Rate-dependent adhesion of viscoelastic contacts. Part II: Numerical model and hysteresis dissipation

In this paper, we propose a numerical model to describe the adhesive normal contact between glass spherical indenter and viscoelastic rough substrate of PDMS material. The accounts for dissipative process under assumption that losses are localized at (micro)-contact lines. Numerical predictions then compared with experimental measurements, which show strong adhesion hysteresis mostly due viscous dissipation occurring during pull-off. This is satisfactorily described by allows distinguish energy loss material from elastic instability. Our analysis shows pull-off force required detach surfaces strongly influenced detachment rate root mean square (rms) roughness amplitude, but it almost unaffected maximum load unloading starts. Moreover, increase in length boundary line separating non-contact regions, observed when moving smooth contacts, negligibly affects dissipation. Such much less significant than reduction area, therefore main parameter governing decrease effective surface specific geometry considered present work.