Improvement of Fourier Polarimetry for Applications in Tomographic Photoelasticity

Yang, Hua; Gibson, S.; Tomlinson, R. A.

doi:10.1007/s11340-006-9112-7

Cited by 4 publications

(4 citation statements)

References 7 publications

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“…As the computational challenges fall to the advance of Moore's law experimentalists are revisiting the requirements for data collection. In the case of polarized light tomography for the study of strain in transparent photoelastic objects systems already exist [3,21,24] and indeed there are explicit analytical [10] as well as numerical [20], reconstruction algorithms for the Truncated Transverse Ray transform, which describes that system for sufficiently small strains.…”

Section: Introductionmentioning

confidence: 99%

Diffraction tomography of strain

Lionheart

Withers

2015

Inverse Problems

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We consider whether it is possible to recover the three dimensional strain field tomographically from neutron and x-ray diffraction data for polycrystalline materials. We show that the distribution of strain transverse to a ray cannot be deduced from one diffraction pattern accumulated along that path, but that a certain moment of that data corresponds to the transverse ray transform of the strain tensor and so may be recovered by inverting that transform given sufficient data. We show that the whole strain tensor can be reconstructed from diffraction data measured using rotations about six directions that do not lie on a projective conic. In addition we give an inversion formula for complete data for the transverse ray transform. We also show that Bragg edge transmission data, which has been suggested for strain tomography with polychromatic data, cannot provide the strain distribution within the material but only the average along the ray path.

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Section: Introductionmentioning

confidence: 99%

Diffraction tomography of strain

Lionheart

Withers

2015

Inverse Problems

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“…This could be due to the irreversible grain dislocations, which is an inherent property of discrete particulate systems. Hence, to avoid any confusion, an integrated (plane and circular) digital photoelastic tomography [17][18][19][20] is referred to as PSAT in particulate engineering. 21 Figure 2 shows the schematic diagram of the axial compression rig used in the experiments.…”

Section: Background Of Photo Stress Analysismentioning

confidence: 99%

Micromechanical analysis of inclusions in particulate media using digital photo stress analysis tomography

2015

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Abstract. An experimental study aimed at sensing the stress distribution characteristics of inclusions inside particulate assemblies subjected to axial compaction is presented. The particulate assemblies are made of powders and grains, in which photoelastic inclusions are embedded along the central axis of the assemblies at different elevations. Digital photo stress analysis tomography is used to obtain the contours of maximum shear-stress distribution and the direction of major principal stress within the inclusions under the external loading. Using this, an analysis is performed for understanding the implications of using Hertz theory based on discrete element modeling for simulating stresses in relatively big inclusions surrounded by particulates. In the case of the inclusions surrounded by the grains, the location at which the peak value in maximum shear stresses occurs within the inclusions deviates from that of Hertzian analysis. This effect is dominant in the case of inclusions residing close to the loading surface. Unlike granular materials, shear-stress distribution characteristics of inclusions in powder surroundings tend to display continuum-like behavior under external compression and points to the need for a deeper understanding of the effects of the surrounding materials in particulate beds with inclusions.

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“…Considerable advances have been made in integrated photoelasticity in recent years with the development of automated systems [5,6,7,8,9], but the obvious potential of birefringent fluids has not been exploited. This research explores the use of automated phase stepping photoelasticity and Computational Fluid Dynamics (CFD) simulations to study three dimensional fluid flow.…”

Section: Introductionmentioning

confidence: 99%

“…The disadvantage of the technique, however, is that the fringes produced represent an integral of the shear stress along the light path, and if the shear stress changes along this path, then the interpretation of the fields can be problematic. Considerable advances have been made in integrated photoelasticity in recent years with the development of automated systems [5,6,7,8,9], but the obvious potential of birefringent fluids has not been exploited. This research explores the use of automated phase stepping photoelasticity and Computational Fluid Dynamics (CFD) simulations to study three dimensional fluid flow.…”

Section: Introductionmentioning

confidence: 99%

Streaming Birefringence - A Step Forward

Spalton

Tomlinson

Garrard

et al. 2008

AMM

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Abstract. An investigation into three dimensional fluid flow has been conducted which combines the use of Computational Fluid Dynamics (CFD) simulations with the experimental phenomenon of Streaming Birefringence. A versatile flow channel was designed and built for use in conjunction with a circular polariscope. The experimental liquid used was an aqueous solution of a dye, commercially known as Milling Yellow NGS with the addition of Sodium Chloride. To extract the flow fields, six image phase stepping photoelasticity was used over backward and forward steps, and flows around a cylinder, and full-field fringe data were obtained. This method needs laminar flow regimes and the Reynolds number of the flow was around 10. To allow direct comparisons of the CFD solutions with the optical results, a macro (UDF) was written to interpret the flow field results from a (FLUENT6) CFD simulation. This integrated the shear stresses across the flow field and banded the results into fringes. A good correlation between the simulated fringes and the shearstrain rate was obtained from these observations.

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Improvement of Fourier Polarimetry for Applications in Tomographic Photoelasticity

Cited by 4 publications

References 7 publications

Diffraction tomography of strain

Diffraction tomography of strain

Micromechanical analysis of inclusions in particulate media using digital photo stress analysis tomography

Streaming Birefringence - A Step Forward

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