Informatics Publishing Limited

K. V. Krishna Sastry ¹, V. Seshagiri Rao ², K. Palanikumar ³, R. Dhanalakshmi ⁴, Abhishek Kuravi ⁵

Affiliations
1 Sathyabama University & Professor in Mechanical Engineering, AVIT, Chennai, IN
2 Mechanical Engineering, St. Joseph’s College of Engineering, Chennai, IN
3 Srisairam Institute of Technology, Chennai, IN
4 Transmission Division, CVRDE, Chennai, IN
5 University of Texas, Austin, US

Abstract

Carbon Fibre Reinforced Carbon (CFRC) Composite material is highly used in advanced industrial sector, especially in manufacturing of space shuttles and other expensive aerospace categories. The material's significant position and its growing importance has created interest among research community about the machining technology of this special material. This paper aims at finding the experimental drilling characteristics values of C-C composite by the combination of Taguchi method and Grey theory Technique. Manufacturing of good quality products at lower cost is the main objective of the modern industrial sector, and this is obtained by using optimal methods to the manufacturing conditions. This paper discusses about the use of Grey Theory to find the optimum drilling values. The experiments were conducted by using a Titanium Nitride coated Carbide drill tool on a carbon-carbon composite material plate with CNC Drilling Machine. This paper explains and demonstrates the influence of optimal set of characteristics, such as Spindle speed, Feed and Tool angle on the Delamination factors.

Keywords

CFRC, C-C Composites, CorelDraw, Delamination, GRA, RCC, Taguchi Method

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K. V. Krishna Sastry ¹, V. Seshagiri Rao ², M. S. Kumar ³, A. Velayudham ⁴, K. Palanikumar ⁵

Affiliations
1 Sathyabama University & Department of Mech. Engg, Aarupadai Veedu Institute of Technology, Chennai, IN
2 St. Joseph's College of Engineering, Chennai, IN
3 SKR Engineering College, Chennai, IN
4 Combat Vehicles Research and Development Establishment, Chennai, IN
5 Sri Sairam Institute of Technology, Chennai, IN

Abstract

The composites are gaining significant position among various materials nowadays due to their unique features and properties. This Technological development in the materials sector has created interest among engineers and scientists to create new materials with different features and required properties. Among the various new developed materials, Carbon Fibre Reinforced Carbon (CFRC) composite material is occupying important place. This composite material is used mostly in the manufacturing of advanced structures like rockets, space shuttles, missiles, aircrafts etc. Generally these composites are very costly in nature and the addition of drilling cost of these materials makes them more costly. Hence the machining parameters are carefully selected, so that no drilling damage is caused during machining. The main objective of this paper is to find the optimal drilling parameters by using Taguchi method and the unique Grey Relational Analysis technique. The drilling experiments were carried out on a RCC composite plate with High speed steel tool on the VMC100 computer numerically controlled drilling machine, at the workshop of Anna university campus, Chennai, India.

Keywords

CFRC Composites, Orthogonal Array, Design of Experiments, GRA, Taguchi Method, VMC100 CNC Machine, RCC Composite Material.

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S. Ravikumar ¹, V. Seshagiri Rao ², S. Prakash ¹

Affiliations
1 Dept of Mech & Production Engg., Sathyabama University, Chennai, IN
2 Dept of Mech Engg., St.Joseph’s College of Engg., Chennai, IN

Abstract

This research presents the microhardness variations studies related to tool pin profiles on dissimilar joints of AA7075-T651 and AA6061-T651 aluminium alloys. The weld consolidation and quality was evaluated through observations of macro and micro structure. The microhardness variations were determined in the cross-section of the weld for different rotational and welding speeds. In all the specimens where the hardness distribution was measured, the AA7075 alloy was located at the Retreating side (RS) and the AA6061 alloy was in the Advancing side (AS). The Friction stir welded materials were joined under three different tool rotational speeds (800, 900 and 1,000 rpm) and three welding speeds (90, 100 and 110 mm/min), which are the two prime joining parameters in Friction stir welding (FSW). The axial load and the tilt angle parameters are kept constant at 12kN & 0°. Three different pin profiles (Taper cylindrical threaded, Taper square threaded and Square) tools were used to consolidate the weld in which the taper cylindrical threaded tool yields higher hardness of about 114.2 HV in the stirred zone with good mixing of these two alloys.

Keywords

Friction Stir Welding, Welding Speed, Rotational Speed, Macrostructure, Microstructure, Microhardness.

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D. Muruganandam ¹, S. Ravikumar ², V. Seshagiri Rao ³, Sushil Lal Das ⁴

Affiliations
1 Dept. of Mechanical Engg., Dhanish Ahmed College of Engg., Chennai, IN
2 Dept. of Mechanical and Production Engg, Sathyabama University, Chennai, IN
3 Dept. of Mechanical Engg., St. Joseph College of Engg., Chennai, IN
4 Jeppiaar Engg. College, Chennai, IN

Abstract

Aluminium alloys have gathered wide acceptance in the fabrication of light weight structures requiring a high strength-to weight ratio and good corrosion resistance. Modern structural concepts demand reductions in both the weight as well as the cost of the production and fabrication of materials. Therefore welding processes have proven more attractive, and there is an urgency to study their potential. Compared to the fusion welding processes that are routinely used for joining structural aluminium alloys, friction stir welding (FSW) process, an emerging solid state joining process was invented in 1991 by TWI, in which the material that is being welded does not melt and recast. The major advantage in FSW process is that the maximum temperature reached is less than 80% of the melting temperature, i.e. the joint is performed in the solid-state and excessive micro structural degradation of the weld zone is avoided. This process uses a non-consumable tool to generate frictional heat in the abutting surfaces. The welding parameters such as tool rotational speed, welding speed, axial force etc., and tool pin profile play a major role in deciding the joint strength. This paper focuses on mechanical properties evaluation and predicting the process parameters in varying rotational and welding speeds of friction-stir welding for the dissimilar precipitation hardenable aluminium alloys ie., between 6xxx (Al-Mg-Si) and 7xxx (Al-Zn-Mg).

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