This title appears in the Scientific Report : 2008 

Theory of the leak-rate of seals
Persson, B. N. J.
Yang, C.
Quanten-Theorie der Materialien; IFF-1
Journal of physics / Condensed matter, 20 (2008) S. 315011
Bristol IOP Publ. 2008
315011
10.1088/0953-8984/20/31/315011
Journal Article
Kondensierte Materie
Journal of Physics: Condensed Matter 20
J
Please use the identifier: http://dx.doi.org/10.1088/0953-8984/20/31/315011 in citations.
Seals are extremely useful devices to prevent fluid leakage. However, the exact mechanism of roughness induced leakage is not well understood. We present a theory of the leak-rate of seals, which is based on percolation theory and a recently developed contact mechanics theory. We study both static and dynamic seals. We present molecular dynamics results which show that when two elastic solids with randomly rough surfaces are squeezed together, as a function of increasing magnification or decreasing squeezing pressure, a non-contact channel will percolate when the (relative) projected contact area, A/A(0), is of the order 0.4, in accordance with percolation theory. We suggest a simple experiment which can be used to test the theory.