Preload dependence of pull-off in soft adhesive contacts

Determine under which material, geometric, relaxation, loading-history, pulling-rate, and finite-size-dissipation conditions preload history influences the pull-off response of soft adhesive contacts, including why nominally circular sphere–flat studies report either negligible or pronounced preload dependence.

Background

The paper situates preload dependence of pull-off within the broader problem of dissipative detachment in soft adhesive contacts. Prior studies of nominally circular sphere–flat contacts have produced conflicting observations: some report little or no dependence on the maximum preceding load, whereas others observe a substantial effect. These discrepancies have been attributed to differences in viscoelastic relaxation, loading history, pulling rate, and finite-size dissipation.

The experiments reported here find comparatively weak preload sensitivity for circular contacts but a clear and increasingly strong dependence for elongated crossed-cylinder contacts. The results therefore suggest that contact geometry may be an additional control parameter, but they do not establish a general criterion that predicts when preload history will be manifested in pull-off behavior across soft adhesive systems.