The application of tribological knowledge is not just restricted to optimizing mechanical and chemical engineering problems.In fact,effective solutions to friction and wear related questions can be found in our everyd...The application of tribological knowledge is not just restricted to optimizing mechanical and chemical engineering problems.In fact,effective solutions to friction and wear related questions can be found in our everyday life.An important part is related to skin tribology,as the human skin is frequently one of the interacting surfaces in relative motion.People seem to solve these problems related to skin friction based upon a trial-and-error strategy and based upon on our sense for touch.The question of course rises whether or not a trained tribologist would make different choices based upon a science based strategy?In other words:Is skin friction part of the larger knowledge base that has been generated during the last decades by tribology research groups and which could be referred to as Science Friction?This paper discusses the specific nature of tribological systems that include the human skin and argues that the living nature of skin limits the use of conventional methods.Skin tribology requires in vivo,subject and anatomical location specific test methods.Current predictive friction models can only partially be applied to predict in vivo skin friction.The reason for this is found in limited understanding of the contact mechanics at the asperity level of product-skin interactions.A recently developed model gives the building blocks for enhanced understanding of friction at the micro scale.Only largely simplified power law based equations are currently available as general engineering tools.Finally,the need for friction control is illustrated by elaborating on the role of skin friction on discomfort and comfort.Surface texturing and polymer brush coatings are promising directions as they provide way and means to tailor friction in sliding contacts without the need of major changes to the product.展开更多
Friction between two contacting surfaces is studied extensively.One of the k n o w n friction theories is Amontons,law which states that the friction force is proportional to the normal force.However,Amontons7 law has...Friction between two contacting surfaces is studied extensively.One of the k n o w n friction theories is Amontons,law which states that the friction force is proportional to the normal force.However,Amontons7 law has been found to be invalid for elastomers.In the present study,the validity of Amontons7 law for short-cut aramid fiber reinforced elastomers is studied.Two types of fillers are used to reinforce the elastomers,namely highly dispersible silica and short-cut aramid fibers.Short-cut aramid fibers with two different surface treatments are used,namely non-reactive fibers with standard oily finish(SF-fibers)and fibers treated with an epoxy coating(EF-fibers).A pin-on-disc tribometer is used to investigate the frictional behavior of the composites in sliding contact with a granite counter surface.The results show that,after the run-in phase,Amontons,law is valid for those composites that are reinforced by short-cut aramid fibers(without reinforcing filler,i.e.,silica)if the contact pressure is below a threshold value.However,once the contact pressure exceeds this threshold value,Amontons'law will be invalid.The threshold contact pressure of the composites containing EF-fibers is higher than of the composites containing SF-fibers.The composites that are reinforced by silica and short-cut aramid fibers do not follow Amontons7 law.展开更多
文摘The application of tribological knowledge is not just restricted to optimizing mechanical and chemical engineering problems.In fact,effective solutions to friction and wear related questions can be found in our everyday life.An important part is related to skin tribology,as the human skin is frequently one of the interacting surfaces in relative motion.People seem to solve these problems related to skin friction based upon a trial-and-error strategy and based upon on our sense for touch.The question of course rises whether or not a trained tribologist would make different choices based upon a science based strategy?In other words:Is skin friction part of the larger knowledge base that has been generated during the last decades by tribology research groups and which could be referred to as Science Friction?This paper discusses the specific nature of tribological systems that include the human skin and argues that the living nature of skin limits the use of conventional methods.Skin tribology requires in vivo,subject and anatomical location specific test methods.Current predictive friction models can only partially be applied to predict in vivo skin friction.The reason for this is found in limited understanding of the contact mechanics at the asperity level of product-skin interactions.A recently developed model gives the building blocks for enhanced understanding of friction at the micro scale.Only largely simplified power law based equations are currently available as general engineering tools.Finally,the need for friction control is illustrated by elaborating on the role of skin friction on discomfort and comfort.Surface texturing and polymer brush coatings are promising directions as they provide way and means to tailor friction in sliding contacts without the need of major changes to the product.
基金This work is part of the Research Program of the Dutch Polymer Institute DPI,The Netherlands(Project No.#782).
文摘Friction between two contacting surfaces is studied extensively.One of the k n o w n friction theories is Amontons,law which states that the friction force is proportional to the normal force.However,Amontons7 law has been found to be invalid for elastomers.In the present study,the validity of Amontons7 law for short-cut aramid fiber reinforced elastomers is studied.Two types of fillers are used to reinforce the elastomers,namely highly dispersible silica and short-cut aramid fibers.Short-cut aramid fibers with two different surface treatments are used,namely non-reactive fibers with standard oily finish(SF-fibers)and fibers treated with an epoxy coating(EF-fibers).A pin-on-disc tribometer is used to investigate the frictional behavior of the composites in sliding contact with a granite counter surface.The results show that,after the run-in phase,Amontons,law is valid for those composites that are reinforced by short-cut aramid fibers(without reinforcing filler,i.e.,silica)if the contact pressure is below a threshold value.However,once the contact pressure exceeds this threshold value,Amontons'law will be invalid.The threshold contact pressure of the composites containing EF-fibers is higher than of the composites containing SF-fibers.The composites that are reinforced by silica and short-cut aramid fibers do not follow Amontons7 law.
