Photoelastic determination of boundary condition for finite element analysis

Abstract

An experimental-numerical hybrid method for determining stress components in photoelasticity is proposed in this study. Boundary conditions for a local finite element model, that is, tractions along boundaries are inversely determined from photoelastic fringes. The tractions can be obtained by the method of linear least-squares from both principal stress difference and principal direction. On the other hand, the tractions can also be determined only from the principal stress difference if nonlinear least-squares is used. After determining the boundary conditions for the local finite element model, the stresses can be obtained by finite element direct analysis. The effectiveness of the proposed method is validated by analyzing the stresses in a perforated plate under tension. Results show that the boundary conditions of the local finite element model can be determined from the photoelastic fringes and then the individual stresses can be obtained by the proposed method.