Many phenomena of scientific and technological interest are described by the evolution of free boundaries or free discontinuities. Examples include the peel front while peeling an adhesive tape, the rupture front of earthquakes, dislocations in solids and the crack set during fracture. This evolution takes place in a heterogeneous medium where the length-scale of the heterogeneities are much smaller than the length scale of the overall phenomena and we are interested in understanding the overall or effective behavior. This effective behavior is not characterized by averaging, but instead dominated by critical events. Thus, the effective behavior can be qualitatively different from the local behavior. This makes such problems difficult to study, but also offers opportunities for exploiting heterogeneities to dramatically material properties. This talk will discuss the underlying issues with examples drawn from fracture, friction, dislocation dynamics, phase boundary propagation and peeling of adhesive tape.
Kaushik Bhattacharya is Howell N. Tyson, Sr., Professor of Mechanics and Professor of Materials Science as well as the Vice-Provost at the California Institute of Technology. He received his B.Tech degree from the Indian Institute of Technology, Madras, India in 1986, his Ph.D from the University of Minnesota in 1991 and his post-doctoral training at the Courant Institute for Mathematical Sciences during 1991-1993. He joined Caltech in 1993. He has held visiting positions at Cornell University (1988), Heriot-Watt University in Scotland 1992), Max-Planck-Institute at Leipzig (1997-98), Isaac Newton Institute at the University of Cambridge (1999), Indian Institute of Science at Bangalore (2001) and the Jet Propulsion Laboratory (2006) and the University of Cambridge (2008-09). He has received the Warner T. Koiter Medal of the American Society of Mechanical Engineering (2015), Graduate Student Council Teaching and Mentoring Award at Caltech (2013), Young Investigator Prize from the Society of Engineering Science (2004), the Special Achievements Award in Applied Mechanics from the American Society of Mechanical Engineers (2004) and the National Science Foundation Young Investigator Award (1994). He was Editor of the Journal of the Mechanics and Physics of Solids (2004-2015). He has delivered numerous plenary, keynote and named lectures including the Midwest Mechanics Lecturer for 2006-07, Southwest Mechanics Lecturer for 2007-08 and Spanish Mechanics Lecturer in 2013.