Photoelastic coatings on flat rotating axisymmetrical parts

Abstract

Body forces generated in photoelastic coatings bonded to rotating metallic parts affect the deformation in the parts. This effect becomes considerable when the coating thickness approaches that of the part. As a result, the observed photoelastic strain pattern is not truly indicative of the strains that would be present in an uncoated part. This interaction is considered analytically and experimentally for the case of a flat circular disk with a central hole when the coating covers the entire disk area and (a) coatings of equal thickness are bonded to both sides of the test part, and (b) the coating is bonded to only one side of the test part. Correction factors are derived which are applicable to problems where the strain field is axisymmetrical. The applicability of the derived correction factors in the vicinity of stress concentrations in the rotating part is considered.