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CONTENTS
Volume 5, Number 2, June 2016
 

Abstract
The objective of the present work is to optimize process parameters namely, cutting speed, feed rate, and depth of cut in milling of AISI 304 stainless steel. In this work, experiments were carried out as per the Taguchi experimental design and an L27 orthogonal array was used to study the influence of various combinations of process parameters on surface roughness (Ra) and material removal rate (MRR). As a dynamic approach, the multiple response optimization was carried out using grey relational analysis (GRA) and desirability function analysis (DFA) for simultaneous evaluation. These two methods are considered in optimization, as both are multiple criteria evaluation and not much complicated. The optimum process parameters found to be cutting speed at 63 m/min, feed rate at 600 mm/min, and depth of cut at 0.8 mm. Analysis of variance (ANOVA) was employed to classify the significant parameters affecting the responses. The results indicate that depth of cut is the most significant parameter affecting multiple response characteristics of GFRP composites followed by feed rate and cutting speed. The experimental results for the optimal setting show that there is considerable improvement in the process.

Key Words
AISI 304 stainless steel; end milling; surface roughness; MRR; GRA; DFA

Address
Naresh N.: Department of Mechanical Engineering, Sree Vidyanikethan Engineering College, Tirupati-517102, India

Rajasekhar, K.: Department of Mechanical Engineering, N.B.K.R. Institute of Science and Technology, Vidyanagar-524413, Nellore, India

Abstract
Stress concentration is an interesting and essential field of study, as it is the prime cause of failure of structural parts under static load. In the current paper, stress and strain concentration factors in unidirectional functionally graded (UDFGM) plate with central circular cutout are predicted by carrying out a finite element study on ANSYS APDL platform. The present study aims to bridge the lacuna in the understandings of stress analysis in perforated functionally graded plates. It is found that the material variation parameter is an important criterion while designing a perforated UDFGM plate. By selecting a proper material variation parameter and direction of material gradation, the stress and strain concentrations can be significantly reduced.

Key Words
FGM; stress concentration; FEM simulation; circular cut-out; perforated plate

Address
Vikas Dhiraj Singh, Nandit Jadvani and Kanak Kalita: Department of Mechanical Engineering, MPSTME, SVKM´s NMIMS Shirpur Campus, Dhule, Maharashtra 425405, India

Kanak Kalita: Department of Aerospace Engineering & Applied Mechanics, Indian Institute of Engineering Science and Technology, Shibpur, Howrah, West Bengal 711103, India

Abstract
KNN-based ceramics modified with small amounts of Bi4Zr3O12 (BiZ) has been synthesized using high-throughput experimentation (HTE). The results from X-ray diffraction show that for samples with base composition (K0.5Na0.5)NbO3 (KNN), the phase present changes from orthorhombic to pseudo-cubic with more than 0.2 mol% BiZ addition; for samples with base composition (K0.48Na0.48Li0.04)(Nb0.9Ta0.1)O3 (KNNLT), the phase present changes from a mixture of orthorhombic and tetragonal symmetry to pseudo-cubic with more than 0.4 mol % while for samples with base composition (K0.48Na0.48Li0.04)(Nb0.86Ta0.1Sb0.04)O3 (KNNLST), the phase present is tetragonal with < 0.3 mol% BiZ addition and transforms to pseudo-cubic with more dopant addition. The microstructures of the samples show that addition of BiZ decreases the average grain size and increases the volume of pores at the grain boundaries. The values of dielectric constant for KNN and KNNLT compositions increase slightly with BiZ addition while that for KNNLST decreases gradually with BiZ addition. The dielectric loss values are between 0.02 and 0.04 for KNNLT and KNNLST compositions while they are ˜ 0.05 for KNN samples. The resistivity values increases with BiZ addition and values in the range of 1010 ω

Key Words
KNN ceramics; high-throughput experimentation; Bi4Zr3O12; ferroelectrics; lead-free

Address
Henry. E. Mgbemere: Department of Metallurgical and Materials Engineering, University of Lagos Akoka Lagos, Nigeria

Theddeus T. Akano: Department of Systems Engineering, University of Lagos Akoka Lagos, Nigeria

Henry. E. Mgbemere and Gerold. A. Schneider: 3Institute of Advanced Ceramics, Hamburg University of Technology, Denickestrasse 15, D-21073 Hamburg, Germany


Abstract
The static analysis of the simply supported functionally graded plate under transverse load by using a new sinusoidal shear deformation theory based on the neutral surface concept is investigated analytically in the present paper. No transversal shear correction factors are needed because a correct representation of the transversal shearing strain is given. The mechanical properties of the FGM plate are assumed to vary continuously through the thickness according to a power law formulation except Poisson´s ratio, which is kept constant. The equilibrium and stability equations are derived by employing the principle of virtual work. Results are provided for thick to thin plates and for different values of the gradient index k, which subjected to sinusoidal or uniformly distributed lateral loads. The accuracy of the present results is verified by comparing it with finite element solution. From the obtained results, it can be concluded that the proposed theory is accurate and efficient in predicting the displacements and stresses of functionally graded plates.

Key Words
Functionally graded material; analytical solution; static analysis; neutral surface concept; power law formulation

Address
Rabia Benferhat,Belkacem Adim: Departement de génie civil, University Ibn Khaldoun Tiaret, BP 78 Zaaroura, 14000 Tiaret, Algerie

Tahar Hassaine Daouadji: Laboratoire de Géomatériaux, Departement de Génie Civil, University de Chlef, Algerie

Rabia Benferhat,Belkacem Adim: Laboratoire de Géomatique et Développement Durable, University Ibn Khaldoun de Tiaret, Algerie

Abstract
In an attempt to reach a balance of performances in homo-polypropylene based system, the effects of single and hybrid reinforcements inclusions comprising calcium carbonate nanoparticles (2, 4 and 6 phc) and glass fibers (10 wt.%) on the mechanical and thermal properties were investigated. Different samples were prepared by employing twin-screw extruder and injection molding machine. In morphological studies, the uniform distribution of glass fibers in PP matrix, relative adhesion between glass fibers and polymer, and existence of nanoparticles in polymer matrix were observed. PP/CaCO3(6 phc) as compared to pure PP and PP/GF had superior tensile and flexural strengths, impact resistance and deformation temperature under load (DTUL). PP/GF/CaCO3(6 phc) composite displayed comparable tensile and flexural strengths and impact resistance to neat PP, while its tensile and flexural moduli and deformation temperature under load (DTUL) were 436%, 99% and 26°C greater respectively. The maximum impact resistance was observed in PP/CaCO3(6 phc). The highest DTUL was perceived in PP hybrid nanocomposite containing 10 wt.% glass fiber and 4 phc CaCO3 nanoparticle.

Key Words
hybrid composites; homo-polypropylene; glass fiber; CaCO3 nanoparticles; mechanical and thermal behavior

Address
Mehran Parhizkar,Abbas Rezaei: Faculty of Mechanical Engineering, University of Maragheh, Maragheh, Iran

Karim Shelesh-Nezhad: Plastics and Composites Engineering Center, Department of Mechanical Engineering, University of Tabriz, Tabriz 51666-1476, Iran


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