Acoustic detection of annealed glass failure in structures subject to long-duration blast

Glass windows are vulnerable components of a building and, in the event of a blast, produce a large damage radius. In the far-field of large explosions, long-duration blast environments can occur. Resulting impulses can cause window failure several kilometres away from the point of detonation. The air blast tunnel (ABT) at MOD Shoeburyness, UK is capable of simulating such blast environments and has been used in a number of experimental trials to quantify annealed glazing response. Current data capture methods rely heavily on high-speed photography to record glass failure time and location of cracking. Accuracy is limited by camera availability, frame rate and shock-induced camera vibration. In this paper, the use of sound via the triangulation of piezo transducers is proposed as a new method of capturing window response in a rapid and aggressive monitoring environment. An array of sensors in known locations allowed time and location of glass failure to be calculated. The method was tested and refined through multiple phases of blast environment experimentation. Triangulation of piezo transducers was found to be a highly accurate and cost-effective method of capturing window failure in a long-duration blast environment of direct relevance to practitioners and forensic examiners.