Center Hole with Inclusion

Abstract

Before, we reported a standard for safety in the circumference of the center hole in the lathe processing. Recently, regenerated material is used. Regenerated material contains an inclusion. Inclusions often become the cause of stress concentration and failures. Every structure possibly includes inclusions. As there are many cases in which high stress arises around an inclusion and causes cracks and exfoliations from the matrix leading to a fracture, it is important to analyze the deformation behaviors around the inclusion. Although there have been many researches through theoretical analysis, research examples of inclusions through experimental analysis are very few. The experiment was conducted by the photoelastic method, finite element method. Polycarbonate was used as a test specimen model, and three different kinds of materials, epoxy resin, PMMA and polyethylene, were used as elliptic inclusions. As a result of this experiment, the experimental equations relating to the equivalent stress were obtained.