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An Interesting Application of Optical Measurement Techniques

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2011 ASEE Annual Conference & Exposition


Vancouver, BC

Publication Date

June 26, 2011

Start Date

June 26, 2011

End Date

June 29, 2011



Conference Session

ELOS Best Paper Nominations

Tagged Division

Division Experimentation & Lab-Oriented Studies

Page Count


Page Numbers

22.186.1 - 22.186.27



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Paper Authors


Bijan Sepahpour College of New Jersey

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Bijan Sepahpour is a registered Professional Engineer and Professor of Mechanical Engineering at TCNJ. He is currently serving as the chairman of the ME department. He is actively involved in the generation of design-oriented exercises and development of laboratory apparatus and experiments in the areas of mechanics of materials and dynamics of machinery for undergraduate engineering programs. Professor Sepahpour did his undergraduate studies at TCNJ and has degrees from New Jersey Institute of Technology (NJIT). He has served as the Chair of ASEE Divisions of Experimentation and Laboratory Oriented Studies (DELOS) in 2006-07 and the Mechanical Engineering in 2007-08. Professor Sepahpour is an active member of ASME and ASEE.

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An Interesting Application of Optical Measurement TechniquesOptical measurement techniques have become widespread tools for engineering applications.This class of measurements are characterized by being free from ambient electrical interference,non contact, non destructive, accurate and reproducible. As a result, an engineering graduateshould not only have appreciation for these valuable techniques, but also develop sufficientunderstanding of their inner workings to allow for the creation/adaptation of such measurementmethods as needed in a research/work environment.Numerous optical techniques are available for both quantitative and qualitative measurements.Many use sophisticated and expensive setups that include imaging components. A set of precisetechniques are based on a combination of inexpensive diode lasers, mirrors, and prisms. It is onadapting these techniques to laboratory experiments that this team will focus on. The following figures display the components of a preliminary design for creation andtesting of an apparatus for measurement of the angle of twist of a bar by application of torque. Amirror attached to the free end of the bar reflects the laser beam back on a scale before and afterthe application of the torque. Using laws of optics and simple trigonometric relations, the angleof twist is easily measured-with high resolution and nearly zero noise.τ = T.r / J (1)φ = T.L / G.J (2)Figure 1. Components and the Setupfor the “Torsion Experiment” Using“Optical Measurement System”Junior Engineering students are collaborating with the author in the “Design of the Experiment”and the “Fabrication of the Apparatus”.

Sepahpour, B. (2011, June), An Interesting Application of Optical Measurement Techniques Paper presented at 2011 ASEE Annual Conference & Exposition, Vancouver, BC. 10.18260/1-2--17467

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