Materials such as glasses (colloidal and molecular) and chemically reacting systems, which are thermodynamically out of equilibrium, undergo evolution of its structure and therefore properties as a function of time. Owing to time dependency, such class of materials do not obey fundamental principles of linear viscoelasticity. We show that by transforming the linear viscoelastic framework from the real time domain to the effective time domain, wherein the material clock is readjusted to account for evolution of relaxation time, fundamental principles of linear viscoelasticity can be applied to the time dependent materials. In this talk, we will discuss successful validation of the Boltzmann superposition principle, the convolution relation, and the Fourier transform relation for creep compliance and stress relaxation modulus for different types of time dependent materials in the effective time domain.
This is a weekly series of informal talks given primarily by members of the soft condensed matter and statistical mechanics groups, but is also open to members of other groups and external visitors. The aim of the series is to promote discussion and learning of various topics at a level suitable to the broad background of the group. Everyone is welcome to attend..