Experimental Study On Frictional Properties Of Human Skin

In daily life, human skin always touches various materials, bringing in a lot of skin frictions. Studying on frictional properties of human skin is very important to reduce the hand and foot injuries caused by friction, increase the comfort of clothes, develop high-quality cosmetics and guide clinic skin-related issue. Besides, studying on frictional properties of human skin is a kind of way of study on the skin difference in various anatomical regions and persons.In this thesis, I improved the FS-â…¡portable skin friction tester, added the sensor protector, guide wheel, marking film and others to the tester. Because this tester is flexible, easy to use, and a wide range of applications, it can not only test the friction coefficients of human upper limbs skin, but also forehead, face, and other anatomical regions.In this thesis, I tested the friction coefficients of the hunman skin for 60 healthy volunteers before and after cosmetic application, and 40 volunteeers with ance by FS-â…¡portable skin frictional tester, and quantitativly studied the effects of normal load, sliding speed, gender, anatomical regions, cosmetic and health condition on frictional properties of human skin. Statistical analysis and orthogonal design were used in data analysis. The results show that: the friction coefficient didn't have general relationship with normal load and sliding speed while normal load ranges from 0.2 to 1.2N and sliding speed ranges from 10 to 60mm/s; The individual differences in friction coefficients of forehead, extensor and flexor aspect of arm, and dorsum are relatively lower than those of cheek and palm; The friction coefficients of cheek and palm of female are much higher than those of male(P<0.05), but the friction coefficients of both extensor and flexor aspect of arm of female are much lower than those of male(P<0.05), friction coefficients of forehead and dorsum manus show no significant differences between the genders (P>0.05); The friction coefficients are clearly different among anatomical regions (P>0.05), the anatomical regions with the highest to the lowest friction coefficients list as: cheeks>palm>forehead>dorsum manus>flexor aspect and extensor aspect of arm for both male and female; The application of cosmetics significantly decreases the friction on cheek, forehead and palm (P<0.05), but the application increases the friction on dorsum manus, both extensor and flexor aspect of arms; The significant differences in friction coefficient between healthy volunteers and volunteers with acne appeared on different anatomical regions; Orthogonal design shows that influence factors, according to the degree of influence to skin friction coefficient, follow a list as anatomical regions>gender>normal load>healthy condition; According to the analysis of the orthogonal layout on the influence of factors, the importance of the factors follows the list as (1) anatomical regions>gender>normal load>healthy condition (2) interaction between anatomical regions and cosmetic condition>anatomical regions>cosmetic condition>normal load>interaction between normal load and cosmetic condition.