STUDY ON FINITE DEFORMATION OF PROTEIN BUBBLE

According to the strain energy density function for finite deformation of viscoelastic material, to the relaxation function of Maxwell mode and to the deformation gradient tensor of bubble, a stress equation for finite deformation of protein bubble is derived. By using above equation and equilibrium equation of bubble, the equation describing the relation between relative deformation rate of inner radius and time is developed for the finite deformation yielded by the dynamic pressure acted on the bubble. Based on this equation, the nonlinear properties of the finite deformation, the effect of the pressure difference, the thickness and the viscosity of the film on the radial deformation of protein bubble are analyzed by numerical simulation method. The results show that, under the action of different load, the radial deformation of protein bubble is extremely nonlinear, the balance size of bubble and the time needed to reach balance state are different. Increasing the thickness and viscosity of protein film can prolong the time needed to reach balance state, and enhance the load-bearing capacity of protein bubble obviously.