Lubomirsky YCHIH-HUNG CHENKarma ABouchbinder E.2022-11-162022-11-16201800319007https://www.scopus.com/inward/record.uri?eid=2-s2.0-85054010647&doi=10.1103%2fPhysRevLett.121.134301&partnerID=40&md5=fec3a7580ac3ccc11175e0b652de5563https://scholars.lib.ntu.edu.tw/handle/123456789/625484The two-dimensional oscillatory crack instability, experimentally observed in a class of brittle materials under strongly dynamic conditions, has been recently reproduced by a nonlinear phase-field fracture theory. Here, we highlight the universal character of this instability by showing that it is present in materials exhibiting widely different near crack tip elastic nonlinearity, and by demonstrating that the oscillations wavelength follows a universal master curve in terms of dissipation-related and nonlinear elastic intrinsic length scales. Moreover, we show that upon increasing the driving force for fracture, a high-velocity tip-splitting instability emerges, as experimentally demonstrated. The analysis culminates in a comprehensive stability phase diagram of two-dimensional brittle fracture, whose salient properties and topology are independent of the form of near tip nonlinearity. © 2018 American Physical Society.Brittle fracture; Crack tips; Phase diagrams; Crack instability; Driving forces; Dynamic condition; Elastic non-linearity; High velocity; Nonlinear elastics; Nonlinear phase; Tip splitting; Stabilityjournal article10.1103/PhysRevLett.121.134301303120792-s2.0-85054010647