CAVITATION INSTABILITY IN RUBBER

Abstract

Rubber materials and structures can fracture because tensile deformation and growth of small pre-existing voids become unstable, leading to failure localization and crack propagation. Thus, it is important to predict the onset of static instability of the growing voids. We consider two typical cases of interest: the instability of 3D voids under the remote hydrostatic tension in the bulk and the instability of 2D voids under the remote biaxial tension in the membrane. For the purpose of analysis, we use constitutive models of natural and styrene-butadiene rubbers with the failure description enforced by energy limiters. The limiters provide the saturation value for the strain energy which indicates the maximum energy that can be stored and dissipated by an infinitesimal material volume. We find that the unstable growth of a 3D bulk void can start when the remote hydrostatic tension reaches the value of ~2 ÷ 3 MPa and the unstable growth of a 2D membrane void can start when the remote biaxial tension reaches the value of ~50 ÷ 60 MPa.