Introduction

Contextual Background

The author of this text has served as instructor for the Northern Illinois University course Experimental Methods in Mechanical Engineering numerous times over two decades of service. In the previous publishing environment, there was a reliance upon foundational texts for students to use as their reference resource:

• Theory and Design for Mechanical Measurements by Richard S. Figliola and Donald E. Beasley (current edition)
• Experimental Methods for Engineers by Jack Holmann (pdf download)
• Introduction to Engineering Experimentation by Anthony J. Wheeler and Ahmad R. Ganji (latest edition)
• Measurement and Data Analysis for Engineering and Science by Patrick F. Dunn (with Michael P. Davis contributing to 4th edit) (full edition history)

Despite having the full background for derivation and application to numerous examples from the textbooks, students often found the lecture-based outline notes as a more efficient resource when analyzing engineering problems within the lab, through homework practice, and during open-resource examinations. In a lecture delivery environment, the hand-written notes that were built by the instructor were transcribed by the students at a frenetic pace; experience indicates, however, that copying and learning are not necessarily parallel processes. Through the pivot to online instruction, the paper-based notes were converted to static, portable document formats that proved to serve as the effective text resource for students. To that end, the subsequent outline in the Open Education Resource is provided as an aid to a broader audience. 

How to use the outline

The text that follows is ordered in a manner that help usher students through the foundational building blocks of experimental data collection and subsequent analysis. Limited prose is provided so that terminology or importance of elements are not hidden within sentence structures. Furthermore, the applicable forms of equations for use is provided; the full background of derivations from fundamental mathematical principles are hyperlinked to other external resources. The intent for the structure is to keep focus on the How to use ... process of the engineer while still having connections to building the knowledge from first principles. 

As an example, the strain gage is tool for measuring the local elongation of a solid sample material. In order to load and deflect the mechanical bonds, the understanding of static force reactions, mechanics of materials, mathematical principles of area moment of inertia, and resistive electronics all need to be connected. As each of those knowledge elements are connected (most curricula have those elements as 4 separate pre-requisite courses), the resource links are provided to remind the reader of the pre-requisite content that should exist in their knowledge base. If there is not an immediate recall, then the reader can start again from the first principles to build to application in the laboratory experiments.

A standard outline structure would follow a sequence of numerical and alphabetical formats: Roman numerical -> Capital letter -> Arabic numeral -> Lower case letter -> numerical value, and so forth. An old example from handwritten notes would be:

• VI. Periodic Signal Analysis, C. Special cases of Fourier Series, 3. Odd functions, b. thus all \(A_{n} = 0\) 

Given the LibreText platform, readers will find the Chapter numbers now replace the roman numeral format. Therefore, when advancing from pages that are organized by the decimal values, the sequence of Capital letters will be a continuum within the chapter itself. Using the outline format hopefully enables more efficient cross referencing both within the text as well as when readers may seek clarification from instructors on the meaning or applicability. (e.g. "Can you explain what is meant by 4-quadrant inverse tangent of 2.B.b when describing phase shift?") 

Organizational Order

Students tossed into a laboratory environment can sometimes feel overwhelmed.

• How does this connect to any sort of theory or equation that has not be "taught" to me recently?
• How should I organize planning, recording, and reporting?
• How do I convert a blank page into a formatted technical document ready for the right audience?

Therefore the sequence attempts to build from Blooms Taxonomy of Learning: readers will be reminded of their prior understanding, apply the principle in a (potentially) new) analytical method through some completed examples, and then evaluated via instructor-derived assessments of examinations or laboratory reports. The overarching sequence of content follows:

1. Organizing the experimental plan; useful questions for independent, learner-initiated projects
2. Sampling and storing time-dependent signals
3. Reporting uncertainty for specific sensors and combinations of multiple measurements
4. Organizing a writing process for technical documents
5. Characterizing linear differential equations in the laboratory
6. Signal analysis via Fourier Series and conversion to frequency domain
7. Fundamental principles of infinite and finite statistics through probability density

The theoretical background to conduct experiments related to many mechanical systems is provided in Chapter 8. These and other experiments can be implemented in any order to emphasize particular sections above as a parallel in-the-lab learning activity. 

The Appendix in Chapter 9 concludes with the page contents from other OER where greater expansion on topics is available without interrupting the outline structure. Each section may have different Creative Commons license depending on authorship. 

Finally, an advance thank you to all who read, find the work helpful in their learning, and provide feedback for continued revision and improvement.