ANALISA PENGARUH KEKASARAN PERMUKAAN DAN SLIP TERHADAP PERFORMANSI PELUMASAN PADA KONTAK SLIDING MENGGUNAKAN METODE VOLUME HINGGA

Abstract

One of the problems in lubrication in MEMS is stiction. Stiction is a phenomenon of adhering one surface to another surface. A method to reduce stiction is by giving the surface with hydrophobic properties. Thus fluid used as lubricant will slip at boundary surface. There are two methods to make slip, i.e. by coating the surface or by giving the surface roughness. Slip is usually described by slip length model in low shear rate and critical shear stress model in high shear rate. All cases in the present work are modeled by sliding contact with infinite width. The problems are solved by finite volume method, in which the solution is divided into discrete control volume and discretised equation is applied on each control volume. Results show that by employing the smooth surface and slip can increase the hydrodynamic pressure. It becomes three times bigger than the no-slip condition. Maximum load support is found when the length of slip region is 0.65 from length of sliding contact with gap ratio of 0.9. The effect of surface roughness can increase the load support in no-slip condition with hr/Lx of 0.6. But in the slip condition, the surface roughness will decrease load support.