A simple photo-elastic experiment to access boundary conditions

F. Douit , Lab MSSMat, UMR 8579 CNRS, Ecole CentraleSupelec, 92295 CHATENAY-MALABRY, France, frederic.douit@centralesupelec.fr

P. Evesque , Lab MSSMat, UMR 8579 CNRS, Ecole CentraleSupelec, 92295 CHATENAY-MALABRY, France, pierre.evesque@ecp.fr

Abstract :

It is proposed a new low-expensive device using photoelasticity to analyze the stress variation in a cylindrical oedometer using its elasticity to determine stress at wall. The grains or powders are contained in a cylindrical hole drilled in a photo-elastic material closed by two pistons. Radial stress is measured though photo-elasticity. The compression can be generated by a press or a jack ; it is controlled, monitored and recorded via a smartphone or a pc through an Arduino set-up recording the applied vertical stress and displacements, while the video records the photoelastic patterns, when the material is compressed or decompressed. Such a method may be useful to study local distribution of stress, its sensitivity to boundary conditions and their evolution, to the exact stress direction....

Pacs # : 5.40 ; 45.70 ; 62.20 ; 83.70.Fn

poudres & grains 22 (3), 16-92 (Juin 2015)