NUMERICAL INVESTIGATION OF A NEW MUZZLE BRAKE FOR BLAST OVERPRESSURE ATTENUATION AT CREW POSITIONS ON THE 155 MM M777 EXTENDED RANGE CANNON

摘要

This paper explores the numerical evaluation of a distinctive new muzzle brake to attenuate blastoverpressure at multiple propellant charges for the crew of the 155 mm M777 Extended Range Cannon,armament for the M777 Towed Howitzer platform. Blast overpressure can cause significant harm topersonnel operating a cannon system, especially systems where the crew is unprotected from the blast,as in this case with a towed howitzer system. Muzzle brakes are affixed to cannon systems in order toreduce the recoil of the cannon. The adverse impact of a muzzle brake is the increased blast overpressureon the crew. The difficulty in designing new muzzle brakes is to maintain system acceptable blast levelswhile obtaining the recoil reduction required. This study examined the blast overpressure of a baselineconfiguration muzzle brake in the numerical finite element code ALE3D and compared the results toexperimental data obtained at Yuma Proving Ground (YPG). Once the simulation was validated, a newmuzzle brake design was simulated in ALE3D and the results compared to the baseline. While the baselinemuzzle brake exceeded the system recoil requirements, its blast overpressure was deemed excessive atboth the highest and second highest propelling charges (Zone 6 and Zone 9S). The new muzzle brake metthe recoil requirements of the system at both zones. At the second highest configuration propellantcharge (Zone 6), the new muzzle brake lowered the peak overpressure compared to the baseline by 18%at multiple elevations of the gun. At the highest configuration propellant charge (Zone 9S), the new muzzlebrake lowered the peak overpressure compared to the baseline by an average of 12% at multipleelevations of the gun. This new muzzle brake is being fabricated and will be experimentally verified atYPG. It will be part of the new 155 mm XM351 Cannon on the Towed M777 Extended Range Howitzersystem.