【作者】 李炜；

【导师】 周仲荣；

【作者基本信息】 西南交通大学 ， 机械设计及理论， 2007， 博士

【摘要】 在日常生活中，人体皮肤离不开与周围环境的摩擦接触，从而产生许多皮肤摩擦学问题。全面了解和掌握皮肤的摩擦学特性对于劳动生活用品和生物医疗器械的开发、皮肤摩擦损伤的防止及皮肤摩擦接触舒适性的改善具有很重要的理论意义和现实意义。本文在UMT-Ⅱ多功能摩擦磨损试验机和自制的ST-1型往复滑动皮肤摩擦试验机上，采用球—面和面—面两种接触模式，对人体天然健康皮肤、疤痕皮肤和动物皮肤进行了在体摩擦试验。使用激光共聚焦扫描显微镜（LCSM）、光学显微镜（Leica，DM RX）和红外热像仪(ThermaCAM^TME30)等设备对皮肤表面轮廓、组织结构和生理反应等进行了详细的观察和分析。从摩擦学、生物学、材料学和生物力学等多学科交叉角度系统地研究了皮肤的往复摩擦行为、损伤机制和舒适度感觉。得到的主要结论如下：1．皮肤在不同往复滑动摩擦条件下可得到平行四边形、椭圆形和半闭合形三种F_t-D曲线，该三种F_t-D曲线与皮肤的应力—应变曲线有关。根据F_t-D曲线形状的不同，皮肤的摩擦运行状态可分为相对滑移区、中间过渡区和粘着区。随着法向载荷增大或往复位移幅值减小，位移协调主要以皮肤弹性变形为主，摩擦系数逐渐减小。在位移和法向载荷不变时，随着频率增加，皮肤摩擦运行状态的相对滑移区逐渐向中间过渡区扩展，中间过渡区向粘着区扩展；摩擦系数在中间过渡区随频率增加逐渐增大，在相对滑移区和粘着区没有显著变化。根据皮肤在摩擦过程中的疼痛感、牵扯感和灼热感等感觉提出皮肤摩擦舒适度表征参量。皮肤最不舒适的感觉和最容易发生损伤的区域是在相对滑移和粘着区之间的中间过渡区。此外，皮肤在摩擦过程中会产生弹性变形、压痕、发热及损伤等生理反应。2．摩擦工况对兔皮肤表面损伤程度及皮肤组织病理性变化存在显著影响。随着法向载荷及频率的增加，往复摩擦对活体兔皮肤表面造成的损伤程度增大，皮下组织内的病理性反应程度加重。兔皮肤表面的摩擦系数随着法向载荷及频率的增加而减小；在整个摩擦过程中，摩擦系数随着摩擦时间的延长而减小，直到达到有组织液参与润滑的稳定状态。3．自然因素对人体皮肤的摩擦特性有显著影响。人体皮肤的摩擦特性与年龄密切相关，随着年龄增长，同一个体不同解剖部位皮肤之间的摩擦特性差异逐渐减小，不同年龄个体同一解剖部位皮肤的摩擦特性会有显著差异。同年龄段的人体皮肤摩擦特性在性别之间无显著差异。汗液通过改变皮肤表面的物理化学性能而对其摩擦学行为产生影响，在汗液逐渐干燥的过程中，皮肤的摩擦运行状态从粘着向相对滑移状态转变，摩擦系数的变化经过从小到大再减小的过程，最后达到稳定值。4．残肢疤痕皮肤、正常皮肤和穿戴假肢皮肤在摩擦性能和舒适度感觉方面存在明显差别。由于皮肤结构的改变，疤痕皮肤在干态和汗液环境中的摩擦系数均大于正常皮肤和穿戴假肢皮肤；在正常皮肤的中间过渡状态和粘着状态，疤痕皮肤的Ft-D曲线会转换成平行四边形，皮肤表面有间歇的相对滑动，造成了摩擦系数波动显著。疤痕皮肤和正常皮肤对因摩擦造成的不适感觉较敏感，穿戴假肢皮肤的耐受性最强。与干燥的假肢穿戴环境相比，汗液增强了皮肤的不舒适感。更多还原

【Abstract】 In everyday life, human skin often rubs on other external surfaces, which has caused many friction problems. Understanding the tribology property of the skin would help to develop living and working implements and biomedical devices, avoid frictional trauma and improve comfortness of the skin.Normal healthy human skin, scar skin and rabbit skin have been tested in vivo under ball-on-flat and flat-on-flat contacts using an UMT- II multi-specimen Biomedical Micro-Tribometer and a homemade ST-1 reciprocal sliding skin friction testing apparatus. The detailed observations and analysis of the skin surface profile, histological structure and physiological response were conducted by using laser confocal scanning microscope （LCSM）, optical microscope （Leica, DM RX） and infrared thermal imagers (ThermaCAM^TM30). The friction behaviour, trauma mechanisms and comfortless sensations were investigated by means of tribology, biology, histology and biomechanics. Main conclusions are drawn as follows:1. Three kinds of F_t-D curve: the quasi-closed, elliptic and parallelepipedic cycles have been obtained under different experimental conditions, which were related with the stress-strain law of the human skin. The friction behaviour of skin consisted of three friction regimes: relative sliding regime, intermediate friction regime and sticking regime depending upon three kinds of F_t-D curve. The accommodation of elastic deformation by the skin appeared to be important at the high normal force or low imposed displacement. The friction coefficient increased as the imposed displacement increased or the normal force diminished. The relative sliding zone extended to the intermediate zone and meanwhile, the intermediate zone extended to the sticking zone when the frequency increased and the imposed displacement and normal force remained the same. The friction coefficient increased as the frequency increased in the intermediate friction regime, and had no remarkable change in the relative sliding and sticking regimes. An evaluating indicator of comfortness sensations of the skin concerning the pain, drag and heat has been proposed and investigated. The volunteer felt that it was the most discomfort at the intermediate friction regime from sticking to relative sliding regime. Furthermore, the physiological responses of elastic deformation, friction mark, rubbing heat and traumas occurred on the skin during testing.2. The friction conditions showed remarkable effects on the skin traumas grade and pathological reactions. The inflammatory reactions of the rabbit subcutaneous traumatic tissue caused by reciprocating friction on rabbit skin enhanced with increasing normal load and reciprocal sliding frequency, which aggravated the traumas on the rabbit skin. The friction coefficients of rabbit skin decreased with increasing normal load and reciprocal sliding frequency. In every process of testing, the friction coefficients decreased with frictional time until reaching lubricative stabilization that the extravasation participated.3. The natural differences of the body had different effects on the skin frictional properties. The skin frictional properties were strongly dependent on the age. The differences of friction coefficients at the different anatomical regions became negligible with the increasing of age. The friction coefficients of different ages at the same anatomical regions had significant differences. The skin frictional properties of different gender at the same anatomical region and age have no significant differences. The artifical perspiration had an effect on the friction behaviour of skin by modifying the physicochemical properties of skin surface. The friction behaviours transited from sticking regime to relative sliding regime in the process of the perspiration drying out. The friction coefficient changed from small to peak value, then decreased until reaching stabile value.4. The tribology properties and comfortless sensations differed remarkably between scar skin of residual limb, healthy skin and wearing prosthetic socket skin. The friction coefficient of the scar skin was bigger than the two other skins. The F_t-D curve of the scar skin changed to parallelepipedic cycle and the friction behaviour had intermittent relative slide in the intermediate friction regime and sticking regime of the healthy skin, which resulted in the friction coefficients fluctuate markedly during testing. The scar and healthy skins were sensitive to the comfortless sensations induced by rubbing. The wearing prosthetic socket skin was tolerant to the comfortless sensations. The perspiration caused more comfortless sensations to the volunteers comparing with the dry prosthetic socket condition.更多还原