  To model rupture dynamics, a friction law must be assumed. Commonly used
constitutive laws for modeling friction include slip-weakening laws which are
characterized by a drop from static to dynamic frictional stress. Within this
framework, the prevailing understanding asserts that the frictional behavior is
solely controlled by the fracture energy -- the area beneath the frictional
stress versus the cumulative slip curve. In particular, it is claimed that the
curve's shape itself has no influence on the system's response. Here we perform
fully dynamic rupture simulations to challenge prevailing beliefs by
demonstrating that the constitutive law shape exerts an intimate control over
rupture profiles. For a consistent fracture energy but varying constitutive law
shapes, the velocity profile is different: each abrupt slope transition leads
to the localization of a distinct velocity peak. For example, in the case of a
bilinear slip-weakening law featuring two different slopes, the rupture
exhibits two distinct velocity peaks. This phenomenon arises from the
transition between a constant weakening rate to another. However, this
distinction does not seem to influence how a rupture responds to a stress
barrier or the cumulative radiated energy emitted. These results are derived
through two separate numerical schemes (spectral boundary integral and finite
element methods) ensuring their independence from the computational approach
employed.
