Showing papers by "K. Ramesh published in 2015"
TL;DR: The use of single-colour image for determining the fringe orders in digital photoelasticity has gained importance in recent years, and in this, the fringe order are obtained by comparing the colou
Abstract: The use of single-colour image for determining the fringe orders in digital photoelasticity has gained importance in recent years, and in this, the fringe orders are obtained by comparing the colou
18 citations
TL;DR: Three methods for noise removal of isoclinic data calculated using a plane polariscope are proposed using an outlier smoothing algorithm and progressive multidirectional progressive smoothing is found to be effective in removing the noise at lower as well as at higher loads.
Abstract: In digital photoelasticity, one gets full-field information about the difference in principal stresses and their orientations by postprocessing the intensity data. Isoclinic data obtained using phase shifting techniques have inherent noise. The higher the external load, the higher the noise. Further, noise removal becomes complex if the isoclinic data has π-jumps, isotropic points, etc. Initially, the origin of the noise in isoclinic data obtained using phase shifting techniques is discussed. An explanation for the presence of excessive noise in a circular polariscope-based algorithm is provided. Three methods for noise removal of isoclinic data calculated using a plane polariscope are proposed using an outlier smoothing algorithm. The first two use quality and standard deviation measures to identify the noise-free pixel from each individual scan. The last method involves progressive multidirectional smoothing. The effectiveness of the proposed smoothing schemes is demonstrated using the benchmark problem of a circular disc under diametral compression. Multidirectional progressive smoothing is found to be effective in removing the noise at lower as well as at higher loads. Finally, this scheme is used to smooth isoclinic data in two other problems, one that has a π-jump and the other that has both an isotropic point and a π-jump.
11 citations
TL;DR: In this article, a methodology involving carrier fringes in conjunction with digital photoelasticity is used to quantify the residual stress in float glass, and the results are verified by six-step phase-shifting technique (a subset of ten-stage phase shifting method) using an automatic polariscope.
Abstract: Residual stresses are generated in float glass at the time of manufacturing due to thermal gradients created during the cooling process. The quantification of these residual stresses is important in glass industries as they affect their cutting quality. Photoelasticity can be used for residual stress analysis of glasses, as glass exhibits stress-induced birefringence. In this study, a methodology involving carrier fringes in conjunction with digital photoelasticity is used to quantify the residual stress in float glass. The results are verified by six-step phase-shifting technique (a subset of ten-step phase-shifting method) using an automatic polariscope. Finally, to demonstrate the utility of the proposed method, the residual stress is measured in float glasses of different thicknesses. A method for approximate estimation of residual stress which does not require sophisticated digital image acquisition and processing systems is also reported.
10 citations
04 Mar 2015
TL;DR: In this article, a model of a dry masonry wall with bricks made up of epoxy, loaded with a concentrated load was used to study the micromechanics of force transmission and interactions between bricks in masonry.
Abstract: Masonry being a composite system is very complex to study with analytical methods alone. Quantitative digital photoelastic analysis using Three Fringe Photoelasticity (TFP) is carried out on a model of a dry masonry wall with bricks made up of epoxy, loaded with a concentrated load. The result obtained provides insight into the micromechanics of force transmission and interactions between bricks in masonry. The result shows that force transmission through the wall occurs at discrete points. A tree like hierarchical pattern of stress flow is observed. It is also observed that the stress percolation results in the existence of stress-free zones in the model domain.
8 citations
TL;DR: In this paper, the authors present a special section guest editorial on digital photoelasticity: Advancements and Applications for OE Vol. 54 Issue 8, No. 2.
Abstract: This PDF file contains the editorial “Special Section Guest Editorial: Digital Photoelasticity: Advancements and Applications” for OE Vol. 54 Issue 08
5 citations