Experimental study into the effect of the closed discontinuity dip angle on the particle acceleration resulted from explosion
The most important effect of a discontinuity when encountered with a wave is the division of wave energy. This process is conducted in the form of dividing the input waves to the reflection and transmission waves. Several researchers have studied the effect of physical and mechanical properties of these discontinuities on waves division. In this study, the effect of the closed discontinuity dip angle has been investigated in the form of experimental tests in scale model. Accordingly, the effect of discontinuity dip from 60 to 120 degrees at 10 degree steps was investigated on particle acceleration of the waves. The results indicated that by increasing the discontinuity dip, the reflection of the waves increase and the vibration is enhanced. On dips greater than 90 degrees, the amount of wave reflection is more than the transmission and at dip angles less than 90 degrees, it is opposite. It was also found that on dips greater than 90 degrees, the ratio of reflection was three times more than the 90 degrees dip and the ratio of reflection is approximately 6 to 7 times more than the transmission of waves. By increasing the angle of discontinuity dip, the attenuation rate of particle acceleration increases where this amount at an angle of 100 degrees is about 30 percent more than that of 90 degrees. Some empirical models for the reflection ratio and the attenuation of the particle acceleration were obtained in terms of the dip angle of discontinuity dip with a high determination coefficient.
Keywords: Blast-induced particle acceleration, closed discontinuity, reflection and transmission of waves, scale model test