Photoelasticity

1
Mechanics of Materials Lab

• Lecture 7
• Photoelasticity
• Experimental Stress Analysis Photoelasticity
• Jiangyu Li
• University of Washington

2
Isochromatic Fringe
3
Isochromatic Fringe
4
Stress-Optic Effect
5
Interference
6
Stress Concentration
Dense fringe indicates higher stress concentration
7
Linear Polarizer
8
Plane Polariscope
Extinction occurs under two consideration (1)
destruction interference (2) parallel
principle axis of stress and polarizer
9
Isoclinic Fringe
Obtain by rotating polarizer and analyzer together
10
Quarter Wave Plate
11
Circular Polariscope
Provide equal amount of light along each of the
polarization directions at every point
12
Isochromatic Fringe
13
Four Point Bending
14
Assignment

• Read note on phtoelasticity posted online