Deformations and strain energy in fragments of tempered glass: experimental and numerical investigation

Abstract

The present paper is adding to the current knowledge by experimentally investigating the change of strain in a fragment of tempered glass. This is done by comparing the surface shape before and after fracture. The present work also aims at validating a FE-model for estimating the remaining strain energy and thereby the stress in a fragment post failure. The FE-model have been established in previous work Nielsen (Glass Struct Eng, 2016. doi:10.1007/s40940-016-0036-z) and is applied here on the specific geometry and initial state of the investigated fragments. This is done by measuring the residual stresses using a Scattered Light Polariscope before failure and thereby determining the initial stress state. The Geometry of the investigated fragment is found by means of a 3D scan. The surface topology of the fragment is found by letting a stylus traverse the surface and recording the shape. These information are then used for setting up a FE-model for calculating the stresses and strains left in the fragment after failure and compare the deformation to the measured.