The analysis of acoustic precursors reveals the physics underlying material failure

The nature of compressive failure in materials that takes place through the accumulation of microscopic dissipative events and their localization within a macroscopic fault remains an open question. On the one hand, it has been described as a standard bifurcation when it comes to predicting the critical compressive load at failure and the orientation of the resulting fault. On the other hand, it has been described as a critical phenomenon to explain the scale-free statistics of the intermittent damage activity preceding localization.

To solve this apparent contradiction, researchers from Institut Jean le Rond d’Alembert deciphered the spatio-temporal structure of failure precursors observed in compression experiments of 2D cellular materials driven to failure. They revealed that precursors are cascades of highly correlated damage events reminiscent of the depinning of driven elastic interfaces, a critical phenomenon controlled by disorder. Yet, the divergence of their size and duration observed close to failure results from the on-coming localization, a standard bifurcation in the homogeneous damage response of the material.

Beyond clarifying a long debate on the nature of compressive failure, these findings have important implications to structural health monitoring applications. Precursors can now be used for assessing the residual lifetime of structures in-service, a crucial issue for planning the predictive maintenance in industry. These findings also provide rich insights through an experimental example on how criticality can go along with standard bifurcation in disordered systems.

References

Mayya, A., Berthier, E., & Ponson, L. (2023). How criticality meets bifurcation in compressive failure of disordered solids. Physical Review X, 13(4). https://doi.org/10.1103/physrevx.13.041014