Ramarathnam Narasimhan obtained the BTech (Mechanical Engineering) (1982) from IIT Madras, MS and PhD (1986) in Applied Mechanics both from the California Institute of Technology. He was Postdoctoral Fellow at Caltech (1987). His doctoral and postdoctoral work, carried out under the supervision of AJ Rosakis, focused on crack initiation and growth in elastic-plastic solids. In particular, he studied for the first time three-dimensional effects on elastic-plastic crack tip fields and observed that such effects are dominant at a distance of half the specimen thickness from the crack front. After returning to India in 1987, he worked for four years at IIT, Mumbai before joining Indian Institute of Science (IISc), Bangalore where he is now Professor, Mechanical Engineering.
Academic and Research Achievements: Narasimhan's areas of interest relate to fracture behavior of solids such as mixed-mode fracture, dynamic ductile crack initiation, fracture of pressure sensitive materials and amorphous alloys. His numerical simulations showed the competition between micro-void coalescence and shear localization near a crack tip under mixed-mode (combined tension and shear) loading. He demonstrated that ductile fracture processes are retarded at high loading rates, particularly in strain rate sensitive plastic solids. He showed that acute reduction in stress triaxiality can occur near a crack tip in a ductile solid when subjected to stress wave loading. He proposed a simple dynamic crack initiation model based on the above fundamental observation which holds the key for understanding hitherto unexplained phenomena such as increased fracture toughness of engineering materials at high rates of loading. He revealed several interesting aspects about mechanics of deformation and fracture of thin, hard films bonded to soft substrates during nanoindentation. He proposed a modified expanding cavity model which can accurately predict the indentation response of pressure sensitive plastic solids such as polymers and metallic glasses. He also carried out in-depth studies on fracture response of metallic glasses and ductile single crystals. He has guided about 17 MSc and PhD students and also taught courses on solid mechanics, finite element methods and fracture mechanics to both undergraduate and postgraduate students.
Other Contributions: Professor Narasimhan served on the Science and Engineering Research Council of DST. He has been on the Editorial boards of Engineering Fracture Mechanics and Current Science and also International Journal of Fracture (Regional Editor).
Awards and Honours: Professor Narasimhan received several awards, notably the Rudolph Kingslake Medal of the SPIE, SS Bhatnagar Prize and the Rustom Choksi Award for Excellence in Research in the Engineering from the IISc. He was elected Fellow of the Indian Academy of Sciences, Bangalore and the Indian National Academy of Engineering.