Pulsating strains

Pulsating strains are modelled analytically using a continuum model with a well defined heterogeneous rheology. The mechanical continuum comprises single circular cylindrical inclusions of isotropic homogeneous viscosity hosted in a less viscous matrix. The analysis concentrates on the behaviour of the competent inclusion and demonstrates that the progressive deformation of the inclusion is entirely controlled by its viscosity ratio to the host and the orientation of the far field stress. The rate of deformation is determined by the stress magnitude and the viscosity of the inclusion, but does not affect the deformation path followed. An extreme case is provided by pure shear deformations where, by definition, the shear rate vanishes from the deformation tensor. Vorticity will then be zero, and strains will develop coaxially without pulsation.