粗糙聚氨酯表面微接触状态下粘着力的模拟

以JKR接触理论和GW粗糙表面模型为基础,将聚氨酯表面与光滑蓝宝石球的接触作为点接触,与玻片的接触看做是多个凸峰与光滑平面的接触,建立接触力学模型分析粘着力与法向力间的关系。结果显示:聚氨酯与蓝宝石球接触时,粘着力不随法向力变化;聚氨酯与载玻片接触时,粘着力随法向力成对数变化,即在法向力很小时,粗糙峰起关键作用,接触点数和接触总面积随法向力增加而增加,粘着力迅速增大,当法向力继续增大达到一定值时,实际接触点数和接触总面积随法向力增加缓慢,表面间趋于饱和接触,故粘着力亦变化缓慢。模拟结果与试验结果接近,说明模拟方法可行、结果可靠。

Simulation on Adhesion of Microscale Contact of Rough Polyurethane Surface

Based on JKR theory and GW rough surface model,the contact of sapphire-ball to polyurethane(PU) is regarded as a single contact and the glass to PU as multi-point contacts.The contact mechanics model is established and the relation of the adhesion to the normal forces is simulated.The preliminary results show that the adhesion does not vary with the normal forces for a single point contact.The adhesion increases with the normal forces according to logarithmic relation for the rough surface contact.The contact points and the real contact area increase with the normal forces when they are small,so the adhesion increases rapidly because of the rough peaks.The contact points and the real contact area increase slowly with the normal force when the normal force increases to the certain value, thus making the adhesion changes slowly.Simulation results are in agreement with experimental results.