International Journal of Technology and Innovation

International Research Journal of Mechanical Engineering Vol.  2 (4) pp. 114-123, April, 2014.  © International Scholars Journals

Full Length Research Paper

Optimization of weld bead geometry in gas metal arc welding process using RSM and fmincon

Shyamal Prabhakar Mittal

Department of Mechanics of Manufacturing and Production, Faculty of Mechanical Engineering, University of Rajasthan, Jaipur, India.

Email: [email protected]

Accepted 17 March, 2014

Abstract

Cladding is a surface modification process in which a specially designed alloy is surface welded in order to enhance corrosion resistant properties. Common cladding techniques include Gas Tungsten Arc Welding (GTAW), submerged arc welding (SAW) and gas metal arc welding (GMAW). Because of high reliability, easiness in operation, high penetration good surface finish and high productivity gas metal arc welding became a natural choice for fabrication industries. This paper presents central composite rotatable design with full replication techniques to predict four critical dimensions of bead geometry. The second order regression method was developed to study the correlations. The developed models have been checked for adequacy and significance. The main and interaction effects of process variables and bead geometry were presented in graphical form. Using fmincon function the process parameters were optimized.

Key words: Gas metal arc welding (GMAW), weld bead geometry, mathematical model.

International Research Journal of Mechanical Engineering Vol.  2 (4) pp. 110-113, April, 2014.  © International Scholars Journals

Full Length Research Paper

Effects of flux composition on behavior and bead geometry in submerged arc welding

Vijay E. Pradesh

Department of Mechanical Engineering, University of Hyderabad, Hyderabad, India.

Email: [email protected]

Accepted 3 March, 2014

Abstract 

Performance of a welding flux is decided by the physical and chemical properties of its constituents. The flux selected should show a good welding behavior and the required weld bead geometry. The mechanical properties of a joint are not only decided by its composition but these also depends on bead geometry, dimensions and physico-chemical properties of fluxes. These properties include surface tension, viscosity, heat capacity, thermal coefficients of expansion, grain size etc. These properties of fluxes primarily affect the flux behavior, bead shape and size, welding speed, current carrying capacity, protection of molten metal, arc stability, slag detachability, capillarity, surface tension and viscosity. Various constituents of a welding flux have major influence on the performance of welding processes and weld bead dimensions. We need to understand the physical properties and behavior of fluxes during submerged arc welding. The influence of specific flux additions on arc stability, viscosity, capillarity, slag detachability and weld bead shape need to be better characterized. It can be inferred that we cannot obtain the weld of desired geometry and composition until we consider the physico-chemical characteristics of flux like slag viscosity, surface tension, arc stability and slag detachability, capillarity and weld penetration. So, while designing the flux or during selection of welding process parameters the above characteristics should be carefully controlled or selected.

Key words: Submerged arc welding, bead width, reinforcement, weld penetration, bead morphology.

International Research Journal of Mechanical Engineering Vol.  2 (3) pp. 100-109, March, 2014. © International Scholars Journals

Full Length Research Paper

Hybrid approach for integration of systematic defensive maintenance policies in hybrid flow-shop preparating to minimize makespan

*Latifa E. Biyouna, Jean E. Dilem and Mohammed Bendjedid

Department of Industrial Engineering, University of Batna, Batna, Algeria.

Email: [email protected]

Accepted 23 February, 2014

Abstract

This paper proposes a novel hybrid algorithm for the integration of systematic preventive maintenance policies in hybrid flow shop scheduling to minimize makespan. We have implemented a problem-solving approach for optimizing the processing time and methods based on metaheuristics. The proposed approach is inspired by the behavior of the human body. This hybridization is between a multi agent system and inspirations of the human body, especially genetics. The effectiveness of our approach has been demonstrated repeatedly in this paper. The proposed approach is applied to three preventive maintenance policies. These policies are intended to maximize the availability or to maintain a minimum level of reliability during the production chain. The results show that our algorithm outperforms existing algorithms. We assumed that the machines might be unavailable periodically during the production scheduling.

Key words: Multi agent systems, emergence, genetic algorithm, makespan, systematic maintenance, scheduling, hybrid flow shop scheduling.

International Research Journal of Mechanical Engineering Vol.  2 (3) pp. 093-099, March, 2014.  © International Scholars Journals

Full Length Research Paper

An analytical study of NOx discharge on croton oil – 1-butanol – diesel in compression ignition (CI) engine

Mizengo Ali Hassan

Department of Sustainable Energy Science and Engineering, Tumaini University Makumira, Moshi, Tanzania.

Email: [email protected]

Accepted 13 February, 2014

Abstract 

Vegetable oils as fuel have received attention in recent years due to their advantages including renewable nature and domestically produced energy resources. Achieving reduced emission is important subject, as it enhances sustainability of biofuels. General factorial experimental design and analysis of variance (ANOVA) is used to analyze how NOx emission is influenced by alcohol content in vegetable oil-diesel fuel blends. Fuel samples 20% croton oil – 80% diesel (20%CRO-80%D2), 15% croton oil – 5% 1-butanol – 80% diesel (15%CRO–5%BU–80%D2), and 10% croton oil – 10% 1-butanol – 80% diesel (10%CRO–10%BU–80%D2) were investigated. Four-cylinder compression-ignition (CI) engine was run at constant speed 3000 RPM, loaded at different loading conditions: low idle as 0 to 100% load condition. The specific fuel consumption and exhaust temperature of fuel blend containing butanol was measured. It was observed that nitrogen oxides (NOx) emission decreases as percentage of butanol alcohol content increases in fuel samples.

Key words: Vegetable oil, butanol, NOx emissions, fuel blends, factorial design, analysis of variance (ANOVA).

International Research Journal of Mechanical Engineering Vol.  2 (3) pp. 087-092, March, 2014. © International Scholars Journals

Full Length Research Paper

Problems in the robot path control caused by AL-7075 chassis alteration and methods of improvement

*Farhad M. Pahlavi, Mohen B. Moshiri and Marjane Majidi

Department of Mechanics of Manufacturing and Production, Faculty of Mechanical Engineering, Allameh Tabataba'i University, Tehran, Iran.

E-mail: [email protected]

Accepted 3 February, 2014

Abstract

In the field of research and manufacturing of control surfaces in robot components using 7075-T6 aluminum alloy, distortion during/after machining occurs because of the material removal forces and residual stresses and it affects robot path control. After the exact inspections, the main factors were found to be the machining strategy parameters in milling operation. This paper first presents flatness significance of robot chassis as a control surface for accurate path control, then discusses main causes of the Al-7075-T6 distortion, and offers methods of distortion reduction in material removal process by non-conventional milling strategy and finally optimum experiment parameters have been carried out. We have concluded this paper with a review of the main findings which will set the domain of our current and future research.

Key words: Aluminum 7075 T6, distortion, control surface, robot, chassis.

International Research Journal of Mechanical Engineering Vol.  2 (2) pp. 080-086, February, 2014. © International Scholars Journals

Full Length Research Paper

An analysis into emission of a plate-fin heat exchanger with strip fins

*Farhad M. Pahlavi, Mohen B. Moshiri and Marjane Majidi

 Department of Mechanical Engineering, Allameh Tabataba'i University,Tehran, Iran.

E-mail: [email protected]

Accepted 22 January, 2014

Abstract

The objective of this study is to analyze the heat transfer by radiation in a plate-fin heat exchanger. Strip fins are employed to enhance heat transfer. Compact heat exchanger has been in use for many applications, including automobile, radiators, air-conditioning systems and electronic cooling devices. However, one of the important application of them is in microturbine cycle, where hot stream enter the heat exchanger with temperature of 950°C. So, heat transfer by radiation is important due to high temperature. However, the results show that when there is forced convection in the plate-fin heat exchanger the radiation is negligible, because of low value of the fin height and flow length.

Key words: Radiation, plate-fin heat exchanger, heat transfer coefficient, forced convection.