Experimental Stress Analysis. Instructor: Prof. K. Ramesh, Department of Applied Mechanics, IIT Madras. The course covers the basic aspects of experimental stress analysis that includes exhaustive treatment of the most versatile techniques like photoelasticity and strain gauges and also a brief introduction to the emerging techniques like digital image correlation. In addition it also provides the fundamental aspects of six different experimental techniques such as Moire, brittle coatings, holography, speckle methods, thermoelastic stress analysis and caustics.
(from nptel.ac.in)
Lecture 04 - Physical Principle of Strain Gauges, Photoelasticity and Moire
Concepts covered in this lecture: Spanner tightening a nut - completeness of a numerical solution, comparison with photoelastic fringes. Physical principle behind various experimental techniques, Strain Gauges, Photoelasticity, Grids for determining plastic strains, Geometric moire, grating details - u and v displacements, Demonstration of fringes due to translation and rotation of gratings of various types.