Curriculum Element: Applications of an Elastomer to Strain Gauges

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Author: Professor Marjorie Rawhouser, Anne Arundel Community College (marawhouser@aacc.edu)

Short Description: Students in electrical engineering or electronics technology courses where electrical circuits are discussed can be provided with strain gauges (with metal foils or elastomers) to understand their role in structural monitoring.

Implementation Levels: Classes focusing on electrical circuits in an Electrical Engineering or Electronics Technology curriculum. Example: Introduction to Electrical Circuits (EET 130) at Anne Arundel Community College.

Description

When an object is stretched in an application, the strain (elongation or contraction) can be measured physically or by the change in resistance of a strain gauge (metal foil) that is attached to the object. The latter is very useful for monitoring the process remotely or in real time. This lesson plan was designed to introduce current and future strain gauges. Traditionally a foil strain gauge in a Wheatstone Bridge circuit is used as a real life example of how analyzing electrical circuits can provide useful information in non-electrical applications. During the activity, students also learn the significant role of strain gauges in structural monitoring. In the newly developed curriculum element, students were introduced to new materials, like elastomers (rubbers) that could potentially be used as strain gauges. So, after building and taking measurements in a Wheatstone Bridge, students were divided into groups and were asked to research, critically analyze and report their findings on potential use of elastomers in strain gauges. As part of their report, student groups discuss the advantages of using elastomers compared to foil strain gauges. Their report also included the challenges to be overcome before elastomer strain gauges could be used in a commercial scale. This curriculum element encourages the students to critically analyze scenarios, to evaluate and solve problems as a team, and to effectively communicate science and technology.

Materials