HigherEd 2.0

Today’s session was very focused on deriving the axial deformation relation PL/AE. This is a very fundamental relation that sees lots of application throughout our course and the rest of the structure curriculum. For example, the truss elements in Arcade essentially use this equation. The equation itself is pretty easy to use, […]

 Lecture module 7, Jan 31 2007: Download

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The main take-away from this lecture is that Poisson’s ratio is an important material parameter. There are lots of cool engineered and natural structures with interesting Poisson’s ratios, but for “typical” engineering materials, we get nu = 0.3.
We also did a small demo on negative Poisson’s ratio materials, and a small video is shown […]

 Lecture module 6, Jan 29 2007: Download

 

 Negative Poisson's ratio demo: Play Now | Play in Popup | Download

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Due date is Friday 2/2, 4 pm.
From Chapter 2: 2-7, 2-15, 2-25, 2-26
From Chapter 3: 3-2, 3-10, 3-19, 3-22
For clarity, in 3-22 both the strut AB and the post CD are made of this polyester material.
One suggestion on 3-10: you have two choices here, either do it on graph paper (hard to […]

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There was a question in class today about why the stress-strain curve looks the way it does, with its increases (strain hardening) and decreases (necking). I don’t do this sort of thing for a living, but I couldn’t explain it better than this.

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Here it is. Be sure to click through on the embedded links to some interesting information on steel carbon content and on the sinking of the Titanic. Key deliverable from today’s session is the wealth of information held within the stress-strain diagram, and the different ways to characterize material properties (i.e., stress vs. […]

 Lecture module 5, Jan 26 2007: Download

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This is the extent of our coverage of Chapter 2, and the main point is that strain is (in our class) calculated as a geometry change. We will not do any limit operations for strain calculations.

 Lecture module 4, Jan 24 2007: Download

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This is a good discussion of the keys from chapter 1: average normal stress, average shear stress, and stress elements. Feel free to link to The Explainer embedded in the podcast (slide #8).
We also briefly mentioned the stress visualizer from Hibbeler. I will try to dig it up and link to it […]

 Lecture module 3: Jan. 22 2007: Download

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The factor of safety is a somewhat mysterious but always necessary recognition that as engineering designers we do not always know everything we would like to know. Former Defense Secretary Donald Rumsfeld provides some unexpected wisdom here. He might say: “You design using the information you have right, not the information you […]

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This post contains several example media files, screenshots of which were included in our recent NSF proposal entitled “HigherEd 2.0″. We use this blog in a number of ways to deliver and exchange a great deal of class information. For instance:

To collaborate. Click here for the blog’s true home page, and feel […]

 Sample video solution: shear and moment diagrams: Download
 Sample lecture podcast: January 19, 2007: Download

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This module has both some review and preview material. The review material mentions the highlights from statics that you need to know. The preview material sets us up to discuss stress, work with stress equations, connect stress to physical deformation mechanisms, and otherwise merge stress with FBD and equilibrium concepts. I would […]

 Lecture module 2: Jan. 19 2007: Download

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