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Siva P V Nadimpalli, Ph.D

PROFESSIONAL EXPERIENCE

Design Engineer in Wind Energy group (14th March 2005- August 11th, 2006)

General Electric India Pvt. Ltd. Bangalore (GE India)

Worked on several projects, the work involves performing aero-elastic simulations of wind turbines to find out their response under a given wind loading conditions and assessing their fatigue life. Apart from this I have also completed a project in which I performed a validation study of the theoretical models used for fatigue life prediction, using experimental data obtained from prototype wind turbines. Also,  I  developed a Matlab GUI for post processing the results of in house codes.

Research Intern (June 2003- August 2003)
Title: Strain Localization, Void Formation and Failure in 6063 aluminium alloy

Supervisor: Dr. Raj K. Mishra

Research conducted at General Motors Research and Development Center, Warren, MI, USA

Research work involves study of localization of damage and void formation in 6063-T4 aluminium samples using optical and electron microscopy combined with numerical and image analysis.  These aluminum samples are tested in an Instron machine before conducting SEM study on them and polished well to enable efficient SEM imaging. The objective of this study is to establish a relation between the equivalent plastic strain and void evolution. Also, experimental determination of forming limit diagram from burst tubes of Aluminium alloy was carried out.

RESEARCH EXPERIENCE

Research Assistant, University of Toronto (Aug, 2006- till date)
Title: Failure load prediction of solder joints  in microelectronic packages

Academic supervisor: Prof. Jan. K. Spelt

Financial support and project guidance from:

• Celestica Inc., Toronto, Ontario, Canada
• Research in Motion Inc. (RIM), Waterloo, Ontario, Canada
• Ontario Centers of Excellence (OCE)
• Natural Sciences and Engineering Research Council of Canada (NSERC)

Solder joints play an important role in microelectronic devices. These devices include circuit boards that are used in aircraft controlling devices etc. Hence, they should have high reliability. The main concern in microelectronic devices is the failure of solder joints due to thermal fatigue and fracture. Significant amount of research was dedicated to thermal fatigure problems, but the solder fracture due to mechanical loads was not studied extensively. The objective of this project is to understand the mixed-mode fracture behavior of solder joints to establish failure prediction methodology for solder joints.

 
Research Assistant, Indian Instirtue of Science, Bangalore, India (2002- 2005)
Title: A numerical study of localized necking during forming of aluminium alloy tubes using a continuum damage model

Academic supervisor: Prof. R. Narasimhan

Financial support from: General Motors Corporation (GM),  MI,  USA

The objectives of this work are, to characterize the mechanical response and failure behaviour due to localized necking, of Al-Mg alloy tubes, under two different free hydroforming processes. Here, the Gurson continuum damage accumulation model is employed along with the Marciniak--Kuczynski (M-K) formulation to predict localized necking. Also, the nature of strain paths experienced by the tube corresponding to the above processes and their influence on the peak pressure and forming limit strains are studied. Finally, the tube deformation in rotary draw bending is briefly examined.

This study includes a series of tube bursting experiments to determine the forming limits experimentally. I enriched my knowledge in finite element modeling, plasticity theory, damage modeling and mechanical testing, while working in this project.