Photoelasticity
An overview of photoelasticity and its several variants ranging from conventional transmission photoelasticity to digital photoelasticity is presented. A representative fringe pattern for each of the variants is provided to give a glimpse of the range of
- PDF / 4,787,715 Bytes
- 42 Pages / 547.087 x 685.984 pts Page_size
- 35 Downloads / 162 Views
Photoelastici 25. Photoelasticity
Krishnamurthi Ramesh
An overview of photoelasticity and its several variants ranging from conventional transmission photoelasticity to digital photoelasticity is presented. A representative fringe pattern for each of the variants is provided to give a glimpse of the range of problems it can solve. The technique basically provides the difference of principal stresses/strains and their orientation at every point in the model domain. It is the only whole-field technique which can study the interior of a threedimensional model. The advancements in digital photoelasticity have made photoelastic analysis more efficient and reliable for solving engineering problems. Photoelasticity is useful as a design tool, to understand complex phenomenological issues, and as an excellent teaching aid for stress analysis. It can be used to study models made of transparent plastics, prototypes made of different materials, and also directly on end products such as glass components. With developments in rapid prototyping and novel methods for fringe plotting from finite element results, the technique is ideally suited for hybrid analysis of complex problems.
25.1 Preliminaries ....................................... 25.1.1 Polarization............................... 25.1.2 Birefringence............................. 25.1.3 Retardation Plates......................
704 704 704 705
25.2.3 Fringe Contours in a Plane Polariscope ................ 25.2.4 Jones Calculus............................ 25.2.5 Ordering of Isoclinics .................. 25.2.6 Ordering of Isochromatics............ 25.2.7 Calibration of Model Materials .....
706 707 708 709 709
25.3 Variants of Photoelasticity..................... 25.3.1 Three-Dimensional Photoelasticity 25.3.2 Dynamic Photoelasticity .............. 25.3.3 Reflection Photoelasticity ............ 25.3.4 Photo-orthotropic Elasticity......... 25.3.5 Photoplasticity...........................
710 710 714 715 717 718
25.4 Digital Photoelasticity ........................... 25.4.1 Fringe Multiplication and Fringe Thinning ................... 25.4.2 Phase Shifting in Photoelasticity .. 25.4.3 Ambiguity in Phase Maps ............ 25.4.4 Evaluation of Isoclinics ............... 25.4.5 Unwrapping Methodologies......... 25.4.6 Color Image Processing Techniques 25.4.7 Digital Polariscopes ....................
719 719 720 723 725 727 729 730
25.5 Fusion of Digital Photoelasticity Rapid Prototyping and Finite Element Analysis. 732 25.6 Interpretation of Photoelasticity Results. 734 25.7 Stress Separation Techniques................. 25.7.1 Shear Difference Technique ......... 25.7.2 Three-Dimensional Photoelasticity 25.7.3 Reflection Photoelasticity ............
735 735 736 736
25.8 Closure ................................................ 737 25.9 Further Reading ................................... 737
25.2 Transmission Photoelasticity ................. 705 25.2.1 Physical Principle ....................... 705 25.2.2 Stress–Optic Law ........................ 706
25.A Appen
Data Loading...
