Abstract

The abstract is a brief (one or two paragraphs) description of what you did and what you found. You may also include a sentence or two about why you did whatever you did, if you feel it is important. The abstract must not be a summary of your thought processes for writing the report. Do not write ``the experiment was completed, the data was analyzed, and conclusions were drawn." Remember, the higher a person is in an organization, the less likely he is to read the entire report. The top managers will often read only the abstract (and if this is interesting, they may read the conclusions) and decide whether or not your project was worthwhile. Also, abstracts of engineering reports and scientific papers are made available to other researchers through computer data bases. Since a potential reader may have to sift through a lot of abstracts, the relevance and quality of your work may be judged on the basis of your abstract alone. Therefore, the abstract must stand on its own.

Included below are two examples of abstracts from students' reports received in recent years (modified to protect the innocent.)

Samples of Plexiglas $^\mathrm{TM}$ (PMMA) were tested in a fracture machine. The relation between fracture toughness and crack length was found by plotting a graph of the results and measuring its slope. A ``best fit" line through the data gave a value of 1.7Pavm which is close to the handbook value of 1MPavm .

This abstract is poorly written because it is vague, imprecise, and inaccurate. The objective of the project is not clear, what was done is inadequately described and mostly irrelevant, and the parameter to which the quoted values belong (i.e., fracture toughness) is not identified. Note how the important information is clearly and accurately conveyed in the following good abstract:

The purpose of this project was to study the phenomenon of static fracture using samples of polymethyl methacrylate, commonly known as Plexiglas $^\mathrm{TM}$ . Using a saw cut and a razor blade, a small crack was initiated in each of seven single edge notched specimens. The specimens were tested to fracture in laboratory air at room temperature at a constant strain rate in a tensile mode I configuration. The size of the crack was varied between specimens to observe the effect of crack size on the fracture strength. It was found that the strength of the samples decreased as the initial crack length increased. Using fracture mechanics equations, the average fracture toughness of the material was calculated to be 1.8MPavm. The results indicated that the fracture toughness is independent of the initial crack size and may be considered to be a material constant for the loading conditions and temperature examined.

An abstract should allow a senior engineer to decide if your report is relevant to a particular effort or, alternatively, indicate to a researcher if your report is worth the time and effort that goes into acquiring and understanding it.