A two-dimensional model for metallic surface roughness resulting from pure waterjet peening

In implant dentistry, successful osseointegration has been improved by creating a rough surface that increases the available surface area with a consequence of better mechanical cell adhesion compared with smooth surfaces. Pure waterjet peening appears to be a promising technique to achieve controlled surface roughening. In this paper, we analyze a simple case (a full cone shape of waterjet, a flat solid target material, and normal impact). The velocity and pressure spatial distributions of the waterjet are derived based on the liquid impact theory, which helpful for narrowing down the range of process parameters. A 2D axis-symmetric model is used to analyze the deformation behavior of the target material. The performance of 2D analysis is evaluated by comparing with Arola's experimental results (Arola, McCain, Kunaporn, and Ramulu, 2001). It shows that the plastic deformation requires a threshold inlet pressure. If the latter reaches the lower limit and keeps increasing, the amount of permanent deformation increases accordingly.