Fig. 1

Simulation of the normal stress step test. During stable sliding at a constant velocity, we applied static normal stress change σ₀ = 5 MPa to σ₁ = 6 MPa. a Shear stress change assuming the aging law. a = 0.012, a−b = − 0.0015, L = 2.25 × 10⁻⁶ m, and α = 0.2. b Shear stress change assuming the normal-stress-dependent Nagata law. The friction parameters were converted using the scaling relations (14) and (15) with c = 1. c The relationship between δ_Lμ and ln(σ₁/σ₀) for the aging law and the Nagata law