Full-Field Determination of Principal-Stress Directions Using Photoelasticity with Plane-Polarized RGB Lights

2005 ◽  
Vol 12 (3) ◽  
pp. 228-232 ◽  
Author(s):  
Pichet Pinit ◽  
Eisaku Umezaki
Keyword(s):  
Principal Stress ◽  
Full Field ◽  
Stress Directions

Determination of In-Situ Stresses From Hydraulically Fractured Spherical Cavities

1983 ◽  
Vol 105 (2) ◽  
pp. 125-127 ◽  
Author(s):  
W. E. Warren
Keyword(s):  
Hydraulic Fracturing ◽  
Principal Stress ◽  
Spherical Cavity ◽  
Hydraulic Fractures ◽  
Stress Measurements ◽  
In Situ Stresses ◽  
Spherical Cavities ◽  
Stress Directions

Several problems in analysis can arise in estimating in-situ stresses from standard hydraulic fracturing operations if the borehole is not aligned with one of the principal stress directions. In these nonaligned situations, the possibility of fracturing a spherical cavity for estimating the in-situ stresses is investigated. The theory utilizes all the advantages of direct stress measurements associated with hydraulic fracturing and eliminates the geometrical problems associated with the analysis of hydraulic fractures in cylindrical boreholes.

Determination of Principal-Stress Directions by Three-Step Color Phase Shifting Technique

2006 ◽  
Vol 321-323 ◽  
pp. 1284-1287
Author(s):  
Pichet Pinit ◽  
Tobita Susumu ◽  
Eisaku Umezaki
Keyword(s):  
Principal Stress ◽  
White Light ◽  
Digital Camera ◽  
Circular Disk ◽  
Dark Field ◽  
Phase Shifting ◽  
Automatic Determination ◽  
Stress Directions ◽  
Field Plane

A three-step phase shifting approach for automatic determination of the isoclinic parameter in photoelasticity is presented. Unreliable isoclinic values affected by the isochromatic parameter are solved using the white light. The method uses three fringe images digitally captured by a digital camera for three different configurations of the dark-field plane polariscope. For a circular disk under compression, results show the method permits the isoclinic parameter in the range -π/2 to π/2 with almost free of the isochromatic parameter and comparable with theory.

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