Experimental and numerical investigation of confined explosion in a blast chamber

An experimental blast program consisting of four tests was conducted in a blast chamber to investigate the effects of cylindrical charges on the peak reflected overpressure and impulse on the wall of the chamber. The charge mass varied from 0.095 kg to 0.2 kg and the standoff distance remained constant at 1.5 m and 1.3 m for the axial and radial directions, respectively. Eight pressure transducers were used in each test to measure the reflected overpressures on confined chamber walls at key locations. A high speed camera was used to record footage of each blast event. The test results indicated that UFC-3-340-02 (Unified Facilities Criteria, 2008) gives a significantly lower prediction for the axially oriented cylindrical charge, and also underestimates the radially oriented cylinder. Another purpose of the blast program was to develop an experimental data set which would validate the AUTODYN model. This would enable the validated AUTODYN model to be used with confidence to generate the overpressure and impulse distribution on a structural element for varying parameters such as the charge shape and charge orientations. Based on the simulated results a new blast model for cylindrical charges has been proposed by considering blast loading on the same level as the charge across the longitudinal direction.