**3. Results and Discussion**

The results of the simulations were analyzed with respect to four characteristics of the coating–PSB interaction—i.e., (1) the suppressive effects of coatings on the operation of PSBs, (2) the normal stress developed in the coating layer along the loading direction, (3) the interfacial normal stress developed perpendicular to the interface, and (4) the interfacial shear stress developed parallel to the interface. For instance, typical results, including the distributions of shear strain, as well as shear and normal stresses of three selected simulations, are shown in Figure 4 for three cases: (a) tcoat = 0.5 μm, dPSB = 1 μm, and Δγpl = 0.01, (b) tcoat = 0.5 μm, dPSB = 8 μm, and Δγpl = 0.002, and (c) tcoat = 2 μm, dPSB = 1 μm, and Δγpl = 0.01, respectively. Note that the dPSB and Δγpl parameters are coupled, as discussed in the previous section. Apparently, all these characteristics appear to be influenced by both the coating thickness and overall loading amplitude (reflected in the density of PSBs). In what follows, we analyze and discuss these influences from the four aforementioned aspects.

**Figure 4.** Contour plots of shear strains within the PSBs, as well as normal and shear stresses near the coating–substrate interfaces (marked using the black dashed lines) for four cases of simulations: (**a**) tcoat = 0.5 μm, dPSB = 1 μm, and Δγpl = 0.01, (**b**) tcoat = 0.5 μm, dPSB = 8 μm, and Δγpl = 0.002, and (**c**) tcoat = 2 μm, dPSB = 1 μm, and Δγpl = 0.01.
