User:Eas4200c.f08.wiki.d/HW1

Introduction
In modern aircraft design a key objective is to produce an aircraft that is light in weight, but strong enough to resist stresses and fatigues that the vehicle is subjected to during flight. Therefore ideal materials for aircraft construction are ones that exhibit high stiffness, strength, and toughness while having a low density and consequently low weight. In order to understand the topic of aerospace structures we must first examine each of these components.

Stiffness is the resistance to deflection and/or deformation generated by a material that is subjected to an applied force. An 18th century British scientist, Thomas Young, was among the first to develop a qualitative method to describe the stiffness of a material. Now, the Young's Modulus of Elasticity, E, is a material property widely used across all fields of engineering and science to describe material stiffness. Young stated that the stress within a material is directly proportional to the strain, with the proportionality constant being E.

$$\sigma\,=E\epsilon\,$$

Strength

Toughness

An example of using different aerospace materials to obtain required structural properties is the F/A-18E (Hornet). In this aircraft various parts are fabricated from different materials in order to maximize the performance of each part based on their individual loading conditions. By doing this, the overall performance of the aircraft is optimized while minimizing the weight, which is the main design criteria in aerospace applications. A few of the numerous materials in the aircraft are listed below along with their locations.
 * Aluminum: Skin
 * Steel: Landing gear
 * Titanium: Engine encasing structure, Stabilator, Wing, Cockpit cover
 * Carbon Epoxy: Fuselage, Aileron, Stabilator, Vertical stabilizer

MediaWiki
MediaWiki is a web-based wiki software application originally written for Wikipedia by Lee Daniel Crocker. Wiki software refers to collaborative software the manages, creates, and edits web pages through common web browser applications as the user interface. The information in wiki software is stored in a file system, while the edits are stored using a relational database management system. The main features of MediaWiki is the rich core feature set and the ability to add extensions, allowing additional functionality. Also, this software is distributed under the terms of the GNU General Public License with some documentation in the public domain; thus, it is a free and open source software, which allows anyone to use and edit the stored content.

The overall idea behind MediaWiki is that by having anyone add information on topics they thoroughly understand, everyone can benefit from the collective knowledge. The let down is that since there is no credibility check before editing a page, people with less than adequate knowledge of a subject or people who's intentions aren't to improve the content can "vandalize" the stored information, whether it be adding incorrect segments or even deleting previous contributions. In order to control this problem, the history of different versions of each web-page is saved, and editors, or custodians, assess each contribution in order to determine the validity. In the case of vandalism, the web-page is simply returned to the last acceptable version.