Characteristics of the Shock Wave Generated in Air by a Blasting Cap
Abstract
The propagation of the shock wave generated in air by a very small surface explosion, a commercial No. 6 electric blasting cap, has been studied. A large number of time-resolved pressure histories were recorded with piezoelectric transducers at distances over the range of 3.05 to 80.8 meters from the explosion point. The observed range of peak air shock pressures was from .02 bars down to .0002 bars. Comparisons with TNT surface burst data for much larger explosions show that the peak pressure-distance attenuation exponents are the same. Based on these pressure-distance data, the yield of the No. 6 electric blasting cap used is approximately 0.4 grams of TNT. Even at the lowest peak pressures measured, the wave shapes are characteristic of typical airblast shock waves. An essentially triangular positive pressure phase is followed by a negative pressure phase of much lower amplitude and longer duration; this is unlike the signatures of sonic booms which are highly symmetric. The effect of the asymmetry on the energy density spectrum of the blasting cap is also discussed.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 18, 1971
- Accession Number
- AD0727083
Entities
People
- Ermine A. Christian
- Lippe D. Sadwin
Organizations
- Naval Ordnance Laboratory