PSI - Issue 71

Gaurish S. Vaze et al. / Procedia Structural Integrity 71 (2025) 395–400

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3. Experimental Setup and Methodology The experimental testing setup for the ballistic impact testing is shown here (Fig. 4)

Fig.4. Experimental Setup. For the ballistic impact test, the cylinder was connected to the regulator hose with the output initially set to 0 bar. After connecting the solenoid to a 24 V DC adapter, the specimen was secured inside the box and the bullet loaded into the barrel. The regulator was adjusted to the desired pressure, and the valve was closed to maintain it before shutting off the cylinder. Activating the power supply released pressurized air, propelling the bullet toward the specimen. The velocity was measured using a velocimeter.

3.1 Analytical determination of velocity of projectile

To determine the velocity of the projectile analytically, muzzle velocity has been considered. The muzzle velocity is the speed of the projectile with respect to the muzzle at the moment it leaves the barrel. By rearranging kinematic equation and using the force-pressure relation, muzzle velocity can be determined by the following equation, ’ ൌ ˆ ሺʹ Ȁሻ ͳȀʹ (1) Where, ’ = Velocity of Projectile P = Pressure exerted on projectile = 150 x ͳͲ ͹ Pa A = Cross sectional area of muzzle = 40.71 x 10⁻⁶ m² L = Length of barrel = 0.6604 m m = Mass of bullet = 4.169 x 10⁻³ Kg ˆ = Coefficient accounting for losses = 0.3 Substituting all the values in the above equation, the value of velocity is observed to be 131.9132 m/s. 3.2 Experimental determination of velocity of projectile . The velocity of the projectile was determined experimentally by using a chronograph velocimeter. A chronograph velocimeter is an electronic device which is used to measure the velocity of projectiles. The following fig. 5 shows the velocimeter.