OS1-4-1 Measurement of Stress Distribution around a Circular Hole in a Plate under Bending Moment using Phase-shifting Method with Reflective Photoelastic Arrangement

Abstract

According to the theories of material strength, where there is a hole in the structure part, an abrupt change in cross section occurs and the stress distribution around the hole will vary correspondingly. Even the size of hole may be small, it should be concerned in design because the stresses in the vicinity of the hole is always much higher than those faraway from the hole and the structure failure often take place in those positions. Due to the complexity of the engineering problems, it is difficult to obtain the stress field around the hole directly by theoretical derivation. Reflective photoelasticity is a widely used experimental full-field technique for accurately measuring surface strains to determine the stresses in a part or structure during static or dynamic testing. Photoelastic phase-shifting method can be used for the determination of the phase values of isochromatics and isoclinics. Conventional Babinet-soleil compensation method and photoelastic phase-shifting technique were utilized to analyze a specimen with a triangle hole and a circular hole under bending. Three groups of results were obtained by conventional compensation method, 8-step phase-shifting method with reflective-type photoelastic arrangement and FEM (ABAQUS) simulation, respectively. They agree with each other relatively well considering experiment error. The reliability of this combined method can both improve and extend the two conventional methods to be applied to more new fields of stress analysis.