June 26, 2011
June 26, 2011
June 29, 2011
Division Experimentation & Lab-Oriented Studies
22.186.1 - 22.186.27
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”.
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