High strain rate characterisation of soda-lime-silica glass and the effect of residual stresses

Abstract

A ring-on-ring test configuration for the equibiaxial flexural testing of flat samples was developed and integrated into a novel modified split-Hopkinson pressure bar (SHPB) setup. The established modifications enabled the application of high-speed cameras for fracture assessment and non-contact displacement measurements using stereo digital image correlation (stereo-DIC). In the present paper, this setup was utilised to characterise the flexural surface strength and stiffness (Young's modulus) of circular, as-received soda-lime-silica glass samples at high strain rates. The effect of residual stresses was also studied by including thermally tempered glass samples divided into four residual stress groups. Despite the frequent application of glass products in the built environment, often post-processed into tempered or laminated glass, these investigations are still rare and thus highly demanded when designing for extreme events such as extreme weather, ballistic impacts, or blast loads. A total of 315 samples were tested at a quasi-static and a dynamic loading rate ranging from 2.0 MPa s -1 to 4.2·10 6 MPa s -1 . It was found that the flexural strength of the glass across residual stress groups was strongly dependent on the applied dynamic loading rate, while the residual stresses themselves showed no significant effect on the loading rate dependency. At the dynamic loading, the strength increased between 60 and 86 %. Within the two tested loading rates, strength increased expectedly with compressive surface stress. From the stereo-DIC displacement measurements, no change in Young's modulus with loading rate was observed.

Characterization of the dynamic mechanical properties of low-iron float glass through Split-Hopkinson-Pressure-Bar tests

“…The DIFs obtained from the present tests are further compared with the data reported in other studies [2,6,13,18,[32][33][34] , as shown in Fig. 18.…”

“…It is worth noting that the results presented in Fig. 18b were determined through different experimental method, including three-point bending tests [32,33] , uniaxial tensile tests using universal high-speed testing machine [34] , and compression/splitting tensile tests [6] or doublering bending tests [13,18] using SHPB facilities. Though the results show a considerable variation, especially in high strain rate levels, a significant strain rate effect can be observed when the strain rate is above 10 0 s -1 .…”

“…Peroni et al [6] Low-iron float glass Meyland et al [13] Annealed float glass Note: The chemical compositions of the glass used in this study were provided by the manufacturer.…”