An experimentally validated contour method/eigenstrains hybrid model to incorporate residual stresses in glass structural designs

Abstract

Contour method–based finite element models together with knowledge of the surface deformation resulted from the stress relaxation along a newly cut-plane were used to construct the residual stresses in commercially available float glass. The results show that the residual stress depth profile of float glass is parabolic. The constructed residual stress profiles, validated to some extent against results of scattered light polariscope experiments, were then used to establish the misfit strains (i.e. eigenstrains) existed in the original glass specimens. It is shown that despite the modelling uncertainty of the contour method and the limitations associated with the scattered light polariscope measurements, the eigenstrain depth profile in a given float glass specimen can be determined to an acceptable accuracy. The article shows that once the underlying eigenstrain distribution in a given thickness of glass has been determined, the complete residual stress distribution can simply be determined by incorporating the eigenstrain profile as a misfit strain in an appropriate finite element model. It is also shown that the hybrid contour method/eigenstrain model enables modelling the residual stress around stress concentration features such as holes and/or stress evolution during subsequent applied loadings, by simply using the knowledge of eigenstrains.