1467 Effect of Phase Angles on Determination of Principal-Stress Directions by Three-Step Color Phase Shifting

2005 ◽  
Vol 2005.1 (0) ◽  
pp. 351-352
Author(s):  
Pichet PINIT ◽  
Susumu TOBITA ◽  
Eisaku UMEZAKI
Keyword(s):  
Principal Stress ◽  
Phase Shifting ◽  
Stress Directions ◽  
Phase Angles

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.

Application of Determination of Principal-Stress Directions by Color Phase Shifting Technique to Model Containing Isotropic Points

2006 ◽  
Vol 326-328 ◽  
pp. 75-78
Author(s):  
Pichet Pinit ◽  
Eisaku Umezaki
Keyword(s):  
Principal Stress ◽  
Circular Ring ◽  
Binary Image ◽  
Phase Shifting ◽  
Entire Domain ◽  
Diametral Compression ◽  
Phase Shifting Technique ◽  
Stress Directions ◽  
Intersection Operation

This paper presents an application of a new point-wise technique for unwrapping the isoclinic parameter determined by a four-step color phase shifting. The unwrapping technique is based on a largest region in a binary image that corresponds to a largest visible-wrapped period of the computed isoclinic parameter. The largest region is obtained using an intersection operation between the extended ranges of the computed isoclinic parameter. The method uses four raw photoelastic fringe images. The technique is applied to a circular ring containing isotropic points subjected to diametral compression. Results show the method provides the correct isoclinic parameter in the true interval over the entire domain.

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.

Sign in / Sign up

Export Citation Format

Share Document