Acceleration measurement as a quantitative method for studying microscopic mechanical avalanches

The non-elastic mechanical response of most materials occurs through impulsive and discrete events called avalanches. Studying avalanches experimentally is challenging, due to their transient nature and small spatial and temporal scales. Existing experimental methods often lack sufficient sensitivity or do not have well-defined relations between the measured signal and the physical processes that generate the avalanche. In this work, we introduce an acceleration measurement of avalanche events by a mass-spring system connected in line with the tested sample. Further, we present a new experimental approach that enables the simultaneous measurement of force, acceleration, and acoustic emission, originating concurrently from the same avalanche events. We validate this approach by studying deformation twinning-induced avalanches in single crystal magnesium and demonstrate that this method offers higher sensitivity compared to high-resolution force measurement. Additionally, we show that the acceleration signal provides direct quantitative information about the avalanche source, such as the local twinned volume.