PSI - Issue 14

Pankaj K. Choudha et al. / Procedia Structural Integrity 14 (2019) 191–198 Author name / Structural Integrity Procedia 00 (2018) 000–000

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Fig. 7. (a) Test setup for RHA and Charge positioning; (b) RHA deformation due to rectangular section on charge side; (c) RHA deformation due to rectangular section on back side.

Fig. 8. (a) RHA deformation due to ‘V’ section on back side, (b) RHA deformation due to ‘V’ on charge side.

The RHA plates of 1000 mm × 500 mm × 40mm were used for evaluation of failure by both type of explosive charge. The plates were kept on 300 mm × 300 mm cement block stacked to create a height of 600 mm above ground. The explosive charges were kept in inverted position as shown in Fig. 7. (a). in the middle of support position aligned with one end of the RHA plate. The RHA plate is bulged and deformed toward the charge side in case of rectangular charge. In case of 'V' section charge, the larger crack in the back is due to weakening of plate due to cutting action and then further large concentrated pressure applied as shown in Fig. 8. (a). The failure or crack generated on the back side is due to bending phenomenon. The cutting action as single straight line has been observed on RHA plate on charge side shown in Fig. 8. (b). The cutting action is observed due to plastic casing of poly carbonate lining on the charge as generally obtained in shape charges. 4. Conclusion The following conclusions are drawn from the above studies. 4.1. The pressure generated from the rectangular section charge and 'V' section bar charge have been compared. There is an enhancement of 2.4 to 3.5 times in peak over pressure and 2.5 to 4.1 times in impulse at 70 mm from base of section of the explosive charge at initiation point and 600 mm away from the initiation point along the charge length. 4.2. The effectiveness of pressure rise has been further validated using RHA plate failure. The failure observed in the 'V' section explosive charge creates cut on RHA in charge side and larger size crack on back side compared to rectangular section. 4.3. It is concluded that effectiveness of blast pressures can be increased by changing the shape of explosive. Acknowledgments We are thankful to the Sandip Tondon, Haribhau Markale and Dr KM Rajan, Director, ARDE, Pune for his support in carrying out above work.