Adhesion and fracture; adhesion; contact mechanics; friction

How can shear loading rate affect the soft adhesive contact area? A new blog post in tribonet.org discusses the problem following the paper "Papangelo, Antonio. (2021). On the Effect of Shear Loading Rate on Contact Area Shrinking in Adhesive Soft Contacts. Tribology Letters. 69." just published in Tribology Letters.

Two surfaces are ”sticky” if breaking their mutual contact requires a finite tensile force. At low fractal dimensions D, there is consensus stickiness does not depend on the upper truncation frequency of roughness spectrum (or ”magnification”). As debate is still open for the case at high D, we exploit BAM theory of Ciavarella and Persson-Tosatti theory, to derive criteria for all fractal dimensions. For high D, we show that stickiness is more influenced by short wavelength roughness with respect to the low D case.

Recently, Dalvi and co-authors have shown detailed experimental data of adhesion of soft spheres with rough substrates with roughness measured down to almost the atomic scale, finding that the Persson and Tosatti theory gave satisfactory predictions of the apparent work of adhesion during loading, once the increase of the surface area due to roughness is correctly computed at extremely small scales.

Specifically, the post requires expert knowledge in experimental and/or computational mechanics of materials and/or tribology. The position is part of a large international EPSRC-SFI funded project aimed at developing next generation textile triboelectric nanogenerators (or T-TENGs) for powering of wearable electronics.  This position will focus on the mechanics and tribology of T-TENGs and will involve both modelling and experimental work.