Measurement of Strain and Stress Distribution of Composite Materials by Electron Moiré Method

A method for measuring the stress and strain distribution in the composite materials and residual stress at the interface in the fiber reinforced composite has been developed. The strains are measured using an electron Moiré method and then the stresses are calculated from these strains. A very fine model grid with frequencies up to 10,000lines/mm can be fabricated using the optical and electron lithography techniques on the surface of the specimen and an electron beam scan which spaces are almost same as that of model grid the can be used for master-grid. The difference of the amount of secondary electrons per a primary electron makes Moiré fringes that consists bright and dark parts. Micro-creep deformation and residual strain and stress near the fibers of composite materials were measured by this method.