w=d ¼ 0:001, using sticking contact (l tbc ¼ 0:5), sliding contact (l tbc ¼ 0:1), and frictionless contact ( l tbc ¼ 0). The results are summarized on Fig. 4(c). When friction is absent, the load, P=pa2r Y 1:6, is insensitive to pene-tration, d=d (Fig. 4(c)). In this limit, the TBC is about 50% softer than its homogeneous counterpart. For ...