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Showing papers by "K. Ramesh published in 1998"


Journal ArticleDOI
TL;DR: Advancements in the last two decades for data acquisition in digital photoelasticity have been brought out in this paper and a need to capture the images in colour is indicated for full automation of data acquisition.

59 citations


Journal ArticleDOI
01 Nov 1998-Strain
TL;DR: A generic approach namely optically enhanced tiling (OET) is presented to construct a composite picture from multiple optically zoomed images to solve the problem of data acquisition in digital photoelasticity using phase shifting technique.
Abstract: In digital fringe pattern analysis information is usually lost in high fringe density zones due to digitisation and quantisation errors. A generic approach namely optically enhanced tiling (OET) is presented to construct a composite picture from multiple optically zoomed images. The procedure is explained with the help of the problem of data acquisition in digital photoelasticity using phase shifting technique.

8 citations


Journal ArticleDOI
01 Nov 1998-Strain
TL;DR: In this article, it is observed that in high stress gradient zones the fringes become brighter, which leads to erroneous results, if not accounted for, in those techniques which use quantitative values of intensity to evaluate the experimental parameters.
Abstract: In digital photoelastic analysis it is observed that in high stress gradient zones the fringes become brighter. It leads to erroneous results, if not accounted for, in those techniques which use quantitative values of intensity to evaluate the experimental parameters. In this note, the reasons for the above phenomenon is investigated and suitable recommendations are given.

3 citations


Journal ArticleDOI
TL;DR: Delale and Erdogan as discussed by the authors evaluated the mode-I SIF by solving singular integral equations numerically and showed that the SIF can be greater than the isotropic material value for certain types of orthotropic materials and can be smaller than the ISM value for some other types of materials.
Abstract: In the case of infinite bodies involving self-equilibrating loads, stress intensity factors (SIFs) for isotropic and orthotropic materials are the same. However, when the specimen is bounded, material orthotropy does influence the value of SIFs. Delale and Erdogan evaluated the mode-I SIF by solving singular integral equations numerically and showed that the SIF can be greater than the isotropic material value for certain types of orthotropic materials and can be smaller than the isotropic material value for certain other types of materials. They also observed that the mode-I SIF is not altered when either the crack is parallel or perpendicular to the fibre. These observations are verified by finite element analysis. The contours of iso-chromatics observable in a photoelasticity experiment are plotted to verify the suitability of finite element (FE) modelling and discretization. Using the FE code developed, the variation of the mode-I SIF for a single-edge notched (SEN) specimen as a function of v...