小肠的结构及边界润滑模型建立

为了实现内窥镜的无损诊治,提高肠道机器人的行走能力,需构建肠道的结构模型和边界润滑模型.本文以小肠为研究对象,表征了其内部结构,测定了肠道内表面摩擦系数与径向应变、载荷和滑动速度之间关系.结果表明:小肠内表面结构由皱襞、绒毛和微绒毛组成;直径变化是影响其摩擦的首要因素,其次是滑动速度和载荷.运用薄膜理论,根据小肠内部结构特征和摩擦系数的变化规律,构建其结构模型及边界润滑模型,并推断出小肠收缩状态润滑形式为流体动压润滑,摩擦阻力主要由肠黏液表面剪切力决定,膨胀时,润滑形式为薄膜润滑,摩擦阻力由肠黏液表面剪切力、绒毛产生的约束力和吸附力决定.

The Structure and Boundary Lubrication Model of Small Intestine

In order to realize nondestructive diagnosis and treatment of endoscope, to improve the walk ability of intestine robot, the structure and boundary lubrication models of intestine need establishing. The small intestine acted as the research object in the paper. We characterized the inner structures and determined the relationships between friction coefficient and diameter, load and sliding velocity. The results show that the small intestine inner structures consisted of plica, villus and micro-villus. The importance of the main factors affecting the friction coefficients were the diameter, the movement velocity and the load in the order. On the basis of inner structures and the variation of friction coefficient of small intestine, the structure and boundary lubrication model were established using the film theory. The lubrication regime was hydrodynamic lubrication when intestine was in contracts. The friction resistance was mainly determined by the shear strength of the mucus rather than load and sliding velocity. The lubrication regime was film lubrication when intestine expanded, and changing load and sliding velocity varied friction. The friction resistance mainly included the shear strength of the mucus, the mechanical resistance and the absorptive force.