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Ramesh M.N.V.,Nalla Malla Reddy Engineering College
International Journal of Mechanics and Materials in Design

The natural frequencies of vibration of a rotating pre-twisted functionally graded cantilever beam are investigated. Rotating cantilever beam with pre-twist made of a functionally gradient material (FGM) consisting of metal and ceramic is considered for the study. The material properties of the FGM beam symmetrically vary continuously in thickness direction from core at mid section to the outer surfaces according to a power-law form. Equations of motion for free vibration are derived using Lagrange's equation and the natural frequencies are determined using Rayleigh-Ritz method. The effect of parameters such as the pre-twist angle, power law index, hub radius and rotational speed on the natural frequencies of rotating functionally graded pre-twisted cantilever beams are examined through numerical studies and comparison is made with the numerical results obtained using other methods reported in literature. The effect of coupling between chordwise and flapwise bending modes on the natural frequencies has also been investigated. © 2013 Springer Science+Business Media Dordrecht. Source

Ramesh Maganti N.V.,Nalla Malla Reddy Engineering College
International Journal of Computational Methods in Engineering Science and Mechanics

Functionally graded materials (FGMs) are designed to achieve a functional performance with gradually variable properties in one or more directions. In this article, free chordwise vibrations of functionally graded double-tapered rotating cantilever beams have been investigated. The functionally graded material of the beam is characterized by continuous variables, Young's modulus, and density that vary along the thickness direction according to a power law. The equations of motion are derived using Lagrange's approach, in which the energy expressions for rotating beam are expressed in terms of hybrid deformation variables. The Rayleigh Ritz method is used to obtain the frequencies of the tapered beam. The effect of the gradient in material proportion, taper ratios, hub radius, and rotational speed on Lagrange's approach with the free chordwise bending vibrations of the tapered beam are investigated and compared with the data in the literature. © 2015 Taylor and Francis Group, LLC. Source

Kumar M.N.,Indian National Remote Sensing Centre | Garimella U.,Center for Faculty Development | Nalla D.,Nalla Malla Reddy Engineering College
Proceedings - Frontiers in Education Conference, FIE

Much research into how people learn and skills required for professional competence has gone into designing curricula in higher education. Benjamin Bloom, Fink, Eric Mazur, Richard Felder and many others have much contributed to the design of aligned courses where outcomes, teaching and assessment complement each other resulting in effective learning. This is the basis of the international accreditation using outcome based education (OBE). Moreover, the Indian accreditation agency National Board of Accreditation (NBA) has adopted outcome based education for colleges seeking accreditation now. In this paper, we specifically describe the work in progress implementation of social constructive approaches such as eBridge and Talent Identification strategies in Nalla Malla Reddy Engineering College (NMREC) which is an affiliated engineering college of Jawaharlal Nehru Technological University (JNTU), Hyderabad, India. These strategies aim at fulfilling all the graduate attributes according to Washington Accord. In the present paper, we propose to show the processes, the data and some outcomes of these initiatives. The measured outcomes have demonstrated the positive influences of social constructivism in skill development and employability of the students. © 2014 IEEE. Source

Shukla A.K.,Nalla Malla Reddy Engineering College | Reddy G.C.M.,Mahatma Gandhi Institute | Shamantha C.R.,HAL | Reddy A.C.S.,Swami Ramananda Tirtha Institute of Science and Technology
Journal of the Institution of Engineers (India): Mechanical Engineering Division

Formability is a measure of the ability of a sheet metal to be stamped or formed successfully into useful components without developing any failures. Sheet metal formability of a material can be assessed by having the knowledge of material properties like yield strength, tensile strength, percentage elongation, strain hardening exponent, anisotropy coefficient etc. Sheet metal forming can be defined as a process in which desired size and shape are obtained through the plastic deformation of a material. Many forming operations like bending, stretching, drawing and coining, especially cup drawing operation in which a cup shaped product is obtained from a flat sheet metal with the help of punch and die, is a combination of different types of forming like - bending, bi-axial stretching, drawing, plane-strain stretching and unbending. Factors influencing drawability are mechanical properties like the plastic strain ratio, strain-hardening exponent, yield strength, modulus of elasticity, etc. Modified Erichsen cupping test is one of the currently used formability tests, which evaluate the ability of sheet metals to be formed into useful components successfully. The formability index is identified as one of the most important formability test results that would be used on a routine basis by industry for grading, selecting and sorting of incoming sheet metals for manufacturing of various components. The test consists of clamping a metal test piece under controlled pressure between retaining ring and die and pressing the test piece into the die by means of a penetrator having a spherical head, until the end point is reached. The depth of penetration thereby obtained is measure as Erichsen number. In older Erichsen test, the results obtained were uncertain, as there was no control on the clamping force. In modified Erichsen test a load of 1000±100 kgf is applied on the test piece clamped between the retaining ring and die with the help of torque wrench. In the present study the equipment for Erichsen cupping test has been designed and fabricated in accordance with the standards laid down in IS - 1756-1961. Rolled sheet metal specimens from mild steel and stainless steel (SS 304) annealed and without annealed, having different thickness such as 1.00 mm, 0.5 mm are used for experiment. Drawability indices (JE) are evaluated using the sheet metal properties. Practical tests with modified Erichsen cupping test equipment have been repeated for different material specimens of different thicknesses using different lubricated condition of PTFE of 0.20 mm, 0.25 mm and 0.30 mm. It is observed from the present experiment that the type of lubricant influences the Erichsen number. It is also observed that the Erichsen number depends upon the thickness of the sheet metal specimen. Therefore it is observed that the Erichsen number not only depends upon the thickness of the sheet metal but also on the property of the material which undergoes deformation. Source

Bhushan T.V.S.M.R.,Nalla Malla Reddy Engineering College | Reddy K.V.K.,JNTUH College of Engineering
Acta Technica CSAV (Ceskoslovensk Akademie Ved)

Experiments have been conducted to investigate natural convection heat transfer from the outer surface of axially inclined square ducts. Steady state heat transfer characteristics are studied at an arbitrary inclination of 45° from vertical in laminar and transition regions in still air, with channel area ratio and orientation as study parameters. Wide range of heat inputs are considered to analyze natural convection under laminar and transition regions under constant heat flux conditions. Empirical correlations are derived for local and average Nusselt and modified Rayleigh numbers. Experimental results were compared with established correlations pertaining to vertical cylinders and enhancement of heat transfer at 45° from vertical orientation were observed. © 2015 Institute of Thermomechanics AS CR, v.v.i. Source

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