Blast response of laminated glass: A gas-gun experimental investigation of the fracture pattern and yield lines observed in full-scale blast tests

The applications of architectural and automotive laminated glass continue to grow. This is largely due to the enhanced safety in extreme events, such as blast. However, the complex interaction between the glass fragments and the polymer interlayer after glass fracture is still only partially understood, with existing analysis methods adopting a semi-empirical approach for the post-fracture response. These include a plastic yield-line analysis based on a failure pattern repeatedly observed during blast tests. In recent research it was demonstrated that yield lines can develop in fractured laminated glass through the composite bending action of the glass fragments, working in compression, together with the interlayer working in tension. This paper investigates the influence of the inertia loading associated with blast response, which has not been explicitly studied previously, with the aim of understanding the pattern of yield lines observed in blast tests. Impact tests are performed on laminated glass specimens using foam projectiles launched from a gas gun, which simulate the loading from a blast pulse. These tests demonstrate that the yield line pattern formed under short-duration dynamic loading depends on the loading intensity, thereby providing further evidence of a dynamic, plastic collapse mechanism in which inertia plays a significant role.