- Pavel KrejĨi, Academy of Sciences of the Czech Republic, Czech Republic 
 
"Dynamic contact of elastoplastic bodies treated as a system of equations 
with hysteresis operators"
A classical mathematical approach to contact problems consists in applying 
different variants of the penalty method, with the intention to let the 
penalty parameter tend to infinity. Here instead, in the case of an 
elastoplastic body in contact with an elastoplastic obstacle, we propose to 
reformulate the problem equivalently as a PDE with hysteresis operators both 
in the constitutive law and in the contact boundary condition. Analytical 
properties of the hysteresis  operators (Lipschitz continuity in suitable 
function spaces, monotonicity, energy inequalities) enable us to construct a 
regular solution by conventional methods and prove its uniqueness and 
continuous data dependence. The hysteresis dissipation terms then appear as 
sources of heat in the bulk and on the boundary in the energy balance. Under 
appropriate
assumptions, the resulting non-isothermal system of momentum and 
energy balance equations then turns out to be well-posed, too. 
This is a 
joint work with Adrien Petrov, INSA Lyon.