Leakage of Metallic Seals: Role of Plastic Deformations

I study the influence of plastic deformations on the leakage of metallic seals. The solids are assumed to deform elastically as long as the stress is below the penetration hardness of the material, and yield plastically when the local stress reaches the penetration hardness. The metal surfaces are assumed to exhibit self-affine fractal surface roughness. We use the Persson contact mechanics theory and the Bruggeman effective medium theory to estimate the leak rate of the plastically deformed interface.