Penetration Experiments With Limestone Targets and Ogive-Nose Steel Projectiles

Abstract

We conducted three sets of depth-of-penetration experiments with limestone targets and 3.0 caliber-radius-head (CRH), ogive-nose steel rod projectiles. The limestone targets had a nominal unconfined compressive strength of 60 MPa, a density of 2.31 kg/m3, a porosity of 15 percent, and a water content less than 0.4 percent. The ogive-nose rod projectiles with length-to-diameter ratios often were machined from 4340~45 and Aer Met 100 R. 53 steel, round stock and had diameters and masses of 7.1 mm, 0.020 kg; 12.7 mm, 0.117 kg; and 25.4 mm, 0.931 kg. Powder guns or a two-stage, light-gas gun launched the projectiles at normal impacts to striking velocities between 0.4 and 1.9 km/s. For the 4340 I&45 and Aer Met 100&53 steel projectiles, penetration depth increased as striking velocity increased to a striking velocity of 1.5 and 1.7 km/s, respectively. For larger striking velocities, the projectiles deformed during penetration without nose erosion, deviated from the shot line, and exited the sides of the target. We also developed an analytical penetration equation that described the target resistance by its density and a strength parameter determined from depth of penetration versus striking velocity data.

Engineering models of high speed penetration into geological shields

“…Frew et al [55] adapted the model by Forrestal et al [56] for limestone shields introducing into the model the unknown "strength constant". Values of this "strength constant" are determined from experiments conducted for different impact velocities ν (other characteristics of the shield and the projectile are the same in all experiments).…”

“…The obtained values of the "strength constant" are averaged, and the average value is used in the predictive model when ν varies. Frew et al [55] conducted three sets of experiments with the limestone shields and 3.0 caliber-radius-head (CRH) ogive-nose steel projectiles which have the length-to-diameter ratios of ten while the impactor shank diameters are different in every set. The authors found that the average "strength constant" can be expressed as a linear function of the impactor shank diameter.…”

An evaluation of the PENCURV model for penetration events in complex targets.

“…Frew, et ai. [19] carried out extensive penetration testing of the identical limestone used in these tests. He defined a nominal limestone density of 2.3 g/cm3 and a nominal UCS of 60 MPa.…”

Penetration analysis of projectile with inclined concrete target

“…Generally, the concrete penetration experiment evaluates survivability, deceleration, penetration depth and residual stress of projectile [1][2][3][4][5]. In this study, we performed a penetration test and analysis of warhead with concrete target.…”