Indian Institute of Technology Palakkad&nbsp;(IIT Palakkad or IIT PKD) is a public autonomous&nbsp;engineering&nbsp;and&nbsp;research&nbsp;institute located in&nbsp;Palakkad,&nbsp;Kerala. It was&nbsp;one of the five new&nbsp;IITs&nbsp;proposed in the&nbsp;2014 Union budget of India. The campus was inaugurated on 3 August 2015. The institute has 94 faculty, 978 students, and 63 non-teaching staffs.

IT Palakkad currently offers four-year Bachelor of Technology (B.Tech) and two years MS programmes in 8 different engineering disciplines including&nbsp;Computer Science, Electrical, Mechanical, Civil among others.

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IIT Palakkad

The title problem is 2-D exterior problem which is solved here by superposing Flamant problems followed by annihilating far-field and boundary tractions using limiting case of Lame’s problem. This method being identical to that used for classical problem of disk under diametral compression (corresponding interior problem), leads to closed-form solution for the exterior problem. Series solution is applicable for distributed loads, which in the limit approaches solution for the title problem. FEM which can model only finite geometries, approximates the infinite domain in the limit. The latter two methods are adopted here for validation of the analytical method by comparison. The analytical method is extended to solve three-point, four-point and n-point loading cases on the circular hole boundary.

Department of Mechanical Engineering

World University root node

Recent Advances in Applied Mechanics

Stress Distribution in Infinitely Long Plate with Circular Hole Loaded by Concentrated Loads

Recent Advances in Computational and Experimental Mechanics, Vol II

Analysis of a Double Edge Cracked Circular Ring Under Diametrical Compression

International Journal of Aerospace and Mechanical Engineering

Mixed mode fracture analyses using finite element method of edge cracked heavy spinning annulus pulley

Fringe tracking and fringe order assignment have become the central topics of current research in digital photoelasticity. Isotropic points (IPs) appearing in low fringe order zones are often either overlooked or entirely missed in conventional as well as digital photoelasticity. We aim to highlight image processing for characterizing IPs in an isochromatic fringe field. By resorting to a global analytical solution of a circular disk, sensitivity of IPs to small changes in far-field loading on the disk is highlighted. A local theory supplements the global closed-form solutions of three-, four-, and six-point loading configurations of circular disk. The local theoretical concepts developed in this paper are demonstrated through digital image analysis of isochromatics in circular disks subjected to three- and four-point loads. © 2015 Society of Photo-Optical Instrumentation Engineers.

Optical Engineering

Digital image analysis around isotropic points for photoelastic pattern recognition

Friction coefficient between a circular-disk periphery and V-block surface was determined by introducing the concept of isotropic point (IP) in isochromatic field of the disk under three-point symmetric loading. IP position on the symmetry axis depends on active coefficient of friction during experiment. We extend this work to asymmetric loading of circular disk in which case two frictional contact pairs out of three loading contacts, independently control the unconstrained IP location. Photoelastic experiment is conducted on particular case of asymmetric three-point loading of circular disk. Basics of digital image processing are used to extract few essential parameters from experimental image, particularly IP location. Analytical solution by Flamant for half plane with a concentrated load, is utilized to derive stress components for required loading configurations of the disk. IP is observed, in analytical simulations of three-point asymmetric normal loading, to move from vertical axis to the boundary along an ellipse-like curve. When friction is included in the analysis, IP approaches the center with increase in loading friction and it goes away with increase in support friction. With all these insights, using experimental IP information, friction angles at three contact pairs of circular disk under asymmetric loading, are determined. © 2015 SPIE.

Proceedings of SPIE - The International Society for Optical Engineering

Characterization of friction at three contact pairs by photoelastic isotropic point (IP)

Mixed mode analysis of obliquely oriented edge cracked semicircular disk under compression

Analysis of edge cracked semicircular disk (ECSD) under mixed-mode loading

Proceedings of ICEM

Analysis of obliquely oriented edge cracked semicircular ring (OECSR)

Isochromatic patterns in the vicinity of frictional contacts furnish vital clues for characterizing friction. Though friction effects are evident in a diametrally loaded circular disk, three-point loading provides better results towards highlighting friction. In this paper, a new method of characterizing friction at loading contacts using photoelastic isochromatics patterns is presented. Location of isotropic points (IPs) formed in three-point and four-point loadings of circular disk is used as a main tool to quantify the friction component using theoretical analysis. Bifurcation of isochromatic fringe loops near the distributed loads is explained by the presence of anti-symmetric Hertzian shear traction in addition to Hertzian normal traction. The classical solution by Flamant for point load at the edge of half plane is used to derive stresses in circular disk for all required loading configurations. A semicircualr ring under three-point loading is examined using photoelasticity to understand the isochromatics pattern theoretically by considering normal and shear traction components at loaded regions. © 2014 Society for Experimental Mechanics.

Experimental Mechanics

Characterizing Frictional Contact Loading via Isochromatics

Edge cracked specimens have been widely utilized for fracture testing. Edge cracked semicircular disk (ECSD) specimen has now been well characterized with regard to its form factor and weight function. This paper presents a modified semicircular ring version of this specimen to enhance the form factor in general while retaining other desirable features. The efficacy of the modified design is proved by combining theory of elasticity solutions with finite element results to arrive at the optimum design geometry. New insights emerging from this work are used to theoretically re-examine the arch-tension and the four-point bend specimens. © 2014 Elsevier Ltd.

Engineering Fracture Mechanics

Analysis of cracked and un-cracked semicircular rings under symmetric loading

Inspired by the Brazilian disk geometry we examine the utility of an edge cracked semicircular disk (ECSD) specimen for rapid assessment of fracture toughness of brittle materials using compressive loading. It is desirable to optimize the geometry towards a constant form factor F for evaluating KI. In this investigation photoelastic and finite element results for KI evaluation highlight the effect of loading modeled using a Hertzian. A Hertzian loading subtending 4° at the center leads to a surprisingly constant form factor of 1.36. This special case is further analyzed by applying uniform pressure over a chord for facilitating testing. © 2013 Elsevier Ltd.

Design and analysis of novel compression fracture specimen with constant form factor: Edge cracked semicircular disk (ECSD)

We analyze the utility of edge cracked semicircular disk (ECSD) for rapid assessment of fracture toughness using compressive loading. Continuing our earlier work on ECSD, a theoretical examination here leads to a novel way for synthesizing weight functions using two distinct form factors. The efficacy of ECSD mode-I weight function synthesized using displacement and form factor methods is demonstrated by comparing with finite element results. Theory of elasticity in conjunction with finite element method is utilized to analyze crack opening potency of ECSD under eccentric compression to explore newer configurations of ECSD for fracture testing. © 2013 Elsevier Ltd.

Synthesis and application of weight function for edge cracked semicircular disk (ECSD)

Edge cracked semicircular disk under compression exhibited form factor constancy over wide range of relative crack lengths. Inspired from this property, edge cracked semicircular ring (ECSR) is analyzed with the aim of enhancing validity range of constant form factor property. Understanding the effects of inner radius and load angle on form factor of ECSR, different combinations of the two are examined towards reaching the aim. Photoelasticity in conjunction with FEM is used to analyze the specimen. A particular combination of inner radius and load angle is found to give constant form factor over an enhanced range.