蛋白质气泡有限变形研究

根据粘弹性材料有限变形的应变能密度函数、Maxwell模型的松弛函数及气泡的变形梯度张量,推导出蛋白质气泡有限变形的应力方程。并结合气泡的平衡方程,得到气泡在动态压力作用下有限变形时内径相对变化率随时间变化的表达式。运用该表达式,通过数值模拟方法,对蛋白质气泡有限变形的非线性特性、径向变形随气泡内外压力差、膜的厚度以及膜的粘性的变化规律进行了计算分析。结果表明:在不同载荷作用下,蛋白质气泡径向变形不但具有明显的非线性特性,而且气泡变形达到平衡时的变形大小和时间也不相同。增加气泡膜的厚度和膜的粘性既可以延长气泡变形达到平衡的时间,又可以大大增强气泡承受载荷的能力。

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.