M Kakandikar Ganesh

Bio: M Kakandikar Ganesh is an academic researcher from Massachusetts Institute of Technology. The author has contributed to research in topics: Necking & Forming limit diagram. The author has co-authored 1 publications.

Experimental and numerical investigations on forming limit curves in micro forming

Abstract: The Forming limit diagram is an important tool in metal forming processes, as it indicates the failure limits for ductile damage and onsite necking. Forming of micro-thin metal sheets (thickness le...

Ductile fracture behavior in micro-scaled progressive forming of magnesium-lithium alloy sheet

Abstract: Micro-scaled progressive sheet metal forming is a promising process for producing bulk microparts, given its advantages of high efficiency and low cost. To enhance forming quality and efficiency, it is important to have an in-depth understanding of the forming mechanism and model the forming process and fracture behavior accurately. However, the prediction of fracture formation in sheet materials at the micro-scale has not yet been well explored, and thus current knowledge is not sufficient to support the continued development and application of microforming technology. This study investigated progressive sheet forming of magnesium-lithium alloy sheets of different grain sizes to produce bulk microparts directly from sheet metal via shearing, extruding, piercing, and blanking. Using the Gurson–Tvergaard–Needleman (GTN) damage model, the effects of the size factor on the formation and evolution of voids were considered, and the shear-modified GTN model was established by combining Thomason’s and Lemaitre’s damage mechanics models. The modified model could predict not only the ductile fracture behavior dominated by tension under high-stress triaxiality at the micro-scale, but also the damage behavior controlled by shear deformation under low-stress triaxiality. The progressive forming process was simulated using the modified model, which was verified by experimentation and simulation. Comparisons of the experiments and simulations revealed the size effects on the forming defects and fracture behaviors of microparts during progressive sheet forming. The results show that the stress during deformation is mainly concentrated at the edge of microparts, and irregular geometric defects including burr, rollover, incline, and bulge become deteriorated with the increase of the initial grain size. This study enhances the understanding and prediction of ductile fracture in the micro-scaled progressive forming of sheet metals.

Formability Assessment with Microstructural Investigations for Zirconium 702 Thin Foils: Bio-Material Applications

Abstract: ABSTRACT Application of Zirconium alloys for biomedical applications have received increasing attention. Unique properties like formation of an internal bone-like apatite layer and also the interaction with magnetic resonance imaging (MRI) diagnostics with better compatibility, low magnetic susceptibility and overall excellent biocompatibility, mechanical properties and resistance to biocorrosion. Forming process is plastic deformation process wherein material undergoes permanent deformation in die cavity without fracture. Local necking, wrinkling, cracking, earing etc are few of observed errors. Due to miniaturization, manufacturing at micro level is essential. Micro forming is difficult to control as thickness of foil is below 100 microns. Hence, investigation and prediction of mechanical properties of the material at micro-level plays a very vital role. The current research focusses on the forming limit curves (FLC), which is one of the way of investigation performed to predict the formability of the material Zirconium 702 (Zr702) with the sheet thickness 100 microns. Nakajima test as per the ASTM 2218–14 standards was applied. Numerical and Experimental FLCs arrived at shows good concordance. Micro-structural study is also performed on the test specimen before and after forming to analyse the behaviour of the material.

Micro Forming and its Application: A Critical Review

Abstract: : In terms of manufacturing methods/processes, micro-manufacturing has received a lot of attention around the world. Micro-forming is one of the most widely used micro-manufacturing techniques. The micro forming is based on the properties of materials based on the process of shaping parts and object by mechanical deformation. Many efforts had been focused on micro-forming, in particular the deep drawing process, because of the method's ability to produce an extensive variety of products, particularly in its conventional macro-process. This method is used to create the majority of everyday items. Although efforts were made to develop micro-forming for industrial use, the technique was deemed to be insufficiently advanced. Much development effort was required, in particular, to design a completely computerized high-extent production micro-forming machine that is dependable and ready to perform always in terms of procedures, material handling, and tooling to assure effective micro-product production. Micro forming, which is discussed in this work, is also one of the often-used micro-forming methods in deforming procedures. Finally, in addition to continuing to improve micro forming, this study aims to investigate the essential methods of the Limit dome height test, Nakajima test, M K Model test, and deep drawing processes and their major concerns in a systematic manner.

Formability Assessment with Microstructural Investigations for Zirconium 702 Thin Foils: Bio-Material Applications

Abstract: Application of Zirconium alloys for biomedical applications have received increasing attention. Unique properties like formation of an internal bone-like apatite layer and also the interaction with magnetic resonance imaging (MRI) diagnostics with better compatibility, low magnetic susceptibility and overall excellent biocompatibility, mechanical properties and resistance to biocorrosion. Forming process is plastic deformation process wherein material undergoes permanent deformation in die cavity without fracture. Local necking, wrinkling, cracking, earing etc are few of observed errors. Due to miniaturization, manufacturing at micro level is essential. Micro forming is difficult to control as thickness of foil is below 100 microns. Hence, investigation and prediction of mechanical properties of the material at micro-level plays a very vital role. The current research focusses on the forming limit curves (FLC), which is one of the way of investigation performed to predict the formability of the material Zirconium 702 (Zr702) with the sheet thickness 100 microns. Nakajima test as per the ASTM 2218–14 standards was applied. Numerical and Experimental FLCs arrived at shows good concordance. Micro-structural study is also performed on the test specimen before and after forming to analyse the behaviour of the material.