User:Muna27

JAGADISH KUMAR, MATERIALS RESERCH CENTRE, INDIAN INSTITUTE OF SCIENCE BANGALORE -560012

RESEARCH INTREST:

Peeling of an Adhesive Tape:

Peeling is a kind of fracture that is important in the context of adhesion and falls into stick-slip systems like the PLC effect, i.e., measured force-velocity curve shows an unstable branch. The problem of peeling of an adhesive tape has been experimentally well studied for a long time but the equations of motion are beset with controversy as these do not produce stick-slip jumps. This has been resolved by showing that the equations of motion fall into the category of differential-algebraic set of equations and hence are singular requiring a special algorithm meant to solve differential algebraic equations. Once this method is used, the dynamical jumps follow naturally. Several experimental features are also explained. It turns out that the kinetic energy of stretched tape is missing and when it is included, the singular nature is lifted and natural stick-slip jumps follow. By including additional dissipative energy that mimics acoustic emission, the contact line dynamics is studied. Many features of acoustic emission automatically follow as also other experimental features such as the stuck-peeled configuration of the peel front. The model predicts chaotic dynamics in the mid range of pull velocities. The existence of chaotic dynamics has been verified though time series analysis of the acoustic emission signals.