  Experimental and theoretical observations have agreed that the onset of
cavitation in soft materials requires higher tensile pressure than pure water.
The extra tensile pressure is required since the cavitating bubble needs to
overcome the elastic energy in soft materials. In this manuscript, we have
developed two models to study and quantify the extra tensile pressure. In the
first approach, we proposed a strain energy based random fiber network (RFN)
failure criteria in which interaction between the cavitating bubble and RFN is
considered. Gelatin samples are prepared for different concentrations, and SEM
images are used to study the microstructural properties of the RFN. A unit-cell
model is introduced to evaluate the geometrical and mechanical properties of
the RFN. The network strain energy formulation is then coupled with the bubble
growth, and the critical condition is set as the fibers ultimate failure
strain. We considered soft materials as homogeneous hyper-elastic Ogden
material, and fracture-based failure criteria are proposed in the second
approach. The critical energy release rate is considered for quantifying the
extra tensile pressure. Both the models are then compared with the existing
cavitation onset criteria of rubber like materials. The validation is done with
the experimental results of threshold tensile pressure for different gelatin
concentrations. We have found that due to the large distribution of the pore
size in the network, the nucleation pressure is similar to water. Both models
can moderately predict the extra tensile pressure within the intermediate range
of gelatin concentrations. For low concentration, the network's non-affinity
plays a significant role and must be incorporated. On the other hand, for
higher concentrations, the entropic deformation dominates, and strain energy
formulation is not adequate.
