ALERT Doctoral School 2022: Data for photoelasticity lesson

Data used for the two-hour photoelasticity lesson on September 29, 2022 at the 2022 ALERT Doctoral School in Aussois, France. In the Data directory, you will find the PEGS-master, PhotoelasticDisks, and Results subdirectories. You will also find the Jupyter notebook ALERTPhotoelasticity_220929_v1.ipynb. Photoelasticity data is in the PhotoelasticDisks subdirectory. N_Image and P_Image contain a sequence of images of 511 bidisperse birefringent disks in simple shear as viewed with unpolarized light and polarized light, respectively. The Positions subdirectory contains the position and radii of the disks in disks in each image. The G2images and radii_highlighted subdirectories contain, respectively: (1) images of each particle colored by G^2 as computed from the photoelasticity images via methods described in (Daniels, et al., Review of Scientific Instruments, 88, 051808 (2017)); (2) images of deformation of the particle with the outlines of each particle highlighted. Computations are performed in the accompanying ALERTPhotoelasticity_220929_v1.ipynb Jupyter notebook, which may be opened on any computer supporting jupyter notebooks or through Google Colab. Within PEGS-master, you can open PeGSDiskSolve.m to solve for inter-particle forces using methods described in Sec. V of (Daniels, et al., Review of Scientific Instruments, 88, 051808 (2017)) and in the thesis of James Puckett (thesis titled "State Variables in Granular Materials: an Investigation of Volume and Stress Fluctuations" and completed at North Carolina State University in 2012). You can also find a script titled "PlotExpVsSynth.m" that compares results from G^2 calculations; results are put into the Results subdirectory. Paths may need to be changed in all scripts. Related content from the doctoral school can be found here: https://github.com/alert-geomaterials/2022-doctoral-school.