User:Eas4200c.f08.vqcrew.c/Homework 7/my

MATLAB Coding Problem Continued

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!Full MATLAB Code - Single Celled Airfoil, Shear Analysis
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!Full MATLAB Code - Multi-Celled Airfoil, Shear Analysis
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!Full MATLAB Code - Critical Buckling Shear Stresses and Buckling Modes
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!Full MATLAB Code - Verification of Lambda Consider the 2x2 $$\mathbf{K}\;$$ matrix:
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\displaystyle \left[ \begin{array}{ll} \frac{\lambda (1 + \vartheta^2)^2}{\vartheta^2} &	 \frac{4}{9} \\	 \frac{4}{9} &	 \frac{16 \lambda (1 + \vartheta^2)^2}{\vartheta^2} \end{array} \right] $$

The determinant of this matrix yields the following:


 * $$\left(\frac{\lambda (1 + \vartheta^2)^2}{\vartheta^2}\right)\left(\frac{16 \lambda (1 + \vartheta^2)^2}{\vartheta^2}\right) - \frac{16}{81} = 0$$

Reducing,


 * $$\lambda^2 = \frac{\vartheta^4}{9(1+\vartheta^2)^2}$$

Thus,


 * $$\lambda = \pm \frac{1}{9} \frac{\vartheta^2}{(1+\vartheta^2)}$$


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!Code Output - Single Celled Airfoil, Shear Analysis
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!Code Output - Multi-Celled Airfoil, Shear Analysis
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Figure 17 shows the minimum critical buckling stresses versus aspect ratio. The blue line is for the 2 equation method, the red line for the 5 equation method, and the green line for clamped conditions. As expected, the clamped conditions stresses are higher. Figure 18 shows the buckling mode shapes perspective view.

The calculated minimum shear stress in the skin panels is approximately 2 orders of magnitude lower than the theoretical buckling stress. While this may be evidence of a coding error, assuming there are no coding issues this would indicate the skin panels are not particularly effective at handling shear loads.

LaTeX Code Editor
The provided LaTeX equation editor was initially quite useful, since no members of the group had any prior experience using this coding language. The interface is very straightforward and easy to use, and since the code is auto-generated, it can be cut and pasted directly into the MediaWiki editing field. The editor also included a preview feature, so it was readily apparent if any mistakes were made during the coding process. However, as the semester progressed, the experience gained from manipulating these codes in the HW reports began to render the editor less efficient. Once one has a basic working knowledge of LaTeX coding, it is far easier to just code a tilde above a bold symbol than it is to individually search out the appropriate buttons to generate the code with the editor. While it is still useful for generating larger codes, such as blank matrices and vectors, most of the required coding for the homework assignments is much more easily done by hand than it is using the editor. In short, the editor is a wonderful learning tool for LaTeX coding, but it less useful for experienced users.

InkScape
Initially, the group generated figures and charts for the homework reports using various different softwares. While there was nothing wrong with the individual submissions, compiling a report using figures generated from multiple sources is less than ideal. It is important for these sorts of assignments to maintain a consistent look and feel throughout, as you would with any sort of paper or technical report. In order to better achieve this state, the group elected to start using only InkScape to generate non-MATLAB figures. Employing InkScape allowed the group to generate consistently uniform figures for the assignments, and the difference is very noticeable in a positive way. Furthermore, InkScape is a vector graphics program, which means that a given image will appear the same regardless of of the size it is scaled to, which is very convenient for thumbnailing on MediaWiki. The end result was that the overall quality of the group's submissions was greatly improved after the adoption of InkScape as the preferred figure generating tool.

WikiEd
At the start of the semester, some of the group members elected to employ WikiEd to assist with the generation of MediaWiki content. The experience with this extension to MediaWiki closely paralleled that of the LaTeX code editor. At first, the extension was very helpful. As with the LaTeX editor, the interface for WikiEd is very straightforward and easy to use. Anytime any non-text code is required, one can simply push a button and the code is generated in the editing field. This was very helpful at the beginning of the semester when the group was still getting familiar with MediaWiki. However, as the semester went on, the extensions became more and more cumbersome. In many cases, it is much faster to simply type in the required code than it is to go hunt for the appropriate button to generate it using WikiEd. Also, it became apparent later on that if one is typing code into a WikiEd-modified editing field, and one accidentally clicks the back button on the browser (or hits the browser back key on the keyboard, if applicable), one loses all of the work entrered into the editing field since the last save. Needless to say, this is an extremely irritating bug. As with the LaTeX editor, the WikiEd extension was initially quite useful for learning purposes but became more of a burden as the semester continued.

MediaWiki vs. E-Learning
It is the general opinion of this group that E-Learning is the slightly superior option for this kind of assignment. While MediaWiki is far more powerful in terms of content handling; that is, ability to handle equations, videos, audio files, etc., it is slightly less user-friendly and has less organizational tools. Although E-Learning is notorious for server issues, generally speaking this can be avoided by approaching assignments in a timely manner. Perhaps the biggest advantage over MediaWiki when using E-Learning is that E-Learning has the built-in capability for transmitting grades to students in a confidential manner. MediaWiki has no method for handling this, and as such requires the use of email for grade distribution. All in all, while MediaWiki is a very powerful tool and a useful tool to be familiar with, E-Learning is still a superior option for class use.