Extensions and comparisons of BAM (Bearing Area Model) for stickiness of hard multiscale randomly rough surfaces

In the present paper, we consider a recent very simple model for the estimate of adhesion between elastic (hard) rough solids with Gaussian multiple scales of roughness (BAM, Bearing Area Model), and compare it in particular with very recent extensive results from the numerical method of Joe, Thouless and Barber (JTB theory), in the range of non-hysteretic behaviour. BAM shows no sensitiveness to rms slopes and curvatures for the pull-off load or the apparent surface energy, in agreement with the JTB theory, but in contrast with the criterion proposed by Pastewka and Robbins for stickiness, especially in the fractal limit. Results show also reasonable accuracy with the JTB theory, and BAM theory is simpler than that of Persson and Scaraggi which involves convolution of adhesion tractions in the regions of separation.