Full-Field Dynamic Displacement and Strain Measurement Using Advanced 3D Image Correlation Photogrammetry

Full-field optical techniques are increasingly appreciated as deformation, stress and strain measuring tools. This article discusses an advanced deformation and strain analysis method based on 3D image correlation photogrammetry that is substantially more robust and has greater dynamic range than other full-field imaging technologies such as ESPI and moiré.

Underlying principles are reviewed, and several applications combining image correlation photogrammetry with stroboscopic illumination and/or high-speed video cameras are presented. Operational strains in ionic polymeric and dielectric elastomer artificial muscles are determined. The use of short-duration white light pulses to study automobile tires on road wheels at speeds up to 150 miles per hour is demonstrated. Initial work with a pulsed laser to study a flywheel in a spin pit at up to 35,000 rpm is described. A notched rubber dogbone sample is pulled to failure at 125% strain in 38 milliseconds, with hundreds of full-field strain maps captured.