Poisson’s ratio, and also […]

 

 Module 6: Mechanical Properties (Part 2): Play Now | Play in Popup | Download

 

 Movie: auxetic material: Play Now | Play in Popup | Download

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I don’t quite have the podcast ready yet, but I do have the pulse pen file for the lecture. Today we mainly focused on material properties in the context of the stress-strain diagram, and we saw the different types of behaviors (elastic, plastic) and also the different in stress-strain curves for different types of […]

 

 Module 5: Mechanical Properties (Part 1): Play Now | Play in Popup | Download

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Welcome to module 4 on strain and deformation. Funny how this semester starts off with all the best engineering jokes about stress, strain, fatigue, and failure. As we discussed, strain in our class is usually calculated as a change in geometry, and you can think of the little thought exercise we did at […]

 

 Module 4: Deformation and Strain: Play Now | Play in Popup | Download

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In module 3, we look at the idea of average normal stress, then move on to a derivation about shear stress. The key idea here is that if we are far enough from the “edges” (where the loads are applied) we can use some sort of integrated quantity to represent the stress. For […]

 

 Module 3: Stress and Failure: Play Now | Play in Popup | Download

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