Alternative Methods of Data Capture for Glass Subjected to Long-duration Blast Loading

The air blast tunnel (ABT) at MoD Shoeburyness is a unique testing facility capable of simulating pressure regimes recorded in long-duration blast events. Long-duration blasts are typically defined by a positive phase duration greater than 100ms, observed in the far field of large explosions. Due to its highly brittle nature, glass panels require high-speed data capture to provide reliable engineering information about their response to blast loading. The harsh environment of the ABT makes accurate collection of this data very difficult. Current methods of data capture depend on interpretation of high-speed video footage, the accuracy of which is severely affected by shock wave induced camera shake. In a series of five companion static loading tests, two different methods of recording glass failure time were trialled; a circuit of conductive paint on the surface of the glass and a series of piezo transducers to record the acoustic profile at breakage. High-speed photography provided an independent correlation. Experimental results demonstrate that piezo transducers are a low-cost and comparatively accurate method of determining the time of glass failure and crack location in a static testing environment. In February 2017, a series of eight full-scale trials in the ABT demonstrated that piezo transducers were capable of replicating these results in a long-duration blast environment.