Faculty Publications

Permanent URI for this communityhttps://idr.nitk.ac.in/handle/123456789/18736

Publications by NITK Faculty

Browse

Subject: search.filters.subject.Crack mouth opening displacement

Search Results

Now showing 1 - 3 of 3
  • No Thumbnail Available
    Item
    Experimental investigation of effect of specimen thickness on fracture toughness of Al-TiC composites
    (Gruppo Italiano Frattura, 2016) Raviraj, M.S.; Sharanaprabhu, C.M.; Mohan Kumar, G.C.
    In this paper, the macro and micro-mechanical fracture behavior was studied for aluminum (Al6061) alloy matrix, reinforced with various proportions of TiC particles such as 3wt%, 5wt% and 7wt%. The Al6061-TiC metal matrix composites were produced by stir casting method to ensure uniform distribution of the TiC particulates in the Al matrix. The compact tension (CT) specimens were machined according to ASTM E399 specifications to evaluate the fracture toughness for Al6061-TiC metal matrix composites. The CT specimens were machined for crack to width (a/W) ratio of 0.5 and thickness to width (B/W) ratios of 0.2 to 0.7 with an increment of 0.1. Load versus crack mouth opening displacement (CMOD) data was plotted to estimate stress intensity factor KQ for various thicknesses of the specimen. The fracture toughness KIC was obtained by plotting stress intensity factor versus thickness to width ratios of specimen data. The fracture toughness of these composites varied between 16.4-19.2 MPa?m. Scanning Electron Microscope (SEM) studies was made on the fractured surface of the specimens to understand the micro-mechanisms of failure involve in these composites. Void initiation is more significant in the matrix near the interface. The micro-cracks grow from these micro-voids and crack propagates by linking these micro cracks locating the crack path preferentially in the matrix adjacent to the interface indicating ductile fracture. © 2016, Gruppo Italiano Frattura. All rights reserved.
  • No Thumbnail Available
    Item
    Effect of specimen crack lengths on stress intensity factor for Al6061-TiC composites using experimental and 3D numerical methods
    (Emerald Group Publishing Ltd. Howard House Wagon Lane, Bingley BD16 1WA, 2017) Raviraj, M.S.; Sharanaprabhu, C.M.; Mohan Kumar, G.C.
    Purpose-The purpose of this paper is to present the determination of critical stress intensity factor (KC) both by experimental method and three-dimensional (3D) finite element simulations. Design/methodology/approach-CT specimens of different compositions of Al6061-TiC composites (3wt%, 5wt% and 7wt% TiC) with variable crack length to width (a/W0.3-0.6) ratios are machined from as-cast composite block. After fatigue pre-cracking the specimens to a required crack length, experimental load vs crack mouth opening displacement data are plotted to calculate the KC value. Elastic 3D finite element simulations have been conducted for CT specimens of various compositions and a/W ratios to compute KC. The experimental results indicate that the magnitude of KC depends on a/W ratios, and significantly decreases with increase in a/W ratios of the specimen. Findings-From 3D finite element simulation, the KC results at the centre of CT specimens for various Al6061-TiC composites and a/W ratios show satisfactory agreement with experimental results compared to the surface. Originality/value-The research work contained in this manuscript was conducted during 2015-2016. It is original work except where due reference is made. The authors confirm that the research in their work is original, and that all the data given in the article are real and authentic. If necessary, the paper can be recalled, and errors corrected. © Emerald Publishing Limited.
  • No Thumbnail Available
    Item
    Role of longitudinal reinforcement on the behavior of under reinforced concrete beams subjected to fatigue loading
    (Elsevier Ltd, 2019) Prashanth, M.H.; Singh, P.; Chandra Kishen, J.M.C.
    In this work, the role of steel reinforcement in under reinforced concrete beams when subjected to flexural fatigue loading is studied using the acoustic emission (AE) technique. Three-point bend notched beams of three different sizes and with varying reinforcement ratios are subjected to step-wise increasing variable amplitude fatigue loading. The crack mouth opening displacement (CMOD) and AE parameters are analyzed to study the evolution of damage, load carrying and failure mechanisms in under reinforced concrete beams. It is concluded that the presence of reinforcement substantially increases the fatigue life. Further, the CMOD could be used as a criterion for failure in reinforced concrete beams under fatigue loading. © 2019 Elsevier Ltd