Smart Speed Imaging in Digital Image Correlation: Application to Seismotectonic Scale Modeling

Smart Speed Imaging in Digital Image Correlation: Application to Seismotectonic Scale Modeling

Blog Article

Analog models of earthquakes and seismic cycles are characterized by strong variations in strain rate: from slow interseismic loading to fast coseismic release of elastic energy.Deformation rates vary accordingly from micrometer per second (e.g., plate tectonic motion) to meter per second (e.g.

, rupture propagation).Deformation values are very small over one seismic cycle, in the order of a few tens of micrometer, because of the scaled nature of such models.This cross-scale behavior poses a major aluminum lotion challenge to effectively monitor the experiments by means of digital image correlation techniques, i.e., at high resolution (>100 Hz) during the coseismic period but without dramatically oversampling the interseismic period.

We developed a smart speed imaging tool which allows on-the-fly scaling of imaging frequency with strain rate, based on an external trigger signal and a buffer.The external trigger signal comes from a force sensor that independently detects stress drops associated with analog earthquakes which triggers storage of a short high frequency image sequence from the buffer.After the event has passed, the system returns to a low speed synovex one grass mode in which image data is downsampled until the next event trigger.Here we introduce the concept of smart speed imaging and document the necessary hard- and soft-ware.We test the algorithms in generic and real applications.

A new analog earthquake setup based on a modification of the Schulze ring-shear tester is used to verify the technique and discuss alternative trigger systems.