静脉壁的力学特性及负压失稳问题

Mechanical Performance and Negative Pressure Instability for Venous Walls

应用一类超弹性应变能函数,通过非线性弹性理论,研究了静脉壁在跨壁压及轴向拉伸联合作用下的变形和应力分布等力学特性,并分析了静脉壁的负压失稳问题.首先利用超弹性材料薄壁圆筒模型,得到了静脉壁在跨壁压及轴向拉伸联合作用下的变形方程,给出了正常静脉压下静脉壁的变形曲线和应力分布曲线,讨论了静脉壁的变形和应力分布规律.然后给出了负跨壁压下静脉壁的变形曲线,并由能量比较讨论了静脉壁的负压失稳问题.

Mechanical properties,such as the deformation and stress distributions for venous walls under the combined loadings of transmural pressure and axial stretch were examined within the framework of nonlinear elasticity with one kind of hyper-elastic strain energy function.The negative pressure instability problem of the venous wall was explained through energy comparison.The deformation equation of the venous wall under the combined loads was obtained with a thin-walled circular cylindrical tube at first.The deformation curves and the stress distributions for the venous wall were given under the normal transmural pressure,and the regulations were discussed.Then,the deformation curves of the venous wall under negative transmural pressure,or when the internal pressure was less than the external pressure,were given.Finally,the negative pressure instability problem was discussed through energy comparison.