Failure modes of complex materials with spatially-correlated mechanical properties -- the critical role of internal damage

The study reports a systematic evaluation of the role of spatially correlated mechanical elements on failure behavior of heterogeneous materials represented by fiber bundle models (FBM) with different load redistribution rules. The increase of spatial correlation FBM for a local load sharing, results in a transition from ductile-like failure characteristics into brittle-like failure. The study identified a global failure criterion based on macroscopic properties (external load and cumulative damage) which is independent of spatial correlation or load redistribution rules. This invariant metric could be applied for early warning of a class of geophysical ruptures.